OK Manual of Food QC_Food Control Laboratory.pdf

ISSN 0254-4725

Manuals of food quality control 1. The food control laboratory

FAO FOOD AND NUTRITION PAPER

Rev. 1

Food and Agriculture Organization of the United Nations

Manuals of food quality control 1. The food control laboratory

FAO FOODAND NUTRITION PAPER

14/1

Rev. 1

by P.G. Martin

revised by J. Weatherwax

and P.G. Martin

p r e p a r e d with the support of the S w e d i s h International Development Authority (SIDA)

Food and Agriculture Organization of the United Nations

Rome, 1997

Reprinted 1997

The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, orconcerning the delimitation of its frontiers or boundaries.

M-87 ISBN 92-5-102489-8

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying or otherwise, without the priorpermission of the copyright owner. Applications for such permission, with a statement of the purpose and extent of the reproduction, should be addressed to the Director, Information Division, Food and Agriculture Organization of the United Nations, Viale delle Terme di Caracalla, 00100 Rome, Italy. © FAO 1986

FOREWORD

T h e c o n t r o l of food safety and quality is an integral part of n a t i o n a l programmes for development. National food control systems are designed to protect the health and welfare of the consumer, to promote the development of trade in food and food products, and to protect the interests of the fair and h o n e s t food p r o d u c e r , processor or m a r k e t e r against dishonest and unfair competition. Emphasis is placed on the prevention of chemical and biological hazards which result from contamination, adulteration or simple mishandling of foods. Also important are the maintenance of general food quality and the control of the use of food additives and food processing procedures. In order must :

to

establish

a workable

food

control

system,

a

national

government

1.

Enact food control legislation.

2.

Promulgate regulations to enforce that legislation.

3.

Create an agency to cond uct the enforcement.

4.

Establish food inspection agencies concerned.

5.

Provide physical facilities including a food control laboratory.

and

analysis

staff

within

the

agency

or

To assist the national governments of developing countries in this process, FAO, with the support of the Swedish International Development Authority (SIDA) has published the series Manuals of Food Quality Control. These are incorporated as part of the FAO Food and Nutrition Paper Series No. 14, and include: No. 14/1 rev. 1

The Food Control Laboratory (revised, 1986)

No. 14/2

Additives, Contaminants, and Techniques by No. 14/7)

No. 14/3

Commodities (replaced by No. 14/8)

No. 14/4

Microbiological Analysis

No. 14/5

Food

No. 14/6

Food for Export

No. 14/7

Food Analysis: General Techniques, Additives, Contaminants, and Composition

No. 14/8

Food Analysis: Identity

(replaced

Inspection

Quality, Adulteration, and Tests of

In a d d i t i o n , FAO, WHO and UNEP jointly have published many guidelines and other documents designed to further assist developing countries in forming adequate food control systems. These publications include: Methods of Sampling and Analysis of Contaminants in Food A Report of the Second Joint FAO/WHO Expert Consultation, Rome - 1978 Guidelines for Establishing or Strengthening National Food C o n t a m i n a t i o n M o n i t o r i n g Programmes - FAO Food Control Series No. 5 - 1979

iii

Guidelines for the Study of Dietary Intakes of Chemical Contaminants - WHO Offset Publication No. 87 - 1985 Guide to Codex Recommendations concerning Residues, Part 2 - Maximum Limits for Pesticide Second Preliminary Issue - Rome - 1985

Pesticide Residues,

Recommended Practices for the Prevention of Mycotoxins in F o o d , Feed and their Products - FAO Food and N u t r i t i o n Paper No. 10, Rome - 1979 Food Standards, Codes of Practice and Methods of Analysis Recommended by the Codex Alimentarius Commission - Joint FAO/WHO Food Standards Programme (several titles) Food Additive Evaluations and Specifications of Purity and I d e n t i t y - Reports and M o n o g r a p h s of the Joint F A 0 / W H 0 Expert Committee on Food Additives (several titles) The above publications, and others, are available to persons and organizations. FAO is also interested in receiving comments regarding this volume and suggestions for future improvement. Please send to: The Chief Food Quality and Standards Service Food Policy and Nutrition Division Food and Agriculture Organization of the United Nations Via delle Terme di Caracalla 00100 Rome, Italy FAO wishes Development of M r . J.* preparation

to acknowledge the generous support of the Swedish International Authority (SIDA), in the preparation of this volume, and the efforts W e a t h e r w a x and M r . P.G. Martin who were responsible for the of the text.

TABLE OF CONTENTS

FOREWORD

1.

SCOPE OF THE FOOD CONTROL LABORATORY MANUAL

2.

LABORATORY 2.1 2.2 2.3 2.4 2.5 2.6 2.7

3.

Establishing the Laboratory Organizational Structure Head of the Laboratory Supervisors Team Leaders Analytical Staff Support Staff

2 3 3 4 5 5 6

General Considerations Basic Structure of the Building Safety Features Ventilation and Air Conditioning Space Utilization Equipment and Instruments Utilities Design References

7 7 10 12 13 15 16 18

LABORATORY ADMINISTRATION 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9

5.

ORGANIZATION

LABORATORY DESIGN 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8

4.

1

Sample Collection Sample Receipt and Assignment Sample Storage and Disposal Budget Purchasing Supplies Management Equipment Maintenance Housekeeping Training

LABORATORY 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8

20 21 22 23 23 26 26 28 28

OPERATIONS

Workp lans Priorities for Analysis Analysis Assignment Analysis Control Analysis Reporting Analysis Review Method Validation Confirming Analysis

. . . . .

v

29 31 31 32 32 33 34 34

6.

LABORATORY 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8

7.

SAFETY

The Safety Programme Basic Safety Rules Fire Safety Chemical Hazards Biological Hazards Physical Hazards Safety and Emergency Equipment First Aid

LABORATORY QUALITY ASSURANCE 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8

35 35 36 37 38 40 42 43

(QA)

Introduction Establishing a QA Programme QA of Reference Standards QA of Instruments QA of Analytical Reports Check Sample Examination Other QA Activities Text References

46 46 49 « . . 55 58 61 66 66

vi

1.

SCOPE OF THE FOOD CONTROL LABORATORY M A N U A L

This m a n u a l is p r i m a r i l y a p r a c t i c a l h a n d b o o k on the e s t a b l i s h m e n t of a food control laboratory. The v a r i o u s organizational, administrative, operational, and d e s i g n c r i t e r i a are d i s c u s s e d in s o m e d e t a i l . A l s o i n c l u d e d is a discussion of laboratory safety to stress the importance of safe operation and the inherent hazards always present in an analytical laboratory. The manual is designed for laboratory management and administration personnel, but the o p e r a t i n g a n a l y s t can g a i n good i n f o r m a t i o n and i n s i g h t s into the problems involved in establishing and operating a food control laboratory. The u s e r of this m a n u a l should a l w a y s k e e p in m i n d that the i n f o r m a t i o n and principles presented are advisory only and represent recommendations on how a food control laboratory may be organized, arranged, etc., not how it must be. This manual is intended as a guide, to help a new laboratory get off to a good s t a r t , or to g u i d e an e s t a b l i s h e d l a b o r a t o r y in w h i c h w o r k is e x p a n d i n g and diversifying. As time goes by, experience builds up and a laboratory tends to develop new methods, modify existing ones or adapt them to other products. All this valuable information should be retained and, if possible, combined with this manual and manuals No. 14/2 and 14/3 in a readily accessible form. At the s a m e t i m e , the a n a l y s t m u s t r e m e m b e r that r e l i a b l e r e s u l t s w i l l o n l y be o b t a i n e d by s t r i c t a d h e r e n c e to the d e t a i l s that m a t t e r and to c a r e f u l and professional work. Analytical chemistry is an exact science, very demanding on the manipulative skills of the worker at the bench. There is no substitute for e x p e r i e n c e but it is hoped this m a n u a l w i l l form a u s e f u l guide w h i l e that experience is developing as well as during routine laboratory operations. Any c o m m e n t s or s u g g e s t i o n s for i m p r o v e m e n t s w i l l be w e l c o m e . T h e s e should be addressed to the address given in the Foreword. The first e d i t i o n of this m a n u a l w a s w r i t t e n in 1977 by Mr. Peter G. M a r t i n , p r e s e n t l y of L y n e , M a r t i n and R a d f o r d , P u b l i c A n a l y s t s , R e a d i n g , B e r k s h i r e , England. The p r e s e n t r e v i s e d e d i t i o n has b e e n p r e p a r e d w i t h Mr. M a r t i n ' s support and assistance by Mr. John Weatherwax, retired Laboratory Director for the United States Food and Drug Administration, Los Angeles, California, USA.

1

2.

2.1

Establishing

the

LABORATORY

ORGANIZATION

Laboratory

The publication, "Guidelines for Developing an Effective National Food Control System", F A O / W H O / U N E P , FAO, Rome, 1976, details the formation of a food control system embodied in a national food quality control service. The purposes of a n a t i o n a l food q u a l i t y c o n t r o l s e r v i c e are to e n s u r e a s u p p l y of s a f e , nutritious and honestly presented food; to protect consumers from foods which are c o n t a m i n a t e d , decomposed, adulterated, injurious or packaged or labelled in a false or misleading way; to promote better quality control of foods by food p r o c e s s o r s and d i s t r i b u t o r s and t h e r e b y e n c o u r a g e d e v e l o p m e n t of the food i n d u s t r y and to i m p r o v e e x p o r t p o t e n t i a l and e n a b l e b e t t e r c o n t r o l of food import s. When consumers and buyers have confidence in the quality and safety of foods, trade increases at both local and international levels. Increased local demand e n c o u r a g e s i n d u s t r y and i n t e r n a t i o n a l t r a d e brings better returns in foreign exchange capital. T h i s c a n a l s o lead to n a t i o n a l d i e t s b e c o m i n g m o r e v a r i e d and n u t r i t i o u s w i t h l o c a l p r o d u c t s o f t e n s u b s t i t u t e d for c o s t l y i m p o r t s . B e s i d e s the o b v i o u s e c o n o m i c and p u b l i c h e a l t h b e n e f i t s , the a d v a n t a g e s in social terms can also be considerable. In m a n y g o v e r n m e n t s t r u c t u r e s t h e r e are s t a f f and f a c i l i t i e s l o c a t e d in d i f f e r e n t a g e n c i e s that a r e i n v o l v e d in s o m e or all a s p e c t s of food c o n t r o l , b u t t h e i r e f f o r t s are o f t e n not h i g h l y e f f e c t i v e due to lack of f a c i l i t i e s , expertise or an adequate legal or a d m i n i s t r a t i v e f r a m e w o r k . These resources s h o u l d be b r o u g h t t o g e t h e r into a u n i f i e d s t r u c t u r e in such a w a y that the p e r s o n n e l a r e b e s t u t i l i z e d and h a v e c l e a r o b j e c t i v e s w i t h the f a c i l i t i e s to c a r r y t h e m out. T h e r e s u l t w o u l d be a p r o p e r l y l i n k e d i n s p e c t o r a t e and l a b o r a t o r y w i t h the n e c e s s a r y a d m i n i s t r a t i v e and l e g a l s u p p o r t i n c l u d i n g , w h e n e v e r possible, an Advisory Board to provide guidance and coordination at national l e v e l . This manual deals only with the establishment of the food control laboratory, a l t h o u g h it is o n l y o n e c o m p o n e n t of a n a t i o n a l food c o n t r o l s e r v i c e . It laboratory there must be a should be n o t e d that f o r an e f f e c t i v e correspondingly effective inspectorate. In a f e w c o u n t r i e s t h e r e is no p r o v i s i o n for an i n s p e c t o r a t e and s a m p l e s are o f t e n o b t a i n e d by the a n a l y s t , thereby using potential analytical time. Having samples submitted by the food industry saves sample collection time, but is inherently a bad practice because the samples cannot be assured of being representative. A food c o n t r o l l a b o r a t o r y is a c o s t l y f a c i l i t y to e s t a b l i s h , so b e s t r e s u l t s will be achieved if the functions of the laboratory are confined to activities r e s u l t i n g f r o m the e n f o r c e m e n t of food l a w , g e n e r a l s u r v e y s on q u a l i t y of f o o d s , e x p o r t / i m p o r t i n s p e c t i o n w o r k and w o r k of an i n v e s t i g a t i o n a l n a t u r e relating to food quality. However, it may, for reasons of economy and o p t i m u m u t i l i z a t i o n of the f a c i l i t i e s , b e c o m e n e c e s s a r y to t a k e up o t h e r s e l e c t e d analytical work provided the laboratory is appropriately equipped. Advice or a n a l y s i s on a fee b a s i s to l o c a l i n d u s t r y m a y be j u s t i f i e d if t h i s d o e s n o t conflict with statutory duties or other government bodies and there are clear guidelines. Such analyses are carried out for advisory purposes and in no way are a substitute for normal food control work.

2

2.2

Organizational

The staffing

Structure

structure

of a typical

food

Head of

Analytical Staff

control

laboratory

is as

follows:

Laboratory

Support Staff

Administrative Staff

The o f f i c e of Head of L a b o r a t o r y ( o t h e r t i t l e s such as " C h i e f " or " D i r e c t o r " a r e o f t e n u s e d ) m a y i n c l u d e a D e p u t y if the l a b o r a t o r y s t a f f is s u f f i c i e n t l y large. U s u a l l y , h o w e v e r , the d u t i e s of the H e a d , in h i s or her a b s e n c e , are assumed by a senior supervisor of the analytical staff. The analytical and support staffs are discussed b e l o w in Sections 2.6 and 2.7, respectively. The administrative staff includes all administrative assistance such as a s e c r e t a r y , t y p i n g and f i l i n g c l e r k s , a m a n a g e m e n t a s s i s t a n t and a librarian (if the laboratory library is of a size to need one). Basically the a d m i n i s t r a t i v e s t a f f are t h o s e p e r s o n s g e n e r a l l y i n v o l v e d in " o f f i c e " or "paperwork" functions. This staff is very important to the smooth operation of a laboratory. It is false e c o n o m y to u n d e r s t a f f the a d m i n i s t r a t i v e g r o u p because their work often m u s t then be done in part by the analytical or support staffs . The secretary for the laboratory generally works directly for the Head. good practice, h o w e v e r , to m a k e the secretary responsive to secretarial of the supervisors.

2.3

Head

of the

It is needs

Laboratory

The H e a d of the l a b o r a t o r y s h o u l d be a g r a d u a t e c h e m i s t or m i c r o b i o l o g i s t trained in food analysis. A postgraduate d i p l o m a particularly relevant to this w o r k is h i g h l y d e s i r a b l e . A l t h o u g h the d u t i e s of the h e a d of the l a b o r a t o r y are m a n y , s o m e m a y be d e l e g a t e d and o t h e r s u n d e r t a k e n b y o t h e r p a r t s of the food control administration. It is therefore not appropriate to do more than d r a w a t t e n t i o n to c e r t a i n a s p e c t s . The o b j e c t i v e of the l a b o r a t o r y is to analyze a large number of samples correctly, quickly and cheaply. This means t h a t a t t e n t i o n m u s t be paid to c a r e f u l s p e n d i n g of the b u d g e t , p r o m o t i o n of good staff relations and maintenance of the highest possible level of technical efficiency and expertise. The laboratory Head may have to give evidence in court or write documents used in c o u r t , in w h i c h c a s e he m u s t h a v e a t h o r o u g h u n d e r s t a n d i n g of food and related law and court procedure. There will also be involvement in c o m m i t t e e work and relations with other organizations. The laboratory Head is usually the spokesman for the laboratory in many instances. The Head must prepare work p l a n s w i t h the i n s p e c t o r a t e and o v e r a l l food c o n t r o l a u t h o r i t i e s . Sampling p l a n s a g r e e d w i t h the i n s p e c t o r a t e s h o u l d aim at a r e a s of c o n c e r n and m a j o r abuses. In the e a r l i e r y e a r s or w h i l e the l a b o r a t o r y r e m a i n s s m a l l , the Head of the laboratory is the one who makes most of the m a n a g e m e n t decisions. The Head is also the person who interacts with higher m a n a g e m e n t . This is a most important aspect as the laboratory m u s t be fully integrated into the executive s tructure in a m e a n i n g f u l w a y . It w o u l d be f u t i l e for a l a b o r a t o r y to w o r k in an administrative v a c u u m , producing r e s u l t s s h o w i n g , for e x a m p l e , that s a m p l e s

3

were contaminated or that there were consignments of food in the distribution c h a i n r e q u i r i n g r e g u l a t o r y a c t i o n , if the food c o n t r o l o r g a n i z a t i o n and i n s p e c t o r a t e took no a c t i o n , or if a t t e m p t e d a c t i o n w a s c o u n t e r m a n d e d at a h i g h e r level. The e x e c u t i v e a r m of the g o v e r n m e n t in this a r e a , the food c o n t r o l s e r v i c e , n e e d s the s a n c t i o n and s u p p o r t of m o r e senior levels of the administration. To play an effective role, the Head of the laboratory must be assured of necessary finance, staff and facilities. When difficulties arise in the supply of these three essential ingredients, it must be possible to bring these difficulties to the attention of persons in positions of higher authority for appropriate action.

2.4

Supervisors

S u p e r v i s o r s s h o u l d a l s o be g r a d u a t e c h e m i s t s or m i c r o b i o l o g i s t s w i t h considerable food analysis experience. The supervisor is the on-site manager of the laboratory. Having supervisors assigned to specific units or areas of work permits the Head to more effectively plan (and execute) the total workload of the laboratory. S u p e r v i s o r s can be e x p e c t e d to do a n a l y t i c a l w o r k in a d d i t i o n to their supervisory duties. H o w e v e r , if their g r o u p e x c e e d s five p r o f e s s i o n a l a n a l y s t s , it is best not to r e q u i r e a d d i t i o n a l a n a l y t i c a l w o r k e x c e p t for occasional problem solving and trouble-shooting. A reasonable m a x i m u m number of a n a l y s t s for one p e r s o n to s u p e r v i s e is 10 to 12. T h i s can be m o r e if n o n professional support staff is added. A supervisor's duties can include many or all of the 1. Assisting the Head in overall the work of the group supervised. 2.

posed

Receiving

and assigning

samples

laboratory

5. Ensuring do the work.

the

that

reports

the

of

6. Ensuring that proper followed by the group.

work

the necessary

laboratory

planning

in s o l v i n g

completed

group has

work

for analysis, within

3. A n s w e r i n g q u e s t i o n s and a s s i s t i n g by individual analysts.

4. Reviewing recommendations.

following:

and

and

the group.

analytical

making

supplies

planning

and

safety and housekeeping

problems

appropriate

equipment

practices

to

are

7. R e c o m m e n d i n g to the Head n e w i n s t r u m e n t s or e q u i p m e n t n e e d e d , and training needs of individual analysts. 8. Taking appropriate disciplinary laboratory rules or regulations. 9.

Acting

to manage the entire

action

laboratory

when

needed

to

enforce

in the absence of the Head.

Supervisors should train one or more analysts in their group to serve as backups, to supervise the group in the supervisor's absence. The back-ups should be given some formal classroom training in supervision in addition to on-thejob experience. A good supervisor is indispensable to the smooth operation of a laboratory. In s e l e c t i n g a s u p e r v i s o r , the Head m u s t k e e p in m i n d that the p r i m a r y job of a s u p e r v i s o r is to m a n a g e , so that s k i l l s in w o r k i n g w i t h p e o p l e are m o r e i m p o r t a n t than s c i e n t i f i c e x p e r t i s e . T h e r e f o r e , a top a d m i n i s t r a t o r w i t h

4

m e d i o c r e science ability is m o s t often a better choice than a top scientist w h o is only a m e d i o c r e (or bad) a d m i n i s t r a t o r . (This p r i n c i p l e h o l d s even m o r e for s e l e c t i o n of the H e a d of the l a b o r a t o r y . ) O f t e n the b e s t a n a l y s t s are g i v e n s u p e r v i s o r jobs as a r e w a r d for their b e n c h e x p e r t i s e . T h i s not only r e m o v e s t h e m (at l e a s t in p a r t ) f r o m t h e i r m o s t v a l u a b l e r o l e as a n a l y s t , b u t it a l s o puts them in the o f t e n u n c o m f o r t a b l e role of s u p e r v i s o r . This can result in an overall d e c r e a s e in that i n d i v i d u a l ' s e f f e c t i v e n e s s . T h i s is n o t to s a y t h a t a t o p a n a l y s t c a n n o t b e a t o p s u p e r v i s o r , many fortunate o r g a n i z a t i o n s have such persons. They are rare, h o w e v e r , and a Head selecting a supervisor s h o u l d be w i l l i n g to a c c e p t lesser scientific c r e d e n t i a l s if the other attributes rank s u f f i c i e n t l y high.

2.5

Team

Leaders

A n o t h e r i m p o r t a n t , and o f t e n o v e r l o o k e d , p o s i t i o n is T e a m L e a d e r . A team leader is a senior analyst w h o h a s b e e n assigned a s m a l l g r o u p , u s u a l l y no m o r e t h a n 4 , to do a s p e c i f i c t a s k or t y p e of a n a l y s i s . T h e l e a d e r h a s no s u p e r v i s o r y functions as such, but is the c o o r d i n a t o r of the g r o u p ' s a c t i v i t i e s and is the contact point for the supervisor. T e a m l e a d e r s are m o s t u s e f u l w h e n a l a r g e n u m b e r of a r e p e t i t i v e type of a n a l y s i s is to be done in a specified period of time. This could be a specific a n a l y t i c a l s u r v e y or a n e m e r g e n c y p u b l i c h e a l t h p r o b l e m r e q u i r i n g s c r e e n i n g analyses. T h e l e a d e r u s u a l l y w o r k s a l o n g w i t h the g r o u p in a d d i t i o n to the coordinative function. S u c h e x p e r i e n c e is o f t e n u s e f u l to d e t e r m i n e if t h e assigned leader has potential as a future supervisor.

2.6

Analytical

Staff

The basic job of the analytical staff is to analyze the s a m p l e s received and to issue a report. They m a y also be required to a p p e a r in court as fact or expert w i t n e s s e s to give e v i d e n c e in r e l a t i o n to a report. They m a y also be called on to o f f e r a d v i c e to i n d u s t r y and t r a d e , to a s s i s t in i m p r o v e m e n t o f f o o d q u a l i t y , or advise on c o n f o r m i t y w i t h s t a n d a r d s or other legal r e q u i r e m e n t s . T h i s c a n i n v o l v e t h e l a b o r a t o r y s t a f f in f a c t o r y v i s i t s a n d e v e n r e q u e s t s to c a r r y out e x p e r i m e n t a l w o r k . W h e t h e r or n o t the l a b o r a t o r y u n d e r t a k e s s u c h w o r k w i l l be a m a t t e r of o r g a n i z a t i o n a l policy. The d e c i s i o n w i l l depend on a n u m b e r of f a c t o r s , i n c l u d i n g the a v a i l a b i l i t y of a l t e r n a t i v e facilities, the n a t u r e of i n d i v i d u a l o w n e r s h i p , etc. T h e i n t e g r i t y of the a n a l y s t is p a r a m o u n t , and s u p e r i o r s m u s t be i n f o r m e d of a n y c o n f l i c t of i n t e r e s t t h a t a r i s e s . A s in t h e c a s e o f f o o d i n s p e c t o r s , it is p r o p e r f o r t h e a n a l y s t s to have no vested interest in regulated industries. This r e q u i r e m e n t is m a n d a t o r y in m a n y countries. A n a l y t i c a l staff can be d r a w n from three levels, u n i v e r s i t y g r a d u a t e s , trained t e c h n i c i a n s f r o m t e c h n i c a n t r a i n i n g c o l l e g e s and u n q u a l i f i e d s t a f f w h o h a v e received o n - t h e - j o b training. The g r a d u a t e s can be c h e m i s t s , m i c r o b i o l o g i s t s , food scientists or fi od t e c h n o l o g i s t s . U n i v e r s i t y d e g r e e s are only a starting q u a l i f i c a t i o n and the-p. w i l l still be a r e q u i r e m e n t for specialized training a n d e x p e r i e n c e in f o o d . n a l y s i s . S t a f f s h o u l d be e n c o u r a g e d to c o n t i n u e to w o r k for s u i t a b l e p o s t g r a d u a t e q u a l i f i c a t i o n s to e n a b l e t h e m to c o m p e t e for h i g h e r posts in the laboratory. S p e c i a l l y trained l a b o r a t o r y t e c h n i c i a n s w h o h a v e f o l l o w e d a t w o to t h r e e y e a r p r a c t i c a l t r a i n i n g c o u r s e in l a b o r a t o r y a n a l y s i s a f t e r c o m p l e t i n g s e c o n d a r y s c h o o l c a n be p a r t i c u l a r l y u s e f u l in carrying out a n u m b e r of routine or even h i g h l y c o m p l e x food analyses. As in the c a s e w i t h u n i v e r s i t y g r a d u a t e s , s p e c i a l i z e d o n - t h e - j o b t r a i n i n g w i l l b e needed for particular types of food analysis.

5

S o m e people w i t h little or no theoretical b a c k g r o u n d often s h o w m a n i p u l a t i v e a n d p r a c t i c a l s k i l l s in t h e l a b o r a t o r y as g o o d or b e t t e r t h a n u n i v e r s i t y graduates. This type of person is often m o r e happy and fulfilled in carrying out c e r t a i n r o u t i n e l a b o r a t o r y tasks than are graduates. E v e r y a t t e m p t should be m a d e to e n c o u r a g e s u c h p e r s o n n e l in t h e i r w o r k and the l a b o r a t o r y H e a d s h o u l d a t t e m p t to s e t u p p a y s c a l e s a n d o t h e r i n c e n t i v e s to r e w a r d such workers. T h e s e w o r k e r s m a y a l s o be e n c o u r a g e d to t a k e c o u r s e s and o b t a i n q u a l i f i c a t i o n s in p r a c t i c a l a s p e c t s o f the w o r k , s u c h as glass-blowing, i n s t r u m e n t r e p a i r , e l e c t r o n i c s , m e t a l - w o r k and o t h e r f i e l d s r e l a t e d to the m a i n t e n a n c e of l a b o r a t o r y e q u i p m e n t . These skills are o f t e n scarce, and just as d i f f i c u l t to m a s t e r , as t h o s e of the g r a d u a t e a n a l y s t and t h e r e is e v e r y j u s t i f i c a t i o n for r e w a r d i n g their a c c o m p l i s h m e n t . It is m o s t i m p o r t a n t that staff e m p l o y e d for repair o p e r a t i o n s are qualified and t h o r o u g h l y trained. In p a r t i c u l a r , e l e c t r o n i c e q u i p m e n t s h o u l d be s e r v i c e d and r e p a i r e d only by qualified i n s t r u m e n t a t i o n technicians.

2.7

Support

Staff

T h e s u p p o r t s t a f f of a l a b o r a t o r y a r e all of t h o s e p e r s o n s w o r k i n g in and for the l a b o r a t o r y w h o are not c o n d u c t i n g a n a l y s e s or are n o t i n v o l v e d in a d m i n i s t r a t i v e duties. S o m e e x a m p l e s of duties include: 1.

Glassware

washing.

2.

Cleaning

and

3.

Disposal

of s a m p l e

4.

Pest

control.

5.

Heavy

lifting

housekeeping

and

maintenance.

reserves

( w h e n no

longer

required).

moving.

Support staff t y p i c a l l y have little or no e d u c a t i o n a l q u a l i f i c a t i o n s beyond a b i l i t y to read and w r i t e . H o w e v e r , they m u s t be w i l l i n g and able to learn o n l y their d u t i e s , but also laboratory safety p r o c e d u r e s .

the not

It is m o s t i m p o r t a n t t h a t s u f f i c i e n t p e r s o n s a r e h i r e d as s u p p o r t . The w o r k t h e y do m u s t be d o n e by s o m e o n e and t h i s is u s u a l l y an a n a l y s t or t e c h n i c i a n w h e n there is i n s u f f i c i e n t support staff. There is no fixed m o d u l e for n u m b e r s of s u p p o r t w o r k e r s , b u t 1 5 - 2 0 % of the n u m b e r of a n a l y t i c a l s t a f f is o f t e n sufficient.

6

3.

3.1

LABORATORY DESIGN

General Considerations

W h e n a new laboratory is being built, two people hold the key positions in producing the right building at the right cost - the architect who designs it and guides its construction, and the analyst (preferably the laboratory Head) w h o explains the technical needs, and w o r k s in close p a r t n e r s h i p w i t h the architect through every stage so that the end result is properly suited to the requirements of the users. It is not often that the analyst has the chance to take part in the planning of a complete new laboratory, more usually he has to make do with old or inadequate buildings. However, these are often more easily extended, changed or adapted as the nature of the w o r k changes, than a n e w e r building, so may in some ways be more advantageous. Indeed, an important point in designing a new laboratory is that provision should be made for future expansion, however unlikely that may seem at the time. The design should also be left as flexible as possible so that changes of emphasis in the work can be a c c o m m o d a t e d . The laboratory should be located a w a y from urban centres and industrial areas in order to minimize problems of contamination. The information in this chapter was taken in part from Industrial Research and D e v e l o p m e n t N e w s , VII No. 3, UN, N.Y., 1975. The principles given apply to food control l a b o r a t o r i e s in general, w h e t h e r n e w c o n s t r u c t i o n or space converted to laboratory use.

3.2

Basic Structure of the Building

An example of the smallest laboratory that would be adequate for a food control programme is shown in Figure 3.1. This design was originally intended to serve 120,000 people although in general this may be regarded as too small a p o p u l a t i o n to justify a separate laboratory. It is intended to be part of a larger b u i l d i n g , but the disposition of r o o m s can be changed to suit local c i r c u m s t a n c e s . Space for essential services such as solvent storage and the usual administrative support must also be provided. Sample preparation should be carried out as far as possible from laboratories working on trace analysis and microbiology or using sensitive instruments. It must be stressed that the figure s h o w n is only an e x a m p l e . New l a b o r a t o r i e s m u s t be c u s t o m - b u i l t to cater for the needs of the situation under consideration. It is best to allow l a b o r a t o r i e s to r e m a i n o p e n - p l a n as far as p o s s i b l e , including the areas used as offices. Exceptions are areas where the activities carried out cause c o n t a m i n a t i o n or are sensitive to it, such as s a m p l e preparation, weighing, microbiology, trace analysis and use of instruments such as gas-liquid chromatographs and spectrophotometers. Lack of v i b r a t i o n is important and therefore concrete is a better structural m a t e r i a l in m u l t i - s t o r e y buildings. S t e e l - f r a m e b u i l d i n g s m a y cause d i f f i c u l t y with some i n s t r u m e n t s . A two storey laboratory adequate for a modest food control programme is shown in Figures 3.2 and 3.3. It consists of a ground floor m a i n l y composed of offices and services and a first floor for analytical work. In addition there should be a flammable solvent storage area separate from the building. W o r k s h o p and g l a s s b l o w i n g facilities are often advantageous and if not otherwise available should be included.

7

1 ni i

>

Food additives and toxicants

Food standards and nutrition Corridor

Overall length 21 m

Microbiology

Media préparai ion

Office Balance room

Sample préparai ion

1vK Entrance 6.2 m

6.2 m

0

I

Figure 3.1 A Minimum Sized Food Control Laboratory

8

Figure 3.2 Ground Floor Plan (mainly office and administrative

9

space)

Figure 3.3 First Floor Plan (laboratory space)

3.3

Safety

Features

The building including : 1.

The

and

laboratory

fire

design

should

a r e a s of c o r r i d o r s

include

a number

s h o u l d be f o r m e d

of

safety

of c o n c r e t e

features

blocks.

2. Services should include a shower sprinkler system near each d o o r w a y so t h a t a w o r k e r c a n t a k e an i m m e d i a t e s h o w e r , c l o t h e s and a l l , in the c a s e of a c c i d e n t a l g e n e r a l c o n t a c t w i t h c o r r o s i v e or p o i s o n o u s l i q u i d s or f i r e .

10

3. wash

There

stations

should

be

(obtainable

built-in from

most

eye

wash

chemical

fountains, supply

or

at

least

portable

eye

firms).

4. The t r a f f i c flow, the e g r e s s p a t t e r n and the p r o p o r t i o n s of the l a b o r a t o r y are a l l s a f e t y c o n s i d e r a t i o n s . I t m u s t a l w a y s be p o s s i b l e to l e a v e the l a b o r a t o r y s a f e l y i r r e s p e c t i v e of the i n i t i a l s i t e of a f i r e . Serious t h o u g h t m u s t be g i v e n to t h e n u m b e r and l o c a t i o n o f f i r e e x t i n g u i s h e r s and s t a n d p i p e s y s t e m s , and to the a v a i l a b i l i t y of s p r i n k l e r systems. 5. L a b o r a t o r i e s s h o u l d b e w e l l - l i t so t h a t t h e o p e r a t o r d o e s n o t h a v e to p e e r too c l o s e l y o v e r p o t e n t i a l l y h a z a r d o u s m a t e r i a l i n o r d e r to see w h a t he is doing. T h e r e s h o u l d be a m p l e w o r k i n g s p a c e and b e n c h t o p s and o t h e r s u r f a c e s s h o u l d be k e p t c l e a r of a l l m a t e r i a l e x c e p t t h a t i n c u r r e n t u s e . 6. Benches are best w i t h o u t s h e l v e s , only s e r v i c e s , these being operated from the f r o n t so t h a t the o p e r a t o r d o e s not h a v e to s t r e t c h a c r o s s the b e n c h . I t i s s t i l l common to s e e r e a g e n t s on s h e l v i n g at t h e b a c k o f b e n c h e s ( o r a b o v e the c e n t r e of d o u b l e - w i d t h b e n c h e s ) b u t i t i s p r o b a b l y s a f e r i f such r e a g e n t s c a n be k e p t on s i d e - s h e l v e s or i n t r a y s w h i c h a r e b r o u g h t to t h e b e n c h as required . 7. F l o o r i n g n e e d s to b e o f a n o n - s l i p m a t e r i a l , r e s i s t a n t to a c i d s a n d s o l v e n t s , b u t n o t so h a r d a s to b e t i r i n g to s t a n d on f o r a f e w h o u r s at a time. No m a t e r i a l i s e n t i r e l y s a t i s f a c t o r y . W e l l - l a i d l i n o l e u m and a f i l l e d e p o x y r e s i n on top of c o n c r e t e a r e a m o n g t h e b e s t a v a i l a b l e . It is a d v i s a b l e n o t to p o l i s h l a b o r a t o r y floors. 8. P o l l u t a n t s g e n e r a t e d w i t h i n t h e l a b o r a t o r y m u s t be r e m o v e d s a f e l y , q u i c k l y and e f f i c i e n t l y . I n p a r t i c u l a r , t o x i c or n o x i o u s g a s e s m u s t be r e m o v e d e x p e d i t i o u s l y t h r o u g h a d u c t s y s t e m t h a t d o e s n o t e x h a u s t n e a r the b u i l d i n g a i r conditioning intake. 9. The b u i l d i n g must be p l a n n e d f o r s e c u r i t y . R e s t r i c t i o n of a c c e s s i s of c o n s i d e r a b l e i m p o r t a n c e b e c a u s e of the e x t r e m e l y v a l u a b l e and sensitive e q u i p m e n t u s e d i n t h e l a b o r a t o r y w o r k a s w e l l as t o p r o t e c t t h e i n t e g r i t y o f official samples. 10. I t i s v e r y a d v i s a b l e to h a v e an e f f i c i e n t f i r e a n d s m o k e d e t e c t i o n system w i t h appropriate alarms. Common f i r e d e t e c t i o n e q u i p m e n t is usually e i t h e r r a t e - o f - t e m p e r a t u r e - r i s e or f i x e d - t e m p e r a t u r e d e t e c t o r u s i n g a s u b s t a n c e of known m e l t i n g p o i n t . T h e r e a r e a d v a n t a g e s ( a n d d i s a d v a n t a g e s ) to e a c h t y p e of d e t e c t o r and the l a b o r a t o r y Head s h o u l d s e l e c t the one he f e e l s b e s t f i t s his laboratory. D e s i g n i n g a l a b o r a t o r y to a f f o r d p r o t e c t i o n a g a i n s t e v e r y k i n d o f h a z a r d w o u l d be a l m o s t i m p o s s i b l e . The a i m s h o u l d be to d e t e r m i n e t h e l e v e l o f s a f e t y for t h e most g e n e r a l a p p l i c a t i o n s and to p r o v i d e s u p p l e m e n t a r y s y s t e m s in a r e a s o f higher h a z a r d . A s a f e s o l v e n t s t o r a g e a r e a i s i d e a l l y s e p a r a t e from t h e l a b o r a t o r y b u i l d i n g i n a stand-alone structure. I t c a n be a s m a l l b u i l d i n g of one room and some p o s s i b l e d e s i g n f e a t u r e s a r e : ( r e a s o n s are g i v e n in p a r e n t h e s i s ) 1. materials

Construction s u r r o u n d the

of cement solvents.)

blocks

or

bricks.

(Only

non-flammable

2. For a s t a n d - a l o n e b u i l d i n g , d o u b l e w a l l s w i t h i n s u l a t i o n between. The e x t e r i o r w a l l c a n be m a t e r i a l other than block or b r i c k . (Provides i n s u l a t i o n from the sun and m a k e s a i r c o n d i t i o n i n g more e f f e c t i v e . ) 3. An e p o x y f i l m to c o v e r t h e e n t i r e walls. ( A n y s o l v e n t s p i l l a g e w i l l p o o l and t h e f l o o r s or w a l l s . )

11

floor plus evaporate,

10 cm up t h e b a s e of t h e r a t h e r than soak through

4. A c o p p e r pipe (about 25 m m ) inside the r o o m , w h i c h goes t h r o u g h the floor and is e m b e d d e d a b o u t 2 m in earth. (A g r o u n d pipe to bleed off any static e l e c t r i c i t y c h a r g e s - w h i c h o f t e n build up w h e n s o l v e n t s are poured). All metal objects in the room are to be attached to the pipe using heavy guage single strand copper wire. Also, attach a short wire with an alligator clip. (This g r o u n d s all m e t a l . The clip is used to g r o u n d any m e t a l cans used for s o l v e n t transfer.) 5. grounding

Storage pipe.

shelves of metal

and connected

by wire

to each other and

the

6. Air c o n d i t i o n i n g is e x t e r n a l , w i t h the e n t r a n c e duct at the top of one c o r n e r of the r o o m and the exit d u c t at the b a s e of the o p p o s i t e c o r n e r . ( T h e r o o m m u s t be c o o l e d as m a n y s o l v e n t s w i l l b o i l at h o t o u t s i d e temperatures. The air entrance on top and exit on the bottom diagonally across the r o o m , w i l l cool the room and w i l l also serve to s w e e p and r e m o v e any solvent fumes on the floor - solvent fumes are generally heavier than air and will pool on the floor.) 7. The door is of m e t a l and f i r e - r a t e d for at least one h o u r , w i t h a positive closure. It must seal well when closed. The door sill is at least 10 cm high. (Fire doors are metal sheathed around cement. The closure, the seal and the h i g h sill all act to p r e v e n t e s c a p e of s o l v e n t , e i t h e r floor s p i l l a g e or fumes.) 8. An air c o n d i t i o n e r exit duct w i t h a fire b a f f l e (to p r e v e n t flash b a c k ) and d u c t e d to exit in the o u t s i d e air at b u i l d i n g r o o f h e i g h t . (Fumes h a v e a b e t t e r c h a n c e of being carried a w a y by b r e e z e s and s o m e o n e s m o k i n g nearby will not present a fire risk.) 9. An extinguisher system, and not water sprinklers.

3.4

Ventilation and Air

which

should

be carbon dioxide or Freon type

Conditioning

An ordinary laboratory may have amounts of lead in the air passing through it in a day which can be measured in milligrams. Natural ventilation, which may provide large quantities of air without cooling, is not generally suitable for laboratories. T h i s is e s p e c i a l l y true in u r b a n a r e a s w h e r e m o t o r t r a f f i c is high. This means that air conditioning is essential for the modern laboratory. A i r c o n d i t i o n i n g not only p r e v e n t s s o m e f o r m s of c o n t a m i n a t i o n , it also p r o v i d e s a s t a b l e t e m p e r a t u r e e n v i r o n m e n t for s e n s i t i v e and s o p h i s t i c a t e d analytical instruments. Most v o l u m e t r i c g l a s s w a r e is c a l i b r a t e d at 20°C and must be recalibrated if used at significantly different temperatures. This is s t i l l a n o t h e r a r g u m e n t for air c o n d i t i o n i n g . T h e i m p o r t a n c e of a i r conditioning to overall laboratory accuracy cannot be overstressed. The exhaust fans in fume hoods result in a negative pressure in the laboratory and in an urban or industrial area this aggravates contamination of the whole l a b o r a t o r y area. A p o s i t i v e p r e s s u r e s y s t e m is c o s t l y as it h a s to be s u f f i c i e n t l y p o w e r f u l to p r o v i d e a c l e a n filtered air s u p p l y w h i c h p a s s e s t h r o u g h f u m e hood e x h a u s t fans as w e l l as o t h e r o u t l e t s . V e n t i l a t i o n by p o s i t i v e p r e s s u r e a s s i s t s the e x h a u s t fans in f u m e h o o d s and is to be preferred. Each f u m e hood should h a v e a s e p a r a t e fan, as there is d a n g e r of cross c o n t a m i n a t i o n from a c o m m o n d u c t i n g s y s t e m . Such a s y s t e m can be essential if the vicinity of the laboratory is prone to contamination and it is necessary to carry out low-level trace analysis. Toxic fumes must be confined as far as possible to fume hoods. These should be away from cross-currents of air and pedestrian traffic. The recommended m i n i m u m air-flow through the open face of a f u m e hood is 0.5 m / s e c . V e n t i l a t i o n s h o u l d be such as to give at least 5 air changes per hour.

12

V a c u u m p u m p s used to evaporate solvents should have the exhaust to the outside a i r , o t h e r w i s e t o x i c l e v e l s of the s o l v e n t m a y be r e a c h e d in the l a b o r a t o r y atmosphere. W a t e r aspirator p u m p s are quite safe w i t h w a t e r - s o l u b l e solvents or acid f u m e s , but not w i t h w a t e r - i m m i s i b l e s o l v e n t s such as p e t r o l e u m ether.

3.5

Space

Utilization

L a b o r a t o r y s p a c e m u s t be a r r a n g e d for m a x i m u m u t i l i z a t i o n as w e l l as p r o p e r w o r k flow. It is usual to a l l o w about 10 square m e t e r s of laboratory space and 3 m e t e r s of b e n c h s u r f a c e p e r a n a l y s t . An e x a m p l e of a l a b o r a t o r y for 8 a n a l y s t s is in Figure 3.4.

Sx FC Fr DS Kj

Figure

" = = = =

Soxhlet bench fume cupboard freezer sink unit Kjeldahl apparatus

3.4

N o t e that e a c h a n a l y s t h a s a l a t e r a l b e n c h a r e a to w o r k at. T h i s f o r m a t is termed 'peninsular' and is quite e f f i c i e n t . An a l t e r n a t e f o r m a t uses 'islands' w h i c h have access on all sides. An e x a m p l e is Figure 3.5.

13

0.7b m

1.50 m

0.75 m

1.50 m

0.75 m

1.50 m

0.75 m

Consider as island benches accessible from every side, or consider as the floor space remaining, the area B being occupied by benches

0

Figure

1

2

3m

3.5

T h e o p t i m u m w i d t h f o r a s i n g l e b e n c h ( a b o u t 75 cm) i s r o u g h l y t h e s a m e as t h e width of the space required by a s t a n d i n g individual. It is therefore convenient, to c o n s i d e r t h e p r o s and c o n s o f i s l a n d b e n c h e s and peninsular b e n c h e s w i t h the a s s i s t a n c e of F i g u r e 3 . 5 . I t c a n r e a d i l y be s e e n t h a t the m a x i m u m b e n c h a r e a i s o b t a i n e d w i t h p e n i n s u l a r b e n c h e s (B a r e a s ) , h o w e v e r , the w o r k i n g s u r f a c e is more a c c e s s i b l e on i s l a n d b e n c h e s (A a r e a s ) . The services a r e m o r e a c c e s s i b l e f o r r e p a i r on i s l a n d b e n c h e s , b u t t h e r e i s l e s s space available for s h e l v i n g close to t h e b e n c h e s . In the c a s e of peninsular b e n c h e s , t h e a n a l y s t w o r k i n g i n a b a y h a s a c c e s s i n e f f e c t to t h r e e w o r k i n g s u r f a c e s at o n c e and t h i s i s v e r y c o n v e n i e n t i f t h e r e a r e s e v e r a l different a n a l y s e s i n p r o g r e s s at the same t i m e . H o w e v e r , the s p a c e b e t w e e n p e n i n s u l a r s s h o u l d a l w a y s be e n o u g h for two p e o p l e to w o r k c o m f o r t a b l y b a c k to b a c k ( a b o u t 1.5 m). I s l a n d b e n c h e s make the c h o i c e of s i t e for w i n d o w s and d o o r s less critical. P e n i n s u l a r b e n c h e s m a y be p r e f e r r e d i f s p a c e i s a t a p r e m i u m a n d t h e y may be s l i g h t l y s a f e r , as the r o u t e s by w h i c h p e o p l e w a l k a b o u t the l a b o r a t o r y t e n d to be m o r e r e s t r i c t e d and p r e d i c t a b l e . W h i c h e v e r is c h o s e n , w h a t i s m o s t i m p o r t a n t i s t h a t t h e s i z e o f t h e r o o m i s c o r r e c t to t a k e a n i n t e g r a l n u m b e r of b e n c h u n i t s w i t h t h e i r a c c o m p a n y i n g floor space. Usually t h e p r o b l e m c a n be p a r t l y s o l v e d b y a w a l l b e n c h at one end or s i d e of t h e l a b o r a t o r y but a l l too o f t e n l a b o r a t o r i e s have such a s i z e or shape t h a t f l o o r s p a c e h a s b e e n w a s t e d , or an e x t r a b e n c h h a s b e e n i n c o n v e n i e n t l y s q u e e z e d in. The s t o r a g e a r e a s in the b e n c h e s s h o u l d be m o d u l a r to a l l o w f l e x i b i l i t y . Many laboratory bench manufacturers have units where the storage areas are interchangeable. Some s a m p l e s of b e n c h a s s e m b l i e s a r e g i v e n in F i g u r e 3 . 6 , w i t h w i d t h s in c e n t i m e t e r s .

14

I

KO

ra

to

I

m »••

•O

+

1M

(O

«-

f

m m m I

+

f-

I

«O

4

"t-

22»

to

I

'«•

+

+

+

+

+

to

110

+

120

4-

+

120

10

120

2%0

120

2$o

120

4-

2 tO

120

2so

+

tO

+4-

4-4-

4"

120

IM

120

4-4rara 1»

M

m

II

II

4-

M

220

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m

rap nu +

Il

I

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ira m m m rap ra era to

M U

4-

)

SO (O

•••

>0

110

4"

HI

..

Figure

m

--

--

+

'

3.6

The o p t i m u m working depth of benches for standing w o r k has been found to be 60 cm for the w o r k i n g s u r f a c e , p l u s 15 cm for the a c c o m m o d a t i o n of a b o v e - b e n c h fitments (such as gas service, electrical sockets and shelves) giving a total depth of 75 cm. The bench heights, h o w e v e r , have always caused some problems b e c a u s e of the v a r i e t y of b e n c h t o p s a v a i l a b l e . Their thickness varies with the different coverings and supporting bases used: 6 cm for ceramic tiles, 4 cm for P y r o c e r a m , 3.7 cm for a c i d - p r o o f s t o n e w a r e , and 2.8 cm for p l a s t i c s . H e i g h t d i f f e r e n c e s in a d j a c e n t b e n c h u n i t s always cause inconvenience to the user. Therefore purchases of new benches m u s t expressly indicate that desks and benches with different coverings must have uniform heights. (Differences c a n be c o m p e n s a t e d for b y u n d e r l a y i n g the b e n c h tops.) B e n c h m o d u l e l e n g t h s are u s u a l l y 60 cm for s i n g l e u n i t s and 90 or 120 cm for d o u b l e u n i t s . This modulus of length in 30 cm steps allows adaptation to nearly any room size. W o r k flow is a very important part of proper space utilization. There should be a l o g i c a l and s y s t e m a t i c a r r a n g e m e n t of s p a c e to p e r m i t f l o w of a n a l y s i s w o r k f r o m s a m p l e r e c e i p t , p r e p a r a t i o n and a n a l y s i s to d i s p o s a l or s t o r a g e . This entails examining the average sample annual workload in relation to the areas and people involved in the various analyses. The best work flow system (within physical constraints of the building) is usually readily apparent.

3.6

Equipment

and

Instruments

The complexity of equipping a laboratory and the consequent delay in production of u s e f u l r e s u l t s s h o u l d n o t be u n d e r e s t i m a t e d . In the e a r l y s t a g e s , the requirements for equipment may seem large and complex but once the laboratory is e s t a b l i s h e d , the r u n n i n g c o s t s a r e r e l a t i v e l y l o w . It is s o m e t i m e s n o t appreciated by the non-technical administrator that an analysis may require 10 or 20 i n d i v i d u a l i t e m s and that if e v e n o n e is n o t a v a i l a b l e the a n a l y s i s cannot be carried out. On the other hand, many items are c o m m o n to different

15

a n a l y s e s so t h a t , o n c e the m a n y h u n d r e d s of i t e m s r e q u i r e d in a food c o n t r o l l a b o r a t o r y h a v e b e e n p r o v i d e d , t h e r e c o m e s a p o i n t at w h i c h p r o d u c t i v i t y c a n rise s h a r p l y and i n v e s t m e n t decrease. The logistical p r o b l e m s of m a i n t e n a n c e , r e p a i r and r e p l a c e m e n t of e q u i p m e n t are also c o n s i d e r a b l e . Adequate provision m u s t be m a d e for obtaining spares and r e p l a c e m e n t parts and for their storage. It is false e c o n o m y if staff are being paid but c a n n o t do an i m p o r t a n t part of their w o r k due to a lack of r e l a t i v e l y i n e x p e n s i v e e q u i p m e n t . S o m e of the i n s t r u m e n t s and e q u i p m e n t needed for c h e m i c a l a n a l y s i s by a m o d e r n food c o n t r o l l a b o r a t o r y are: (for purposes of this listing, ' i n s t r u m e n t s ' are m e a s u r i n g d e v i c e s and ' e q u i p m e n t ' are p r o c e s s i n g d e v i c e s . Apparatus made p r i m a r i l y of glass are not included).

Instruments

A n a l y t i c a l balance pH m e t e r Spectrophotometer, UV-visible, double-beam S p e c t r o p h o t o m e t e r , atomic a b s o r p t i o n H i g h P e r f o r m a n c e Liquid C h r o m a t o g r a p h (with UV and d i f f e r e n t i a l r e f r a c t i v e index d e t e c t o r s ) Gas C h r o m a t o g r a p h (with flame i o n i z a t i o n and e l e c t r o n capture d e t e c t o r s )

Equipment

Blender Grinder Pulverizing hammer mill Air o v e n , forced draft V a c u u m o v e n , with pump M u f f l e furnace Centrifuge Refrigerator Freezer H e a t e r s and hot plates Steam and w a t e r b a t h s W a t e r still or d e i o n i z e r

All of the above e q u i p m e n t and i n s t r u m e n t s are m o v e a b l e , a l t h o u g h the larger or m o r e s e n s i t i v e units are g e n e r a l l y not m o v e d , once placed. The m a j o r i t e m s of fixed e q u i p m e n t constructed in place are the fume hoods. The e x t e n s i v e use of s o l v e n t s , a s h i n g and n o x i o u s c h e m i c a l s in f o o d a n a l y s i s , r e q u i r e s m o r e f u m e h o o d s t h a n o t h e r t y p e s of l a b o r a t o r y w o r k . In f a c t , to e x p e r i e n c e d food a n a l y s t s , t h e r e n e v e r s e e m to b e e n o u g h h o o d s , e v e n in a w e l l equipped laboratory. F u m e h o o d s m a y be p u r c h a s e d p r e - f a b r i c a t e d w i t h o u t l e t s for services. The m a t e r i a l of c o n s t r u c t i o n is m o s t i m p o r t a n t , e s p e c i a l l y if the hood has to w i t h s t a n d acid fumes in general and p e r c h l o r i c acid in p a r t i c u l a r . The s u p p l i e r m u s t be g i v e n full d e t a i l s of the use to w h i c h the fume hood w i l l be put. H o o d s c a n be c o n s t r u c t e d out of l o c a l m a t e r i a l s s u c h as w o o d , p r e f e r a b l y hard w o o d s , coated w i t h epoxy resins. Such should n e v e r be used for acid d i g e s t i o n s , but only for solvent e x t r a c t i o n work.

3.7

Utilities

E l e c t r i c i t y m u s t either be a stable supply, or the voltage m u s t be stabilized by e i t h e r one large s t a b i l i z e r for the w h o l e l a b o r a t o r y , or by a unit for each of the i n s t r u m e n t s r e q u i r i n g it. A b o u t 40 w a t t s per s q u a r e m e t e r has b e e n

16

suggested. The laboratory pictured in Figure 3.3 has 160 double 13-amp socket outlets. This apparently large n u m b e r adds considerably to the efficiency of a n a l y t i c a l o p e r a t i o n s and to their s a f e t y . The s a m e l a b o r a t o r y has 110 gas p o i n t s , e x c l u d i n g t h o s e to the f u m e h o o d s . T h e r e m u s t b e s e v e r a l cold w a t e r taps per b e n c h to a l l o w for r i n s i n g , c o n d e n s e r s , etc., but h o t w a t e r can be restricted to those sinks w h e r e apparatus is washed. In a larger laboratory a distribution system for distilled or deionized water would be advantageous.

The following utilities

for fume hoods have been

Fume Hood Length

(•):

Gas taps (front controlled) Water taps (front controlled) Cup sinks Compressed air valves (front controlled) Two-phased electrical sockets Three-phased electrical sockets

suggested:

1.2

1.5

1.8

2 2 1

2 3 2

3 4 2

1 2

1 3

1 4

1

1

1

S p e c i a l m e t h o d s , s u c h as t r a c e a n a l y s i s , u s u a l l y r e q u i r e d i s t i l l a t i o n f r o m g l a s s a p p a r a t u s of w a t e r i n i t i a l l y p a r t i a l l y p u r i f i e d by d i s t i l l a t i o n or deionization. The initial purification produces water very low in salts, but if the o r i g i n a l s u p p l y c o n t a i n s o r g a n i c m a t t e r t h i s m a y n o t be r e m o v e d , and traces of resin material m a y be present. A s t e a d y s u p p l y of c o m p r e s s e d air is r e q u i r e d for an a t o m i c absorption s p e c t r o p h o t o m e t e r (AAS) and is v e r y u s e f u l to h a v e a v a i l a b l e at the b e n c h . A c o m p r e s s o r is s u i t a b l e for use w i t h the i n s t r u m e n t but if used for o t h e r purposes at the same time it m u s t be capable of supplying those needs without a f f e c t i n g the AAS s u p p l y . A p a r t f r o m the i n a c c u r a c y that w i l l r e s u l t from a change in the flame characteristics, sudden failure of the air m a y result in a flashback, which is expensive if the mixing chamber is destroyed, and could be dangerous. H o w e v e r , it m u s t be emphasized that m a n u f a c t u r e r s design this part of the i n s t r u m e n t to be as safe as p o s s i b l e u n d e r f l a s h b a c k c o n d i t i o n s . Therefore, in m a n y ways it is probably better to have a separate air supply to the AAS. T h i s i n s t r u m e n t a l s o has to be p r o v i d e d w i t h a v e n t i l a t i o n h o o d to remove gases formed during operation, particularly if nitrous oxide is used as the fumes are very toxic. Utility services require a large space but need to be concealed for aesthetic r e a s o n s , y e t r e q u i r e an e a s y a c c e s s for r e p a i r p u r p o s e s . To s a t i s f y t h e s e conflicting demands, the main runs may be in voids above false ceilings and in floor ducts. Secondary services are then run to outlet points on benches taken from floor level along the wall behind benches in voids especially incorporated in the design of the bench fittings. Frequent access points are provided for maintenance purposes. Drain pipes should be of high density polythene or copolymer polypropylene with screwed joints. T h e s e s h o w g o o d r e s i s t a n c e to m o s t o r g a n i c and i n o r g a n i c chemicals. The d r a i n a g e l i n e s m a y be e m b e d d e d in the f l o o r i n g . As it is not acceptable to discharge laboratory w a s t e s d i r e c t l y i n t o t h e s e w e r a g e s y s t e m , all w a s t e from l a b o r a t o r y sinks and o t h e r w a s t e f i t t i n g s s h o u l d be led f i r s t into dilution pots (about 5 litre capacity) before being released into the m a i n sewers. Buildings can be designed to include a large dilution tank where all l a b o r a t o r y sink w a s t e is d i r e c t e d b e f o r e e n t e r i n g the s e w e r a g e s y s t e m . For laboratories with high mineral acid use, sink traps of inert duriron often work well.

17

3.8

Design

References

1.

B e c k , H. L u f t u n g s e i g e n s c h a f t e n von L a b o r a b z u g e n ( V e n t i l a t i o n p o w e r of laboratory fume cupboard). Weinheim, Chemie-Ingenieur-Technik, 1964 (No. 3 6 ) (in G e r m a n ) .

2.

Be r u f s g e n o s s e n s c h a f t fur d i e c h e m i s c h e I n d u s t r i e , R i c h t l i n i e n fur c h e m i s c h e L a b o r a t o r i e n Nr. 12 ( D i r e c t i v e s for c h e m i c a l l a b o r a t o r i e s no. 12) Weinheim, Verlag-Chemie, 1972 (in German).

3.

DECHEMA Erfahrungs austausch; Laborbau (DECHEMA sharing laboratory design). Frankfurt/M. DECHEMA, 1969 (in German).

4.

Decken, C.B. v.d. a n d B. H u n d o r f . Untersuchungen uber die stromungstechnischen Vorgange in der Kapelle eines Laborabzug (Experiments about flow within the cabin of a fume cupboard). Darmstadt, GIT 1968 (No. 8) (in G e r m a n ) .

5.

D e u t s c h e r V e r e i n von Gas und W a s s e r f a c h m a n n e r n ( D V G W ) N o r m e n F e d e r a t i o n of Gas and W a t e r S p e c i a l i s t S t a n d a r d s ) E s c h b o r n , Republic of Germany (in German).

(German Federal

a.

Was serversorgung; Verbrauchanlagen D W G W W 503-1966.

piping)

b.

T e c h n i s c h e R e g e l n fur Bau und P r u f u n g von v o r g e f e r t i g t e n B a u t e i l e n mit Gas und Wasserinstallation ( S p e c i f i c a t i o n for c o n s t r u c t i o n and testing of prefabricated appliances with gas and water installations) D V G W GW 3 (1968).

c.

Technische Regeln fur die Installation von Gasanlagen in Laboratorien (Specifications for gas service installations in laboratories) DVGW G 621 (1971). (Pressure

experience:

(Water supply: service

gas regulation) Koln, Carl Heymann's Verlag

6.

Druckgasverordnung (in G e r m a n ) .

7.

Dunkl/Geyer. R a t i o n a l e L o s u n g e n von L a b o r b a u und L a b o r e i n r i c h tungsprob1emen in H o c h s c h u l e n , Industrieunternehmumgen und i m Gesundheitswesen der USA (Rational solutions of problems in the design of laboratory building and equipment for u n i v e r s i t i e s , i n d u s t r y and p u b l i c h e a l t h in the U n i t e d States). In B e i t r a g e zur U n i v e r s i t a t s p l a n u n g ( C o n t r i b u t i o n s to the p l a n n i n g of u n i v e r s i t i e s ) . F r a n k f u r t / M . D E C H E M A , 1970 (Heft 6) (in G e r m a n ) .

8.

F e u r i c h , H. R o h r n e t z e fur S a u e r s t o f f , D r u c k l u f t , V a c u u m , K o h l e n s a u r e in K r a n k e n h a u s e r n und L a b o r a t o r i e n (Service p i p i n g for o x y g e n , c o m p r e s s e d air, vacuum and carbon dioxide in hospitals and laboratories) Darmstadt, G I T 1 9 6 4 (nos. 8, 9 and 10) (in G e r m a n ) .

9.

D e u t s c h e I n d u s t r i e N o r m t'DIN) ( G e r m a n Beuth-Vertrieb G m b H (all in German) plant;

principles,

Industrial

a.

Ventilation English).

b.

Fire resistance 4102-1970.

c.

Space lighting by daylight; principles.

DIN 4034-1969.

d.

Laboratory furniture; 12 912-1973.

laboratory

of building

DIN

Standard).

materials

ceramic

18

tiles

1946-1960,

and

for

Part

structural

1

Berlin,

(also

elements.

bench

tops.

in

DIN

DIN

e.

Laboratory furniture; cup sinks.

DIN

12-914-1973.

f.

Laboratory 1973.

g.

L a b o r a t o r y furniture; large-size DIN 12 916-1972.

h.

Colour code for fluids on h a n d l e v e r s and h a n d w h e e l s of laboratory taps. DIN 12-920-1971.

i.

Laboratory furniture; benches, dimensions.

j.

Laboratory 1972.

k.

Heating plant, English).

1.

Traffic ways in buildings.

m.

Ventilation of laboratories. VID 2051-1966.

furniture; sinks w i t h integrated o v e r f l o w . DIN 12 915-

furniture;

smoke

fume

tiles

cupboards,

stacks.

DIN

DIN

18

for laboratory bench

tops.

DIN 12 922-1972. dimensions.

160-1968;

DIN

part

12

923-

1 (also

in

18-225-1958.

10.

Geyer, F. A n f o r d e r u n g e n an L a b o r b a u t e n ( R e q u i r e m e n t s for laboratory b u i l d i n g ) D a r m s t a d t , GIT (No. 1 2, 1 967 and No. 1 1968) (in German).

11.

/Richtlinien fur die Planung und den Bau von Laboratorien (Principles for design and building of laboratories) Weinheim, C h e m i e - I n g e n i e u r - T e c h n i k , 1971. (No. 11) (in German).

12.

Role et interet de la normalisation dans 1 ' aménagement et l'equipement des l a b o r a t o i r e s , Courrier de la N o r m a l i s a t i o n , No. 228 n o v e m b r e - d e c e m b r e , 1972 (in French).

13.

The role and significance of standarization of laboratory equipment and furniture. Laboratory Practice (London) No. 4, 1973.

14.

Laboratory furniture and fittings: BS 3202-1959, London, British Institution.

15.

Strangmann, W. Wasserverbrauch in chemischen und biologischen Laboratorien (Water consumption in chemical and biological laboratories). Darmstadt, GIT, 1964 (No. 6) (in German).

16.

Unfallverhutungsvorschrift: Medizinische Laboratoriumsarbeiten (Prescription for accident prevention: work in medical laboratories) Frankfurt/M. H G U V V ) (in German).

17.

United States Department of Health, Education and Welfare, Health Research Laboratory Design, Bethesda, Maryland NIH 1968 (Publication 1807).

18.

V e r b a n d D e u t s c h e r E 1 e k t r o t e c h n i k e r ( V D E ) N o r m e n (Union of G e r m a n E l e c t r i c a l Engineers s t a n d a r d s ) O f f e n b a c h / M a i n , Federal Republic of Germany (in German).

19.

A Literature Survey and Design Study of Fume Cupboards and Systems, Hughes, D., 1980, Science Reviews Ltd., London.

19

Standards

Fume-Dispersal

4.

4.1

LABORATORY ADMINISTRATION

Sample Collection

Work scheduling is greatly facilitated by arranging a sampling programme for r o u t i n e m o n i t o r i n g w i t h the i n s p e c t o r a t e . Close c o o p e r a t i o n w i t h the inspectorate will pay great dividends in improved efficiency in sampling. It i s o f t e n a l s o n e c e s s a r y to h a v e part of the l a b o r a t o r y staff a v a i l a b l e for urgent work and for samples such as consumer complaints, export certification and c h e c k i n g of i m p o r t s , w h e r e t h e r e is o f t e n l i t t l e n o t i c e g i v e n b e f o r e the arrival of the sample. S i n c e the l a b o r a t o r y r e l i e s on the i n s p e c t o r a t e for a s t e a d y w o r k l o a d , the inspectorate and laboratory supervisors must be in frequent contact in order to m a i n t a i n the w o r k l o a d in the l a b o r a t o r y at a r e a s o n a b l e level. As part of a general food control programme, there is need to: 1. Regularly inspect foods at different stages in the manufacturing distribution chains using planned surveillance programmes.

and

2. C a r r y out g e n e r a l s u r v e y s of the q u a l i t y of the food s u p p l y t h r o u g h random sampling and analysis, samples being taken from factories, warehouses and retailers. 3. Monitor certain specific problem areas with regard to food safety specific foods or classes of foods for specific potential risks, (e.g. level of metallic contaminants, pesticide residues, mycotoxins, etc.). 4.

Inspect foods for export, for certification of quality

(if needed).

5. Inspect food imports. This is b e s t d o n e on a l l c o n s i g n m e n t s by f o r m a l s a m p l i n g c a r r i e d out s y s t e m a t i c a l l y in representative of the lot.

imported a manner

6. Formal sampling should also be done on locally produced food products b a s e d o n t h e f o o d i n s p e c t o r s ' o b s e r v a t i o n s , or b e c a u s e a r a n d o m o r investigatory sample under the regular programme was unsatisfactory, or because the product is one that requires thorough surveillance. Analysis of formal and informal samples is also necessary in an emergency such as an outbreak of foodpoisoning . National sampling programmes yield important benefits in terms of efficiency. The I n s p e c t o r a t e and the L a b o r a t o r y a s s i s t e d and g u i d e d by o t h e r a g e n c y o f f i c i a l s or an a d v i s o r y b o a r d , as a p p r o p r i a t e , should p e r i o d i c a l l y plan overall programmes to locate and deal with different problems in the areas of food q u a l i t y and c o n s u m e r p r o t e c t i o n . In each case the o b j e c t i v e s of the p r o g r a m m e should be clearly defined. A l t h o u g h s a m p l e s m a y be c l a s s i f i e d in a n u m b e r of w a y s , it is c o n v e n i e n t to consider two broad divisions, "formal" samples and "informal" samples. Formal samples are those taken to determine if the foods comply with national or local l a w s or r e g u l a t i o n s . R e g u l a t o r y a c t i o n m a y r e s u l t from r e p o r t s r e c e i v e d on such samples. Informal samples may be taken for purposes of monitoring or as part of survey work. Formal follow-up samples can be taken if informal samples receive adverse laboratory reports. Formal or informal samples will also be taken under other circumstances, such as a follow-up to a consumer complaint. When samples are of the nature and required from the e x p e r i e n c e , from from the r o u t i n e

sent to the laboratory, the inspector must send full details purpose of sampling and any other relevant data. The results analysis will usually be clear, either from the analyst's own p r i o r d i s c u s s i o n w i t h the i n s p e c t o r or h i s s u p e r v i s o r s , or i n f o r m a t i o n g i v e n w i t h the s a m p l e . A w e l l q u a l i f i e d and

20

t r a i n e d i n s p e c t o r m a y a l s o w i s h to d i s c u s s the need for an a n a l y s i s that the a n a l y s t w o u l d not r o u t i n e l y c a r r y out. It is the d u t y of the l a b o r a t o r y H e a d to decide how these requests are to be met. The inspector's sample submission form should give all necessary details about the sample. These details may include the product n a m e , place of collection, reason for collection, type of samples (consumer c o m p l a i n t , official, survey, etc.), inspector's name, m o d e of s a m p l i n g , lot n u m b e r , s h i p p e r if so transported, size of consignment and similar relevant details, together with any s p e c i a l i n f o r m a t i o n that m a y be of a s s i s t a n c e to the a n a l y s t , such as suspected contamination. T h e s a m p l e s h o u l d a l s o be s e a l e d by the i n s p e c t o r with an official seal.

4.2

Sample Receipt and

Assignment

W h e n a food s a m p l e is r e c e i v e d for a n a l y s i s , t h e r e m u s t be a s y s t e m to t r a c k the sample throughout it's initial storage, analysis and later reserve storage. This is usually embodied in a record keeping system which is keyed to a unique n u m b e r a s s i g n e d to the s a m p l e at the t i m e of s a m p l i n g . T h i s n u m b e r c a n be sequential (i.e. 0001 to 9999) or can be devised to give information (i.e. 0245 - 0 7 , the 2 4 t h s a m p l e t a k e n in 1 985 u n d e r s a m p l i n g p r o g r a m m e n u m b e r 7). The r e c o r d m u s t s h o w each m o v e m e n t of a s a m p l e , its r e c e i p t , a s s i g n m e n t to a l a b o r a t o r y p e r s o n for a n a l y s i s , r e t u r n to the s a m p l e c u s t o d i a n , and e v e n t u a l disposition. One of the a d m i n i s t r a t i v e s t a f f s h o u l d be g i v e n this r e c o r d keeping function and closely supervised by a senior administrator, as well as supervised in general by the laboratory Head. It is usually best to use a card record system rather than a log book as cards are more flexibly handled and may be filed in groups under different headings. M a n y card record systems have been devised including 5x8 cards with coded sites on the periphery for punching. Other cards are pre-printed with spaces to be filled in w i t h appropriate data. Regardless of the card system selected, there are certain items of information which should be on each card:

1.

Sample

number.

2.

Product

3.

Date

4.

Date received

5.

Type of sample

6.

Method

7.

Storage

8.

Date assigned

9.

To whom assigned

name.

sampled. at the

laboratory.

(survey, complaint,

of storage

etc.).

(dry, refrigeration,

location (coded for

for easy

freezing,

etc.).

finding).

analysis. (the analyst

10.

Date returned

(from

11.

From whom returned

12.

Reserve

13.

Final disposition

should

initial

to show

receipt).

analyst). (may be different

storage method

and

from

the original

analyst).

location.

or disposal

of sample, method

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and

date.

Note that the above uses the sample record only to record physical m o v e m e n t and location, not analytical results. The reason is that the analytical worksheet and the sample record are usually in two different locations. T h e s a m p l e r e c o r d card s h o u l d be p r e p a r e d and in the c u s t o d y of one p e r s o n until the reserve sample is destroyed. This person is often called the Sample Custodian and in small laboratories could have other duties as well. The job of S a m p l e C u s t o d i a n is c r i t i c a l to the o p e r a t i o n of m o s t l a b o r a t o r i e s . The person employed in this post m u s t be very reliable, but m a y find the duties of the job s l i g h t l y m o n o t o n o u s . C o m b i n i n g the d u t i e s of s a m p l e c u s t o d i a n w i t h k e e p i n g the l a b o r a t o r y s t o r e is o f t e n d o n e in m e d i u m or l a r g e r sized laboratories. The laboratory store of chemicals, glassware and other fittings r e q u i r e s c a r e f u l c o n t r o l as d o e s r e o r d e r i n g of m a t e r i a l s in s h o r t s u p p l y , issuance of supplies to analysts, etc. Combining the jobs of Sample Custodian and S t o r e K e e p e r c a n c r e a t e a c h a l l e n g i n g and i n t e r e s t i n g p o s t . Another approach to the job of Sample Custodian in smaller laboratories is to split the job b e t w e e n several people with different senior assistants under the various section leaders being responsible for samples from a particular source, or for particular groups of products. W h e n a s a m p l e is a s s i g n e d , the a n a l y s t s h o u l d p h y s i c a l l y sign or i n i t a l the s a m p l e c a r d to s h o w c u s t o d y . W h e n a s a m p l e r e s e r v e is r e t u r n e d to the C u s t o d i a n , the C u s t o d i a n w o u l d sign or i n i t i a l . A f t e r a s s i g n i n g the s a m p l e , the S u p e r v i s o r m u s t h a v e s o m e m e a n s of t r a c k i n g s a m p l e s u n d e r a n a l y s i s w i t h proposed or possible completion dates. The sample card could be used for this. The card would then be in the hands of the Supervisor during analysis and would be returned to the Custodian on completion.

4.3

Sample Storage

and

Disposal

S a m p l e s t o r a g e , b o t h i n i t i a l and r e s e r v e , is c r i t i c a l to a s a m p l e a n a l y s i s . Improper storage can completely i n v a l i d a t e a n y a n a l y t i c a l r e s u l t s . Ideally, the s a m p l e is to be s t o r e d in a m a n n e r to p r e v e n t a c h a n g e in the a t t r i b u t e being examined, from the time of sampling, through analysis, and into reserve storage. To i l l u s t r a t e the i m p o r t a n c e of p r o p e r s t o r a g e , if a fresh food sample to be examined for decomposition is not hard frozen until examination, it very likely will decompose even further. The analyst is then not sure how m u c h of the d e c o m p o s i t i o n found is due to sample mishandling. The usual storage areas are dry (room temperature storage), refrigeration and freezing. K e e p in m i n d t h i n g s that c a n h a p p e n d u r i n g s t o r a g e . For e x a m p l e , insects or other vermin can attack dry storage, mould frequently occurs during refrigeration, and frozen products often have "freezer burn" where the food has desiccated. Steps to m i n i m i z e these problems include using correct containers (i.e. glass or m e t a l for dry storage, no paper bags), proper sample preparation (i.e. g l a z i n g f r o z e n s a m p l e s w h e r e p o s s i b l e , to r e d u c e d e h y d r a t i o n ) , and frequent checks on those stored samples which are m o s t subject to change. Sample disposal is, or can be, a relatively simple matter. The only problems arise w h e n there is a hazard involved in the destruction, or where the sample r e m a i n s must have special treatment. An e x a m p l e is a s a m p l e of g r o u n d n u t s heavily contaminated with aflatoxin. The sample itself presents a hazard to the disposer and may be a hazard to others if not detoxified. The analyst best k n o w s any h a z a r d s i n v o l v e d , so s h o u l d i n f o r m the S a m p l e C u s t o d i a n of a n y special disposal requirements.

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4.4

Budget

The need should be appreciated for as flexible a budgetary system as possible. C o n t i n g e n c y funds are i m p o r t a n t for the r u n n i n g of a l a b o r a t o r y . Budgets should be a r r a n g e d so that funds are r e a d i l y a v a i l a b l e for u r g e n t s u p p l i e s , s p a r e s and r e p a i r s and the o t h e r d a y - t o - d a y n e e d s of the l a b o r a t o r y w h i c h cannot wait for the usually slow cycle of fiscal machinery utilized for annual budgets in most governments. The Laboratory Head must have adequate control of the b u d g e t and o p e r a t e it under c l e a r l y d e f i n e d rules. T h e s e should be s u f f i c i e n t l y f l e x i b l e that he or she r e t a i n s d i s c r e t i o n a r y p o w e r s e n a b l i n g t r a n s f e r of funds b e t w e e n c e r t a i n b u d g e t c l a s s e s as o c c a s i o n d e m a n d s . For e x a m p l e , funds for c a p i t a l e q u i p m e n t w i l l u s u a l l y be n o n - t r a n s f e r a b 1 e w h i l e funds in two s e p a r a t e c l a s s e s for c h e m i c a l s and e x p e n d a b l e e q u i p m e n t m a y reasonably be transferred between one another. The b u d g e t p r e p a r a t i o n p r o c e s s should i n v o l v e all l e v e l s of l a b o r a t o r y management from the Supervisors to the Head. Supervisors especially gain an a p p r e c i a t i o n for h o w m o n i e s can or c a n n o t be spent by p r e p a r i n g a b u d g e t increment for their group. B u d g e t s t y p i c a l l y are planned for one y e a r , but should be d i v i d a b l e into quarters, seasons, projects or s o m e o t h e r l o g i c a l d i s t r i b u t i o n f o r m a t . Each Supervisor should have the responsibility (overseen and approved by the Head) for the b u d g e t p u r c h a s e s by h i s group. All o f f - b u d g e t i t e m s m u s t be fully justified. If sufficiently important, an off-budget item may take precedence over the purchase of budgeted material.

4.5

Purchasing

The s e l e c t i o n and s p e c i f i c a t i o n of l a b o r a t o r y e q u i p m e n t t o g e t h e r w i t h the p l a n n i n g of space r e q u i r e m e n t s ( i n c l u d i n g f l e x i b i l i t y for f u t u r e e x p a n s i o n ) should always precede, or at least go hand in hand with, building design. Less industrial countries often lack l a b o r a t o r y s u p p l i e s and e q u i p m e n t , t e c h n i c a l assistance and maintenance services. The limited over-all marketing potential, and the large variety of laboratory and scientific instruments available from foreign suppliers and manufacturers, make it generally uneconomical for local businessmen to establish stocks or to employ qualified service engineers. The p r o b l e m in m a n y c o u n t r i e s is c o m p o u n d e d by f o r e i g n e x c h a n g e and i m p o r t r e s t r i c t i o n s w h i c h o f t e n do not e v e n p e r m i t the c o m m e r c i a l i m p o r t of spare parts. As a result, scientific laboratories in developing countries cannot, or can only to a l i m i t e d e x t e n t , find t e c h n i c a l a s s i s t a n c e locally. They m u s t r e l y on the support and c o o p e r a t i o n of s u p p l i e r s based p e r h a p s t h o u s a n d s of miles away. Several conclusions can be drawn from this situation. One of them is that b e f o r e s e l e c t i n g any e q u i p m e n t , a c a r e f u l study should be m a d e to determine : 1. Which of the many possible suppliers and manufacturers of equipment h a v e local r e p r e s e n t a t i v e s or o f f i c e s c a p a b l e of p r o v i d i n g i n s t a l l a t i o n and maintenance services? 2. W h a t e x p e r i e n c e do p o t e n t i a l s u p p l i e r s h a v e in d e a l i n g special conditions obtaining in less industrialized countries?

with

the

E q u i p m e n t s p e c i f i c a t i o n s m u s t be p r e p a r e d very carefully and clearly. There are countless examples of cases where lack of detail in specifying has led to the p u r c h a s e of i n c o m p l e t e or u n s u i t a b l e a p p a r a t u s . It should be u n d e r s t o o d that s u p p l e m e n t a r y e q u i p m e n t or a c c e s s o r i e s , if not s p e c i f i e d , w i l l not be quoted for in the s u p p l i e r ' s bid. M o s t b r o c h u r e s or c a t a l o g u e s p u b l i s h e d by equipment manufacturers give only general information, without complete order specifications. A s e l e c t i o n based p u r e l y on such l i t e r a t u r e o f t e n leads to misunderstandings. No indication is usually given of essential accessories not

23

included in the basic instrument, of optional accessories with explanations for t h e i r p a r t i c u l a r a p p l i c a t i o n , or o f e s s e n t i a l o p e r a t i n g s u p p l i e s and r e c o m m e n d e d spare parts. S c i e n t i f i c i n s t i t u t i o n s in less i n d u s t r i a l i z e d countries have had the experience that because of insufficient specifications (or lack of e x p e r i e n c e on the part of the s u p p l i e r s ) they w e r e s u p p l i e d w i t h incomplete equipment. W h i l e the s u p p l i e r m a y b e l i e v e that n o n - s p e c i f i e d e q u i p m e n t is a l r e a d y a v a i l a b l e , the s c i e n t i s t in the l a b o r a t o r y m a y be s u f f e r i n g s e r i o u s and annoying delays in putting the equipment into operation. New orders have to be processed, and up to a year may be required to obtain the necessary additional supplies. Most manufacturers restrict their supplies to the parts they produce in t h e i r o w n w o r k s . T h e y a r e u s e d to the s i t u a t i o n w i t h i n t h e i r o w n c o u n t r y w h e r e m i n o r a c c e s s o r i e s such as s t a n d s , c l a m p s , t u b i n g , g l a s s w a r e and e v e n small instruments like pH-meters, balances and thermostats c o m m o n l y found in a laboratory are either available i m m e d i a t e l y or may be obtained quickly from a local dealer. W h e n dealing with less industrialized countries, h o w e v e r , it is frequently wrong to assume that the same situation obtains. Large laboratory supply companies offer a m o r e comprehensive range of supplies than individual manufacturers as their delivery p r o g r a m m e usually includes a full range of instruments and auxiliary equipment. Another advantage offered by the l a r g e c o m p a n i e s is the e c o n o m y g a i n e d by d e a l i n g w i t h o n l y one s o u r c e rather than having to deal with a n u m b e r of individual manufacturers. Service f a c i l i t i e s for i n s t a l l a t i o n and m a i n t e n a n c e of the e q u i p m e n t can also be coordinated and provided m u c h m o r e easily by a large organization. If experts h a v e to be c o m m i s s i o n e d for each i n d i v i d u a l p i e c e of c o m p l e x e q u i p m e n t , the expense b e c o m e s prohibitive. C o m p l e x a p p a r a t u s r e q u i r e s s p e c i a l t r a i n i n g for the o p e r a t o r s . Engineers p e r f o r m i n g the installation usually provide some basic training. Depending on the experience of the scientist who is to work with the equipment, h o w e v e r , a m o r e f a r - r e a c h i n g p r o g r a m m e of t r a i n i n g m a y be n e c e s s a r y , w h i c h c a n n o t be i m p a r t e d by the e n g i n e e r in the field. In such c a s e s , s p e c i a l t r a i n i n g p r o g r a m m e s should be arranged in advance of the purchase, preferably before the equipment is delivered. P r o c u r e m e n t r u l e s d e m a n d , a l m o s t e v e r y w h e r e , that the c h e a p e s t o f f e r s be accepted. Applied to the purchase of scientific e q u i p m e n t , strict observation of such r u l e s m a y turn out to be a v e r y e x p e n s i v e w a y of e q u i p p i n g a laboratory. Precise specifications are a good m e a n s of obtaining correct and reliable offers. O n l y such o f f e r s a l l o w a just c o m p a r i s o n of the s c o p e of d e l i v e r y and the p r i c e s of d i f f e r e n t b i d d e r s . In o r d e r to o b t a i n a n u n d i s t o r t e d p i c t u r e of c o m p a r a t i v e d a t a , o n l y t e c h n i c a l l y e x p e r i e n c e d and c o m m e r c i a l l y capable manufacturers and suppliers should be invited to submit offers. Only a limited number of firms that can satisfy every requirement as to q u a l i t y , e x p e r i e n c e in h a n d l i n g c o m p r e h e n s i v e s u p p l i e s , r e l i a b i l i t y in c o n n e c t i o n w i t h d e l i v e r y s c h e d u l e s , t e c h n i c a l a s s i s t a n c e and m a i n t e n a n c e s e r v i c e s h o u l d be i n v i t e d to t e n d e r . T h i s m a y e v e n lead to i n d i v i d u a l f i r m s being selected as suppliers for entire laboratory equipment lots or specialized instruments on a proprietary or s ingle-tender basis. I n v i t a t i o n s to bid s h o u l d a l w a y s g i v e c l e a r i n d i c a t i o n s of the c u r r e n c y and t e r m s in w h i c h o f f e r s are to be s u b m i t t e d ; if i n d i v i d u a l p r i c e s a r e to be q u o t e d e x - w o r k s , f.o.b. port of s h i p m e n t , c & f. or c.i.f. p o r t of d e s t i n a t i o n ; if s h i p m e n t is d e s i r e d b y air or sea; and w h e t h e r or n o t the c o s t of p a c k i n g should be included. It is worth pointing out that North A m e r i c a n firms have a d i f f e r e n t i n t e r p r e t a t i o n of the t e r m "f.o.b." (free on b o a r d s h i p ) f r o m European suppliers. The latter observe the internationally accepted definition of the t e r m , a c c o r d i n g to w h i c h f.o.b. p r i c e s i n c l u d e c o s t and all c h a r g e s of delivery including packing, up to "on board ship" in the seaport or airport of shipment. In the U n i t e d S t a t e s of A m e r i c a , h o w e v e r , "f.o.b." is n o r m a l l y u n d e r s t o o d as f.o.b. f a c t o r y , and p r i c e s do not i n c l u d e p a c k i n g , inland

24

f r e i g h t , l o a d i n g c h a r g e s , d o c u m e n t a t i o n or e x p o r t h a n d l i n g , all of w h i c h are charged separately. The term f.a.s. is used to denote "free alongside ship". If a b i d d e r d e v i a t e s from the t e r m s laid d o w n in the t e n d e r i n v i t a t i o n , h i s o f f e r s h o u l d be c a r e f u l l y e x a m i n e d as it m a y h a v e b e e n i n t e n d e d to o b t a i n a superficial advantage in price comparison only. A careful technical scrutiny of the s p e c i f i c a t i o n s g i v e n in a b i d d e r ' s o f f e r and a c o m p a r i s o n w i t h the i l l u s t r a t e d l i t e r a t u r e a t t a c h e d to the bid w i l l , in m a n y c a s e s , e l i m i n a t e q u o t a t i o n s w h i c h at f i r s t g l a n c e look c h e a p e r . Accessories may have been p u r p o s e l y left out to g a i n an a d v a n t a g e over o t h e r b i d d e r s . Sometimes minor b u t i m p o r t a n t d i f f e r e n c e s in p e r f o r m a n c e d a t a c a u s e c o n s i d e r a b l e price variations. M a n y n a t i o n a l and i n t e r n a t i o n a l o r g a n i z a t i o n s i n v i t e o f f e r s from o r i g i n a l manufacturers only, demand ing that the c o m m i s s ion usually allowed to agents be offered as a discount. The disadvantages of this procedure are that orders are quite frequently placed w i t h firms which readily accept these conditions but which have neither experience nor agents in the purchasing country. Thus, the scientists in less industrali zed countries are denied the benefit of any kind of t e c h n i c a l a s s i s t a n c e . W h e n c o m p a r i n g p r i c e q u o t a t i o n s , the o f f e r of an i n t e r n a t i o n a l l a b o r a t o r y e q u i p m e n t s u p p l i e r m a y o c c a s i o n a l l y be found to b e substantially higher than that of a manufacturer. In such cases it can only be r e c o m m e n d e d t h a t the e x p e r i e n c e and a f t e r - s a l e s s e r v i c e i n c o r p o r a t e d in the offer should be carefully considered. One aspect of equipment purchase that causes problems is the time given for the s u b m i s s i o n of o f f e r s . O f t e n it is far too s h o r t . It s h o u l d be r e a l i z e d t h a t long lists of specifications prepared for a project over an extended period of time cannot normally be quoted for in a space of only two or three weeks - the t i m e that m i g h t be left to a s u p p l i e r a f t e r d e l a y s in m a i l are t a k e n into account. The q u a l i t y of o f f e r s m i g h t be c o n s i d e r a b l y i m p r o v e d if m o r e t i m e were allowed. D e c i s i o n s on bid a c c e p t a n c e s h o u l d n o t be d e l a y e d b e y o n d the n o r m a l validity of offers. Another serious problem that is often encountered concerns damage in transit Extensive d a m a g e and even total loss and the insurance covering such damage. can result from the rough handling of consignments in ports where no mechanized m e a n s of t r a n s p o r t (such as f o r k - l i f t t r u c k s ) is a v a i l a b l e . D e l a y s m a y be e n c o u n t e r e d in c l e a r i n g c o n s i g n m e n t s t h r o u g h c u s t o m s , and s h e l t e r e d s t o r a g e facilities are often quite inadequate. Cases containing expensive equipment m a y be s u b j e c t e d to the m o s t a d v e r s e c l i m a t i c c o n d i t i o n s - h u m i d i t y , h e a v y tropical rains, extreme heat and dust. No economically justifiable method of p a c k i n g can p r e v e n t d a m a g e to e q u i p m e n t u n d e r such c o n d i t i o n s . Sometimes, b e c a u s e of c u s t o m s f o r m a l i t i e s and a d m i n i s t r a t i v e d e l a y s in h a v i n g the consignments unpacked and examined, insurance coverage has already expired by the t i m e the e q u i p m e n t a r r i v e s at its d e s t i n a t i o n and a c l a i m can be l o d g e d . T h e n , m o r e t i m e and e f f o r t is u s u a l l y s p e n t on f i x i n g r e s p o n s i b i l i t y than on how the situation might be avoided in the future. Replacement parts required to repair transport damage should be obtainable with a m i n i m u m of delay and administrative red tape. Laboratories should have the authority, in an emergency, to place small orders direct with suppliers. With or without such emergency order facilities, h o w e v e r , scientists usually depend on (and prefer cooperation with) the experienced and flexible supplier who is in regular contact w i t h his customer, who extends unbureaucratic help and who even provides, when necessary, free replacements and repair facilities in order to c o n t r i b u t e to the p r i m e o b j e c t i v e in the e s t a b l i s h m e n t of a s c i e n t i f i c institute, useful and effective work and uninterrupted operation.

25

4.6

Supplies

Management

Supplies routinely used by a laboratory include solvents, reagents, chemicals, g l a s s w a r e and o t h e r a n a l y t i c a l m a t e r i a l s . By d e f i n i t i o n , s u p p l i e s are considered to be consumables and must be constantly replaced as used. T h e r e m u s t t h e r e f o r e b e an a c c u r a t e a c c o u n t i n g s y s t e m to r e c o r d r e c e i p t , u s e and f u t u r e n e e d . T h i s is d o n e in a v a r i e t y of w a y s but a card s y s t e m is the m o s t versatile. The Supplies Record Card can contain such data as:

Name of product Date purchased Where purchased Amount (including units if more than one Expiration date (if any) Special storage requirements (if any) Amount dispensed.

container)

S m a l l m e t a l t a g s p a i n t e d w i t h b r i g h t c o l o u r s can be p u r c h a s e d and d i f f e r e n t tags affixed to cards for flagging purposes. For e x a m p l e , a red tag m a y m e a n the supply is low and should be reordered within a given time. Having a w o r k a b l e supplies m a n a g e m e n t s y s t e m t e n d s to p r e v e n t c i r c u m s t a n c e s w h e r e a n a l y s e s h a v e s t o p p e d b e c a u s e a c r i t i c a l m a t e r i a l is s u d d e n l y u s e d up. L i k e b u d g e t i n g , it is a p r o c e s s of m a i n t a i n i n g c o n t r o l of a c r i t i c a l a r e a to promote overall smooth operation of the laboratory.

4.7

Equipment

Maintenance

W h e n the food analyst goes beyond organoleptic examinations, he or she must use s o m e i t e m of e q u i p m e n t to p r o c e s s or to m e a s u r e the s a m p l e a t t r i b u t e of interest. It is critically important, therefore, that all items of equipment be properly and promptly maintained, and repaired when needed. T h e d e g r e e of s o p h i s t i c a t i o n of e q u i p m e n t v a r i e s d r a m a t i c a l l y from a straightforward pH m e t e r to a complex spectrophotometer. M a n y laboratories in developing countries have great difficulty in o b t a i n i n g r e p a i r of any e q u i p m e n t , sophisticated or otherwise. It is therefore reasonable to require that proper maintenance of the equipment be routinely scheduled and completed, hopefully to delay the day when outright repairs are necessary. T h e b e s t c i r c u m s t a n c e , of c o u r s e , is to e s t a b l i s h an o p e r a t i n g r e p a i r and m a i n t e n a n c e w o r k s h o p w i t h qualified technical staff. This can be essential for l a r g e i n s t i t u t e s h a v i n g a d i s p r o p o r t i o n a t e l y l a r g e i n v e s t m e n t in e x p e n s i v e equipment. E v e n in the a b s e n c e of an o r g a n i z e d w o r k s h o p , s o m e a n a l y s t s or technicians can be given training in repair and maintenance techniques, often by local instrument suppliers. If adequate service is available locally, serious consideration should be given to purchase of service contracts. The usual service contract involves checking the e q u i p m e n t at s p e c i f i e d i n t e r v a l s and p e r f o r m i n g n e c e s s a r y m a i n t e n a n c e . E m e r g e n c y r e p a i r s are u s u a l l y d i s c o u n t e d in p r i c e b e c a u s e of the s e r v i c e contract. Service contracts are especially important for analytical balances, to m a i n t a i n proper calibration. A history of an instrument's maintenance and repair can become very important. It p r o v i d e s a s u m m a r y of the i n s t r u m e n t ' s o p e r a t i o n o v e r a g i v e n p e r i o d , b u t m o r e i m p o r t a n t l y , it can p r o v i d e a j u s t i f i c a t i o n for r e p l a c e m e n t of old and o u t w o r n items. Recording the cost is important as it is then readily apparent

26

w h e n an i n s t r u m e n t c o s t s m o r e to k e e p o p e r a t i n g t h a n it is w o r t h . A preprinted 5 x 8 c a r d c a n c o n v e n i e n t l y b e u s e d to r e c o r d s u c h i n f o r m a t i o n . An e x a m p l e of s u c h a c a r d ( f r o n t a n d r e a r ) is s h o w n in F i g u r e s 4.1 a n d 4 . 2 .

T y p e of Machin*

MACHINE PART I -

DETAILS

OF

HISTORY

CARD

MACHINE

B r a n d a n d Modal N o .

Vendor

L o c a t i o n of m a c h i n e (State dept./scction)

H o w o p e r a t e d ( T i c k in appropriate b o x )

Machine N o .

C o u n t r y of Manufacture

Data of P u r c h a i e

Purchase Price

Guarantee P e r i o d

T e r m s of Guarantee

•

P A R T II -

Manual

•Etactrk

•

Electronic

DETAILS OF MAINTENANCE Service A g e n t

Per lOd

Maintenance C o n t r a c t

Name

From

Cott ($) (per a n n u m )

To

Spare parts included? Yes

No

N u m b e r of

C o m m e n t » o n f i r m ' » service

(per a n n u m )

Figure 4.1 Front Side

F A R T HI -

OF

BREAKDOWNS S e r v i c i n g / R e o a i r details (State cause of b r e a k d o w n a n d parts c h a n g e d , etc!

Date

P A R T IV

OETAILS

-

COMMON D E F E C T S

I d n c n b * with d . u i l i

pm

Response time of Service A g e n t

f r « * j . n ç y . cHactsl

Figure 4.2 Rear Side

27

Cumulative Cost

C o s t of Repair

Time taken to repair

S

4

S

4

4.8

Housekeeping

L a b o r a t o r y c l e a n l i n e s s is very i m p o r t a n t , not only to m a i n t a i n a good appearance, but to p r e v e n t s o m e f o r m s of c o n t a m i n a t i o n . Housekeeping a c t i v i t i e s go beyond c l e a n i n g and tidying in the l a b o r a t o r y . It i n c l u d e s i n s e c t and o t h e r pest c o n t r o l . M o s t l a b o r a t o r i e s m u s t do their o w n pest control to minimize contamination from control agents. Commercial pest control firms usually do not have an appreciation of laboratory contamination problems. L a b o r a t o r i e s m u s t be r o d e n t - p r o o f in c o n s t r u c t i o n . E l e c t r i c a l d e v i c e s are available for killing flying insects. Food may arrive contaminated with insect eggs so that proper storage is inadequate without fumigation. Fumigation by halogenated hydrocarbons or use of organochlorine compounds against insects are l i k e l y s o u r c e s of l a b o r a t o r y c o n t a m i n a t i o n and are best a v o i d e d w h e n e v e r possible. T h e y all h a v e a s i g n i f i c a n t v a p o u r p r e s s u r e and m u s t be kept w e l l a w a y from s e n s i t i v e e q u i p m e n t such as gas c h r o m a t o g r a p h s and from s a m p l e s requiring analysis for pesticide residues. H o u s e k e e p i n g should involve s c h e d u l e d as w e l l as ad hoc c l e a n i n g and pest control. O f t e n a good t i m e is the last h o u r of a w o r k w e e k . A scheduled activity quickly becomes routine and is consequently in the awareness of the laboratory analysts. This awareness is important because, as can be shown by e x p e r i e n c e , not all p e r s o n s are n e a t , c l e a n and tidy in their e v e r y d a y activities. M a n a g e m e n t m u s t d e m o n s t r a t e a c o n t i n u i n g c o m m i t m e n t to good housekeeping principles if the analysts are to accept those principles.

4.9

Training

W h e n an a n a l y s t is first hired in a food c o n t r o l l a b o r a t o r y , a c o n t i n u i n g s e r i e s of t r a i n i n g and e d u c a t i o n a l e x p e r i e n c e s b e g i n . The n e w a n a l y s t is t a u g h t , u s u a l l y on the job, the v a r i e d a n a l y s e s and m e t h o d s used by the laboratory. Most often this is by what amounts to an apprenticeship approach where the new analyst is assigned to work with a senior. It is best, however, to have a formal, structured training programme designed to acquaint the new analyst with the work in a logical sequence. Otherwise the training becomes haphazard with the training sequence dependent on incoming work. O n c e past the f o r m a l initial t r a i n i n g , the a n a l y s t s t a r t s a c o n t i n u i n g knowledge updating process. Food analysis is a rapidly changing subject and it is i m p o r t a n t that a n a l y s t s attend s y m p o s i a , r e f r e s h e r c o u r s e s and other educational programmes in order to keep up to date. In developing countries it may be necessary to schedule travel to other areas from time to time for such t r a i n i n g . T h i s e f f o r t is e n h a n c e d if the l a b o r a t o r y is a b l e to s u b s c r i b e to the more active research journals in food analysis. The analysts are then able to keep abreast of new advances, especially newer analytical methods. Should an a n a l y s t s h o w i n t e r e s t and a p t i t u d e for s u p e r v i s i o n , then he or she s h o u l d be g i v e n f o r m a l c l a s s r o o m t r a i n i n g in s u p e r v i s o r y p r i n c i p l e s . This w o u l d be in a d d i t i o n to o n - t h e - j o b e x p e r i e n c e under the t u t e l a g e of a supervisor or the Head. It is important that the classroom instruction be done because it is here that the analyst learns supervision and management theory and techniques other than those used by his laboratory. On-the-job experience as an acting supervisor is necessary but tends to be one dimensional because it teaches only the systems and techniques used by that laboratory.

28

5.

5.1

LABORATORY

OPERATIONS

Workplans

T h e a n n u a l w o r k p l a n is the c o r n e r s t o n e to m a n a g i n g a food c o n t r o l l a b o r a t o r y . It p r o v i d e s a m e a n s of e s t i m a t i n g s t a f f a n d r e s o u r c e s n e c e s s a r y to do a f i x e d n u m b e r of a n a l y s e s . C o n v e r s e l y , g i v e n a f i x e d s t a f f , the w o r k p l a n can e s t i m a t e h o w m u c h w o r k can be d o n e . W o r k p l a n d a t a is a l w a y s o n l y an e s t i m a t e , a l t h o u g h its a c c u r a c y o f t e n w i t h u s e d u e t o r e f i n i n g o f t i m e m o d u l e s u s e d in c a l c u l a t i o n s . i m p o r t a n t t i m e m o d u l e s in w o r k p l a n n i n g are:

improves The two

1. T h e a n a l y s t p r o d u c t i v e y e a r : T h i s is t h a t t o t a l t i m e i n a n a v e r a g e year that one a n a l y s t s p e n d s doing o n l y s a m p l e a n a l y s i s . Time spent during w o r k h o u r s d o i n g o t h e r t h i n g s is d e d u c t e d . A n e x a m p l e of t h e d e t e r m i n a t i o n of t h i s m o d u l e is as f o l l o w s :

Total

time a v a i l a b l e

(based

on 4 0 h o u r w o r k

week)

2080 hr s

Time deductions N a t i o n a l and l o c a l h o l i d a y s Illness P e r s o n a l leave time Training A d m i n i s t r a t i v e time Other n o n - a n a l y s i s time Total time d e d u c t i o n s Total analysis

time

(2080 -

80 40 80 200 80 400 880

hr s hrs hr s hrs hrs hrs hrs

1200 hrs

880)

T h i s m e a n s ( b a s e d on the a b o v e e x a m p l e ) that for n a n a l y s t s , the e x p e c t n x 1 2 0 0 h o u r s of p r o d u c t i v e w o r k d u r i n g t h e y e a r .

laboratory

can

T h e a b o v e t i m e d e d u c t i o n f i g u r e s w e r e t a k e n for e x a m p l e p u r p o s e s o n l y . Each i n d i v i d u a l l a b o r a t o r y w i l l be d i f f e r e n t . In d e t e r m i n i n g d e d u c t i o n s , c o n s i d e r the f o l l o w i n g : a.

Holiday

time

is u s u a l l y

fixed

b.

I l l n e s s and p e r s o n a l t i m e a v e r a g e s can be t a k e n f r o m staff The a d m i n i s t r a t i v e r e c o r d s f o r t h e p r e c e e d i n g o n e or t w o y e a r s . a v e r a g e of the p r e v i o u s y e a r is b e s t u s e d as the m o d u l e . T h e r e a s o n is that the s t a f f u s u a l l y h a v e m o r e p e r s o n a l t i m e m a d e a v a i l a b l e to t h e m as t h e i r s e n i o r i t y i n c r e a s e s .

c.

M a n a g e m e n t m u s t d e c i d e h o w m u c h t i m e w i l l be set a s i d e e a c h y e a r for t r a i n i n g . N o t e in the e x a m p l e t h a t t r a i n i n g t i m e is a b o u t 10% of the t o t a l . If the s t a f f is r e l a t i v e l y y o u n g and i n e x p e r i e n c e d , m o r e t i m e w i l l be r e q u i r e d . C o n v e r s e l y an a l l - s e n i o r s t a f f m a y r e q u i r e l e s s .

d.

A d m i n i s t r a t i v e t i m e is d i f f i c u l t to e s t i m a t e as t h e r e are u s u a l l y few or no r e c o r d s to go b y . It i n c l u d e s t i m e a s a c t i n g supervisor, general library reading, and o t h e r a s s i g n e d or incidental administrative activities.

e.

O t h e r n o n - a n a l y s i s t i m e is also o n l y an e s t i m a t e , a l t h o u g h s o m e t i m e r e c o r d s m a y be a v a i l a b l e . It i n c l u d e s g e n e r a l r e s e a r c h o r m e t h o d development activities, quality assurance work, equipment m a i n t e n a n c e , t i m e s p e n t s e r v i n g as a t r a i n e r , a n d a n y o t h e r n o n a n a l y s i s w o r k time not included e l s e w h e r e .

29

by government

policy.

2. T h e a n a l y t i c a l h o u r s r e q u i r e d per s a a p l e : The f i r s t step is to d e f i n e w h a t is i n c l u d e d in a s a m p l e a n a l y s i s , as t h i s o b v i o u s l y a f f e c t s the total time. Activities which are suggested to be included are: a.

Sample receipt and

preparation.

b.

Analysis.

c.

M e t h o d d e v e l o p m e n t or p r o b l e m s o l v i n g r e q u i r e d of a g i v e n s a m p l e . (As o p p o s e d to g e n e r a l d e v e l o p m e n t or r e s e a r c h , w h i c h w o u l d b e included in non-analysis time.)

d.

S t a n d a r d i z a t i o n a c t i v i t i e s r e l a t e d to a g i v e n s a m p l e . standard solutions and curves for example.)

e.

Preparation

of analytical

report and

(Preparing

calculations.

The next step is to prepare a list of all the different analyses conducted and e s t i m a t e individual analytical times based on experience. If some analyses are d o n e b y t e a m s in a p r o d u c t i o n - 1 i n e a r r a n g e m e n t , e s t i m a t e the t o t a l t i m e required by totalling the time and correcting to an individual analyst basis. For e x a m p l e , if 4 analysts working as a team can produce 32 completed samples in an 8 h o u r p e r i o d , t h e n t h e a v e r a g e a b s o l u t e s a m p l e t i m e is 0.25 hours/analysis. H o w e v e r , it required 4 analysts and to correct the time to an i n d i v i d u a l a n a l y s t b a s i s - 4 x 0.25 = 1.0 h o u r s / ana 1 ys i s . T h i s w o u l d be the figure used in calculations. *

The laboratory is now able to make good estimates on what and h o w m u c h work can be d o n e . It is a s i m p l e m a t t e r of m u l t i p l y i n g the n u m b e r s of a n a l y s t s a v a i l a b l e d u r i n g the y e a r t i m e s the p r o d u c t i v e y e a r t i m e m o d u l e to g a i n the total analytical hours available. This can then be spread among the types of a n a l y s e s to be d o n e , u s i n g the h o u r s / a n a l y s i s m o d u l e s . A l t h o u g h m a n y of the m o d u l e s are e s t i m a t e s , it is still a better and m o r e accurate w a y to d e t e r m i n e w h a t can be d o n e , than r e l y i n g on m e m o r y and s h e e r g u e s s e s . ( R e g a r d i n g the n u m b e r s of a n a l y s t s a v a i l a b l e d u r i n g the y e a r , k e e p in m i n d t h a t t h i s m a y change by new hires or projected losses, so include these future projections in the annual estimate). T h e a b o v e c a l c u l a t i o n m e c h a n i c s of a w o r k p l a n do not a d d r e s s the m e a n s of d e c i d i n g the a n n u a l w o r k p r i o r i t i e s . T h i s is u s u a l l y d o n e in p a r t b y organizational policy and in part by m e e t i n g s of senior operational managers, s u c h as the L a b o r a t o r y and I n s p e c t o r a t e H e a d s . All p l a n n e d w o r k and t i m e modules depend on proper work scheduling and flow. If samples are collected too fast or too slow, the laboratory efficiency suffers. There m u s t therefore be an extremely close working relationship and liaison b e t w e e n the inspectorate and l a b o r a t o r y . No work plan would be complete without some form of contingency planning. The o l d a d a g e s t a t e s t h a t , "... If s o m e t h i n g c a n go w r o n g , it w i l l ...". T h e r e f o r e , t h e r e s h o u l d be at least a p r o v i s i o n in a a n n u a l w o r k p l a n for e m e r g e n c i e s or u n e x p e c t e d p r o b l e m s . A m a j o r p u b l i c h e a l t h d i s a s t e r , for e x a m p l e , could require an all-out laboratory effort, negating workplan work for some period of time. The contingency plan would simply and clearly state w h a t t y p e s of a n a l y s e s ( u s u a l l y the l o w e s t p r i o r i t y ) w o u l d be e l i m i n a t e d in the event of an emergency.

30

5.2

Priorities

for

General analytical laboratory policy.

Analysis

priorities are usually s o m e w h a t fixed by organizational H o w e v e r , a suggested priority structure would be:

Priority 1

Poisonings or public health

Priority 2

K n o w n or resulting

Priority 3

Informational

injury complaints analyses.

s u s p e c t e d law or in direct injury. surveys

and

health

other

emergency

violations,

and other routine

or

not

work.

M o s t of the w o r k of a l a b o r a t o r y is u s u a l l y in the t h i r d p r i o r i t y c a t e g o r y , with a smattering of priority two and only infrequently, priority one. W i t h i n a g i v e n p r i o r i t y , the w o r k c a n be s u b - g r o u p e d by r e l a t i v e i m p o r t a n c e . It is conceivable that work of very low importance never gets done because of the continuing press of higher priority analyses. If it appears that such is the c a s e , the s u p e r v i s o r m u s t a d v i s e the H e a d of the p r o b l e m s and s u g g e s t r e v i s i o n of the p l a n n e d w o r k load for the s u p e r v i s o r ' s g r o u p . The w o r k p l a n s discussed in the previous Section often undergo mid-year or periodic revision based on such happenings.

5.3

Analysis

Assignaient

A s s u m i n g the p r i o r i t y nas b e e n p r e v i o u s l y a s s i g n e d , the a n a l y s i s a s s i g n m e n t includes two key considerations, n a m e l y w h a t is to be done and what analytical method to use. T h e a n a l y s i s to be c a r r i e d out on a s a m p l e m a y be p r e d e t e r m i n e d as p a r t of a planned sampling p r o g r a m m e or by legal requirements. Experience gained by the analyst may enable him to have firm views on the tests to be done. The purpose of the a n a l y s i s m u s t be b o r n e c l e a r l y in m i n d , e.g. for e x p o r t c e r t i f i c a t i o n , the t e s t s r e q u i r e d by the i m p o r t i n g c o u n t r y m u s t be c a r r i e d o u t , for e x c i s e purposes, the constituent that fixes the duty payable and so on. When samples are examined under the general and specific provisions of laws pertaining to consumer protection and food quality, the analysis m u s t be designed to answer certain questions such as: Does the food meet established m i n i m u m quality and safety standards? Is it of the quality, substance and nature demanded by the purchaser? Is it correctly labelled? Are any claims on the label justifiable and l e g a l ? D o e s it c o n t a i n n o n - p e r m i t t e d a d d i t i v e s or p e r m i t t e d o n e s in excess? Are any contaminants present at unacceptable levels? R o u t i n e t e s t s on the p h y s i c a l c h a r a c t e r i s t i c s of m o s t c o m m o n food s a m p l e s should be carried out. Less frequently, tests may be made for preservatives, prohibited colours and other a d u l t e r a n t s . T h e a d u l t e r a n t s , c o n t a m i n a n t s and compositional deficiencies looked for should be changed from time to time to show if previously unsuspected infringements are present. The analyst m u s t be aware of the problems facing manufacturers and of developments in technology and choose non-routine tests in the light of this information. In this way the r e g u l a t o r y a n a l y s t acts as a s u p p o r t to the l e g i t i m a t e m a n u f a c t u r e r w h i l e protecting the consumer. The analyst must establish that he can obtain reliable results with the method used. G e n e r a l l y , it is p r e f e r a b l e to use a m e t h o d t h a t h a s b e e n s u b j e c t e d to collaborative study. If the analyst has difficulty with such a method it is likely to be due to a deficiency in training or in facilities, rather than the method itself. Sometimes it is d u e to p o o r e x p r e s s i o n of t h e e x a c t

31

e x p e r i m e n t a l d e t a i l s in the m e t h o d as published. R e f e r e n c e to the source w i l l usually resolve such difficulty. It is n o t a l w a y s n e c e s s a r y to u s e a collaborated method. H o w e v e r , s u c h m e t h o d s s h o u l d be f i r s t c h o i c e if the p a r a m e t e r is b e i n g d e t e r m i n e d in t h e l a b o r a t o r y f o r t h e f i r s t t i m e or if a p r o d u c t has not been a n a l y z e d p r e v i o u s l y . It is i m p o r t a n t to f o l l o w the p r o c e d u r e s ior v a l i d a t i n g a m e t h o d . M a n y o t h e r m e t h o d s m a y be e q u a l l y g o o d , but m a y not, for v a r i o u s reasons, have been subjected to c o l l a b o r a t i v e studies or r u g g e d n e s s t e s t s . As a r e s u l t the a n a l y s t m a y run into unexpected d i f f i c u l t i e s if he h a s to t a k e the m e t h o d d i r e c t l y f r o m a b o o k . If a m e t h o d has b e e n in use and found to give r e l i a b l e results it should not be changed for another until the n e w m e t h o d has been s h o w n to be of e q u a l or b e t t e r r e l i a b i l i t y in that p a r t i c u l a r l a b o r a t o r y ( i r r e s p e c t i v e o f i t s c o l l a b o r a t i v e status). C o n s i d e r a b l e stress is quite r i g h t l y put on c o l l a b o r a t i v e testing at the p r e s e n t t i m e , but it should not be f o r g o t t e n that a r e l i a b l e m e t h o d is only a p r e c o n d i t i o n to o b t a i n i n g the r i g h t a n s w e r . T h e a b i l i t y of the a n a l y s t to use the m e t h o d is the e s s e n t i a l r e q u i r e m e n t and the p e r s o n t a k i n g the r e s p o n s i b i l i t y for the result, w h e t h e r the analyst h i m s e l f or the s u p e r v i s o r , m u s t be c o n f i d e n t of this.

5.4

Analysis

Control

C o n t r o l is a v e r y i m p o r t a n t s u p e r v i s o r y f u n c t i o n . It is n o t s u f f i c i e n t to s i m p l y a s s i g n w o r k and w a i t for r e s u l t s . T h e r e m u s t be s o m e type of a c t i v e control in the form of expected c o m p l e t i o n datas, f o l l o w - u p i n q u i r i e s , or other i n d i c a t i o n s of active interest. This does not m e a n p e e r i n g over the a n a l y s t ' s s h o u l d e r , but it does m e a n that the s u p e r v i s o r has c e r t a i n fixed e x p e c t a t i o n s on w o r k c o m p l e t i o n and e n f o r c e s those e x p e c t a t i o n s . T h e r e are several m e t h o d s of control but one of the m o r e e f f e c t i v e is also one of the s i m p l e s t . The s u p e r v i s o r p r e p a r e s a card for each a n a l y s t . When a s a m p l e is a s s i g n e d to the a n a l y s t , the s a m p l e n u m b e r is r e c o r d e d on the c a r d along w i t h a p r o j e c t e d date of c o m p l e t i o n . W h e n an a n a l y s i s report is r e c e i v e d the entry is lined through. W h e n a'card has been filled, it is discarded and a n e w one p r e p a r e d . The p r o j e c t e d c o m p l e t i o n d a t e r e p r e s e n t s t h e s u p e r v i s o r ' s e s t i m a t e of an a c c e p t a b l e analysis t i m e , a s s u m i n g no p r o b l e m s . The s u p e r v i s o r s c a n s t h e c a r d s of a l l a n a l y s t s e v e r y d a y or so a n d if a d a t e h a s e x p i r e d b u t no report r e c e i v e d , the supervisor inquires of the s a m p l e status. The analyst m a y be h a v i n g d i f f i c u l t y a n d h a d n o t m e n t i o n e d it. A f t e r d i s c u s s i o n , the s u p e r v i s o r d e c i d e s if a n a l y s i s s h o u l d c o n t i n u e and if so, a s s i g n s a n e w projected c o m p l e t i o n date. The s u p e r v i s o r m u s t also a s s i g n n e w dates w h e n ongoing w o r k m u s t be interrupted by a s s i g n m e n t of h i g h e r p r i o r i t y analyses.

5.5

Analysis

Reporting

A n a l y s i s r e p o r t s are the end p r o d u c t of all of the w o r k of the l a b o r a t o r y and t h e r e f o r e m u s t be b o t h c o m p l e t e a n d a c c u r a t e . R e s u l t s of a n a l y s i s are o f t e n i m p o r t a n t facts in legal p r o c e e d i n g s . The w a y in w h i c h the technical results p r o d u c e d by the l a b o r a t o r y reach the court is d i f f e r e n t u n d e r d i f f e r e n t legal codes. O n e e x t r e m e is the U.K. w h e r e a c e r t i f i c a t e of a n a l y s i s is a l e g a l l y v a l i d d o c u m e n t w h i c h m a y b e a c c e p t e d as p r i m a f a c i e e v i d e n c e o f t h e f a c t s stated therein. Under R o m a n law, the l a b o r a t o r y report is a technical but not l e g a l d o c u m e n t w h i c h the c o u r t is e m p o w e r e d to a c c e p t or r e j e c t . In t h e U.S.A., f e d e r a l a c t i o n is u s u a l l y i n i t i a t e d by a d o c u m e n t o r i g i n a t i n g in the J u s t i c e D e p a r t m e n t on the basis of i n f o r m a t i o n from a t e c h n i c a l source. Under both R o m a n law and in the U.S.A., all prepared laboratory and technical records r e l e v a n t to t h e s a m p l e m a y h a v e to be p r o d u c e d in c o u r t and t h e s a m p l e r and analyst cross-examined. T h i s o c c u r s l e s s f r e q u e n t l y u n d e r U.K. l a w w h e r e c r o s s - e x a m i n a t i o n of the expert w i t n e s s is u s u a l l y all that is done, a l t h o u g h if he did refer to original notes or c a l c u l a t i o n s they w o u l d b e c o m e a v a i l a b l e to the c o u r t as in the U.S.A. T h u s , it is m a i n l y u n d e r l e g a l c o d e s d e r i v e d

32

from Roman and c o m m o n law that the report or certificate of the analyst assumes greater importance. U n d e r b o t h R o m a n and U.S.A. l a w the e n t i r e l a b o r a t o r y records relating to the sample must be capable of wi ths tand ing the scrutiny of the c o u r t and d e f e n s e l a w y e r s . The p r a c t i c a l e f f e c t of t h e s e d i f f e r e n c e s is not great. Under any system it is necessary for the regulatory chemist to have legally impeccable laboratory data records and to report against samples in a w a y that is u n d e r s t a n d a b l e to the l a y m a n , b r i e f , s u c c i n c t , and free from irrelevancy. T h e f o r m a t of an a n a l y s i s r e p o r t is d i c t a t e d by the a d m i n i s t r a t i v e and legal needs of the organization. The report form should be preprinted with blocks or l i n e s of i n f o r m a t i o n p l a c e d in d e s i g n a t e d a r e a s on the f o r m . This p e r m i t s faster and m o r e uniform write-up, as well as easier final review (the reviewer knows where to look on the form for different information). A complete report form would have spaces for the following information:

Sample number Product name Product description and amount Date received for analysis Labelling (if any) Analysis method used Analysis results Reserve product amount Date completed Total analysis time in hours (if needed

for time

modules).

Raw work data and standardization information can be placed on the reverse side of the analysis report or can be kept separately in notebooks. In any case it s h o u l d be a c c e s s i b l e to the r e v i e w e r in the e v e n t of q u e s t i o n . It is b e s t to include all raw data so that the entire sequence of work can be reconstructed later if needed. Calculations m u s t be clear w i t h all equations stated. There is no w a y to d e t e r m i n e if a c a l c u l a t i o n is c o r r e c t w i t h o u t c h e c k i n g the T h i s , of c o u r s e , m e a n s c a l c u l a t i o n s y s t e m u s e d , as w e l l as the a r i t h m e t i c . that all dilutions or other operations affecting the final calculation must be clearly stated in the raw data. R e s u l t s m u s t a l w a y s be r e p o r t e d o n l y to a n u m b e r of s i g n i f i c a n t figures j u s t i f i e d by the a c c u r a c y and p r e c i s i o n of the m e t h o d . In g e n e r a l , it is p r u d e n t to r e p o r t to as few s i g n i f i c a n t f i g u r e s as p o s s i b l e c o n s o n a n t w i t h stating the facts the report has to convey. For e x a m p l e , for most purposes it m a y be a d e q u a t e to r e p o r t a s a m p l e as c o n t a i n i n g "not less ( m o r e ) than 70 percent of y". The report m u s t be clear and confined to factual information, and statements which cannot be substantiated must not be made.

5.6

Analysis

Review

T h e a n a l y s t should not d r a w c o n c l u s i o n s from the w o r k r e p o r t e d . T h i s is r i g h t f u l l y the job of the s u p e r v i s o r , w h o is n o r m a l l y the a n a l y s i s r e p o r t reviewer. The reviewer should ask himself a number of questions while reading the report. Any negative answers should be clarified by the analyst before the report is accepted. Some possible questions are: Is the report generally complete? (Any missing required information?) Are the product descriptions adequate? Was the correct method used? Has sufficient work been done to draw a conclusion? Have the proper standards and reagents been used? Is there a blank? Are the calculations easy to follow and accurate? Are any strike-outs or discarded data explained?

33

5.7

Method

Validation

As discussed e l s e w h e r e , it is correct and proper to use collaboratively studied methods w h e r e possible. Such methods have already been shown to be capable of use in different laboratories. H o w e v e r , it is often necessary or advisable to use a locally developed method or one which was selected from the literature, but a b o u t w h i c h l i t t l e is k n o w n . In such c a s e s the m e t h o d m u s t be v a l i d a t e d for use in the local laboratory. Method validation can take many forms, but the usual procedure is to examine a k n o w n s a m p l e , or a k n o w n m a t e r i a l a d d e d to a s a m p l e , to d e t e r m i n e the m e t h o d accuracy and precision. For a contaminant residue, as example, a k n o w n amount of reference grade contaminant would be added to a blank sample and replicate assays done to determine the percentage recoveries. In this type of recovery v a l i d a t i o n it is i m p o r t a n t to be s u r e w h a t p a r t or p a r t s of the a n a l y s i s are being evaluated. A g a i n u s i n g the c o n t a m i n a n t e x a m p l e , a d d i t i o n of the r e f e r e n c e c o n t a m i n a n t to the s a m p l e e x t r a c t s o l u t i o n d o e s n o t e v a l u a t e the e x t r a c t i o n of the c o n t a m i n a n t , o n l y its p a s s a g e t h r o u g h c l e a n - u p and f i n a l assay. C o n t i n u i n g r e c o r d s of m e t h o d v a l i d a t i o n s should be kept for future reference and to d e m o n s t r a t e the u s e f u l n e s s of the m e t h o d s . N e g a t i v e d a t a is a l s o desirable. For e x a m p l e , if a method was tried and could not be satisfactorily validated, that information should be recorded to avoid future attempts. T h e r e c o v e r y d e t e r m i n a t i o n is o n l y one type of d i r e c t v a l i d a t i o n . T h e r e are also indirect validations where concurrent analyses are run on a given sample using a new method as well as an established, accepted method. This provides a direct experimental comparison. T h i s is a good s y s t e m w h e n an a l t e r n a t e procedure is needed for an official or referee method.

5.8

Confirming

Analysis

W h e n an o r i g i n a l a n a l y s i s s h o w s the s a m p l e to be in v i o l a t i o n of l a w or regulations in some m a n n e r , the supervisor m u s t decide if a second analysis by the o r i g i n a l a n a l y s t is n e e d e d . T h i s s h o u l d o n l y be d o n e if t h e r e is s o m e doubt that the original analysis w a s done correctly. In the event that there are no apparent errors in the original analysis, then a c o n f i r m i n g a n a l y s i s b y a s e c o n d a n a l y s t s h o u l d be d o n e as f o l l o w s : A fresh p o r t i o n of s a m p l e s h o u l d be p r e p a r e d ( u n l e s s it is n e c e s s a r y or d e s i r a b l e to u s e the o r i g i n a l ) and a n a l y z e d u s i n g a s e c o n d m e t h o d (if p o s s i b l e ) and n e w standard reference material. If the a d v e r s e f i n d i n g s are r e p e a t e d by the c o n f i r m i n g analyst, then it is extremely likely that a violation exists. If, h o w e v e r , t h e r e is no c o n f i r m a t i o n , then the s u p e r v i s o r m u s t m e e t w i t h b o t h a n a l y s t s and d e c i d e w h a t is to be d o n e . It m a y be t h a t the m e t h o d s are n o t c o m p a t i b l e , if so a recheck using the original method might be in order. It is a l s o o f t e n v e r y u s e f u l to c r o s s c h e c k the s t a n d a r d s u s e d b y e a c h a n a l y s t to ensure they compare. Confirming analysis is basically an attempt to ensure that any violation of law The e n f o r c e m e n t laboratory or regulation has substance and is not a mistake. c a n n o t a f f o r d to m a k e any m i s t a k e s , so it is n e c e s s a r y to p r o v e that all adverse results are correct.

34

6.

6.1

The Safety

LABORATORY

SAFETY

Programme

The Head of the laboratory and supervisors must emphasize to all the laboratory staff, their c o m m i t m e n t and d e t e r m i n a t i o n to e n s u r e s a f e l a b o r a t o r y w o r k i n g conditions. One staff m e m b e r s h o u l d be a p p o i n t e d the " S a f e t y O f f i c e r " and given the responsibility to m o n i t o r safety procedures, practices and equipment on a routine periodic basis. In a large laboratory, the Safety Officer may be assisted by a c o m m i t t e e of two or three analysts. The d u t i e s of the S a f e t y O f f i c e r (and c o m m i t t e e w h e r e a p p r o p r i a t e ) s h o u l d be d e t a i l e d in the l a b o r a t o r y S a f e t y P r o g r a m m e . This p r o g r a m m e would indicate safety requirements, hazards, equipment and emergency procedures. Items which can be included in a laboratory Safety P r o g r a m m e are discussed in the following sections. It should be r e m e m b e r e d that the Head h a s the final a u t h o r i t y as w e l l as r e s p o n s i b i l i t y for l a b o r a t o r y s a f e t y , so t h a t the S a f e t y O f f i c e r m a y only make recommendations.

6.2

Basic

Safety

Rules

E a c h l a b o r a t o r y s h o u l d d e v e l o p its o w n set of g e n e r a l s a f e t y r u l e s , and m a k e sure that all m e m b e r s of staff are aware of them by supplying personal copies of the r u l e s and by p o s t i n g c o p i e s on n o t i c e - b o a r d s . T h e r u l e s s h o u l d be changed and developed in the light of experience. Some that should be included are listed below: 1. B e c o m e f a m i l i a r w i t h the l o c a t i o n and use of e m e r g e n c y (e.g., f i r e e x t i n g u i s h e r ; e y e w a s h f o u n t a i n s ; s a f e t y s h o w e r s ; cabinets). Know where to go in case of fire.

equipment, f i r s t aid

2. Before beginning a sample analysis, review possible hazards connected w i t h the a s s i g n m e n t and take the n e c e s s a r y p r e c a u t i o n s to e l i m i n a t e or counteract the hazard. 3. Use, when appropriate, the safety equipment provided for protection, (e.g., s a f e t y g o g g l e s ; face s h i e l d s ; v a r i o u s t y p e s of g l o v e s ) . Wear a laboratory coat routinely since its purpose is to serve as protective clothing. 4. Bring all accidents and hazardous supervisor or Head immediately.

conditions

to the attention of

the

5. W h e n l i f t i n g h e a v y o b j e c t s , use the legs i n s t e a d of the b a c k . Bend the knees and hold the back straight so that the lifting effort is accomplished w i t h the legs r a t h e r than the back. L i f t s l o w l y to j u d g e the w e i g h t of the object. If too heavy, obtain assistance and/or use a lifting device. 6. Be jewelry (like equipment. entangled in

extremely careful of loose clothing, neckties, scarves, dangling necklaces) and long h a i r w h e n u s i n g r e v o l v i n g or r e c i p r o c a t i n g K e e p such i t e m s b o u n d or c o n f i n e d so that they w i l l not be the equipment.

7. T u r n off l a b o r a t o r y s e r v i c e s (gas, w a t e r , etc.) at the s e r v i c e c o c k w h e n not in use. Changes in pressure m a y suddenly dislodge tubing connected to an apparatus and lead to an accident or possible injury. 8. Always use mechanical aids, such as safety bulbs when pipetting hazardous material. Never use the mouth.

35

or pipette

fillers,

9. Use fume hoods for any analytical operations of solvents, or w h e n noxious fumes will be generated.

their

10. Keep the contents.

work

area

neat

11. Any chemicals, whether m u s t be washed off immediately.

even

12. Keep fire escape temporarily.

routes

and

tidy,

toxic

and

13. No one s h o u l d w o r k a l o n e available in the event of accident.

with

or not,

doors

in the

all

which

clear

involving

large

containers

are

at all

laboratory,

labelled

spilled

times.

so that

amounts

on

the

Do not

with

hands

block,

assistance

is

14. The last person to leave the laboratory at the end of the working day m u s t c h e c k that all e q u i p m e n t t h a t s h o u l d be t u r n e d o f f h a s b e e n . (This d o e s not release each individual operator from his duty to turn off the equipment no longer in use.) The laboratory Head in consultation with staff m a y prefer to operate a duty roster for opening the laboratory in the morning and closing at the end of the w o r k i n g day.

6.3

Fire

Safety

A laboratory m u s t unfortunately be regarded as one of the more likely places in w h i c h a fire w i l l o c c u r and it is t h e r e f o r e p r u d e n t to h a v e the l o c a l c h i e f fire officer visit the building, be familiarized with the problems and advise the laboratory staff about local fire regulations and further safety m e a s u r e s that s h o u l d be t a k e n . F i r e and s m o k e d e t e c t o r s m a y be i n s t a l l e d in the b u i l d i n g and c o n n e c t e d so t h a t in the e v e n t of f i r e , an a l a r m is g i v e n at a fire s t a t i o n . C a r e m u s t be taken that s m o k e d e t e c t o r s are not set off a c c i d e n t a l l y by b e g i n n i n g the a s h i n g of s a m p l e s in the o p e n l a b o r a t o r y or excessive formation of smoke in other ways. S t a f f m u s t h a v e c l e a r i n s t r u c t i o n s of the a c t i o n to be t a k e n in c a s e of fire. Such i n s t r u c t i o n s s h o u l d be p o s t e d p r o m i n e n t l y in v a r i o u s p a r t s of the building. O c c a s i o n a l l y t h e r e s h o u l d be a fire d r i l l to c h e c k that e v e r y o n e k n o w s w h a t to do in the case of a s e r i o u s fire and to m a k e sure that the building can be evaculated in an orderly and rapid manner. Once evacuated, a r o l l c a l l is t a k e n to c h e c k that no one r e m a i n s in the b u i l d i n g . Such a roll call m u s t be completed in a very few minutes and therefore should be called in groups if the total staff exceeds about 20-30. A fire evacuation must include switching off the electricity supply to the affected area, as short-circuits may result in further fire hazard. Isolation switches are important to enable restricted areas of the building to be cut off from the supply. H o w e v e r , for a p r a c t i c e d r i l l , the s w i t c h i n g off can be s i m u l a t e d . W h e n n e w s t a f f are introduced, they m u s t have the drill explained to them and be shown where fire e x t i n g u i s h e r s , b l a n k e t s , h o s e s and b u c k e t s are k e p t , and h o w the s p r i n k l e r system w o r k s if there is one. Breathing apparatus should be available at two or three points in the building, and an adequate n u m b e r of people instructed in its use. In dealing with a fire in a laboratory toxic fumes are always possible. F i r e e x t i n g u i s h e r s in the l a b o r a t o r y s h o u l d be of the c a r b o n d i o x i d e type. Pressurized dry chemical extinguishers are suitable for general use, but should n o t be u s e d a r o u n d c o m p u t e r s or o t h e r s e n s i t i v e e l e c t r o n i c e q u i p m e n t . The r e a s o n is that it is n e a r l y i m p o s s i b l e to c l e a n the dry c h e m i c a l out of the instrument., and the instrument could be irreparably damaged. Carbon dioxide units work best. Everyone in the laboratory should have used an extinguisher at l e a s t o n c e , so t h a t t h e y k n o w h o w to r e m o v e the s a f e t y p i n as r a p i d l y as possible and are not disconcerted by the sudden noise when it is activated. If

36

any s t r u c t u r a l part of the b u i l d i n g a p p e a r s a f f e c t e d by a s m a l l f i r e , it is a d v i s a b l e to i n f o r m the fire s t a t i o n , s i n c e a f i r e that m a y a p p e a r to b e extinguished in fact may be smouldering behind a panel or other structure and break out again several hours later, perhaps after the laboratory is closed for the night. A d i s c u s s i o n of b u l k s o l v e n t s t o r a g e and c o n s t r u c t i o n of a s t o r a g e r o o m is contained in Section 3.3 of this manual. The quantitites of f l a m m a b l e liquids in the laboratory should be kept at a m i n i m u m . Bottles should be stored away f r o m h e a t , s u n l i g h t and any s o u r c e of n a k e d f l a m e . V a p o u r s such as t h o s e of diethyl ether can flow along surfaces such as floors and benches and thus, by c o n t a c t w i t h a n a k e d f l a m e or a h o t s u r f a c e (such as a m u f f l e f u r n a c e or h o t p l a t e ) b e c o m e i g n i t e d . S o l v e n t s m u s t be s t o r e d in an e x p l o s i o n - p r o o f refrigerator, separately from acids and other reagents. Some chemicals ignite spontaneously on mixing, for example concentrated nitric acid with alcohols. E l e c t r i c a l e q u i p m e n t m a y be the s o u r c e of a fire d u e to f a u l t y wiring, inadequate earthing, failure causing sparks or local overheating or switchgear sparks. A l l e l e c t r i c a l e q u i p m e n t s h o u l d c a r r y a f u s e w h i c h b l o w s at an amperage s l i g h t l y in e x c e s s of that r e q u i r e d by the e q u i p m e n t . It is c o m m o n p l a c e to find that equipment drawing only one or two amps have a 13 or 15 Flammable amp fuse which is unlikely to be of any use if anything goes wrong. vapour near electrical equipment represents a fire hazard unless the instrument h a s b e e n r e n d e r e d " e x p l o s i o n p r o o f " by s e a l i n g t h o s e s e c t i o n s w h e r e a s p a r k could occur. Motors m u s t be serviced regularly. Lack of attention m a y result in o v e r h e a t i n g and s u b s e q u e n t fire. C e n t r i f u g i n g of v o l a t i l e flammable s o l v e n t s is h a z a r d o u s if the c e n t r i f u g e m o t o r is n o t e x p 1 o s i o n - p r o o f , especially if the tube breaks. S t a t i c e l e c t r i c i t y and s t a t i c s p a r k s can be a real p r o b l e m in a h o t and dry climate. They can result from wearing clothes m a d e of synthetic m a t e r i a l s , or by simply walking across a carpet.

6.4

Chemical

Hazards

All c h e m i c a l s s h o u l d be c o n s i d e r e d as p o t e n t i a l l y h a z a r d o u s and s h o u l d be treated with caution. As far as possible, dangerous c h e m i c a l s should be stored away from the laboratory and away from others with which they violently react. Y e l l o w p h o s p h o r u s and p i c r i c acid m u s t be k e p t u n d e r w a t e r , s o d i u m and potassium metal under oil. Explosive peroxides can be formed in diethyl ether. T h e y s h o u l d a l w a y s be r e m o v e d if f o u n d to be p r e s e n t , as an e x p l o s i v e concentration of p e r o x i d e m a y b e f o r m e d if t h e e t h e r is d i s t i l l e d . Distillation should be stopped while there is plenty of solvent remaining in the d i s t i l l a t i o n flask and care s h o u l d be t a k e n not to o v e r h e a t the flask. D u s t m a y c a u s e the e x p l o s i v e d e c o m p o s i t i o n of h y d r o g e n p e r o x i d e of o v e r 30 percent concentration. Peroxides in general can be explosive, and must not be allowed to come into contact with reducing agents or f l a m m a b l e solvents. They should be kept in dark bottles in a refrigerator. Hydrogen fluoride solution is e x t r e m e l y dangerous as contact w i t h the skin may result in lesions that fail to heal. Disposable plastic gloves must always be worn when this solution is being handled. Calcium gluconate gel or solution or another antidote should be available in the first-aid cabinet. Toxic levels of nitrogen dioxide can be produced during the use of the nitrous oxide-acetylene flame in atomic absorption spectrophotometry and consequently ventilation must be good. The recommended threshold limit value (TLV) for 40 m i n u t e s exposure is 5 ppm. Tubes for testing contaminated air are available c o m m e r c i a l l y from laboratory supply firms. It is important that bottles containing sodium and potassium (for example w h e n these have been used for drying ether) are not left near a washing-up area in case an inexperienced or unobservant person attempts to wash the bottle in the

37

u s u a l way. In fact, all c o n t a i n e r s ( b e a k e r s , e t c ) c o n t a i n i n g h a z a r d o u s material must first be rinsed or otherwise treated by the analyst to remove the h a z a r d , b e f o r e giving to g l a s s w a r e w a s h i n g . The need for this is o b v i o u s as the analyst is the only one who knows of the hazard and how to eliminate it. All reagent bottles, flasks or other containers must be properly labelled, even if the c o n t e n t s are c o n s i d e r e d h a r m l e s s . A d h e s i v e w a r n i n g s t i c k e r s can be p u r c h a s e d from c h e m i c a l s u p p l y f i r m s . T h e s e can be used in a d d i t i o n to the container label to highlight hazards. When emptying acids and chromic acid cleaning solutions into the drains, first fill the sink with water, pour the acid or cleaning solution into the sink, and then let the w a t e r run out. A l l o w the tap to r e m a i n on full for a few additional minutes. Dilution should always be sufficient to reduce the acid concentration to less than one normal. Store acid containers in inert trays if the acid c o n c e n t r a t i o n is g r e a t e r than 2N. P o l y e t h y l e n e t r a y s are s u i t a b l e . Handle concentrated ammonium hydroxide and solutions of potassium and sodium hydroxide which are ION or above as if they were concentrated acids and observe the s a m e p r e c a u t i o n s as for acids. Do not store A L K A L I in the s a m e tray w i t h ACID. Do not store concentrated alkalies in glass-stoppered bottles.

6.5

Biological

Hazards

This manual is concerned primarily with a chemical analysis laboratory rather than a m i c r o b i o l o g i c a l one. H o w e v e r , t h e r e are b i o l o g i c a l h a z a r d s in the typical chemical analysis laboratory. The m o s t s e r i o u s of these are the c a r c i n o g e n i c r e a g e n t s or r e f e r e n c e m a t e r i a l s c o m m o n to f o o d c o n t r o l laboratories. Carcinogens must always be handled with extreme care, using all available protective gear. The f o l l o w i n g listing is of s u b s t a n c e s used in a food c o n t r o l l a b o r a t o r y , or found as food contaminants, which are suspected or k n o w n to be carcinogens: Category

Reference

Aflatoxins

Potent

carcinogen

6,7

4-(or p-) Aminobiphenyl Biphenylamine

Potent

carcinogen

1,2,6

Asbestos

Carc inogen

Auramine, or 4,4'dimethylaminobenzophenonimide

Suspected

carcinogen

2,6

Benzene, benzol(e)

Suspected

carcinogen

4,5,6

Benzidine, diamide,

Potent

carcinogen

2,6

3,4-(or 1,2-) Benzpyrene

Potent

carcinogen

6

Cadmium and Compounds (mainly inorganic)

Suspected

Carbon

Carc inogen

4,4'-biphenyldiaminobiphenyl

tetrachloride

Suspected

Chloroform (trichlorome thane) Chromium

salts (3 and

6+)

Carc inogen

38

3,6

carcinogen

6,9

6 carcinogen

9

3,6,7

N»e

Catetory

Reference

Coal tar, Creosote oils (polycyclic mixtures)

Care inogen

3,4,6

DDT

Suspected

(p,p*

or o,p')

o-Dianisidine

Care inogen

Diazomethane

Suspected

Dichloroethane

Carcinogen

4-Diethylaminoazobenzene (Butter Y e l l o w )

Suspected

N,N-Dimethylnitrosamine

Potent

Dimethyl

Carcinogen

sulphide

1,4-Dioxane ether

(diethylene

carcinogen

2,6 carcinogen

4,5,6 -

carcinogen

carcinogen

-

6,8 -

6,9

Carcinogen

Teratogen

Formamide

5,6

-

Suspected

carcinogen

2

Magenta basic or Basic fuchsin (basic red 9, basic violet, 14 rosaniline)

Suspected

carcinogen

2,6

Mineral

Carc inogen

3,6

1-Naphthylamine (1-amino-naphthalene)

Care inogen

2,6

2-Naphthylamine (2-amino-naphthalene)

Potent

Nickel

Carcinogen

4,6

Nitrobenzene

Carcinogen

-

Nitrosamines

Potent

-

Patulin

Suspected

carcinogen

6

Rhodamine B

Suspected

carcinogen

9

Suspected

carcinogen

6

Magenta

acid or Acid

oils

and

fuchsin

(heavy)

salts

Sodium diethyl Soot, carbon

dithiocarbamate

black

carcinogen

carcinogen

Carcinogen

1,2,6

3,6

Tannins

Suspected

carcinogen

5,6

Thioacetamide

Suspected

carcinogen

4,5,6

Thiourea

Suspected

carcinogen

4,5,6

Trichloroethylene

Suspected

carcinogen

6

Vinylchloride

Carcinogen

Zearalenone

monomer

Suspected

39

10 carcinogen

11,12

The references noted

in the listing

are:

1.

Bo y 1 and, E. (1 963). "The B i o c h e m i s t r y of B l a d d e r Cancer." Springfield, Illinois.

2.

C h e s t e r B e a t t y R e s e a r c h I n s t i t u t e (1966). " P r e c a u t i o n s for L a b o r a t o r y Workers who handle Carcinogenic Aromatic Amines." The Institute, London; reprinted with additional notes 1971, i. 7 pp.

3.

Clayson, D.B.

4.

D e w h u r s t , F. (1972). 10, 57-85, passim.

5.

Hueper, Cancer."

6.

From International Agency for Research on Cancer, IARC Monographs on the " E v a l u a t i o n of C a r c i n o g e n i c Risk of C h e m i c a l s to Man." IARC, L y o n / W H O , Geneva/HMSO, London.

7.

R o e , F.J.C. and L a n c a s t e r , M.C. (1964), " N a t u r a l M e t a l l i c Br. med. Bull., 2J)> 127-133. Substances as Carcinogens."

8.

S e a r l e , C.E. (1972).

9.

National Institute of Occupational S a f e t y and H e a l t h (1975) - " S u s p e c t e d C a r c i n o g e n s List." U n i t e d S t a t e s D e p a r t m e n t of H e a l t h E d u c a t i o n and Welfare Publication No. (NIOSH) 75-188.

10.

Maltoni,

11.

Ueno, Y. and Kubota, K., (1976), Cancer Research, 36_ (2) 445-451.

12.

Schoental, R. , (1974), Br. J. Cancer, 30, ISS _2, 181.

6.6

Physical

(1962).

"Chemical Carcinogenesis." "Carcinogens

C.C. T h o m a s ,

Churchill.

in the L a b o r a t o r y . "

W.C. and C o n w a y , W.D. (1964). "Chemical C.C. Thomas, Springfield, Illinois.

Lab. Equip. Dig.,

Carcinogenesis

and

and

other

" C h e m i c a l C a r c i n o g e n s . " C h e m . Ind., (3) 1 1 1 - 1 1 6 .

C. and Lefemine, G., (1974), Environmental

Research, _7, p.387.

Hazards

There are many physical hazards in a laboratory. Most are avoidable by use of c o m m o n sense. It is advisable, however, to prepare some instructions for new e m p l o y e e s and p e r i o d i c a l l y r e m i n d o t h e r s . The f o l l o w i n g are s o m e p r o p o s e d instructions, grouped by operation.

Glassware Handling

1. Do not use b r o k e n or chipped g l a s s w a r e or r e t u r n it to s t o r a g e . If it is b e y o n d r e p a i r , d i s p o s e of it. W h e n in d o u b t r e g a r d i n g p r o p e r d i s p o s a l , consult the supervisor. Always use gloves in handling broken glass. 2. R e m o v e s h a r p or jagged e d g e s from g l a s s w a r e b e f o r e u s i n g it. polish the edges on all glass tubing.

Fire

3. Broken glass in sinks present a definite hazard since glass may not be v i s i b l e in the p r e s e n c e of w a t e r . W h e n b r o k e n in the sink, r e m o v e it promptly. F u r t h e r m o r e , c o n s i d e r the p o s s i b i l i t y of the p r e s e n c e of b r o k e n glass when reaching into the sink for any purpose.

40

4. Inserting tubing into stoppers or rubber tubing can result in serious cuts, which can be prevented if the following precautions are observed: a. b. c. d. e.

Wet the tubing and/or stopper or rubber tubing. Wear gloves or wrap a towel around the palms of the hands. Do not use e x c e s s i v e force - cut the h o l e b i g g e r or b o r e a n e w hole . Use the fingers and not the hands when making the insertion. Insert glass or metal tubing entirely through stoppers to assure that the end may not be closed over by heat or solvent action on the stopper.

5. To remove glass tubing or thermometers from rubber, preferably cut a w a y the r u b b e r . T h i s is p a r t i c u l a r l y true if the t u b i n g or s t o p p e r has b e e n in place over an extended period of time or has been subjected to heat. 6. In handling beakers, support them by grasping around the sides, never over the top. If one hand will not reach more than half way around the beaker, use both hands. Support large beakers (one litre or more) from the bottom when in use. 7. W h e n h e a t i n g l i q u i d s in g l a s s by m e a n s of a gas f l a m e , p r o t e c t the glass from direct contact with the flame by use of a wire gauze or a centered wire gauze. 8. W h e n p l a c i n g l i q u i d s in b o t t l e s w h i c h h a v e a p o s i t i v e c l o s u r e , reserve more than 5 percent of the volume as air space to allow for expansion due to temperature changes. 9. Do not force s t o p c o c k s or ground g l a s s s t o p p e r s . Use a s t o p c o c k puller. If the n a t u r e of the c o n t e n t s of the v e s s e l p e r m i t s , cool the shell until the plug is cold, then heat the shell of the joint momentarily. Withdraw the plug quickly before it too has been expanded by the heat.

Vacuus Operations

1. Protect glassware under vacuum from physical cracks and result in collapse with explosive violence.

shock which might

2. Do not subject flat-bottom flasks heavy walls specifically for such service.

unless

to vacuum

cause

constructed

with

3. Guard s t a n d a r d - w a l 1 ( s p h e r i c a l ) flasks larger than one l i t r e , w h e n used in v a c u u m s e r v i c e , by a shield that is a d e q u a t e to stop all flying g l a s s if collapse should occur. 4. C h o o s e cork or r u b b e r s t o p p e r s used in v a c u u m s e r v i c e c a r e f u l l y . They must be of such size that they will not be drawn through the opening which they are intended to close. 5.

Relieve vacuum before attempting

to disassemble

equipment.

6. Do not s t o p p e r h o t flasks c o n t a i n i n g u n c o n d e n s e d v a p o u r s or To do so will subject them to vacuum on cooling.

41

steam.

Equipment

Handling

1. W h e n using a m a n u a l cork b o r e r , do not hold the s t o p p e r in the p a l m of the hand. Place the stopper large end down on a soft, flat surface and hold in p l a c e w i t h the t h u m b and f o r e f i n g e r . K e e p the b o r e r sharp and l u b r i c a t e with water or glycerine to prevent binding. Do not force the borer through the stopper but twist to cut the material. Use stout gloves for added protection in case of slippage. 2. Do not lift the cover of a c e n t r i f u g e until r o t a t i o n has Keep the cover closed when the centrifuge is not in use.

stopped.

3. C y l i n d e r s c o n t a i n i n g i n d u s t r i a l gases must be properly anchored by chains or heavy straps or held in stands. Reactive gases should be stored away from each other (e.g. do not store a c e t y l e n e near oxygen). Gas s u p p l i e s for gas liquid chromatography and atomic absorption spectroscopy are best kept on the other side of the wall from the instrument and connected via a small duct in the w a l l . C y l i n d e r s t o r a g e p o i n t s s h o u l d be p r o t e c t e d from the w e a t h e r , p a r t i c u l a r l y in dusty areas w h e r e grit can get into the c y l i n d e r v a l v e , but they s h o u l d be s u f f i c i e n t l y w e l l - v e n t i l a t e d to p r e v e n t l e a k i n g gas f r o m reaching dangerous levels. 4. Flexible tubing attached to gas supplies must be wired on or held by clips and must be able to withstand any likely pressure. The sudden bursting or b l o w i n g off of a piece of tubing is s t a r t l i n g and m a y c a u s e an a c c i d e n t if someone nearby is carrying out a hazardous operation. 5. A rapid decrease of cooling water due to a fall in mains pressure or a cut in the supply can damage equipment such as a still and also be hazardous. A c o n s t a n t head d e v i c e in a t r a n s p a r e n t c o n t a i n e r w i l l give s o m e w a r n i n g of this. However, if water pressure fluctuations are a frequent problem, a header tank in the roof of the building may be advisable. Electrical equipment can be fitted with automatic cutouts that turn off the electricity supply in case of water failure.

6.7

Safety and Emergency

Equipment

" S a f e t y " e q u i p m e n t is that d e s i g n e d to p r o t e c t a n d / o r p r e v e n t i n j u r y and is used b e f o r e an a c c i d e n t h a p p e n s . " E m e r g e n c y " e q u i p m e n t is used a f t e r an accident (or other emergency) to minimize the injury or damage. Therefore, eye goggles are "safety" and eye wash fountains are "emergency" equipment. U s i n g these d e f i n i t i o n s , the f o l l o w i n g are lists of safety and equipment which every laboratory should include in their inventory:

emergency

Safety Equipment

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Rubber aprons. Eye goggles. Face shields.. Disposable plastic or rubber gloves. Bench shields (portable, clear plastic). Pipetting bulbs. Heavy rubber carriers for acid and alkali bottles. Metal safety cans for flammable solvents. M e t a l solvent s t o r a g e c a b i n e t s (about 45 g a l l o n storage of solvents used daily in the laboratory). Respirator filter masks (for dust or fumes). 42

capacity).

(For

Emergency

1. 2. 3. 4. 5. 6.

Equipment

Hand-held fire extinguishers (carbon dioxide preferably, see Section 6.3) . Fire blankets (wall mounted). Eye wash stations (built-in fountains or portable kits). S p i l l a g e a b s o r b e n t kits for both a c i d s and s o l v e n t s ( a v a i l a b l e commercially or can be assembled locally). Emergency shower (in the laboratory, drenching full-on or -off valve operated by a pull chain or loop). Respirator mask with oxygen supply.

A major item of emergency equipment not included in the above list is the aid cabinet. This is discussed in detail in Section 6.8.

first

All such e q u i p m e n t is u s e l e s s if e i t h e r not a v a i l a b l e or not in s e r v i c e a b l e condition. The Safety Officer (see Section 6.1) should periodically check both the s t o r a g e l o c a t i o n s (if n o t in u s e ) and the c o n d i t i o n of all safety and emergency equipment. The laboratory staff must also be trained in the use of the equipment and use must be enforced when necessary.

6.8

First

Aid

First aid by definition is that initial assistance given to lessen the effect of injury. If the injury is sufficiently minor, then first aid will probably s u f f i c e for t r e a t m e n t . H o w e v e r , for s e r i o u s and e v e n m o d e r a t e l y s e r i o u s i n j u r i e s , m e d i c a l h e l p m u s t be g i v e n as soon as p o s s i b l e . Any first aid m e a s u r e s w o u l d be only to give t e m p o r a r y h e l p u n t i l m e d i c a l t r e a t m e n t is available. S o m e o n e on the l a b o r a t o r y s t a f f s h o u l d be t r a i n e d in f i r s t - a i d , particularly in giving artificial respiration techniques. Some chemicals such as c y a n i d e are q u i c k - a c t i n g and there is r a r e l y t i m e to w a i t for a d o c t o r to arrive, or transfer the patient to the hospital. T h o u g h t s h o u l d be g i v e n to the l o c a l h a z a r d s that m i g h t be e x p e c t e d and the c o n t e n t s of a first aid c a b i n e t d e s i g n e d to m a t c h . The c a b i n e t should be l o c a t e d in the l a b o r a t o r y p r o p e r and be a c c e s s i b l e . A first-aid cabinet suitable for a laboratory of 10-50 employees could contain the following: 1.

A copy of a leaflet giving advice on first aid

2. A s u f f i c i e n t n u m b e r (not l e s s unmedicated dressings for injured fingers.

than

12)

treatment. of

small

sterilized

3. A s u f f i c i e n t n u m b e r (not less than 6 ) of m e d i u m - s i z e d unmedicated dressings for injured hands or feet.

sterilized

4. A sufficient number (not less than 6) of large sterilized dressings for other injured parts.

unmedicated

5. A sufficient number (not less than 24) of adhesive wound an approved type and of assorted sizes. 6. A s u f f i c i e n t n u m b e r (not less than 4 ) of unbleached calico, the longest size of which measures and each of the other sides not less than 36 inches. 7.

small

A sufficient supply of adhesive

8. A sufficient packets.

supply

t r i a n g u l a r b a n d a g e s of not less than 51 inches

plaster.

of a b s o r b e n t

43

dressings of

sterilized

cotton

in

individual

9. approved

A sufficient supply of approved type and size.

10. A sufficient n u m b e r separate sealed packets.

(not

less

eye o i n t m e n t

than 4 ) of

11.

A rubber bandage or pressure bandage.

12.

Safety pins.

13.

A tube of antiseptic

in a container

sterilized

of an

eye-pads

in

cream.

It is suggested that, in addition to the above provisions (which cater primarily for cuts and heat burns) each chemical laboratory first aid cabinet should contain: 1. 2. 3. 4.

A tablespoon. Bottle of Epsom salts (magnesium sulphate). Bottle of milk of magnesia (dose - two tablespoonfuls). Bottle of 1 percent acetic acid.

Hydrogen cyanide, soluble cyanides and nitriles which hydrolyse readily to HCN when inhaled or ingested may call for treatment with capsules (0.3 ml) of amyl nitrite w h i c h are easily crushed in a cloth from w h i c h the vapour can be inhaled. The following antidote for cyanide ingestion casualties consists of two solutions which should be made up and left ready for immediate use:

S o l u t i o n A: 158 g ferrous sulphate crystals and 3 g citric acid crystals in a litre of cold distilled w a t e r (the solution m u s t be inspected regularly and be replaced if any deterioration has occurred). S o l u t i o n B: distilled water.

60 g anhydrous

sodium

carbonate

dissolved

in a litre

of

50 ml of solution A is placed in a 170 ml w i d e - n e c k e d bottle closed by a p o l y t h e n e - c o v e r e d cork and labelled clearly "CYANIDE A N T I D O T E A". 50 ml of solution B is s i m i l a r l y bottled and labelled "CYANIDE A N T I D O T E B". Both b o t t l e s should bear the legend "Mix the w h o l e contents of bottles "A" and "B" and swallow the mixture". The merit of the basic ferrous hydroxide suspension is that when swallowed it is likely to induce vomiting while at the same time forming insoluble non-toxic iron c o m p l e x e s with the cyanide. It m u s t be s t r e s s e d , h o w e v e r , that the i m m e d i a t e s u m m o n i n g of a doctor, w h o can a d m i n i s t e r an approved injection, is of the u t m o s t i m p o r t a n c e in cases of cyanide poisoning. Kits for the intravenous treatment of cyanide poisoning by doctors are available. A kit should be at hand in any o r g a n i z a t i o n w h e r e cyanides are handled regularly. I o d i n e , if i n g e s t e d , s h o u l d be t r e a t e d w i t h sodium thio s ul pha te. An appropriate weight of the crystals in a bottle to make up a 1 percent solution when water is added to a set mark, will provide the right solution for taking internally and also for swabbing on skin contaminated with iodine. In some o r g a n i z a t i o n s , the a d m i n i s t r a t i o n of oxygen through a f a c e - m a s k has become part of first aid procedures for certain types of casualty. When it is certain that a casualty has stopped breathing, artificial respiration should be applied immediately. The "mouth-to-nose" and "mouth-to-mouth" procedures are now the methods of first choice and are described in "New Essential First-Aid" by A. Ward Gardner and C. J. Roylande (Pan Books), among others. The mouth-tomouth procedure must be used when the casualty has a nasal obstruction. Where injuries to the face and m o u t h m a k e the use of these m e t h o d s i m p o s s i b l e , or w h e r e cyanide poisoning is k n o w n or suspected, the Sylvester method can be

44

used. This is described in "First Aid" (2nd E d i t i o n 1965) published by St. John A m b u l a n c e A s s o c i a t i o n , The St. A n d r e w A m b u l a n c e A s s o c i a t i o n and the British Red Cross Society, as well as in standard medical texts. Bromine, formic acid, hydrofluoric acid and other acid burns on the skin can be treated with magnesia/glycerol paste prepared by triturating 200 g magnesium oxide with 240 ml glycerol, the paste being applied liberally over the affected areas. Dilute ammonia (1 volume ammonia added to 15 volumes of water) has also been found e f f e c t i v e in reducing the degree of b u r n i n g w i t h b r o m i n e , formic acid and hydrofluoric acid. The laboratory should have at least one book (preferably more) on first aid and laboratory safety. There are m a n y such available. Some of the better ones are : 1.

"Handbook of L a b o r a t o r y Safety", Steere, N.V., C h e m i c a l Rubber Cleveland, Ohio.

2.

"Hazards in the Chemical Laboratory", C h e m i s t r y , U.K. 1 977.

3.

"Fire P r o t e c t i o n for L a b o r a t o r i e s Using C h e m i c a l s " , National Protection Association, Batterymarch Park, Quincy, MA 02269.

4.

American Chemical Society, "Safety in the Chemical Laboratory" Vol 1 ACS 1967 (reprinted from "Journal of C h e m i c a l Education", January 1964 January 1967), and Vol 2, ACS 1971.

5.

M a n u f a c t u r i n g C h e m i s t s ' A s s o c i a t i o n Guide for safety Laboratory, 2nd Ed, Van Nostrand Reinhold, 1972.

6.

Medical 1973 .

Muir.

G.D. (Ed.) Royal

Company,

Institute

of

Fire

in the

Chemical

in Laboratories",

MRC, U.K.

7.

P r e c a u t i o n s for L a b o r a t o r y W o r k e r s who Handle Carcinogenic Amines, The Chester Beatty Research Institute, London, 1966.

Aromatic

8.

Reference Book of P r o t e c t i v e Association, London, 1981-82.

Research

Council, "Safety

Precautions

E q u i p m e n t , Industrial Safety Manufacturers

45

7. LABORATORY QUALITY ASSURANCE

7.1

(QA)

Introduction

A laboratory engaged in food control analysis must have some means of assuring that their analytical results are of the highest quality. Errors in analysis can o f t e n m e a n s e r i o u s e c o n o m i c l o s s e s for the food i n d u s t r y or i m p o r t e r , as well as possible illness or injury to the consuming public. This assurance of quality is not limited to confirming that a food found to be unacceptable, is in fact b a d . It is e q u a l l y i m p o r t a n t to a s s u r e that f o o d s f o u n d to b e a c c e p t a b l e , are in fact good. To do this r e q u i r e s an u n d e r s t a n d i n g and c o m m i t m e n t by the laboratory m a n a g e m e n t as well as the operating staff, that high quality in analysis is the foremost objective. O f t e n , the t e r m s " Q u a l i t y C o n t r o l " and " Q u a l i t y A s s u r a n c e " are used interchangeably when discussing analytical quality. H o w e v e r , G a r f i e l d (1) m a k e s a d i s t i n c t i o n b e t w e e n the t w o . He d e f i n e s Q u a l i t y c o n t r o l a s , "...a p l a n n e d s y s t e m of a c t i v i t i e s w h o s e p u r p o s e is to p r o v i d e a q u a l i t y p r o d u c t . " Conversely, he defines Quality Assurance as, "...a planned system of activities w h o s e p u r p o s e is to p r o v i d e a s s u r a n c e that the q u a l i t y c o n t r o l p r o g r a m is actually effective." Therefore, Quality Control encompasses all of the myriad r e v i e w , checking and operational procedures routinely used by the laboratory to m a i n t a i n high analytical quality. ( M a n y of t h e s e are d i s c u s s e d in the preceeding Chapters 4 and 5.) The following discussions of Quality Assurance u s e s G a r f i e l d ' s d e f i n i t i o n and c o v e r s t h o s e p r o c e d u r e s u s e d to c o n f i r m t h a t high quality is being maintained.

7.2

Establishing

a QA

Programme

To be successful, quality assurance must be a formal planned activity which is designed to fit the needs of the laboratory. A formal QA p r o g r a m m e is prepared by establishing: 1.

The acceptable

quality

for a given

2.

A periodic review to confirm this

3.

A system of documentation

4.

Appropriate

laboratory

function.

quality.

to record

the results of the

follow-up to correct any deficiencies

reviews.

found.

The first step is to decide the functions that should have formal review. Some s u g g e s t i o n s a r e s t a n d a r d s s t o r a g e and h a n d l i n g , p r e p a r a t i o n of a n a l y s i s r e p o r t s , i n s t r u m e n t m a i n t e n a n c e and l a b o r a t o r y s a f e t y . T h e l a b o r a t o r y Head should carefully examine the entire laboratory operation, by audit review if n e c e s s a r y , and s e l e c t those f u n c t i o n s w h i c h need i m p r o v e m e n t or w h i c h w o u l d benefit from periodic monitoring. A QA p r o g r a m m e should be d y n a m i c and subject to change when needed. Therefore a detailed QA review could be conducted until it is felt that the function under review will continue to operate smoothly, at w h i c h t i m e the r e v i e w could be l e s s e n e d and a n o t h e r f u n c t i o n g i v e n i n - d e p t h coverage . T h e r e v i e w i t s e l f is n o r m a l l y l i m i t e d to the c r i t i c a l p a r t s of the f u n c t i o n under review. For e x a m p l e , a r e v i e w of s t a n d a r d s t o r a g e and h a n d l i n g c o u l d include: accounting for all standards by inventory and checking proper storage; c h e c k i n g t h a t no s t a n d a r d h a s e x c e e d e d its e x p i r a t i o n or d i s p o s a l d a t e ; and visual, p h y s i c a l a n d / o r c h e m i c a l c h e c k s to i n d i c a t e s t a n d a r d s are not contaminated or decomposed.

46

The "acceptable quality" standard is set by the laboratory. If some error rate is acceptable in daily practice, then that rate b e c o m e s the quality standard. The laboratory will always be striving for perfection, and the QA p r o g r a m m e is one means to identify those areas which need improvement towards the ideal. Quality Assurance programmes are u s u a l l y a l s o r e q u i r e d for laboratory certification. An e x a m p l e is G u i d e 25 of the I n t e r n a t i o n a l O r g a n i z a t i o n for S t a n d a r d i z a t i o n ( I S O ) (2). U n d e r P a r t 4, " Q u a l i t y S y s t e m " it s t a t e s the following :

1. The laboratory shall operate an internal quality assurance p r o g r a m m e a p p r o p r i a t e to the t y p e , r a n g e and v o l u m e of w o r k p e r f o r m e d . The quality assurance p r o g r a m m e shall be documented in a quality manual which is available for u s e b y the l a b o r a t o r y s t a f f . T h e q u a l i t y m a n u a l s h a l l be m a i n t a i n e d relevant and current by a responsible m e m b e r of the laboratory staff. A person or persons having responsibility for q u a l i t y a s s u r a n c e w i t h i n the l a b o r a t o r y shall be designated by the laboratory m a n a g e m e n t and have direct access to top management.

2.

The quality manual

shall contain

information

regarding:

a.

The structure of the laboratory

(organizational

charts);

b.

The operational and functional duties and services pertaining to quality, so that each person concerned will know the extent and the limits of his responsibility;

c.

General quality assurance

d.

Quality assurance appropriate ;

e.

Where appropriate, m a t e r i a l , etc.;

f.

S a t i s f a c t o r y a r r a n g e m e n t s for f e e d b a c k and c o r r e c t i v e whenever testing discrepancies are detected;

g.

Procedure

procedures;

procedures

proficiency

specific

testing,

for dealing with technical

for

use

each

of

test,

as

reference

action

complaints.

3. The quality system shall be systematically and periodically reviewed by or on b e h a l f of m a n a g e m e n t to e n s u r e the c o n t i n u e d e f f e c t i v e n e s s of the arrangements, and corrective action initiated. Such reviews shall be recorded together with details of any corrective action taken.

This clearly states the importance that m u s t be placed on QA in the analytical laboratory. N o t e the key p r o g r a m m e e l e m e n t s are r e v i e w , d o c u m e n t a t i o n and follow-up. It A Quality Assurance p r o g r a m m e must obviously be tailored to specific needs. c a n be (and o f t e n is) an e x t e n s i v e and c o m p l e x d o c u m e n t w h i c h c o v e r s all aspects of the laboratory work. An example is the Quality Manual recommended for t e s t i n g l a b o r a t o r i e s b y the I L A C (3). T h e v a r i o u s s u b j e c t s i n c l u d e d in a complete Manual, listed alphabetically, are:

47

DEFINITIONS Quality Manual Quality System Terminology Testing Laboratory Test Method Test Report ENVIRONMENT External Internal

Controls Controls

E Q U I P M E N T , TESTING AND

MEASURING

Calibration Identification Inter laboratory Correlation P r i o r to U s e Programmes U s e of I n - S e r v i c e T e s t E q u i p m e n t U s e of R e f e r e n c e S t a n d a r d s External In-house O v e r l o a d e d or M i s h a n d l e d Periodic Maintenance P u r c h a s i n g and A c c e p t a n c e P r o c e d u r e s Records LABORATORY DESCRIPTION Confidential Information Employee Responsibility F i e l d s of A c t i v i t y Identification Minimizing Improper Influence Organizational Structure Proprietary Rights Technical Management Personnel QUALITY MANAGEMENT SYSTEM Corrective Action F i e l d s of T e s t i n g A c t i v i t i e s Obj ec t i v e P r o f i c i e n c y and I n t e r l a b o r a t o r y C o m p a r i s o n T e s t i n g Quality Assurance Management Q u a l i t y M a n u a l - R e v i s i o n and D i s t r i b u t i o n Quality Policy Quality System Audit R e s p o n s i b i l i t y for Q u a l i t y A s s u r a n c e S y s t e m Reference Materials Resources Employed Scope S u b c o n t r a c ting Technical Complaints U p d a t i n g and C o n t r o l of D o c u m e n t s U s e of E x t e r n a l F a c i l i t i e s RECORDS C o n f i d e n t i a l i t y and S e c u r i t y H i s t o r i c a l F i l e of T e s t M e t h o d s Maintenance

48

SAMPLES/ITEMS TO BE TESTED P r o t e c t i o n from Damage R e c e i p t and D i s p o s a l Security STAFF Deputy Assignments Job D e s c r i p t i o n s P e r s o n n e l Records S u p e r v i s ion Other Measures TEST METHODS AND PROCEDURES I n d e x of Documents S e l e c t i o n of Test Methods Use of Non-Standard Test Methods TEST REPORTS/TEST Computerized Format Revision Verification

DOCUMENTS Date

of

Dsta

T h e a b o v e i l l u s t r a t e s h o w c o m p l e x and t h o r o u g h the d o c u m e n t a t i o n f o r a QA programme can b e . O b v i o u s l y , not a l l l a b o r a t o r i e s w i l l need such c o m p l e t e n e s s . H o w e v e r , t h e r e i s a m i n i m u m QA p r o g r a m m e w h i c h s h o u l d be d o n e e v e n in the s m a l l e s t of food c o n t r o l l a b o r a t o r i e s . T h i s should i n c l u d e the four key a r e a s where q u a l i t y c h e c k i n g is needed most. These are r e f e r e n c e standard m a t e r i a l used in a n a l y s i s , laboratory measuring instruments, a n a l y s i s r e p o r t s and the t e c h n i c a l p r o f i c i e n c y of the a n a l y t i c a l s t a f f . The l a t t e r can be r e v i e w e d in p a r t by use of a c h e c k s a m p l e a n a l y s i s p r o g r a m m e . T h e s e f o u r QA c h e c k a r e a s a r e d i s c u s s e d in d e t a i l in s u c c e e d i n g S e c t i o n s 7 . 3 to 7 . 6 . O t h e r r e l a t e d QA a c t i v i t i e s are d i s c u s s e d under S e c t i o n 7 . 7 .

7.3

QA of R e f e r e n c e

Standards

F o r p u r p o s e s of t h i s S e c t i o n , a " R e f e r e n c e S t a n d a r d " i s a p u r e c h e m i c a l or b i o l o g i c a l s u b s t a n c e w h i c h may be used for c o m p a r i s o n d u r i n g the q u a n t i t a t i v e a n d / o r q u a l i t a t i v e a n a l y s i s of a c o n s t i t u e n t or a t t r i b u t e of a f o o d . Of c o u r s e , " p u r e " is a r e l a t i v e term. Some m e t a l e l e m e n t s c a n be r o u t i n e l y o b t a i n e d in 9 9 . 9 9 9 % p u r i t y , w h i l e many o r g a n i c s u b s t a n c e s would be c o n s i d e r e d " p u r e " at 9 5 % . The a n a l y s t m u s t j u d g e i f t h e r e f e r e n c e s t a n d a r d u s e d i s s u f f i c i e n t l y pure for a n a l y s i s p u r p o s e s . R e f e r e n c e s t a n d a r d s can be d i v i d e d i n t o three g r o u p s :

1. Primary: These are m a t e r i a l s which have been a n a l y z e d and c e r t i f i e d by a n a t i o n a l s t a n d a r d s o r g a n i z a t i o n or o t h e r a c c e p t a b l e organization. 2. Secondary: S u b s t a n c e s whose p u r i t y is commercial s u p p l i e r s or o r g a n i z a t i o n s o t h e r than the

certified above.

by

the p u r i t y certifying

analysis

by

3. Other: This i n c l u d e s a l l r e f e r e n c e s t a n d a r d s w h i c h are c o n s i d e r e d a c c e p t a b l e by t h e u s e r , b u t w h i c h do n o t f a l l i n t h e a b o v e t w o g r o u p i n g s . T h e s e can i n c l u d e l o c a l l y o b t a i n e d m a t e r i a l s w h i c h h a v e u n d e r g o n e r e p l i c a t e a n a l y s i s and have been compared to p r i m a r y or s e c o n d a r y r e f e r e n c e s t a n d a r d s , to calculate purity.

49

S u b s t a n c e s l a b e l l e d , " p u r e " , " c h e m i c a l l y p u r e " , "c.p.", " p u r i f i e d " or " h i g h e s t p u r i t y " s h o u l d a l w a y s b e c o n s i d e r e d s u s p e c t as t h e i r a c t u a l p u r i t y o f t e n v a r i e s widely. T h e y m u s t be c o m p a r e d to s u i t a b l e r e f e r e n c e s t a n d a r d s b e f o r e u s e as a standard themselves. As p r i m a r y and s o m e s e c o n d a r y r e f e r e n c e s t a n d a r d s a r e o f t e n q u i t e e x p e n s i v e , it c a n b e e c o n o m i c a l to o b t a i n a s u p p l y o f a c h e a p e r p u r e m a t e r i a l a s a w o r k i n g standard. It c a n b e a n a l y z e d in c o m p a r i s o n to t h e p r i m a r y ( o r s e c o n d a r y ) r e f e r e n c e s t a n d a r d and the p u r i t y d e t e r m i n e d . The analyst m u s t be c a r e f u l , h o w e v e r , to a v o i d i m p u r i t i e s in the l o c a l m a t e r i a l , w h i c h w i l l c r e a t e p r o b l e m s during analysis. T h e f o l l o w i n g is a l i s t o f s o m e s o u r c e s in t h e U n i t e d S t a t e s s e c o n d a r y r e f e r e n c e s t a n d a r d s of t h e i n d i c a t e d m a t e r i a l s :

Reference

Standards

for p r i m a r y

Source

Number

Alcohols

21

Alkenes

21

Antibiotics

(Chlortetracycline

HC1)

(Erythromycin)

15

(Monensin

14

Sodium)

(Oxytetracycline (Penicillin

Base)

"G" P r o c a i n e )

(Streptomycin

Sulfate)

(Tylosin) Atomic

Absorption

Bacterial Blood

(Metals)

Reference

12 11 12 14 22

Cultures

1, 2 , 3, 4

Group/Typing

9

Chemicals, Industrial

1 9 , 3 2 , 38

Contaminants, Drinking Water Drugs

13

1 0 , 34

(Animal)

1 8 , 2 5 , 31

(U.S. Schedules

I, II)

1 6 , 1 7 , 18

(U.S. Schedules

III, IV, V, VI)

18

Ethanol, Absolute

37

Fibers, Synthetic

21

Fuels, Motor

35

Lead

(Alcoholic Beverages)

34

(Blood)

20

(Motor Fuels)

22

50

or

Reference

Standards

Source

Metals (Foods, Feeds, Fertilizers)

Htmber

23, 30, 36

(Fish, Sediments, Fuel Oil)

23

(Sludge)

34 17,

Mycotoxins Pesticides

21, 24, 25, 26

19, 21, 32, 33

Phenylalanine (PKU)

3, 4

Salmonella Typing & Grouping Antisera

1, 3

Shigella Grouping Antisera

1, 5

Species (Known Fish)

27, 28

(Known Meats)

29

Spirits (Distilled Congeners)

36

Streptococcus

8

Thallium (Standard 1000 ppm)

19

Trichinosis

3

Tuleremia

5

Viral Agent Antisera

1, 6, 7

Wine (Reference)

23

The U.S. sources referred to above, listed by number are: 1.

Department of Health and Human Services Public Health Service Centers for Disease Control Atlanta, GA 30333

2.

American Type Culture Collection 12301 Parklawn Drive Rockville, MD 20852

3.

Difco Laboratories P.O. Box 1058 Detroit, MI 48232

4.

BBL Microbiology Systems P.O. Box 243 Cockeysville, MD 21030

5.

Fisher Scientific 7633 Hull Street Road Suite 2000D Richmond, VA 23235

6.

M A Bioproducts Briggs Ford Road Building 100 Walkersville, MD 21793 51

7.

Flow Laboratories, Inc. 7655 Old Springhouse Road McLean, VA 22102

8.

Wellcome Diagnostics Research Triangle Park North Carolina 27709

9.

American Dade P.O. Box 520672 Miami, FL 33152

10

Environmental Resource Associates 5540 Marshall Arvada, CO 80002

11

ICN Nutritional Biochemicals P.O. Box 28050 Cleveland, OH 44128

12

Pfizer Laboratories 235 E. 42nd Street New York, NY 10017

13

Lederle Laboratories Division of American Cyanamid One Cyanamid Plaza Wayne, NJ 07470

14

Eli Lilly and Company 307 E. McCarty Street Indianapolis, IN 46285

15

Aldrich Chemical Company Milwaukee, WI 53233

16

U.S. Drug Enforcement Administration Special Testing Laboratory 7704 Old Springhouse Road McLean, VA 22102

17

Applied Science P.O. Box 440 State College, PA 16801

18

United States Pharmacopeia Convention Inc. 12601 Twinbrook Parkway Rockville, MD 20852

19

Aldrich Chemical Company P.O. Box 355 Milwaukee, WI 53201

20,

E. S. A. Inc. 45 Wiggins Avenue Bedford, MA 01730

21,

Supelco Inc. Supelco Park Bellefonte , PA 16823

22,

Fisher Scientific Company 711 Forbes Avenue Pittsburgh, PA 15219

Division

52

(US-DEA)

23.

National Bureau of Standards Office of Standard -and Reference Materials Room B 311, Chemistry Building Washington, DC 20234

24.

The Myco Laboratory Company P.O. Box 321 Chesterfield, MO 63017

25.

Sigma Chemical Company P.O. Box 14508 St. Louis, MO 63178

26.

Eureka 215 - 26th Street Sacramento, CA 95816

27.

U.S. Department of Commerce National Oceanic and Atmospheric Northeast Inspection Office P.O. Box 1188, Emerson Avenue Gloucester, MA 01930

Admin.

28.

VA Institute of Marine Science College of William and Mary Gloucester Point, VA 23062

29.

VA Dept. of Agriculture and Consumer Division of Animal Health 1 North 14th Street Richmond, VA 23219

30.

American Dade Division American Hospital Supply Corp. Miami, FL 33152

31.

Pfaltz and Bower Inc. 375 Fairfield Avenue Stamford, CN 06902

32.

U.S. Environmental Protection Agency Pesticides, Industrial Chemicals Repository Research Triangle Park, NC 27711

33.

U.S. Environmental Protection Agency Analytical Chemistry Section Building 306, Room 101, ARC - East Beltsville, MD 20705

34.

U.S. Environmental Protection Agency EMSL - Cincinnati 26 West St. Clair Street Cincinnati, OH 45268

35.

Phillips Chemical Company Drawer 0 Borger, TX 79007

36.

J. T. Baker Chemical Company 222 Red School Lane Phillipsburg, NJ 08865

37.

U.S. Industrial Chemical Company Tuscola, IL 61953

53

Services

(MD-8)

38.

Chem Service P.O. Box 194 West Chester, PA

19380

Once a stock of appropriate reference standards has been obtained, they must be recorded, used and stored properly. A records book or file cards can be used, with the following information noted for each standard: 1.

Standard name and date

2.

Source

3.

Code or lot number.

4.

Purity.

5.

Expiration date

(if any).

6.

Special

storage

requirements.

7.

Storage

location.

(from where

received.

obtained).

M a n y laboratories assign a number to the standard container for accountability purposes. If the s t a n d a r d is o n e w h i c h m a y d e t e r i o r a t e on s t o r a g e , t h e n the record should also include dates and results when stability checks were m a d e . If it is deemed necessary for control, there could be a check-out and - i n sheet for the s t a n d a r d , w h i c h the a n a l y s t w o u l d d a t e and i n i t i a l w h e n u s i n g the material. T h i s is n o t u s u a l l y d o n e e x c e p t for e x t r e m e l y d a n g e r o u s or h i g h l y sensitive substances which must be accounted for. It is o f t e n c o n v e n i e n t to s t o r e r e f e r e n c e s t a n d a r d s in a r e a s n e a r w h e r e t h e a n a l y s e s are b e i n g d o n e (i.e. p e s t i c i d e s t a n d a r d s in the p e s t i c i d e s r e s i d u e analysis section of a larger food laboratory). H o w e v e r , the storage area m u s t be separate from other chemical storage and clearly marked as to its contents. E x a m p l e s are a marked refrigerator section or cabinet with clear warnings or i n s t r u c t i o n s that o n l y s p e c i f i c r e f e r e n c e s t a n d a r d s are to be s t o r e d t h e r e . T h i s p e r m i t s a c c o u n t i n g for a s t a n d a r d l o c a t i o n as w e l l as e n s u r i n g t h a t a reference standard is not mistakenly used as a non-standard chemical. If periodic testing is done to check stability, then the test protocol should be k e p t w i t h the s t a n d a r d r e c o r d . The r e c o r d w o u l d also c o n t a i n the test r e s u l t s , d a t e , a n a l y s t n a m e and a n y s u p p o r t i n g d o c u m e n t s s u c h as s p e c t r a or chromatograms. W i t h all Quality Control procedures in would consist of a periodic review of: 1. Records c o n d i t i o n of the correct times?)

for?

the

Quality

Assurance

checking

(Are they complete and current? Do they reflect the actual standard? H a v e a p p r o p r i a t e s t a b i l i t y t e s t s b e e n r u n at

2. Storage (is If not, w h y ? )

3. review?

place,

the

storage proper?

Are the stored

standards

Physical Condition ( W h e r e w a s the s t a n d a r d at the Any physical evidence of deterioration or m i s h a n d l i n g ? )

accounted

time

of

the

The t i m i n g of the r e v i e w w o u l d d e p e n d on n e e d . An i n i t i a l c y c l e of t h r e e m o n t h s is s u g g e s t e d . T h i s c a n b e i n c r e a s e d or d e c r e a s e d as c o n d i t i o n s and review results dictate.

54

M a n a g e m e n t and e a c h a n a l y s t m u s t r e m e m b e r that r e f e r e n c e s t a n d a r d s are e x t r e m e l y i m p o r t a n t to an a n a l y t i c a l l a b o r a t o r y , a n d m u s t b e treated accordingly. The p e r s o n m a k i n g the QA r e v i e w s h o u l d be a s e n i o r a n a l y s t or s u p e r v i s o r w h o h a s a k n o w l e d g e and a p p r e c i a t i o n for p r o b l e m s t h a t i m p r o p e r , contaminated or deteriorated reference standards can create for the analyst.

7.4

QA of

Instruments

A f t e r r e f e r e n c e s t a n d a r d s , m e a s u r i n g i n s t r u m e n t s are the m o s t s e n s i t i v e and troublesome items for an a n a l y t i c a l l a b o r a t o r y . I n s t r u m e n t m a i n t e n a n c e and r e p a i r are o b v i o u s l y i m p o r t a n t and are d i s c u s s e d e l s e w h e r e . Of e q u a l (or possibly greater) importance is an o r g a n i z e d p r o c e d u r e to p e r i o d i c a l l y c h e c k the instrument performance. If the performance parameters to be checked are s e l e c t e d c a r e f u l l y , t h e n the a n a l y s t h a s a r e a s o n a b l e m e a s u r e of w h e t h e r the i n s t r u m e n t is o p e r a t i n g p r o p e r l y , on a c o n t i n u i n g b a s i s . O n c e a p e r f o r m a n c e c h e c k i n g p r o t o c o l is d e c i d e d u p o n , an i n d i v i d u a l p e r f o r m a n c e r e c o r d c a n b e p r e p a r e d for e a c h i n s t r u m e n t . T h i s can be a s e p a r a t e n o t e b o o k w h i c h is k e p t p h y s i c a l l y n e a r the i n s t r u m e n t , or c a n be p a r t of the m a i n t e n a n c e and r e p a i r record kept for each instrument. The frequency of performance checking varies considerably, again depending on c i r c u m s t a n c e and p r e v i o u s c h e c k r e s u l t s . If a c h e c k r e s u l t indicates maintenance or repair, then a follow-up check (after the repair, etc.) should be scheduled before the next routine QA check time. The routine use of m a n y instruments involves some form of performance checking. An example is a working standard injection into a gas chromatograph first thing in the m o r n i n g , to c h e c k i n s t r u m e n t r e s p o n s e . T h i s is n e c e s s a r y and h a s its place to assure the analyst that the instrument is operating properly for that day. For p u r p o s e s of a QA p e r f o r m a n c e c h e c k , h o w e v e r , t h e r e s h o u l d be a separate and distinct checking programme. S o m e l a b o r a t o r i e s m a k e a d i s t i n c t i o n b e t w e e n r o u t i n e i n s t r u m e n t s used by e s s e n t i a l l y all a n a l y s t s (i.e. b a l a n c e s , s p e c t r o p h o t o m e t e r s , etc.) and t h o s e used o n l y by h i g h l y t r a i n e d s p e c i a l i s t s (i.e. m a s s s p e c t r o m e t e r s , etc.). The p e r f o r m a n c e c h e c k i n g of the f o r m e r c a n b e d o n e b y any a s s i g n e d a n a l y s t . The latter, h o w e v e r , should be checked by trained analyst only. A suggested performance checking protocol laboratory instruments is as follows:

Analytical

1.

and

schedule

for

some

general

Balances

Sensitivity

(bimonthly)

Check balance sensitivity using three standard weights (10g, lg and 100 mg). Weight used should be traceable to certified weights of at l e a s t U.S. C l a s s S. S e n s i t i v i t y s h o u l d be w i t h i n the balance specifications.

2.

Calibration

(annual)

Best done in connection using standard weights.

with

annual

55

cleaning

and

maintenance,

again

Spectrophotometers

1.

(ultraviolet and

Wavelength

Accuracy

visible)

(bimonthly)

Check by recording over entire UV-visible w a v e l e n g t h range using H o l m i u m and D i d y m i u m f i l t e r s ( u s u a l l y o b t a i n a b l e f r o m t h e i n s t r u m e n t m a n u f a c t u r e r or a l a r g e s u p p l y f i r m ) . Run two spectra for comparison. Results should not differ from published values more t h a n + 1.0 n m at a n y w a v e l e n g t h .

2.

Photometric

Accuracy

(bimonthly)

P r e p a r e a s o l u t i o n of 60 _+ 0.25 m g p o t a s s i u m d i c h r o m a t e in o n e l i t r e of 0.01N s u l p h u r i c a c i d . ( T h i s s o l u t i o n is q u i t e s t a b l e a n d o n c e p r e p a r e d can be used a long time). S c a n this s o l u t i o n f r o m 2 1 0 to 450 n m . T h e f o l l o w i n g a b s o r b a n c e s (+ 1% f u l l s c a l e ) s h o u l d o c c u r at the i n d i c a t e d w a v e l e n g t h s :

Wavelength

(nm)

Absorbance

235 257 313 350

0.747 0.869 0.293 0.644

A l t e r n a t i v e l y , t h e U.S. N a t i o n a l B u r e a u of S t a n d a r d s h a s a v a i l a b l e for p u r c h a s e S R M 9 3 0 , a g l a s s f i l t e r w h i c h c a n b e u s e d s i m i l a r l y and which has certified wavelength/absorbance values.

Spectrophotometer

1.

(infrared)

Wavelength Accuracy

(trimonthly)

Scan a standard polystyrene film. The following peaks indicated w a v e n u m b e r s w i t h i n the listed a c c u r a c y :

Wavenumber

(cm

1.

Baseline

(atomic

+ _+ + +

absorption)

(daily when

Absorbance

the

6 6 2 2

used)

U s i n g f l a m e o n l y , the r e c o r d e r b a s e l i n e s h o u l d .005 a b s o r b a n c e u n i t s in a f i v e m i n u t e p e r i o d .

2.

at

Accuracy

2851 1601 1028 907

Spectrophotometer

occur

(daily when

not vary m o r e

than +

used)

T h r e e c o n s e c u t i v e a b s o r b a n c e c h e c k s of the v a r y m o r e t h a n _+ .005 a b s o r b a n c e u n i t s .

56

same

solution

should

not

3.

Detection Limit

(monthly)

Prepare a solution of a metal standard sufficiently dilute to give a response of two times the baseline absorbance under ideal conditions. T h i s b e c o m e s the ' d e t e c t i o n l i m i t ' s t a n d a r d . M a k e four r e p l i c a t e aspirations to check reproducibility.

Gas

Chromatograph

1.

Column Oven

(semiannual)

Check column oven temperature using

2.

Gas Flow Rate

pyrometer.

(monthly)

C h e c k f l o w rates of all c a r r i e r bubble meter or other device.

3.

a calibrated

Detector Response

(daily when

and

detector

gases

u s e d , using

a

used)

Compare present detector response with the response obtained when new or w h e n last c l e a n e d and c a l i b r a t e d . (in s o m e d e t e c t o r s , n o t a b l y e l e c t r o n c a p t u r e , a d e t e r i o r a t i n g r e s p o n s e i n d i c a t e s a need for cleaning).

High Performance Liquid

1.

Chrcmatograph

Column Resolution (daily when

used)

Prepare a solution of two or more substances which the column should resolve under normal analytical conditions. Use this to check column performance each time the column is used.

2.

Detector Response (daily when used) C h e c k d e t e c t o r r e s p o n s e using a k n o w n c o n c e n t r a t i o n standard and compare to a response previously obtained under ideal conditions.

The above p e r f o r m a n c e c h e c k s are only s u g g e s t i o n s . The best a p p r o a c h is to read the o p e r a t i o n s m a n u a l for e a c h i n s t r u m e n t and s e l e c t key o p e r a t i n g p a r a m e t e r s or s p e c i f i c a t i o n s of i n t e r e s t to p r e p a r e the p r o t o c o l . Also, instruments or equipment other than those mentioned above should be considered for a p e r f o r m a n c e check p r o g r a m m e . The g o v e r n i n g factor should be the instrument or equipment importance to the laboratory. The QA p r o g r a m m e on i n s t r u m e n t p e r f o r m a n c e c h e c k i n g m u s t also include a p e r i o d i c r e v i e w to i n s u r e the c h e c k s are b e i n g m a d e and that a p p r o p r i a t e follow-up action is taken if a check discloses a possible performance problem. This follow-up could be maintenance, cleaning, repair, calibration, etc. Any follow-up action should be recorded in the notebook kept with the instrument.

57

7.5

QA of Analytical

Reports

As discussed in preceding Section 5.5, the analytical report is the culmination of all of the l a b o r a t o r y ' s e f f o r t s . T h e r e are m a n y t y p e s and f o r m a t s for analysis reports. T h e y v a r y from s i m p l e to d e t a i l e d , but all are s u b j e c t to the same problem, h u m a n error. A Quality Assurance p r o g r a m m e for analytical reports is basically an after-the-fact or retrospective review of a document w h i c h h a s a l r e a d y b e e n t h r o u g h the n o r m a l s u p e r v i s o r y and m a n a g e m e n t r e v i e w process. It is d e s i g n e d to d e t e c t r e p o r t w r i t e - u p and r e v i e w e r r o r s so that appropriate procedures can be instituted to prevent their reoccurrence. Although report formats m a y vary according to organizational need, the report m u s t be c o m p l e t e enough to enable the reviewer to reconstruct the analysis and to c h e c k the a n a l y t i c a l r e a s o n i n g as w e l l as d a t a and c a l c u l a t i o n s . For e x a m p l e , in ISO Guide 25 (2) under part 12, "Test Reports", it states:

1. The work carried out by the testing laboratory shall be covered by a report w h i c h accurately, clearly and u n a m b i g u o u s l y p r e s e n t s the t e s t r e s u l t s and all other relevant information.

2.

Each test report

shall

include at least

the following

information:

a.

Name and address of testing

b.

Unique identification of each page of the report.

c.

Name and address of

d.

Description and identification of the test

e.

D a t e of r e c e i p t of test tests, as appropriate.

f.

A s t a t e m e n t to the e f f e c t that the test r e s u l t s r e l a t e o n l y to the items tested.

g.

Identification

h.

Description of sampling

i.

Any d e v i a t i o n s , additions specification, and any other test .

j.

Disclosure ut ilized.

k.

M e a s u r e m e n t s , e x a m i n a t i o n s and d e r i v e d r e s u l t s , s u p p o r t e d by t a b l e s , g r a p h s , s k e t c h e s , p h o t o g r a p h s as a p p r o p r i a t e , and any failure identified.

1.

A statement on measurement

m.

A s i g n a t u r e a n d t i t l e of p e r s o n ( s ) a c c e p t i n g technical responsibility for the test report and date of issue.

n.

A s t a t e m e n t that t h e r e p o r t s h a l l n o t be r e p r o d u c e d full without the approval of the testing laboratory.

of

report

(such

as serial

number),

and

of

performance

of

client.

of the test

any

company.

item

and

date(s)

of

specification, method

procedure, where

and

procedure.

relevant.

to or e x c l u s i o n s from the test information relevant to a specific

non-standard

58

item.

test

uncertainty

method

(where

or

procedure

relevant).

except

in

3. Particular care and attention shall be paid to the arrangement of the test report, especially with regard to presentation of the test data and ease of assimilation by the reader. The format shall be carefully and specifically a s s i g n e d for e a c h type of test c a r r i e d o u t , but the h e a d i n g s shall be standardized as far as possible. The U.S. Food and Drug A d m i n i s t r a t i o n " A n a l y s t W o r k s h e e t " good example for purposes of discussing an analytical report is relatively complete and includes space for all pertinent analytical summary. The r e v e r s e of the form w o u l d be used and calculations as the analysis progresses.

(Figure 7.1) is a QA programme. It data including an for r a w w o r k d a t a

An a n a l y t i c a l r e p o r t QA p r o g r a m m e should i n v o l v e r e v i e w of a p r e d e t e r m i n e d n u m b e r of c o m p l e t e d r e p o r t s on a m o n t h l y or b i m o n t h l y b a s i s . The r e p o r t s should be r e p r e s e n t a t i v e of the k i n d s of w o r k d o n e , w i t h a b o u t as m a n y w h i c h s h o w law v i o l a t i o n s as are u s u a l l y e n c o u n t e r e d . An e x a m p l e could be ten r e p o r t s w i t h t w o b e i n g v i o l a t i v e ( a s s u m i n g the v i o l a t i o n rate is about 20%). The object is to gain a relatively representative sampling of completed reports in order to evaluate overall report writing. If some section of the laboratory has substandard reports, then their coverage can be selectively increased until it a p p e a r s that the r e p o r t s are s a t i s f a c t o r y . T h i s is one of the p r i m e f u n c t i o n s of QA r e v i e w s ( w h a t e v e r the t y p e ) - to p i n p o i n t p r o b l e m areas and give them visibility until the problem is solved. An example of an analytical report review protocol is one which has been used by the U.S. Food and Drug A d m i n i s t r a t i o n for QA r e v i e w of their A n a l y t i c a l Worksheets. Their protocol consists of a listing of performance factors that their Worksheet (Figure 7.1) must meet, as follows: 1.

2.

Accuracy and

Completeness

a.

Worksheet clearly describes received by the analyst.

b.

Worksheet fully and accurately reflects continuity and of sample.

c.

Information on the Collection Report.

d.

T h e u s e of a p p r o p r i a t e equipment is described.

e.

C a l c u l a t i o n s are a c c u r a t e , easy to f o l l o w , and are c h e c k e d . This includes checking of conversion factors, normality factors, etc., for accuracy of recording.

f.

If m o r e than one p e r s o n p a r t i c i p a t e d in worksheet clearly indicates who did what.

g.

Sample reserve or disposition is correctly

h.

E r r o r s are noted by s t r i k i n g t h r o u g h the i n c o r r e c t inserting, initialing and dating the new entry.

i.

Any discarded

Analytical

worksheet

results are

the

sample

and

is compatible

standards,

condition

with

reagents,

the

the

and

when

integrity

Inspection

special

analysis,

the

reported. entry

and

explained.

Methodology

The a p p r o p r i a t e m e t h o d is used and is r e f e r e n c e d on the worksheet. Analyses performed and methods used are consistent with appropriate instructions or as directed by the Supervisor.

59

ANALYST WORKSHEET 3. S E A L S •

NONE

•

INTACT

•

BROKEN

1. P R O D U C T

4. D A T E

REC'D

2. S A M P L E

5. R E C E I V E D

FROM

NUMBER

6. D I S T R I C T O R L A B O R A T O R Y

7. D E S C R I P T I O N O F S A M P L E

8. NET CONTENTS

•

NOT APPLICABLE

DECLARE/UNIT

•

NOT DETERMINED

AMOUNT

UNITS E X A M I N E D

% OF

10. S U M M A R Y O F

11. R E S E R V E

.ORIGINAL(S) LABELING

FOUND.

DECLARED

.COPIES •

SUBMITTED

SUBMITTED

NONE

ANALYSIS

SAMPLE

1 2 . L. A N A L Y S T S I G N A T U R E (Broke

Seal •

) WORKSHEET CHECK 14. D A T E

FORM FD 431 (1/77)

P R E V I O U S E D I T I O N IS O B S O L E T E .

Figure USFDA

Analyst

60

7.1 Worksheet

REPORTED

PAGE

OF

PAGES

3.

4.

b.

Sample is analyzed so laws or regulations.

c.

Deviations worksheet.

d.

Any unofficial method

Supervisory

from

the

as

to

permit

referenced

used

application

method

are

of

appriopriate

explained

on

the

is validated.

Review

a.

The a n a l y s i s and m e t h o d o l o g y w a s a p p r o p r i a t e indicated on the inspection collection report.

b.

L a b o r a t o r y c o n c l u s i o n s and final d e c i s i o n supported by information on the worksheet.

c.

If the sample is classified performed (if possible).

Time

Frames

a.

Sample analysis

violative,

to

are

the

problem

accurate

a confirming

analysis

and

is

time frames are met.

Any deviations from the above which are found during the r e v i e w , are recorded and an a t t e m p t m a d e to d e t e r m i n e h o w they o c c u r r e d . T h e r e v i e w e r m a y find a p a t t e r n s u c h as c e r t a i n e r r o r s a r e c o n s i s t e n t l y m a d e , i n d i c a t i n g a n e e d for specific training. A l l f o l l o w - u p a c t i v i t i e s and a c t i o n s t a k e n to c o r r e c t p r o b l e m s , m u s t be detailed and documented to provide laboratory m a n a g e m e n t with a continuing basis to evaluate improvement.

7.6

Check Samplé

Examination

O n e of the m o s t c o m m o n w a y s to e v a l u a t e o v e r a l l i n d i v i d u a l or l a b o r a t o r y p e r f o r m a n c e in a g i v e n a n a l y s i s , is b y u s e of k n o w n c h e c k s a m p l e s . This i n c l u d e s b o t h i n t r a ( w i t h i n ) the l a b o r a t o r y and i n t e r ( b e t w e e n ) like laboratories. The A m e r i c a n Chemical Society (ACS) in their 1980 Guidelines for Data Quality Evaluation, stated: "At the o u t s e t , a l a b o r a t o r y s h o u l d d e m o n s t r a t e its p r o f i c i e n c y u s i n g prototype and non-critical samples, thereby reducing the probability that bad d a t a w i l l be g e n e r a t e d on c r i t i c a l s a m p l e s , e s p e c i a l l y t h o s e i n v o l v i n g complicated unknown mixtures. An i n t r a l a b o r a t o r y q u a l i t y c o n t r o l p r o g r a m s h o u l d i n c l u d e the use of b l i n d s a m p l e s in a d d i t i o n to c h e c k s a m p l e s w h o s e v a l u e s are k n o w n to the a n a l y s t s . A l l a n a l y s t s s h o u l d be m o n i t o r e d b y the quality control procedures, and any assessment of laboratory performance should include all of the analysts involved, or at least a random selection of those analysts. I n t e r l a b o r a t o r y Q u a l i t y A s s u r a n c e p r o g r a m s s h o u l d also use b l i n d s a m p l e s in a d d i t i o n to c h e c k s a m p l e s , in o r d e r to p r o v i d e a r e a l i s t i c assessment of the performance of the method that is achievable in the field." L a t e r , in 1 9 8 2 , the A C S m a d e an a d d i t i o n a l s t a t e m e n t reliability and acceptability of analysis data:

regarding

improving

" I d e a l l y , for a g i v e n m e t h o d , i n t e r l a b o r a t o r y v a r i a b i l i t y s h o u l d b e the s a m e as i n t r a l a b o r a t o r y v a r i a b i l i t y : In real s i t u a t i o n s , h o w e v e r , the i n t e r l a b o r a t o r y v a r i a b i l i t y is a l m o s t a l w a y s g r e a t e r . T h e r e f o r e , it is necessary to determine for a given method the variability of the m e a s u r e m e n t s ( r a n d o m e r r o r ) b e t w e e n l a b o r a t o r i e s in o r d e r to m a k e a l l o w a n c e s for t h o s e differences in i n t e r p r e t i n g the r e s u l t s of a n a l y s e s . For any p r o p e r l y

61

validated procedure, however, interlaboratory results will be consistent with i n t r a 1 a b o r a t o r y r e s u l t s / t h a t is, t h e u n c e r t a i n t y i n t e r v a l s (including s y s t e m a t i c error b o u n d s ) for all q u a l i f i e d l a b o r a t o r i e s ( i n d i v i d u a l l y and collectively) will overlap the true value. (This presumes that the measurement method, itself, has negligible bias.)" The various

factors

influencing

final

analysis data are shown in Figure 7.2.

DATA

Figure 7.2

During 1984, the U.S. Association of Food and Drug Officials (AFDO) assembled a listing of proficiency and check sample programs available through various U.S. a g e n c i e s and o r g a n i z a t i o n s . The listing is as f o l l o w s , giving c h e c k s a m p l e type, the product involved and the check sample program sponsor:

Check Sample Type

Program Sponsor

Product(s)

Aflatoxins

Milk, Corn

2

Alcohol

Blood

3

Antibiotics

Meat

4

Antibiotics

Milk

6

Arsenic

Meat, Poultry

4

Filters

5

Asbestos

(Number of Fibres)

Bacteriology

Milk, General

Bioassay of Antibiotics

Feed s

8

Cations

Water

9

Cereal

1

Water

9

Cereal

Components

Coliforms

62

Food

6,7

Drinking Water, Fatty

Prograai Sponsor

Product(s)

Check Sample Type Contaminants

Water

9

Fats and

Acids

Oils

2

Fertilizers

Fértilizers

13

Fibre

Fibre

11

Flammables

Various

11

Fluoride

Water

Food

Various

Characterization

Components

Herbicides and Industrial Lead and

Chemicals

FEP

Medicated Metals

Organics

Feeds

(Cations)

Metals and

Foods

Urine and

17

Water

10

Fish

6

Blood

7

Feed s

8

Food

6

Water

Minerals

Microb iology Microscopic

7

14

Various Characterization

Products

18,19

Feed s

15

Mould s

Mycology

7

Organic

Chemicals

Water

Organic

Solvents

Charcoal

Organics

Semi-Volatile

Organochlorine

Tube

Synthetic

Compounds

PCB's and Chlorinated

14

Organics

Leachate

12

Plasma

10

Fat, Blood Meats,

5

Poultry

4

Phosphatase

Milk

6

Protein/Moisture/Fat/Salt

Meat

4

Residues,

Meats,

Pesticide

Poultry

Pesticides/Herbicides

Water

Pesticides/Herbicides

Vegetables,

Smalley Oil

Feed s

2

Milk

6

Somatic

Cell

Meals Count

and Drinking

4

Sulfonamide s

Meats,

Vitamins

Milk, Feed,

Waste Water

Parameters

Water

63

Foods

Poultry Foods

Water

9,10,14 6,16

4 1 9

The U . S . s p o n s o r s

for the above c h e c k sample p r o g r a m s

1.

A m e r i c a n A s s o c i a t i o n of C e r e a l 3340 P i l o t K n o b Road St. P a u l , MN 55121

2.

A m e r i c a n Oil C h e m i s t s Society 508 South Sixth Street C h a m p a i g n , IL 61820

3.

U . S . D e p a r t m e n t of T r a n s p o r t a t i o n Transportation Systems Center, Kendall Cambridge, MA 02142

are

Chemists

Square

4.

U . S . D e p a r t m e n t of A g r i c u l t u r e , FSIS P . O . Box 5080 S t . L o u i s , MO 63115

5.

N a t i o n a l I n s t i t u t e of O c c u p a t i o n a l Safety and H e a l t h C h e m i c a l R e f e r e n c e L a b o r a t o r y (PAT) (R-3) 4676 C o l o m b i a P a r k w a y C i n c i n n a t i , OH 4 5 2 2 6

6.

U . S . Food and D r u g A d m i n i s t r a t i o n 1090 T u s c u l u m A v e n u e C i n c i n n a t i , OH 4 5 2 2 6

7.

U . S . C e n t e r for D i s e a s e C o n t r o l Chief, Performance Evaluation Branch, Laboratory P r o g r a m O f f i c e , A t l a n t a , GA 3 0 3 3 3 Telephone: (404) 329-3847

8.

A m e r i c a n A s s o c i a t i o n of Feed C o n t r o l c/o L a w and C o m p a n y P . O . B o x 1558 A t l a n t a , GA 30301

9.

U . S . Environmental Protection QA B r a n c h , EMSL C i n c i n n a t i , OH 4 5 2 6 8

10.

U . S . E n v i r o n m e n t a l P r o t e c t i o n A g e n c y , QA D i v i s i o n E M S L , P . O . Box 15027 Las V e g a s , NV 89114 T e l e p h o n e : (702) 7 9 8 - 2 1 0 0

11.

Forensic Science Foundation Collaborative Testing Services, Inc. 8343-A Greensboro Drive M c L e a n , V A 22102

12.

A m e r i c a n S o c i e t y for Testing 1916 R a c e S t r e e t P h i l a d e l p h i a , PA 19103

13.

A s s o c i a t i o n of A m e r i c a n Plant Food C o n t r o l O f f i c i a l s c/o W . Penn Z e n t m e y e r V A D e p a r t m e n t of A g r i c u l t u r e and C o n s u m e r S e r v i c e s P . O . Box 1163 R i c h m o n d , VA 23201 Telephone: (804) 786-3511

Officials

Agency

Material

64

14.

U.S. Geological Survey 5293 Ward Road Arvada, CO 80002 Telephone: (303) 234-3975

15.

American Association of Feed Attn: Mrs. Janet Windsor 1118 Apple Drive Mechanicsburg, PA 17055

16.

Association of Food and Drug Officials of the Southern States c/o George Fong Division of Chemistry Florida Department of Agriculture and Consumer Services 3125 Connor Boulevard Tallahassee, FL 32301

17.

National Food Processors Association 1133 20th Street, NW Washington, DC 20016 Telephone: (202) 331-5955

18.

College of American Pathologists 7400 N. Skokie Boulevard Skokie, IL 60077 Telephone: (312) 677-3500

19.

American Association of Bioanalysts Proficiency Testing Service 205 W. Levee Street Brownsville, TX 78520 Telephone: (512) 546-5315

Microscopists

It is a d v i s a b l e to p a r t i c i p a t e in as m a n y i n t e r - 1 a b o r a t o r y c h e c k s a m p l e p r o g r a m s as are a v a i l a b l e in the a r e a s of i n t e r e s t to the l a b o r a t o r y . The s p o n s o r i n g o r g a n i z a t i o n s u s u a l l y p r o v i d e a s u m m a r y r e p o r t to p a r t i c p a t i n g l a b o r a t o r i e s , w h i c h g i v e s an e v a l u a t i o n of the l a b o r a t o r y ' s p e r f o r m a n c e as compared to o t h e r p a r t i c i p a n t s . T h e i n t e r - 1 a b o r a t o r y p r o g r a m can be supplemented by an intra program to highlight specific areas of concern which W h e n s e l e c t i n g s a m p l e s for an are n o t c o v e r e d in the inter p a r t i c i p a t i o n . intra program, the following considerations should be taken into account: 1.

The capability laboratory.

to analyze

the

sample must be w i d e l y available

2.

The analytical method must be one that

3.

The sample should cover a variety of analytical identification steps if possible.

4.

The product must be readily available and reasonable

is generally

in the

employed.

techniques,

including

in cost.

A l w a y s keep in mind that the evaluation of check sample results must include all aspects of the analysis. In cases where there is a large discrepancy from the expected or true result, the laboratory must investigate all aspects of the analysis (as given in Figure 7.2) to d e t e r m i n e w h a t specific analysis area or areas are suspect. From this, the laboratory should take appropriate action to prevent reoccurrence of a similar difficulty.

65

7.7

Other QA Activities

Some important QA review programmes were discussed in the preceding Sections. Many other areas of laboratory operations would also benefit from QA review. Keeping in mind the definition for Quality Assurance given in Section 7.1, any l a b o r a t o r y o p e r a t i o n can be r e v i e w e d to d e t e r m i n e if c o r r e c t p r o c e d u r e s are being followed and to identify procedural weaknesses.' Examples are:

1. S a f e t y - The laboratory safety programme can be periodically reviewed (about every three months) to determine that safety and emergency materials are on hand and b e i n g used. T h i s w o u l d i n c l u d e a c h e c k of any i n j u r y or a c c i d e n t records and a review that appropriate follow-up corrective measures were taken. 2. S u p p l y M a n a g e m e n t - R e f e r e n c e s t a n d a r d h a n d l i n g and s t o r a g e w a s discussed earlier. The s a m e g e n e r a l p r i n c i p l e s a p p l y to all l a b o r a t o r y supplies, such as glassware, chemicals, solvents and others. A QA review would focus on whether supplies are being ordered, stored and distributed properly. 3. S a m p l e M a n a g e m e n t - The s a m p l e s r e c e i v e d by the l a b o r a t o r y for analysis must be accounted for. This is even more critical when the laboratory is i n v o l v e d in food l a w e n f o r c e m e n t . An a c c o u n t a b i l i t y s y s t e m s h o u l d be e s t a b l i s h e d and in o p e r a t i o n (see S e c t i o n s 4.2 and 4.3). The QA r e v i e w w o u l d determine that the system is working properly and that samples are accounted for throughout their receipt, storage, analysis and final disposition. 4. T r a i n i n g - This m a y s e e m an odd area for QA r e v i e w , but it r a n k s in importance to most other laboratory operations. A QA review of training could i n c l u d e c h e c k s of o n g o i n g f o r m a l t r a i n i n g p r o g r a m m e s for n e w a n a l y s t s and checks of training needs and records for experienced analysts. The importance of t r a i n i n g c a n n o t be o v e r e m p h a s i z e d and a QA r e v i e w p r o g r a m m e o f t e n g i v e s training needed visibility to management.

The above are only examples and laboratory management must select with care the o p e r a t i o n a l areas n e e d e d for Q u a l i t y A s s u r a n c e r e v i e w . R e m e m b e r that any laboratory function can be (and often should be) subject to QA review.

7.8

Text

1.

G A R F I E L D , F.M., Laboratories, 2. VA, U.S.A.

2.

ISO Guide 25, 1982. General Requirements for the Technical Competence Testing Laboratories. International Organization for Standards.

3.

INTERNATIONAL LABORATORY Report of Task Force D.

Farther

References 1985. Q u a l i t y A s s u r a n c e P r i n c i p l e s for A n a l y t i c a l Association of Official Analytical Chemists, Arlington,

ACCREDATION

CONFERENCE,

London.

Oct.

of

1984.

Reading

B E R M A N , G.A. (Ed.) 1980. Testing Laboratory Performance: Accreditation, NBS P u b l i c a t i o n 591, National Bureau Gaithersburg, MD, U.S.A.

E v a l u a t i o n and of Standards,

Chemistry Quality Assurance Handbook, Volume 1, Principles, U.S. Department Agriculture, Food Safety and Inspection Service, Washington, DC, U.S.A.

66

of

D U N C A N , A.J. 1974. Q u a l i t y C o n t r o l and I n d u s t r i a l Richard D. Irwin, Inc., Homewood, IL., U.S.A.

Statistics,

4th

Ed.,

G A R F I E L D , F.M. et al (Ed.) 1980. O p t i m i z i n g C h e m i c a l L a b o r a t o r y P e r f o r m a n c e T h r o u g h the A p p l i c a t i o n of Q u a l i t y A s s u r a n c e P r i n c i p l e s , A s s o c i a t i o n of Official Analytical Chemists, Arlington, VA, U.S.A. H O R W I T Z , W. 1981. A C S S y m p o s i u m S e r i e s No. 1 6 0 , T h e P e s t i c i d e C h e m i s t and Modern Toxicology, "Analytical M e a s u r e m e n t s : H o w Do You K n o w Your Results Are Right". American Chemical Society, Washington, DC, U . S . A . INHORN, S.L. (Ed.) 1977. Quality Assurance Practices for Health American Public Health Association, Washington, DC, U.S.A. JURAN, J.M. & GRYNA, F.M. J U R A N , J.M., McGraw-Hill.

GRYNA,

1980.

Quality

F.M. & B I N G H A M ,

Planning

B.S.

1974.

and Analysis, Quality

Laboratories,

McGraw-Hill.

Control

Handbook,

SHERMA, J. (Ed.) 1976. Manual of Analytical Quality Control for Pesticides in H u m a n and Environmental Media, U.S. Environmental Protection Agency, Research Triangle Park, NC, U.S.A. Y O U D E N , W.J. & S T E I N E R , E.H. 1975. S t a t i s t i c a l M a n u a l of Association of Official Analytical Chemists, Arlington, VA, U.S.A.

67

the

AOAC,

F A O T E C H N I C A L PAPERS F A O F O O D A N D N U T R I T I O N PAPERS 1/1 1/2

R e v i e w of f o o d c o n s u m p t i o n surveys 1 9 7 7 Vol. 1. Europe, N o r t h A m e r i c a , Oceania, 1 9 7 7 (E) R e v i e w of f o o d c o n s u m p t i o n s u r v e y s 1 9 7 7 V o l . 2 . A f r i c a , Latin A m e r i c a , Near East, Far East, 1 9 7 9 (E)

2

Report of t h e joint F A O / W H O / U N E P c o n f e r e n c e o n m y c o t o x i n s , 1 9 7 7 (E F S)

3

Report o f a j o i n t F A O / W H O expert c o n s u l t a t i o n o n dietary f a t s and oils in h u m a n nutrition,

4

JECFA s p e c i f i c a t i o n s for i d e n t i t y and purity of t h i c k e n i n g a g e n t s , a n t i c a k i n g agents, a n t i m i c r o b i a l s , a n t i o x i d a n t s and emulsifiers,

18 Rev. 1

Bibliography of f o o d c o n s u m p t i o n s u r v e y s , 1 9 8 4 (E)

18 Rev. 2

Bibliography of f o o d c o n s u m p t i o n s u r v e y s , 1 9 8 7 (E)

18 Rev. 3

Bibliography of f o o d c o n s u m p t i o n s u r v e y s , 1 9 9 0 (E)

19

JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of carrier s o l v e n t s , emulsifiers and stabilizers, e n z y m e preparations, f l a v o u r i n g a g e n t s , f o o d colours, s w e e t e n i n g agents and o t h e r f o o d additives, 1 9 8 1 (E F)

20 21 22

Legumes in h u m a n n u t r i t i o n , 1 9 8 2 (E F S) M y c o t o x i n surveillance - a guideline, 1 9 8 2 (E) Guidelines for agricultural t r a i n i n g curricula in A f r i c a , 1 9 8 2 (E F)

23

M a n a g e m e n t of g r o u p f e e d i n g p r o g r a m m e s , 1 9 8 2 (E F P S) Food and n u t r i t i o n in t h e m a n a g e m e n t of g r o u p feeding p r o g r a m m e s , 1 9 9 3 (E F S) Evaluation o f n u t r i t i o n i n t e r v e n t i o n s , 1 9 8 2 (E) JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of b u f f e r i n g agents, salts; e m u l s i f i e r s , t h i c k e n i n g a g e n t s , stabilizers; f l a v o u r i n g a g e n t s , f o o d colours, s w e e t e n i n g agents and m i s c e l l a n e o u s f o o d additives, 1 9 8 2 (E F) Food c o m p o s i t i o n tables for t h e Near East,

1 9 7 7 (E F S)

1 9 7 8 (E) 5 5 Rev. 1 5 Rev. 2

JECFA - guide t o s p e c i f i c a t i o n s , 1 9 7 8 (E F) JECFA - guide t o s p e c i f i c a t i o n s , 1 9 8 3 (E F) JECFA - guide t o s p e c i f i c a t i o n s , 1 9 9 1 (E)

6

The f e e d i n g of w o r k e r s in developing countries, 1 9 7 6 (E S) JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of f o o d c o l o u r s , e n z y m e preparations and other f o o d a d d i t i v e s , 1 9 7 8 (E F)

7

8

W o m e n in f o o d p r o d u c t i o n , f o o d handling and n u t r i t i o n , 1 9 7 9 (E F S)

9

A r s e n i c and t i n in f o o d s : r e v i e w s of c o m m o n l y u s e d m e t h o d s of analysis, 1 9 7 9 (E)

10 11 12

P r e v e n t i o n of m y c o t o x i n s , 1 9 7 9 (E F S) The e c o n o m i c value of breast-feeding, 1 9 7 9 (E F) JECFA s p e c i f i c a t i o n s for i d e n t i t y and purity of f o o d c o l o u r s , f l a v o u r i n g agents and other f o o d a d d i t i v e s , 1 9 7 9 (E F)

2 3 Rev. 1 24 25

26 27 28

1 9 8 3 (E) Review of f o o d c o n s u m p t i o n s u r v e y s 1 9 8 1 , 1 9 8 3 (E) JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of b u f f e r i n g agents, salts, e m u l s i f i e r s , stabilizers, t h i c k e n i n g agents, e x t r a c t i o n s o l v e n t s , f l a v o u r i n g agents, s w e e t e n i n g agents and m i s c e l l a n e o u s f o o d additives, 1 9 8 3 (E F) Post-harvest losses in quality of f o o d grains, 1 9 8 3 (E F)

13

Perspective o n m y c o t o x i n s , 1 9 7 9 (E F S)

14 14/1 1 4 / 1 Rev.1

Manuals of food quality control: Food c o n t r o l l a b o r a t o r y , 1 9 7 9 (Ar E) The f o o d c o n t r o l laboratory, 1 9 8 6 (E)

14/2

A d d i t i v e s , c o n t a m i n a n t s , t e c h n i q u e s , 1 9 8 0 (E)

14/3 14/4

C o m m o d i t i e s , 1 9 7 9 (E) M i c r o b i o l o g i c a l analysis, 1 9 7 9 (E F S)

30

F A O / W H O f o o d additives d a t a s y s t e m , 1 9 8 4 (E)

3 0 Rev. 1

14/5 14/6 1 4 / 6 Rev.1 14/7

Food Food Food Food

31/1

F A O / W H O f o o d additives data s y s t e m , 1 9 8 5 (E) JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of f o o d colours, 1 9 8 4 (E F)

c o n t a m i n a n t s and c o m p o s i t i o n , 1 9 8 6 (C E) Food analysis: q u a l i t y , adulteration and t e s t s of

32

14/8

i d e n t i t y , 1 9 8 6 (E) I n t r o d u c t i o n t o f o o d s a m p l i n g , 1 9 8 8 (Ar C E F S) T r a i n i n g in m y c o t o x i n s analysis, 1 9 9 0 (E S) M a n a g e m e n t of f o o d c o n t r o l p r o g r a m m e s ,

33

14/9 14/10 14/11

1 9 9 1 (E) Q u a l i t y a s s u r a n c e in the f o o d c o n t r o l m i c r o b i o l o g i c a l laboratory, 1 9 9 2 (E F S) Pesticide residue analysis in t h e f o o d c o n t r o l l a b o r a t o r y , 1 9 9 3 (E F) Q u a l i t y assurance in t h e f o o d c o n t r o l chemical

35

R e v i e w of f o o d c o n s u m p t i o n s u r v e y s 1 9 8 5 , 1 9 8 6 (E)

36

Guidelines for c a n m a n u f a c t u r e r s and f o o d canners, 1 9 8 6 (E) JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of certain f o o d additives, 1 9 8 6 (E F)

l a b o r a t o r y , 1 9 9 3 (E) I m p o r t e d f o o d inspection, 1 9 9 3 (E F) Radionuclides in f o o d , 1 9 9 4 (E) C a r b o h y d r a t e s in h u m a n nutrition, 1 9 8 0 (E F S) A n a l y s i s of f o o d c o n s u m p t i o n s u r v e y data for d e v e l o p i n g c o u n t r i e s , 1 9 8 0 (E F S) JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of s w e e t e n i n g a g e n t s , e m u l s i f y i n g agents, f l a v o u r i n g a g e n t s and other f o o d additives, 1 9 8 0 (E F) Bibliography of f o o d c o n s u m p t i o n s u r v e y s , 1 9 8 1 (E)

38

JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of certain f o o d additives, 1 9 8 8 (E)

39

Quality c o n t r o l in f r u i t and v e g e t a b l e p r o c e s s i n g , 1 9 8 8 (E F S) D i r e c t o r y of f o o d and n u t r i t i o n i n s t i t u t i o n s in the Near East, 1 9 8 7 (E) Residues of s o m e v e t e r i n a r y d r u g s in animals and f o o d s , 1 9 8 8 (E)

14/12 14/13 14/14 14/15 14/16 15 16 17

18

inspection, 1981 for e x p o r t , 1 9 7 9 for e x p o r t , 1 9 9 0 analysis: general

(Ar E) (Rev. 1 9 8 4 , E S) (E S) (E S) t e c h n i q u e s , additives,

29

31/2

JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of f o o d additives, 1 9 8 4 (E F)

34

37

40 41 41/2

Residues of v e t e r i n a r y d r u g s in f o o d s , 1 9 8 5 (E/F/S) Nutritional implications of f o o d aid: an a n n o t a t e d bibliography, 1 9 8 5 (E) JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of certain f o o d additives, 1 9 8 6 (E F)

Residues of s o m e v e t e r i n a r y d r u g s in animals and f o o d s . T h i r t y - f o u r t h m e e t i n g of t h e j o i n t F A O / W H O Expert C o m m i t t e e o n Food A d d i t i v e s , 1 9 9 0 (E)

41/3

41/4

Residues of s o m e veterinary drugs in animals and f o o d s . T h i r t y - s i x t h m e e t i n g of the joint F A O / W H O Expert C o m m i t t e e o n Food A d d i t i v e s , 1 9 9 1 (E) Residues of s o m e v e t e r i n a r y drugs in animals and

55

Sampling plans for a f l a t o x i n analysis in p e a n u t s and c o r n , 1 9 9 3 (E)

56

Body m a s s index - A m e a s u r e of c h r o n i c energy d e f i c i e n c y in adults, 1 9 9 4 (E F S) Fats and oils in h u m a n n u t r i t i o n , 1 9 9 5 (Ar E F S)

f o o d s . T h i r t y - e i g h t h m e e t i n g of t h e joint F A O / W H O Expert C o m m i t t e e o n Food A d d i t i v e s , 1 9 9 1 (E)

57 58

The use of hazard analysis critical c o n t r o l point (HACCP) principles in f o o d c o n t r o l , 1 9 9 5 (E F S)

41/5

Residues of s o m e veterinary drugs in animals and

59 60

N u t r i t i o n e d u c a t i o n for t h e public, 1 9 9 5 (E F S) Food f o r t i f i c a t i o n : t e c h n o l o g y and quality c o n t r o l , 1 9 9 6 (E)

41/6

f o o d s . Fortieth m e e t i n g of t h e J o i n t F A O / W H O Expert C o m m i t t e e on Food A d d i t i v e s , 1 9 9 3 (E) Residues of s o m e v e t e r i n a r y drugs in animals and

61 62

B i o t e c h n o l o g y and f o o d s a f e t y , 1 9 9 6 (E) N u t r i t i o n e d u c a t i o n for t h e public - D i s c u s s i o n papers of t h e FAO Expert C o n s u l t a t i o n , 1 9 9 6 (E)

63 64

Street f o o d s , 1 9 9 7 (E/F/S) W o r l d w i d e regulations for m y c o t o x i n s 1 9 9 5 - A c o m p e n d i u m , 1 9 9 7 (E) Risk m a n a g e m e n t and f o o d s a f e t y , 1 9 9 7 (E)

f o o d s . F o r t y - s e c o n d m e e t i n g of the J o i n t F A O / W H O Expert C o m m i t t e e on Food A d d i t i v e s , 1 9 9 4 (E) 41/7

41/8

Residues of s o m e f o o d s . Forty-third Expert C o m m i t t e e Residues of s o m e

veterinary d r u g s in animals and m e e t i n g of t h e J o i n t F A O / W H O o n Food A d d i t i v e s , 1 9 9 4 (E) veterinary drugs in animals and

41/9

f o o d s . F o r t y - f i f t h m e e t i n g of t h e J o i n t F A O / W H O Expert C o m m i t t e e o n Food A d d i t i v e s , 1 9 9 6 (E) Residues of s o m e v e t e r i n a r y drugs in animals and f o o d s . F o r t y - s e v e n t h m e e t i n g of t h e J o i n t F A O / W H O Expert C o m m i t t e e o n Food A d d i t i v e s , 1 9 9 7 (E)

65

Availability: November 1 9 9 7 Ar

-

Arabic

C E F

-

Chinese English French

Multil

Multilingual Out of print In preparation

42 42/1

Traditional f o o d plants, 1 9 8 8 (E) Edible plants of Uganda. The value o f w i l d and

P

-

Portuguese

S

-

Spanish

43

c u l t i v a t e d plants as f o o d , 1 9 8 9 (E) Guidelines for agricultural training curricula in A r a b c o u n t r i e s , 1 9 8 8 (Ar)

44

R e v i e w of f o o d c o n s u m p t i o n s u r v e y s 1 9 8 8 ,

FAO Sales Agents

FAO. Viale delle Terme di Caracalla, 00100Rome,

45 46

1 9 8 8 (E) Exposure of i n f a n t s and children t o lead, 1 9 8 9 (E) S t r e e t f o o d s , 1 9 9 0 (E/F/S)

47/1

Utilization of t r o p i c a l f o o d s : cereals, 1 9 8 9 (E F S)

47/2 47/3 47/4

Utilization of t r o p i c a l f o o d s : roots and t u b e r s , 1 9 8 9 (E F S) Utilization of t r o p i c a l f o o d s : trees, 1 9 8 9 (E F S) Utilization o f t r o p i c a l f o o d s : tropical beans,

47/5

1 9 8 9 (E F S) Utilization of t r o p i c a l f o o d s : t r o p i c a l oil seeds, 1 9 8 9 (E F S)

47/6 47/7 47/8

Utilization of t r o p i c a l f o o d s : sugars, spices and s t i m u l a n t s , 1 9 8 9 (E F S) Utilization of t r o p i c a l f o o d s : fruits and leaves, 1 9 9 0 (E F S) Utilization of t r o p i c a l f o o d s : animal p r o d u c t s , 1 9 9 0 (E F S)

48

N u m b e r not assigned

49

JECFA s p e c i f i c a t i o n s for i d e n t i t y and purity of c e r t a i n f o o d additives, 1 9 9 0 (E)

50 51

Traditional f o o d s in the Near East, 1 9 9 1 (E) Protein quality evaluation. Report of t h e J o i n t F A O / W H O Expert C o n s u l t a t i o n , 1 9 9 1 (E F)

52/1

C o m p e n d i u m of f o o d additive s p e c i f i c a t i o n s V o l . 1, 1 9 9 3 (E) C o m p e n d i u m of f o o d additive s p e c i f i c a t i o n s -

52/2

V o l . 2 , 1 9 9 3 (E) 52 Add. 1 52 Add. 2 52 Add. 3 52 Add. 4 52 Add. 5 53 54

C o m p e n d i u m of f o o d additive A d d e n d u m 1, 1 9 9 2 (E) C o m p e n d i u m of f o o d additive A d d e n d u m 2, 1 9 9 3 (E) C o m p e n d i u m of f o o d additive A d d e n d u m 3, 1 9 9 5 (E) C o m p e n d i u m of f o o d additive A d d e n d u m 4 , 1 9 9 6 (E)

specifications specifications specifications specifications -

C o m p e n d i u m of f o o d additive s p e c i f i c a t i o n s A d d e n d u m 5, 1 9 9 7 (E) M e a t and m e a t p r o d u c t s in h u m a n n u t r i t i o n in d e v e l o p i n g c o u n t r i e s , 1 9 9 2 (E) N u m b e r not assigned

The FAO Technical Papers are available or directly

through

the

authorized

from Sales and Marketing Italy•

Group,

- --

'

'

'

». •

. • ••

.

- -• -

'

. .

I

ISBN 92-5-102489-8

9 M

.87

7 8 9 2 5 1

ISSN 0254-4725

0 2 4 8 9 8 T0432E/2/9.97/500

ISSN 0254-4725

Manuals of food quality control 1. The food control laboratory

FAO FOOD AND NUTRITION PAPER

Rev. 1

Food and Agriculture Organization of the United Nations

Manuals of food quality control 1. The food control laboratory

FAO FOODAND NUTRITION PAPER

14/1

Rev. 1

by P.G. Martin

revised by J. Weatherwax

and P.G. Martin

p r e p a r e d with the support of the S w e d i s h International Development Authority (SIDA)

Food and Agriculture Organization of the United Nations

Rome, 1997

Reprinted 1997

The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, orconcerning the delimitation of its frontiers or boundaries.

M-87 ISBN 92-5-102489-8

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying or otherwise, without the priorpermission of the copyright owner. Applications for such permission, with a statement of the purpose and extent of the reproduction, should be addressed to the Director, Information Division, Food and Agriculture Organization of the United Nations, Viale delle Terme di Caracalla, 00100 Rome, Italy. © FAO 1986

FOREWORD

T h e c o n t r o l of food safety and quality is an integral part of n a t i o n a l programmes for development. National food control systems are designed to protect the health and welfare of the consumer, to promote the development of trade in food and food products, and to protect the interests of the fair and h o n e s t food p r o d u c e r , processor or m a r k e t e r against dishonest and unfair competition. Emphasis is placed on the prevention of chemical and biological hazards which result from contamination, adulteration or simple mishandling of foods. Also important are the maintenance of general food quality and the control of the use of food additives and food processing procedures. In order must :

to

establish

a workable

food

control

system,

a

national

government

1.

Enact food control legislation.

2.

Promulgate regulations to enforce that legislation.

3.

Create an agency to cond uct the enforcement.

4.

Establish food inspection agencies concerned.

5.

Provide physical facilities including a food control laboratory.

and

analysis

staff

within

the

agency

or

To assist the national governments of developing countries in this process, FAO, with the support of the Swedish International Development Authority (SIDA) has published the series Manuals of Food Quality Control. These are incorporated as part of the FAO Food and Nutrition Paper Series No. 14, and include: No. 14/1 rev. 1

The Food Control Laboratory (revised, 1986)

No. 14/2

Additives, Contaminants, and Techniques by No. 14/7)

No. 14/3

Commodities (replaced by No. 14/8)

No. 14/4

Microbiological Analysis

No. 14/5

Food

No. 14/6

Food for Export

No. 14/7

Food Analysis: General Techniques, Additives, Contaminants, and Composition

No. 14/8

Food Analysis: Identity

(replaced

Inspection

Quality, Adulteration, and Tests of

In a d d i t i o n , FAO, WHO and UNEP jointly have published many guidelines and other documents designed to further assist developing countries in forming adequate food control systems. These publications include: Methods of Sampling and Analysis of Contaminants in Food A Report of the Second Joint FAO/WHO Expert Consultation, Rome - 1978 Guidelines for Establishing or Strengthening National Food C o n t a m i n a t i o n M o n i t o r i n g Programmes - FAO Food Control Series No. 5 - 1979

iii

Guidelines for the Study of Dietary Intakes of Chemical Contaminants - WHO Offset Publication No. 87 - 1985 Guide to Codex Recommendations concerning Residues, Part 2 - Maximum Limits for Pesticide Second Preliminary Issue - Rome - 1985

Pesticide Residues,

Recommended Practices for the Prevention of Mycotoxins in F o o d , Feed and their Products - FAO Food and N u t r i t i o n Paper No. 10, Rome - 1979 Food Standards, Codes of Practice and Methods of Analysis Recommended by the Codex Alimentarius Commission - Joint FAO/WHO Food Standards Programme (several titles) Food Additive Evaluations and Specifications of Purity and I d e n t i t y - Reports and M o n o g r a p h s of the Joint F A 0 / W H 0 Expert Committee on Food Additives (several titles) The above publications, and others, are available to persons and organizations. FAO is also interested in receiving comments regarding this volume and suggestions for future improvement. Please send to: The Chief Food Quality and Standards Service Food Policy and Nutrition Division Food and Agriculture Organization of the United Nations Via delle Terme di Caracalla 00100 Rome, Italy FAO wishes Development of M r . J.* preparation

to acknowledge the generous support of the Swedish International Authority (SIDA), in the preparation of this volume, and the efforts W e a t h e r w a x and M r . P.G. Martin who were responsible for the of the text.

TABLE OF CONTENTS

FOREWORD

1.

SCOPE OF THE FOOD CONTROL LABORATORY MANUAL

2.

LABORATORY 2.1 2.2 2.3 2.4 2.5 2.6 2.7

3.

Establishing the Laboratory Organizational Structure Head of the Laboratory Supervisors Team Leaders Analytical Staff Support Staff

2 3 3 4 5 5 6

General Considerations Basic Structure of the Building Safety Features Ventilation and Air Conditioning Space Utilization Equipment and Instruments Utilities Design References

7 7 10 12 13 15 16 18

LABORATORY ADMINISTRATION 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9

5.

ORGANIZATION

LABORATORY DESIGN 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8

4.

1

Sample Collection Sample Receipt and Assignment Sample Storage and Disposal Budget Purchasing Supplies Management Equipment Maintenance Housekeeping Training

LABORATORY 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8

20 21 22 23 23 26 26 28 28

OPERATIONS

Workp lans Priorities for Analysis Analysis Assignment Analysis Control Analysis Reporting Analysis Review Method Validation Confirming Analysis

. . . . .

v

29 31 31 32 32 33 34 34

6.

LABORATORY 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8

7.

SAFETY

The Safety Programme Basic Safety Rules Fire Safety Chemical Hazards Biological Hazards Physical Hazards Safety and Emergency Equipment First Aid

LABORATORY QUALITY ASSURANCE 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8

35 35 36 37 38 40 42 43

(QA)

Introduction Establishing a QA Programme QA of Reference Standards QA of Instruments QA of Analytical Reports Check Sample Examination Other QA Activities Text References

46 46 49 « . . 55 58 61 66 66

vi

1.

SCOPE OF THE FOOD CONTROL LABORATORY M A N U A L

This m a n u a l is p r i m a r i l y a p r a c t i c a l h a n d b o o k on the e s t a b l i s h m e n t of a food control laboratory. The v a r i o u s organizational, administrative, operational, and d e s i g n c r i t e r i a are d i s c u s s e d in s o m e d e t a i l . A l s o i n c l u d e d is a discussion of laboratory safety to stress the importance of safe operation and the inherent hazards always present in an analytical laboratory. The manual is designed for laboratory management and administration personnel, but the o p e r a t i n g a n a l y s t can g a i n good i n f o r m a t i o n and i n s i g h t s into the problems involved in establishing and operating a food control laboratory. The u s e r of this m a n u a l should a l w a y s k e e p in m i n d that the i n f o r m a t i o n and principles presented are advisory only and represent recommendations on how a food control laboratory may be organized, arranged, etc., not how it must be. This manual is intended as a guide, to help a new laboratory get off to a good s t a r t , or to g u i d e an e s t a b l i s h e d l a b o r a t o r y in w h i c h w o r k is e x p a n d i n g and diversifying. As time goes by, experience builds up and a laboratory tends to develop new methods, modify existing ones or adapt them to other products. All this valuable information should be retained and, if possible, combined with this manual and manuals No. 14/2 and 14/3 in a readily accessible form. At the s a m e t i m e , the a n a l y s t m u s t r e m e m b e r that r e l i a b l e r e s u l t s w i l l o n l y be o b t a i n e d by s t r i c t a d h e r e n c e to the d e t a i l s that m a t t e r and to c a r e f u l and professional work. Analytical chemistry is an exact science, very demanding on the manipulative skills of the worker at the bench. There is no substitute for e x p e r i e n c e but it is hoped this m a n u a l w i l l form a u s e f u l guide w h i l e that experience is developing as well as during routine laboratory operations. Any c o m m e n t s or s u g g e s t i o n s for i m p r o v e m e n t s w i l l be w e l c o m e . T h e s e should be addressed to the address given in the Foreword. The first e d i t i o n of this m a n u a l w a s w r i t t e n in 1977 by Mr. Peter G. M a r t i n , p r e s e n t l y of L y n e , M a r t i n and R a d f o r d , P u b l i c A n a l y s t s , R e a d i n g , B e r k s h i r e , England. The p r e s e n t r e v i s e d e d i t i o n has b e e n p r e p a r e d w i t h Mr. M a r t i n ' s support and assistance by Mr. John Weatherwax, retired Laboratory Director for the United States Food and Drug Administration, Los Angeles, California, USA.

1

2.

2.1

Establishing

the

LABORATORY

ORGANIZATION

Laboratory

The publication, "Guidelines for Developing an Effective National Food Control System", F A O / W H O / U N E P , FAO, Rome, 1976, details the formation of a food control system embodied in a national food quality control service. The purposes of a n a t i o n a l food q u a l i t y c o n t r o l s e r v i c e are to e n s u r e a s u p p l y of s a f e , nutritious and honestly presented food; to protect consumers from foods which are c o n t a m i n a t e d , decomposed, adulterated, injurious or packaged or labelled in a false or misleading way; to promote better quality control of foods by food p r o c e s s o r s and d i s t r i b u t o r s and t h e r e b y e n c o u r a g e d e v e l o p m e n t of the food i n d u s t r y and to i m p r o v e e x p o r t p o t e n t i a l and e n a b l e b e t t e r c o n t r o l of food import s. When consumers and buyers have confidence in the quality and safety of foods, trade increases at both local and international levels. Increased local demand e n c o u r a g e s i n d u s t r y and i n t e r n a t i o n a l t r a d e brings better returns in foreign exchange capital. T h i s c a n a l s o lead to n a t i o n a l d i e t s b e c o m i n g m o r e v a r i e d and n u t r i t i o u s w i t h l o c a l p r o d u c t s o f t e n s u b s t i t u t e d for c o s t l y i m p o r t s . B e s i d e s the o b v i o u s e c o n o m i c and p u b l i c h e a l t h b e n e f i t s , the a d v a n t a g e s in social terms can also be considerable. In m a n y g o v e r n m e n t s t r u c t u r e s t h e r e are s t a f f and f a c i l i t i e s l o c a t e d in d i f f e r e n t a g e n c i e s that a r e i n v o l v e d in s o m e or all a s p e c t s of food c o n t r o l , b u t t h e i r e f f o r t s are o f t e n not h i g h l y e f f e c t i v e due to lack of f a c i l i t i e s , expertise or an adequate legal or a d m i n i s t r a t i v e f r a m e w o r k . These resources s h o u l d be b r o u g h t t o g e t h e r into a u n i f i e d s t r u c t u r e in such a w a y that the p e r s o n n e l a r e b e s t u t i l i z e d and h a v e c l e a r o b j e c t i v e s w i t h the f a c i l i t i e s to c a r r y t h e m out. T h e r e s u l t w o u l d be a p r o p e r l y l i n k e d i n s p e c t o r a t e and l a b o r a t o r y w i t h the n e c e s s a r y a d m i n i s t r a t i v e and l e g a l s u p p o r t i n c l u d i n g , w h e n e v e r possible, an Advisory Board to provide guidance and coordination at national l e v e l . This manual deals only with the establishment of the food control laboratory, a l t h o u g h it is o n l y o n e c o m p o n e n t of a n a t i o n a l food c o n t r o l s e r v i c e . It laboratory there must be a should be n o t e d that f o r an e f f e c t i v e correspondingly effective inspectorate. In a f e w c o u n t r i e s t h e r e is no p r o v i s i o n for an i n s p e c t o r a t e and s a m p l e s are o f t e n o b t a i n e d by the a n a l y s t , thereby using potential analytical time. Having samples submitted by the food industry saves sample collection time, but is inherently a bad practice because the samples cannot be assured of being representative. A food c o n t r o l l a b o r a t o r y is a c o s t l y f a c i l i t y to e s t a b l i s h , so b e s t r e s u l t s will be achieved if the functions of the laboratory are confined to activities r e s u l t i n g f r o m the e n f o r c e m e n t of food l a w , g e n e r a l s u r v e y s on q u a l i t y of f o o d s , e x p o r t / i m p o r t i n s p e c t i o n w o r k and w o r k of an i n v e s t i g a t i o n a l n a t u r e relating to food quality. However, it may, for reasons of economy and o p t i m u m u t i l i z a t i o n of the f a c i l i t i e s , b e c o m e n e c e s s a r y to t a k e up o t h e r s e l e c t e d analytical work provided the laboratory is appropriately equipped. Advice or a n a l y s i s on a fee b a s i s to l o c a l i n d u s t r y m a y be j u s t i f i e d if t h i s d o e s n o t conflict with statutory duties or other government bodies and there are clear guidelines. Such analyses are carried out for advisory purposes and in no way are a substitute for normal food control work.

2

2.2

Organizational

The staffing

Structure

structure

of a typical

food

Head of

Analytical Staff

control

laboratory

is as

follows:

Laboratory

Support Staff

Administrative Staff

The o f f i c e of Head of L a b o r a t o r y ( o t h e r t i t l e s such as " C h i e f " or " D i r e c t o r " a r e o f t e n u s e d ) m a y i n c l u d e a D e p u t y if the l a b o r a t o r y s t a f f is s u f f i c i e n t l y large. U s u a l l y , h o w e v e r , the d u t i e s of the H e a d , in h i s or her a b s e n c e , are assumed by a senior supervisor of the analytical staff. The analytical and support staffs are discussed b e l o w in Sections 2.6 and 2.7, respectively. The administrative staff includes all administrative assistance such as a s e c r e t a r y , t y p i n g and f i l i n g c l e r k s , a m a n a g e m e n t a s s i s t a n t and a librarian (if the laboratory library is of a size to need one). Basically the a d m i n i s t r a t i v e s t a f f are t h o s e p e r s o n s g e n e r a l l y i n v o l v e d in " o f f i c e " or "paperwork" functions. This staff is very important to the smooth operation of a laboratory. It is false e c o n o m y to u n d e r s t a f f the a d m i n i s t r a t i v e g r o u p because their work often m u s t then be done in part by the analytical or support staffs . The secretary for the laboratory generally works directly for the Head. good practice, h o w e v e r , to m a k e the secretary responsive to secretarial of the supervisors.

2.3

Head

of the

It is needs

Laboratory

The H e a d of the l a b o r a t o r y s h o u l d be a g r a d u a t e c h e m i s t or m i c r o b i o l o g i s t trained in food analysis. A postgraduate d i p l o m a particularly relevant to this w o r k is h i g h l y d e s i r a b l e . A l t h o u g h the d u t i e s of the h e a d of the l a b o r a t o r y are m a n y , s o m e m a y be d e l e g a t e d and o t h e r s u n d e r t a k e n b y o t h e r p a r t s of the food control administration. It is therefore not appropriate to do more than d r a w a t t e n t i o n to c e r t a i n a s p e c t s . The o b j e c t i v e of the l a b o r a t o r y is to analyze a large number of samples correctly, quickly and cheaply. This means t h a t a t t e n t i o n m u s t be paid to c a r e f u l s p e n d i n g of the b u d g e t , p r o m o t i o n of good staff relations and maintenance of the highest possible level of technical efficiency and expertise. The laboratory Head may have to give evidence in court or write documents used in c o u r t , in w h i c h c a s e he m u s t h a v e a t h o r o u g h u n d e r s t a n d i n g of food and related law and court procedure. There will also be involvement in c o m m i t t e e work and relations with other organizations. The laboratory Head is usually the spokesman for the laboratory in many instances. The Head must prepare work p l a n s w i t h the i n s p e c t o r a t e and o v e r a l l food c o n t r o l a u t h o r i t i e s . Sampling p l a n s a g r e e d w i t h the i n s p e c t o r a t e s h o u l d aim at a r e a s of c o n c e r n and m a j o r abuses. In the e a r l i e r y e a r s or w h i l e the l a b o r a t o r y r e m a i n s s m a l l , the Head of the laboratory is the one who makes most of the m a n a g e m e n t decisions. The Head is also the person who interacts with higher m a n a g e m e n t . This is a most important aspect as the laboratory m u s t be fully integrated into the executive s tructure in a m e a n i n g f u l w a y . It w o u l d be f u t i l e for a l a b o r a t o r y to w o r k in an administrative v a c u u m , producing r e s u l t s s h o w i n g , for e x a m p l e , that s a m p l e s

3

were contaminated or that there were consignments of food in the distribution c h a i n r e q u i r i n g r e g u l a t o r y a c t i o n , if the food c o n t r o l o r g a n i z a t i o n and i n s p e c t o r a t e took no a c t i o n , or if a t t e m p t e d a c t i o n w a s c o u n t e r m a n d e d at a h i g h e r level. The e x e c u t i v e a r m of the g o v e r n m e n t in this a r e a , the food c o n t r o l s e r v i c e , n e e d s the s a n c t i o n and s u p p o r t of m o r e senior levels of the administration. To play an effective role, the Head of the laboratory must be assured of necessary finance, staff and facilities. When difficulties arise in the supply of these three essential ingredients, it must be possible to bring these difficulties to the attention of persons in positions of higher authority for appropriate action.

2.4

Supervisors

S u p e r v i s o r s s h o u l d a l s o be g r a d u a t e c h e m i s t s or m i c r o b i o l o g i s t s w i t h considerable food analysis experience. The supervisor is the on-site manager of the laboratory. Having supervisors assigned to specific units or areas of work permits the Head to more effectively plan (and execute) the total workload of the laboratory. S u p e r v i s o r s can be e x p e c t e d to do a n a l y t i c a l w o r k in a d d i t i o n to their supervisory duties. H o w e v e r , if their g r o u p e x c e e d s five p r o f e s s i o n a l a n a l y s t s , it is best not to r e q u i r e a d d i t i o n a l a n a l y t i c a l w o r k e x c e p t for occasional problem solving and trouble-shooting. A reasonable m a x i m u m number of a n a l y s t s for one p e r s o n to s u p e r v i s e is 10 to 12. T h i s can be m o r e if n o n professional support staff is added. A supervisor's duties can include many or all of the 1. Assisting the Head in overall the work of the group supervised. 2.

posed

Receiving

and assigning

samples

laboratory

5. Ensuring do the work.

the

that

reports

the

of

6. Ensuring that proper followed by the group.

work

the necessary

laboratory

planning

in s o l v i n g

completed

group has

work

for analysis, within

3. A n s w e r i n g q u e s t i o n s and a s s i s t i n g by individual analysts.

4. Reviewing recommendations.

following:

and

and

the group.

analytical

making

supplies

planning

and

safety and housekeeping

problems

appropriate

equipment

practices

to

are

7. R e c o m m e n d i n g to the Head n e w i n s t r u m e n t s or e q u i p m e n t n e e d e d , and training needs of individual analysts. 8. Taking appropriate disciplinary laboratory rules or regulations. 9.

Acting

to manage the entire

action

laboratory

when

needed

to

enforce

in the absence of the Head.

Supervisors should train one or more analysts in their group to serve as backups, to supervise the group in the supervisor's absence. The back-ups should be given some formal classroom training in supervision in addition to on-thejob experience. A good supervisor is indispensable to the smooth operation of a laboratory. In s e l e c t i n g a s u p e r v i s o r , the Head m u s t k e e p in m i n d that the p r i m a r y job of a s u p e r v i s o r is to m a n a g e , so that s k i l l s in w o r k i n g w i t h p e o p l e are m o r e i m p o r t a n t than s c i e n t i f i c e x p e r t i s e . T h e r e f o r e , a top a d m i n i s t r a t o r w i t h

4

m e d i o c r e science ability is m o s t often a better choice than a top scientist w h o is only a m e d i o c r e (or bad) a d m i n i s t r a t o r . (This p r i n c i p l e h o l d s even m o r e for s e l e c t i o n of the H e a d of the l a b o r a t o r y . ) O f t e n the b e s t a n a l y s t s are g i v e n s u p e r v i s o r jobs as a r e w a r d for their b e n c h e x p e r t i s e . T h i s not only r e m o v e s t h e m (at l e a s t in p a r t ) f r o m t h e i r m o s t v a l u a b l e r o l e as a n a l y s t , b u t it a l s o puts them in the o f t e n u n c o m f o r t a b l e role of s u p e r v i s o r . This can result in an overall d e c r e a s e in that i n d i v i d u a l ' s e f f e c t i v e n e s s . T h i s is n o t to s a y t h a t a t o p a n a l y s t c a n n o t b e a t o p s u p e r v i s o r , many fortunate o r g a n i z a t i o n s have such persons. They are rare, h o w e v e r , and a Head selecting a supervisor s h o u l d be w i l l i n g to a c c e p t lesser scientific c r e d e n t i a l s if the other attributes rank s u f f i c i e n t l y high.

2.5

Team

Leaders

A n o t h e r i m p o r t a n t , and o f t e n o v e r l o o k e d , p o s i t i o n is T e a m L e a d e r . A team leader is a senior analyst w h o h a s b e e n assigned a s m a l l g r o u p , u s u a l l y no m o r e t h a n 4 , to do a s p e c i f i c t a s k or t y p e of a n a l y s i s . T h e l e a d e r h a s no s u p e r v i s o r y functions as such, but is the c o o r d i n a t o r of the g r o u p ' s a c t i v i t i e s and is the contact point for the supervisor. T e a m l e a d e r s are m o s t u s e f u l w h e n a l a r g e n u m b e r of a r e p e t i t i v e type of a n a l y s i s is to be done in a specified period of time. This could be a specific a n a l y t i c a l s u r v e y or a n e m e r g e n c y p u b l i c h e a l t h p r o b l e m r e q u i r i n g s c r e e n i n g analyses. T h e l e a d e r u s u a l l y w o r k s a l o n g w i t h the g r o u p in a d d i t i o n to the coordinative function. S u c h e x p e r i e n c e is o f t e n u s e f u l to d e t e r m i n e if t h e assigned leader has potential as a future supervisor.

2.6

Analytical

Staff

The basic job of the analytical staff is to analyze the s a m p l e s received and to issue a report. They m a y also be required to a p p e a r in court as fact or expert w i t n e s s e s to give e v i d e n c e in r e l a t i o n to a report. They m a y also be called on to o f f e r a d v i c e to i n d u s t r y and t r a d e , to a s s i s t in i m p r o v e m e n t o f f o o d q u a l i t y , or advise on c o n f o r m i t y w i t h s t a n d a r d s or other legal r e q u i r e m e n t s . T h i s c a n i n v o l v e t h e l a b o r a t o r y s t a f f in f a c t o r y v i s i t s a n d e v e n r e q u e s t s to c a r r y out e x p e r i m e n t a l w o r k . W h e t h e r or n o t the l a b o r a t o r y u n d e r t a k e s s u c h w o r k w i l l be a m a t t e r of o r g a n i z a t i o n a l policy. The d e c i s i o n w i l l depend on a n u m b e r of f a c t o r s , i n c l u d i n g the a v a i l a b i l i t y of a l t e r n a t i v e facilities, the n a t u r e of i n d i v i d u a l o w n e r s h i p , etc. T h e i n t e g r i t y of the a n a l y s t is p a r a m o u n t , and s u p e r i o r s m u s t be i n f o r m e d of a n y c o n f l i c t of i n t e r e s t t h a t a r i s e s . A s in t h e c a s e o f f o o d i n s p e c t o r s , it is p r o p e r f o r t h e a n a l y s t s to have no vested interest in regulated industries. This r e q u i r e m e n t is m a n d a t o r y in m a n y countries. A n a l y t i c a l staff can be d r a w n from three levels, u n i v e r s i t y g r a d u a t e s , trained t e c h n i c i a n s f r o m t e c h n i c a n t r a i n i n g c o l l e g e s and u n q u a l i f i e d s t a f f w h o h a v e received o n - t h e - j o b training. The g r a d u a t e s can be c h e m i s t s , m i c r o b i o l o g i s t s , food scientists or fi od t e c h n o l o g i s t s . U n i v e r s i t y d e g r e e s are only a starting q u a l i f i c a t i o n and the-p. w i l l still be a r e q u i r e m e n t for specialized training a n d e x p e r i e n c e in f o o d . n a l y s i s . S t a f f s h o u l d be e n c o u r a g e d to c o n t i n u e to w o r k for s u i t a b l e p o s t g r a d u a t e q u a l i f i c a t i o n s to e n a b l e t h e m to c o m p e t e for h i g h e r posts in the laboratory. S p e c i a l l y trained l a b o r a t o r y t e c h n i c i a n s w h o h a v e f o l l o w e d a t w o to t h r e e y e a r p r a c t i c a l t r a i n i n g c o u r s e in l a b o r a t o r y a n a l y s i s a f t e r c o m p l e t i n g s e c o n d a r y s c h o o l c a n be p a r t i c u l a r l y u s e f u l in carrying out a n u m b e r of routine or even h i g h l y c o m p l e x food analyses. As in the c a s e w i t h u n i v e r s i t y g r a d u a t e s , s p e c i a l i z e d o n - t h e - j o b t r a i n i n g w i l l b e needed for particular types of food analysis.

5

S o m e people w i t h little or no theoretical b a c k g r o u n d often s h o w m a n i p u l a t i v e a n d p r a c t i c a l s k i l l s in t h e l a b o r a t o r y as g o o d or b e t t e r t h a n u n i v e r s i t y graduates. This type of person is often m o r e happy and fulfilled in carrying out c e r t a i n r o u t i n e l a b o r a t o r y tasks than are graduates. E v e r y a t t e m p t should be m a d e to e n c o u r a g e s u c h p e r s o n n e l in t h e i r w o r k and the l a b o r a t o r y H e a d s h o u l d a t t e m p t to s e t u p p a y s c a l e s a n d o t h e r i n c e n t i v e s to r e w a r d such workers. T h e s e w o r k e r s m a y a l s o be e n c o u r a g e d to t a k e c o u r s e s and o b t a i n q u a l i f i c a t i o n s in p r a c t i c a l a s p e c t s o f the w o r k , s u c h as glass-blowing, i n s t r u m e n t r e p a i r , e l e c t r o n i c s , m e t a l - w o r k and o t h e r f i e l d s r e l a t e d to the m a i n t e n a n c e of l a b o r a t o r y e q u i p m e n t . These skills are o f t e n scarce, and just as d i f f i c u l t to m a s t e r , as t h o s e of the g r a d u a t e a n a l y s t and t h e r e is e v e r y j u s t i f i c a t i o n for r e w a r d i n g their a c c o m p l i s h m e n t . It is m o s t i m p o r t a n t that staff e m p l o y e d for repair o p e r a t i o n s are qualified and t h o r o u g h l y trained. In p a r t i c u l a r , e l e c t r o n i c e q u i p m e n t s h o u l d be s e r v i c e d and r e p a i r e d only by qualified i n s t r u m e n t a t i o n technicians.

2.7

Support

Staff

T h e s u p p o r t s t a f f of a l a b o r a t o r y a r e all of t h o s e p e r s o n s w o r k i n g in and for the l a b o r a t o r y w h o are not c o n d u c t i n g a n a l y s e s or are n o t i n v o l v e d in a d m i n i s t r a t i v e duties. S o m e e x a m p l e s of duties include: 1.

Glassware

washing.

2.

Cleaning

and

3.

Disposal

of s a m p l e

4.

Pest

control.

5.

Heavy

lifting

housekeeping

and

maintenance.

reserves

( w h e n no

longer

required).

moving.

Support staff t y p i c a l l y have little or no e d u c a t i o n a l q u a l i f i c a t i o n s beyond a b i l i t y to read and w r i t e . H o w e v e r , they m u s t be w i l l i n g and able to learn o n l y their d u t i e s , but also laboratory safety p r o c e d u r e s .

the not

It is m o s t i m p o r t a n t t h a t s u f f i c i e n t p e r s o n s a r e h i r e d as s u p p o r t . The w o r k t h e y do m u s t be d o n e by s o m e o n e and t h i s is u s u a l l y an a n a l y s t or t e c h n i c i a n w h e n there is i n s u f f i c i e n t support staff. There is no fixed m o d u l e for n u m b e r s of s u p p o r t w o r k e r s , b u t 1 5 - 2 0 % of the n u m b e r of a n a l y t i c a l s t a f f is o f t e n sufficient.

6

3.

3.1

LABORATORY DESIGN

General Considerations

W h e n a new laboratory is being built, two people hold the key positions in producing the right building at the right cost - the architect who designs it and guides its construction, and the analyst (preferably the laboratory Head) w h o explains the technical needs, and w o r k s in close p a r t n e r s h i p w i t h the architect through every stage so that the end result is properly suited to the requirements of the users. It is not often that the analyst has the chance to take part in the planning of a complete new laboratory, more usually he has to make do with old or inadequate buildings. However, these are often more easily extended, changed or adapted as the nature of the w o r k changes, than a n e w e r building, so may in some ways be more advantageous. Indeed, an important point in designing a new laboratory is that provision should be made for future expansion, however unlikely that may seem at the time. The design should also be left as flexible as possible so that changes of emphasis in the work can be a c c o m m o d a t e d . The laboratory should be located a w a y from urban centres and industrial areas in order to minimize problems of contamination. The information in this chapter was taken in part from Industrial Research and D e v e l o p m e n t N e w s , VII No. 3, UN, N.Y., 1975. The principles given apply to food control l a b o r a t o r i e s in general, w h e t h e r n e w c o n s t r u c t i o n or space converted to laboratory use.

3.2

Basic Structure of the Building

An example of the smallest laboratory that would be adequate for a food control programme is shown in Figure 3.1. This design was originally intended to serve 120,000 people although in general this may be regarded as too small a p o p u l a t i o n to justify a separate laboratory. It is intended to be part of a larger b u i l d i n g , but the disposition of r o o m s can be changed to suit local c i r c u m s t a n c e s . Space for essential services such as solvent storage and the usual administrative support must also be provided. Sample preparation should be carried out as far as possible from laboratories working on trace analysis and microbiology or using sensitive instruments. It must be stressed that the figure s h o w n is only an e x a m p l e . New l a b o r a t o r i e s m u s t be c u s t o m - b u i l t to cater for the needs of the situation under consideration. It is best to allow l a b o r a t o r i e s to r e m a i n o p e n - p l a n as far as p o s s i b l e , including the areas used as offices. Exceptions are areas where the activities carried out cause c o n t a m i n a t i o n or are sensitive to it, such as s a m p l e preparation, weighing, microbiology, trace analysis and use of instruments such as gas-liquid chromatographs and spectrophotometers. Lack of v i b r a t i o n is important and therefore concrete is a better structural m a t e r i a l in m u l t i - s t o r e y buildings. S t e e l - f r a m e b u i l d i n g s m a y cause d i f f i c u l t y with some i n s t r u m e n t s . A two storey laboratory adequate for a modest food control programme is shown in Figures 3.2 and 3.3. It consists of a ground floor m a i n l y composed of offices and services and a first floor for analytical work. In addition there should be a flammable solvent storage area separate from the building. W o r k s h o p and g l a s s b l o w i n g facilities are often advantageous and if not otherwise available should be included.

7

1 ni i

>

Food additives and toxicants

Food standards and nutrition Corridor

Overall length 21 m

Microbiology

Media préparai ion

Office Balance room

Sample préparai ion

1vK Entrance 6.2 m

6.2 m

0

I

Figure 3.1 A Minimum Sized Food Control Laboratory

8

Figure 3.2 Ground Floor Plan (mainly office and administrative

9

space)

Figure 3.3 First Floor Plan (laboratory space)

3.3

Safety

Features

The building including : 1.

The

and

laboratory

fire

design

should

a r e a s of c o r r i d o r s

include

a number

s h o u l d be f o r m e d

of

safety

of c o n c r e t e

features

blocks.

2. Services should include a shower sprinkler system near each d o o r w a y so t h a t a w o r k e r c a n t a k e an i m m e d i a t e s h o w e r , c l o t h e s and a l l , in the c a s e of a c c i d e n t a l g e n e r a l c o n t a c t w i t h c o r r o s i v e or p o i s o n o u s l i q u i d s or f i r e .

10

3. wash

There

stations

should

be

(obtainable

built-in from

most

eye

wash

chemical

fountains, supply

or

at

least

portable

eye

firms).

4. The t r a f f i c flow, the e g r e s s p a t t e r n and the p r o p o r t i o n s of the l a b o r a t o r y are a l l s a f e t y c o n s i d e r a t i o n s . I t m u s t a l w a y s be p o s s i b l e to l e a v e the l a b o r a t o r y s a f e l y i r r e s p e c t i v e of the i n i t i a l s i t e of a f i r e . Serious t h o u g h t m u s t be g i v e n to t h e n u m b e r and l o c a t i o n o f f i r e e x t i n g u i s h e r s and s t a n d p i p e s y s t e m s , and to the a v a i l a b i l i t y of s p r i n k l e r systems. 5. L a b o r a t o r i e s s h o u l d b e w e l l - l i t so t h a t t h e o p e r a t o r d o e s n o t h a v e to p e e r too c l o s e l y o v e r p o t e n t i a l l y h a z a r d o u s m a t e r i a l i n o r d e r to see w h a t he is doing. T h e r e s h o u l d be a m p l e w o r k i n g s p a c e and b e n c h t o p s and o t h e r s u r f a c e s s h o u l d be k e p t c l e a r of a l l m a t e r i a l e x c e p t t h a t i n c u r r e n t u s e . 6. Benches are best w i t h o u t s h e l v e s , only s e r v i c e s , these being operated from the f r o n t so t h a t the o p e r a t o r d o e s not h a v e to s t r e t c h a c r o s s the b e n c h . I t i s s t i l l common to s e e r e a g e n t s on s h e l v i n g at t h e b a c k o f b e n c h e s ( o r a b o v e the c e n t r e of d o u b l e - w i d t h b e n c h e s ) b u t i t i s p r o b a b l y s a f e r i f such r e a g e n t s c a n be k e p t on s i d e - s h e l v e s or i n t r a y s w h i c h a r e b r o u g h t to t h e b e n c h as required . 7. F l o o r i n g n e e d s to b e o f a n o n - s l i p m a t e r i a l , r e s i s t a n t to a c i d s a n d s o l v e n t s , b u t n o t so h a r d a s to b e t i r i n g to s t a n d on f o r a f e w h o u r s at a time. No m a t e r i a l i s e n t i r e l y s a t i s f a c t o r y . W e l l - l a i d l i n o l e u m and a f i l l e d e p o x y r e s i n on top of c o n c r e t e a r e a m o n g t h e b e s t a v a i l a b l e . It is a d v i s a b l e n o t to p o l i s h l a b o r a t o r y floors. 8. P o l l u t a n t s g e n e r a t e d w i t h i n t h e l a b o r a t o r y m u s t be r e m o v e d s a f e l y , q u i c k l y and e f f i c i e n t l y . I n p a r t i c u l a r , t o x i c or n o x i o u s g a s e s m u s t be r e m o v e d e x p e d i t i o u s l y t h r o u g h a d u c t s y s t e m t h a t d o e s n o t e x h a u s t n e a r the b u i l d i n g a i r conditioning intake. 9. The b u i l d i n g must be p l a n n e d f o r s e c u r i t y . R e s t r i c t i o n of a c c e s s i s of c o n s i d e r a b l e i m p o r t a n c e b e c a u s e of the e x t r e m e l y v a l u a b l e and sensitive e q u i p m e n t u s e d i n t h e l a b o r a t o r y w o r k a s w e l l as t o p r o t e c t t h e i n t e g r i t y o f official samples. 10. I t i s v e r y a d v i s a b l e to h a v e an e f f i c i e n t f i r e a n d s m o k e d e t e c t i o n system w i t h appropriate alarms. Common f i r e d e t e c t i o n e q u i p m e n t is usually e i t h e r r a t e - o f - t e m p e r a t u r e - r i s e or f i x e d - t e m p e r a t u r e d e t e c t o r u s i n g a s u b s t a n c e of known m e l t i n g p o i n t . T h e r e a r e a d v a n t a g e s ( a n d d i s a d v a n t a g e s ) to e a c h t y p e of d e t e c t o r and the l a b o r a t o r y Head s h o u l d s e l e c t the one he f e e l s b e s t f i t s his laboratory. D e s i g n i n g a l a b o r a t o r y to a f f o r d p r o t e c t i o n a g a i n s t e v e r y k i n d o f h a z a r d w o u l d be a l m o s t i m p o s s i b l e . The a i m s h o u l d be to d e t e r m i n e t h e l e v e l o f s a f e t y for t h e most g e n e r a l a p p l i c a t i o n s and to p r o v i d e s u p p l e m e n t a r y s y s t e m s in a r e a s o f higher h a z a r d . A s a f e s o l v e n t s t o r a g e a r e a i s i d e a l l y s e p a r a t e from t h e l a b o r a t o r y b u i l d i n g i n a stand-alone structure. I t c a n be a s m a l l b u i l d i n g of one room and some p o s s i b l e d e s i g n f e a t u r e s a r e : ( r e a s o n s are g i v e n in p a r e n t h e s i s ) 1. materials

Construction s u r r o u n d the

of cement solvents.)

blocks

or

bricks.

(Only

non-flammable

2. For a s t a n d - a l o n e b u i l d i n g , d o u b l e w a l l s w i t h i n s u l a t i o n between. The e x t e r i o r w a l l c a n be m a t e r i a l other than block or b r i c k . (Provides i n s u l a t i o n from the sun and m a k e s a i r c o n d i t i o n i n g more e f f e c t i v e . ) 3. An e p o x y f i l m to c o v e r t h e e n t i r e walls. ( A n y s o l v e n t s p i l l a g e w i l l p o o l and t h e f l o o r s or w a l l s . )

11

floor plus evaporate,

10 cm up t h e b a s e of t h e r a t h e r than soak through

4. A c o p p e r pipe (about 25 m m ) inside the r o o m , w h i c h goes t h r o u g h the floor and is e m b e d d e d a b o u t 2 m in earth. (A g r o u n d pipe to bleed off any static e l e c t r i c i t y c h a r g e s - w h i c h o f t e n build up w h e n s o l v e n t s are poured). All metal objects in the room are to be attached to the pipe using heavy guage single strand copper wire. Also, attach a short wire with an alligator clip. (This g r o u n d s all m e t a l . The clip is used to g r o u n d any m e t a l cans used for s o l v e n t transfer.) 5. grounding

Storage pipe.

shelves of metal

and connected

by wire

to each other and

the

6. Air c o n d i t i o n i n g is e x t e r n a l , w i t h the e n t r a n c e duct at the top of one c o r n e r of the r o o m and the exit d u c t at the b a s e of the o p p o s i t e c o r n e r . ( T h e r o o m m u s t be c o o l e d as m a n y s o l v e n t s w i l l b o i l at h o t o u t s i d e temperatures. The air entrance on top and exit on the bottom diagonally across the r o o m , w i l l cool the room and w i l l also serve to s w e e p and r e m o v e any solvent fumes on the floor - solvent fumes are generally heavier than air and will pool on the floor.) 7. The door is of m e t a l and f i r e - r a t e d for at least one h o u r , w i t h a positive closure. It must seal well when closed. The door sill is at least 10 cm high. (Fire doors are metal sheathed around cement. The closure, the seal and the h i g h sill all act to p r e v e n t e s c a p e of s o l v e n t , e i t h e r floor s p i l l a g e or fumes.) 8. An air c o n d i t i o n e r exit duct w i t h a fire b a f f l e (to p r e v e n t flash b a c k ) and d u c t e d to exit in the o u t s i d e air at b u i l d i n g r o o f h e i g h t . (Fumes h a v e a b e t t e r c h a n c e of being carried a w a y by b r e e z e s and s o m e o n e s m o k i n g nearby will not present a fire risk.) 9. An extinguisher system, and not water sprinklers.

3.4

Ventilation and Air

which

should

be carbon dioxide or Freon type

Conditioning

An ordinary laboratory may have amounts of lead in the air passing through it in a day which can be measured in milligrams. Natural ventilation, which may provide large quantities of air without cooling, is not generally suitable for laboratories. T h i s is e s p e c i a l l y true in u r b a n a r e a s w h e r e m o t o r t r a f f i c is high. This means that air conditioning is essential for the modern laboratory. A i r c o n d i t i o n i n g not only p r e v e n t s s o m e f o r m s of c o n t a m i n a t i o n , it also p r o v i d e s a s t a b l e t e m p e r a t u r e e n v i r o n m e n t for s e n s i t i v e and s o p h i s t i c a t e d analytical instruments. Most v o l u m e t r i c g l a s s w a r e is c a l i b r a t e d at 20°C and must be recalibrated if used at significantly different temperatures. This is s t i l l a n o t h e r a r g u m e n t for air c o n d i t i o n i n g . T h e i m p o r t a n c e of a i r conditioning to overall laboratory accuracy cannot be overstressed. The exhaust fans in fume hoods result in a negative pressure in the laboratory and in an urban or industrial area this aggravates contamination of the whole l a b o r a t o r y area. A p o s i t i v e p r e s s u r e s y s t e m is c o s t l y as it h a s to be s u f f i c i e n t l y p o w e r f u l to p r o v i d e a c l e a n filtered air s u p p l y w h i c h p a s s e s t h r o u g h f u m e hood e x h a u s t fans as w e l l as o t h e r o u t l e t s . V e n t i l a t i o n by p o s i t i v e p r e s s u r e a s s i s t s the e x h a u s t fans in f u m e h o o d s and is to be preferred. Each f u m e hood should h a v e a s e p a r a t e fan, as there is d a n g e r of cross c o n t a m i n a t i o n from a c o m m o n d u c t i n g s y s t e m . Such a s y s t e m can be essential if the vicinity of the laboratory is prone to contamination and it is necessary to carry out low-level trace analysis. Toxic fumes must be confined as far as possible to fume hoods. These should be away from cross-currents of air and pedestrian traffic. The recommended m i n i m u m air-flow through the open face of a f u m e hood is 0.5 m / s e c . V e n t i l a t i o n s h o u l d be such as to give at least 5 air changes per hour.

12

V a c u u m p u m p s used to evaporate solvents should have the exhaust to the outside a i r , o t h e r w i s e t o x i c l e v e l s of the s o l v e n t m a y be r e a c h e d in the l a b o r a t o r y atmosphere. W a t e r aspirator p u m p s are quite safe w i t h w a t e r - s o l u b l e solvents or acid f u m e s , but not w i t h w a t e r - i m m i s i b l e s o l v e n t s such as p e t r o l e u m ether.

3.5

Space

Utilization

L a b o r a t o r y s p a c e m u s t be a r r a n g e d for m a x i m u m u t i l i z a t i o n as w e l l as p r o p e r w o r k flow. It is usual to a l l o w about 10 square m e t e r s of laboratory space and 3 m e t e r s of b e n c h s u r f a c e p e r a n a l y s t . An e x a m p l e of a l a b o r a t o r y for 8 a n a l y s t s is in Figure 3.4.

Sx FC Fr DS Kj

Figure

" = = = =

Soxhlet bench fume cupboard freezer sink unit Kjeldahl apparatus

3.4

N o t e that e a c h a n a l y s t h a s a l a t e r a l b e n c h a r e a to w o r k at. T h i s f o r m a t is termed 'peninsular' and is quite e f f i c i e n t . An a l t e r n a t e f o r m a t uses 'islands' w h i c h have access on all sides. An e x a m p l e is Figure 3.5.

13

0.7b m

1.50 m

0.75 m

1.50 m

0.75 m

1.50 m

0.75 m

Consider as island benches accessible from every side, or consider as the floor space remaining, the area B being occupied by benches

0

Figure

1

2

3m

3.5

T h e o p t i m u m w i d t h f o r a s i n g l e b e n c h ( a b o u t 75 cm) i s r o u g h l y t h e s a m e as t h e width of the space required by a s t a n d i n g individual. It is therefore convenient, to c o n s i d e r t h e p r o s and c o n s o f i s l a n d b e n c h e s and peninsular b e n c h e s w i t h the a s s i s t a n c e of F i g u r e 3 . 5 . I t c a n r e a d i l y be s e e n t h a t the m a x i m u m b e n c h a r e a i s o b t a i n e d w i t h p e n i n s u l a r b e n c h e s (B a r e a s ) , h o w e v e r , the w o r k i n g s u r f a c e is more a c c e s s i b l e on i s l a n d b e n c h e s (A a r e a s ) . The services a r e m o r e a c c e s s i b l e f o r r e p a i r on i s l a n d b e n c h e s , b u t t h e r e i s l e s s space available for s h e l v i n g close to t h e b e n c h e s . In the c a s e of peninsular b e n c h e s , t h e a n a l y s t w o r k i n g i n a b a y h a s a c c e s s i n e f f e c t to t h r e e w o r k i n g s u r f a c e s at o n c e and t h i s i s v e r y c o n v e n i e n t i f t h e r e a r e s e v e r a l different a n a l y s e s i n p r o g r e s s at the same t i m e . H o w e v e r , the s p a c e b e t w e e n p e n i n s u l a r s s h o u l d a l w a y s be e n o u g h for two p e o p l e to w o r k c o m f o r t a b l y b a c k to b a c k ( a b o u t 1.5 m). I s l a n d b e n c h e s make the c h o i c e of s i t e for w i n d o w s and d o o r s less critical. P e n i n s u l a r b e n c h e s m a y be p r e f e r r e d i f s p a c e i s a t a p r e m i u m a n d t h e y may be s l i g h t l y s a f e r , as the r o u t e s by w h i c h p e o p l e w a l k a b o u t the l a b o r a t o r y t e n d to be m o r e r e s t r i c t e d and p r e d i c t a b l e . W h i c h e v e r is c h o s e n , w h a t i s m o s t i m p o r t a n t i s t h a t t h e s i z e o f t h e r o o m i s c o r r e c t to t a k e a n i n t e g r a l n u m b e r of b e n c h u n i t s w i t h t h e i r a c c o m p a n y i n g floor space. Usually t h e p r o b l e m c a n be p a r t l y s o l v e d b y a w a l l b e n c h at one end or s i d e of t h e l a b o r a t o r y but a l l too o f t e n l a b o r a t o r i e s have such a s i z e or shape t h a t f l o o r s p a c e h a s b e e n w a s t e d , or an e x t r a b e n c h h a s b e e n i n c o n v e n i e n t l y s q u e e z e d in. The s t o r a g e a r e a s in the b e n c h e s s h o u l d be m o d u l a r to a l l o w f l e x i b i l i t y . Many laboratory bench manufacturers have units where the storage areas are interchangeable. Some s a m p l e s of b e n c h a s s e m b l i e s a r e g i v e n in F i g u r e 3 . 6 , w i t h w i d t h s in c e n t i m e t e r s .

14

I

KO

ra

to

I

m »••

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+

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(O

«-

f

m m m I

+

f-

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«O

4

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22»

to

I

'«•

+

+

+

+

+

to

110

+

120

4-

+

120

10

120

2%0

120

2$o

120

4-

2 tO

120

2so

+

tO

+4-

4-4-

4"

120

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120

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M

m

II

II

4-

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220

H t-

m

rap nu +

Il

I

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ira m m m rap ra era to

M U

4-

)

SO (O

•••

>0

110

4"

HI

..

Figure

m

--

--

+

'

3.6

The o p t i m u m working depth of benches for standing w o r k has been found to be 60 cm for the w o r k i n g s u r f a c e , p l u s 15 cm for the a c c o m m o d a t i o n of a b o v e - b e n c h fitments (such as gas service, electrical sockets and shelves) giving a total depth of 75 cm. The bench heights, h o w e v e r , have always caused some problems b e c a u s e of the v a r i e t y of b e n c h t o p s a v a i l a b l e . Their thickness varies with the different coverings and supporting bases used: 6 cm for ceramic tiles, 4 cm for P y r o c e r a m , 3.7 cm for a c i d - p r o o f s t o n e w a r e , and 2.8 cm for p l a s t i c s . H e i g h t d i f f e r e n c e s in a d j a c e n t b e n c h u n i t s always cause inconvenience to the user. Therefore purchases of new benches m u s t expressly indicate that desks and benches with different coverings must have uniform heights. (Differences c a n be c o m p e n s a t e d for b y u n d e r l a y i n g the b e n c h tops.) B e n c h m o d u l e l e n g t h s are u s u a l l y 60 cm for s i n g l e u n i t s and 90 or 120 cm for d o u b l e u n i t s . This modulus of length in 30 cm steps allows adaptation to nearly any room size. W o r k flow is a very important part of proper space utilization. There should be a l o g i c a l and s y s t e m a t i c a r r a n g e m e n t of s p a c e to p e r m i t f l o w of a n a l y s i s w o r k f r o m s a m p l e r e c e i p t , p r e p a r a t i o n and a n a l y s i s to d i s p o s a l or s t o r a g e . This entails examining the average sample annual workload in relation to the areas and people involved in the various analyses. The best work flow system (within physical constraints of the building) is usually readily apparent.

3.6

Equipment

and

Instruments

The complexity of equipping a laboratory and the consequent delay in production of u s e f u l r e s u l t s s h o u l d n o t be u n d e r e s t i m a t e d . In the e a r l y s t a g e s , the requirements for equipment may seem large and complex but once the laboratory is e s t a b l i s h e d , the r u n n i n g c o s t s a r e r e l a t i v e l y l o w . It is s o m e t i m e s n o t appreciated by the non-technical administrator that an analysis may require 10 or 20 i n d i v i d u a l i t e m s and that if e v e n o n e is n o t a v a i l a b l e the a n a l y s i s cannot be carried out. On the other hand, many items are c o m m o n to different

15

a n a l y s e s so t h a t , o n c e the m a n y h u n d r e d s of i t e m s r e q u i r e d in a food c o n t r o l l a b o r a t o r y h a v e b e e n p r o v i d e d , t h e r e c o m e s a p o i n t at w h i c h p r o d u c t i v i t y c a n rise s h a r p l y and i n v e s t m e n t decrease. The logistical p r o b l e m s of m a i n t e n a n c e , r e p a i r and r e p l a c e m e n t of e q u i p m e n t are also c o n s i d e r a b l e . Adequate provision m u s t be m a d e for obtaining spares and r e p l a c e m e n t parts and for their storage. It is false e c o n o m y if staff are being paid but c a n n o t do an i m p o r t a n t part of their w o r k due to a lack of r e l a t i v e l y i n e x p e n s i v e e q u i p m e n t . S o m e of the i n s t r u m e n t s and e q u i p m e n t needed for c h e m i c a l a n a l y s i s by a m o d e r n food c o n t r o l l a b o r a t o r y are: (for purposes of this listing, ' i n s t r u m e n t s ' are m e a s u r i n g d e v i c e s and ' e q u i p m e n t ' are p r o c e s s i n g d e v i c e s . Apparatus made p r i m a r i l y of glass are not included).

Instruments

A n a l y t i c a l balance pH m e t e r Spectrophotometer, UV-visible, double-beam S p e c t r o p h o t o m e t e r , atomic a b s o r p t i o n H i g h P e r f o r m a n c e Liquid C h r o m a t o g r a p h (with UV and d i f f e r e n t i a l r e f r a c t i v e index d e t e c t o r s ) Gas C h r o m a t o g r a p h (with flame i o n i z a t i o n and e l e c t r o n capture d e t e c t o r s )

Equipment

Blender Grinder Pulverizing hammer mill Air o v e n , forced draft V a c u u m o v e n , with pump M u f f l e furnace Centrifuge Refrigerator Freezer H e a t e r s and hot plates Steam and w a t e r b a t h s W a t e r still or d e i o n i z e r

All of the above e q u i p m e n t and i n s t r u m e n t s are m o v e a b l e , a l t h o u g h the larger or m o r e s e n s i t i v e units are g e n e r a l l y not m o v e d , once placed. The m a j o r i t e m s of fixed e q u i p m e n t constructed in place are the fume hoods. The e x t e n s i v e use of s o l v e n t s , a s h i n g and n o x i o u s c h e m i c a l s in f o o d a n a l y s i s , r e q u i r e s m o r e f u m e h o o d s t h a n o t h e r t y p e s of l a b o r a t o r y w o r k . In f a c t , to e x p e r i e n c e d food a n a l y s t s , t h e r e n e v e r s e e m to b e e n o u g h h o o d s , e v e n in a w e l l equipped laboratory. F u m e h o o d s m a y be p u r c h a s e d p r e - f a b r i c a t e d w i t h o u t l e t s for services. The m a t e r i a l of c o n s t r u c t i o n is m o s t i m p o r t a n t , e s p e c i a l l y if the hood has to w i t h s t a n d acid fumes in general and p e r c h l o r i c acid in p a r t i c u l a r . The s u p p l i e r m u s t be g i v e n full d e t a i l s of the use to w h i c h the fume hood w i l l be put. H o o d s c a n be c o n s t r u c t e d out of l o c a l m a t e r i a l s s u c h as w o o d , p r e f e r a b l y hard w o o d s , coated w i t h epoxy resins. Such should n e v e r be used for acid d i g e s t i o n s , but only for solvent e x t r a c t i o n work.

3.7

Utilities

E l e c t r i c i t y m u s t either be a stable supply, or the voltage m u s t be stabilized by e i t h e r one large s t a b i l i z e r for the w h o l e l a b o r a t o r y , or by a unit for each of the i n s t r u m e n t s r e q u i r i n g it. A b o u t 40 w a t t s per s q u a r e m e t e r has b e e n

16

suggested. The laboratory pictured in Figure 3.3 has 160 double 13-amp socket outlets. This apparently large n u m b e r adds considerably to the efficiency of a n a l y t i c a l o p e r a t i o n s and to their s a f e t y . The s a m e l a b o r a t o r y has 110 gas p o i n t s , e x c l u d i n g t h o s e to the f u m e h o o d s . T h e r e m u s t b e s e v e r a l cold w a t e r taps per b e n c h to a l l o w for r i n s i n g , c o n d e n s e r s , etc., but h o t w a t e r can be restricted to those sinks w h e r e apparatus is washed. In a larger laboratory a distribution system for distilled or deionized water would be advantageous.

The following utilities

for fume hoods have been

Fume Hood Length

(•):

Gas taps (front controlled) Water taps (front controlled) Cup sinks Compressed air valves (front controlled) Two-phased electrical sockets Three-phased electrical sockets

suggested:

1.2

1.5

1.8

2 2 1

2 3 2

3 4 2

1 2

1 3

1 4

1

1

1

S p e c i a l m e t h o d s , s u c h as t r a c e a n a l y s i s , u s u a l l y r e q u i r e d i s t i l l a t i o n f r o m g l a s s a p p a r a t u s of w a t e r i n i t i a l l y p a r t i a l l y p u r i f i e d by d i s t i l l a t i o n or deionization. The initial purification produces water very low in salts, but if the o r i g i n a l s u p p l y c o n t a i n s o r g a n i c m a t t e r t h i s m a y n o t be r e m o v e d , and traces of resin material m a y be present. A s t e a d y s u p p l y of c o m p r e s s e d air is r e q u i r e d for an a t o m i c absorption s p e c t r o p h o t o m e t e r (AAS) and is v e r y u s e f u l to h a v e a v a i l a b l e at the b e n c h . A c o m p r e s s o r is s u i t a b l e for use w i t h the i n s t r u m e n t but if used for o t h e r purposes at the same time it m u s t be capable of supplying those needs without a f f e c t i n g the AAS s u p p l y . A p a r t f r o m the i n a c c u r a c y that w i l l r e s u l t from a change in the flame characteristics, sudden failure of the air m a y result in a flashback, which is expensive if the mixing chamber is destroyed, and could be dangerous. H o w e v e r , it m u s t be emphasized that m a n u f a c t u r e r s design this part of the i n s t r u m e n t to be as safe as p o s s i b l e u n d e r f l a s h b a c k c o n d i t i o n s . Therefore, in m a n y ways it is probably better to have a separate air supply to the AAS. T h i s i n s t r u m e n t a l s o has to be p r o v i d e d w i t h a v e n t i l a t i o n h o o d to remove gases formed during operation, particularly if nitrous oxide is used as the fumes are very toxic. Utility services require a large space but need to be concealed for aesthetic r e a s o n s , y e t r e q u i r e an e a s y a c c e s s for r e p a i r p u r p o s e s . To s a t i s f y t h e s e conflicting demands, the main runs may be in voids above false ceilings and in floor ducts. Secondary services are then run to outlet points on benches taken from floor level along the wall behind benches in voids especially incorporated in the design of the bench fittings. Frequent access points are provided for maintenance purposes. Drain pipes should be of high density polythene or copolymer polypropylene with screwed joints. T h e s e s h o w g o o d r e s i s t a n c e to m o s t o r g a n i c and i n o r g a n i c chemicals. The d r a i n a g e l i n e s m a y be e m b e d d e d in the f l o o r i n g . As it is not acceptable to discharge laboratory w a s t e s d i r e c t l y i n t o t h e s e w e r a g e s y s t e m , all w a s t e from l a b o r a t o r y sinks and o t h e r w a s t e f i t t i n g s s h o u l d be led f i r s t into dilution pots (about 5 litre capacity) before being released into the m a i n sewers. Buildings can be designed to include a large dilution tank where all l a b o r a t o r y sink w a s t e is d i r e c t e d b e f o r e e n t e r i n g the s e w e r a g e s y s t e m . For laboratories with high mineral acid use, sink traps of inert duriron often work well.

17

3.8

Design

References

1.

B e c k , H. L u f t u n g s e i g e n s c h a f t e n von L a b o r a b z u g e n ( V e n t i l a t i o n p o w e r of laboratory fume cupboard). Weinheim, Chemie-Ingenieur-Technik, 1964 (No. 3 6 ) (in G e r m a n ) .

2.

Be r u f s g e n o s s e n s c h a f t fur d i e c h e m i s c h e I n d u s t r i e , R i c h t l i n i e n fur c h e m i s c h e L a b o r a t o r i e n Nr. 12 ( D i r e c t i v e s for c h e m i c a l l a b o r a t o r i e s no. 12) Weinheim, Verlag-Chemie, 1972 (in German).

3.

DECHEMA Erfahrungs austausch; Laborbau (DECHEMA sharing laboratory design). Frankfurt/M. DECHEMA, 1969 (in German).

4.

Decken, C.B. v.d. a n d B. H u n d o r f . Untersuchungen uber die stromungstechnischen Vorgange in der Kapelle eines Laborabzug (Experiments about flow within the cabin of a fume cupboard). Darmstadt, GIT 1968 (No. 8) (in G e r m a n ) .

5.

D e u t s c h e r V e r e i n von Gas und W a s s e r f a c h m a n n e r n ( D V G W ) N o r m e n F e d e r a t i o n of Gas and W a t e r S p e c i a l i s t S t a n d a r d s ) E s c h b o r n , Republic of Germany (in German).

(German Federal

a.

Was serversorgung; Verbrauchanlagen D W G W W 503-1966.

piping)

b.

T e c h n i s c h e R e g e l n fur Bau und P r u f u n g von v o r g e f e r t i g t e n B a u t e i l e n mit Gas und Wasserinstallation ( S p e c i f i c a t i o n for c o n s t r u c t i o n and testing of prefabricated appliances with gas and water installations) D V G W GW 3 (1968).

c.

Technische Regeln fur die Installation von Gasanlagen in Laboratorien (Specifications for gas service installations in laboratories) DVGW G 621 (1971). (Pressure

experience:

(Water supply: service

gas regulation) Koln, Carl Heymann's Verlag

6.

Druckgasverordnung (in G e r m a n ) .

7.

Dunkl/Geyer. R a t i o n a l e L o s u n g e n von L a b o r b a u und L a b o r e i n r i c h tungsprob1emen in H o c h s c h u l e n , Industrieunternehmumgen und i m Gesundheitswesen der USA (Rational solutions of problems in the design of laboratory building and equipment for u n i v e r s i t i e s , i n d u s t r y and p u b l i c h e a l t h in the U n i t e d States). In B e i t r a g e zur U n i v e r s i t a t s p l a n u n g ( C o n t r i b u t i o n s to the p l a n n i n g of u n i v e r s i t i e s ) . F r a n k f u r t / M . D E C H E M A , 1970 (Heft 6) (in G e r m a n ) .

8.

F e u r i c h , H. R o h r n e t z e fur S a u e r s t o f f , D r u c k l u f t , V a c u u m , K o h l e n s a u r e in K r a n k e n h a u s e r n und L a b o r a t o r i e n (Service p i p i n g for o x y g e n , c o m p r e s s e d air, vacuum and carbon dioxide in hospitals and laboratories) Darmstadt, G I T 1 9 6 4 (nos. 8, 9 and 10) (in G e r m a n ) .

9.

D e u t s c h e I n d u s t r i e N o r m t'DIN) ( G e r m a n Beuth-Vertrieb G m b H (all in German) plant;

principles,

Industrial

a.

Ventilation English).

b.

Fire resistance 4102-1970.

c.

Space lighting by daylight; principles.

DIN 4034-1969.

d.

Laboratory furniture; 12 912-1973.

laboratory

of building

DIN

Standard).

materials

ceramic

18

tiles

1946-1960,

and

for

Part

structural

1

Berlin,

(also

elements.

bench

tops.

in

DIN

DIN

e.

Laboratory furniture; cup sinks.

DIN

12-914-1973.

f.

Laboratory 1973.

g.

L a b o r a t o r y furniture; large-size DIN 12 916-1972.

h.

Colour code for fluids on h a n d l e v e r s and h a n d w h e e l s of laboratory taps. DIN 12-920-1971.

i.

Laboratory furniture; benches, dimensions.

j.

Laboratory 1972.

k.

Heating plant, English).

1.

Traffic ways in buildings.

m.

Ventilation of laboratories. VID 2051-1966.

furniture; sinks w i t h integrated o v e r f l o w . DIN 12 915-

furniture;

smoke

fume

tiles

cupboards,

stacks.

DIN

DIN

18

for laboratory bench

tops.

DIN 12 922-1972. dimensions.

160-1968;

DIN

part

12

923-

1 (also

in

18-225-1958.

10.

Geyer, F. A n f o r d e r u n g e n an L a b o r b a u t e n ( R e q u i r e m e n t s for laboratory b u i l d i n g ) D a r m s t a d t , GIT (No. 1 2, 1 967 and No. 1 1968) (in German).

11.

/Richtlinien fur die Planung und den Bau von Laboratorien (Principles for design and building of laboratories) Weinheim, C h e m i e - I n g e n i e u r - T e c h n i k , 1971. (No. 11) (in German).

12.

Role et interet de la normalisation dans 1 ' aménagement et l'equipement des l a b o r a t o i r e s , Courrier de la N o r m a l i s a t i o n , No. 228 n o v e m b r e - d e c e m b r e , 1972 (in French).

13.

The role and significance of standarization of laboratory equipment and furniture. Laboratory Practice (London) No. 4, 1973.

14.

Laboratory furniture and fittings: BS 3202-1959, London, British Institution.

15.

Strangmann, W. Wasserverbrauch in chemischen und biologischen Laboratorien (Water consumption in chemical and biological laboratories). Darmstadt, GIT, 1964 (No. 6) (in German).

16.

Unfallverhutungsvorschrift: Medizinische Laboratoriumsarbeiten (Prescription for accident prevention: work in medical laboratories) Frankfurt/M. H G U V V ) (in German).

17.

United States Department of Health, Education and Welfare, Health Research Laboratory Design, Bethesda, Maryland NIH 1968 (Publication 1807).

18.

V e r b a n d D e u t s c h e r E 1 e k t r o t e c h n i k e r ( V D E ) N o r m e n (Union of G e r m a n E l e c t r i c a l Engineers s t a n d a r d s ) O f f e n b a c h / M a i n , Federal Republic of Germany (in German).

19.

A Literature Survey and Design Study of Fume Cupboards and Systems, Hughes, D., 1980, Science Reviews Ltd., London.

19

Standards

Fume-Dispersal

4.

4.1

LABORATORY ADMINISTRATION

Sample Collection

Work scheduling is greatly facilitated by arranging a sampling programme for r o u t i n e m o n i t o r i n g w i t h the i n s p e c t o r a t e . Close c o o p e r a t i o n w i t h the inspectorate will pay great dividends in improved efficiency in sampling. It i s o f t e n a l s o n e c e s s a r y to h a v e part of the l a b o r a t o r y staff a v a i l a b l e for urgent work and for samples such as consumer complaints, export certification and c h e c k i n g of i m p o r t s , w h e r e t h e r e is o f t e n l i t t l e n o t i c e g i v e n b e f o r e the arrival of the sample. S i n c e the l a b o r a t o r y r e l i e s on the i n s p e c t o r a t e for a s t e a d y w o r k l o a d , the inspectorate and laboratory supervisors must be in frequent contact in order to m a i n t a i n the w o r k l o a d in the l a b o r a t o r y at a r e a s o n a b l e level. As part of a general food control programme, there is need to: 1. Regularly inspect foods at different stages in the manufacturing distribution chains using planned surveillance programmes.

and

2. C a r r y out g e n e r a l s u r v e y s of the q u a l i t y of the food s u p p l y t h r o u g h random sampling and analysis, samples being taken from factories, warehouses and retailers. 3. Monitor certain specific problem areas with regard to food safety specific foods or classes of foods for specific potential risks, (e.g. level of metallic contaminants, pesticide residues, mycotoxins, etc.). 4.

Inspect foods for export, for certification of quality

(if needed).

5. Inspect food imports. This is b e s t d o n e on a l l c o n s i g n m e n t s by f o r m a l s a m p l i n g c a r r i e d out s y s t e m a t i c a l l y in representative of the lot.

imported a manner

6. Formal sampling should also be done on locally produced food products b a s e d o n t h e f o o d i n s p e c t o r s ' o b s e r v a t i o n s , or b e c a u s e a r a n d o m o r investigatory sample under the regular programme was unsatisfactory, or because the product is one that requires thorough surveillance. Analysis of formal and informal samples is also necessary in an emergency such as an outbreak of foodpoisoning . National sampling programmes yield important benefits in terms of efficiency. The I n s p e c t o r a t e and the L a b o r a t o r y a s s i s t e d and g u i d e d by o t h e r a g e n c y o f f i c i a l s or an a d v i s o r y b o a r d , as a p p r o p r i a t e , should p e r i o d i c a l l y plan overall programmes to locate and deal with different problems in the areas of food q u a l i t y and c o n s u m e r p r o t e c t i o n . In each case the o b j e c t i v e s of the p r o g r a m m e should be clearly defined. A l t h o u g h s a m p l e s m a y be c l a s s i f i e d in a n u m b e r of w a y s , it is c o n v e n i e n t to consider two broad divisions, "formal" samples and "informal" samples. Formal samples are those taken to determine if the foods comply with national or local l a w s or r e g u l a t i o n s . R e g u l a t o r y a c t i o n m a y r e s u l t from r e p o r t s r e c e i v e d on such samples. Informal samples may be taken for purposes of monitoring or as part of survey work. Formal follow-up samples can be taken if informal samples receive adverse laboratory reports. Formal or informal samples will also be taken under other circumstances, such as a follow-up to a consumer complaint. When samples are of the nature and required from the e x p e r i e n c e , from from the r o u t i n e

sent to the laboratory, the inspector must send full details purpose of sampling and any other relevant data. The results analysis will usually be clear, either from the analyst's own p r i o r d i s c u s s i o n w i t h the i n s p e c t o r or h i s s u p e r v i s o r s , or i n f o r m a t i o n g i v e n w i t h the s a m p l e . A w e l l q u a l i f i e d and

20

t r a i n e d i n s p e c t o r m a y a l s o w i s h to d i s c u s s the need for an a n a l y s i s that the a n a l y s t w o u l d not r o u t i n e l y c a r r y out. It is the d u t y of the l a b o r a t o r y H e a d to decide how these requests are to be met. The inspector's sample submission form should give all necessary details about the sample. These details may include the product n a m e , place of collection, reason for collection, type of samples (consumer c o m p l a i n t , official, survey, etc.), inspector's name, m o d e of s a m p l i n g , lot n u m b e r , s h i p p e r if so transported, size of consignment and similar relevant details, together with any s p e c i a l i n f o r m a t i o n that m a y be of a s s i s t a n c e to the a n a l y s t , such as suspected contamination. T h e s a m p l e s h o u l d a l s o be s e a l e d by the i n s p e c t o r with an official seal.

4.2

Sample Receipt and

Assignment

W h e n a food s a m p l e is r e c e i v e d for a n a l y s i s , t h e r e m u s t be a s y s t e m to t r a c k the sample throughout it's initial storage, analysis and later reserve storage. This is usually embodied in a record keeping system which is keyed to a unique n u m b e r a s s i g n e d to the s a m p l e at the t i m e of s a m p l i n g . T h i s n u m b e r c a n be sequential (i.e. 0001 to 9999) or can be devised to give information (i.e. 0245 - 0 7 , the 2 4 t h s a m p l e t a k e n in 1 985 u n d e r s a m p l i n g p r o g r a m m e n u m b e r 7). The r e c o r d m u s t s h o w each m o v e m e n t of a s a m p l e , its r e c e i p t , a s s i g n m e n t to a l a b o r a t o r y p e r s o n for a n a l y s i s , r e t u r n to the s a m p l e c u s t o d i a n , and e v e n t u a l disposition. One of the a d m i n i s t r a t i v e s t a f f s h o u l d be g i v e n this r e c o r d keeping function and closely supervised by a senior administrator, as well as supervised in general by the laboratory Head. It is usually best to use a card record system rather than a log book as cards are more flexibly handled and may be filed in groups under different headings. M a n y card record systems have been devised including 5x8 cards with coded sites on the periphery for punching. Other cards are pre-printed with spaces to be filled in w i t h appropriate data. Regardless of the card system selected, there are certain items of information which should be on each card:

1.

Sample

number.

2.

Product

3.

Date

4.

Date received

5.

Type of sample

6.

Method

7.

Storage

8.

Date assigned

9.

To whom assigned

name.

sampled. at the

laboratory.

(survey, complaint,

of storage

etc.).

(dry, refrigeration,

location (coded for

for easy

freezing,

etc.).

finding).

analysis. (the analyst

10.

Date returned

(from

11.

From whom returned

12.

Reserve

13.

Final disposition

should

initial

to show

receipt).

analyst). (may be different

storage method

and

from

the original

analyst).

location.

or disposal

of sample, method

21

and

date.

Note that the above uses the sample record only to record physical m o v e m e n t and location, not analytical results. The reason is that the analytical worksheet and the sample record are usually in two different locations. T h e s a m p l e r e c o r d card s h o u l d be p r e p a r e d and in the c u s t o d y of one p e r s o n until the reserve sample is destroyed. This person is often called the Sample Custodian and in small laboratories could have other duties as well. The job of S a m p l e C u s t o d i a n is c r i t i c a l to the o p e r a t i o n of m o s t l a b o r a t o r i e s . The person employed in this post m u s t be very reliable, but m a y find the duties of the job s l i g h t l y m o n o t o n o u s . C o m b i n i n g the d u t i e s of s a m p l e c u s t o d i a n w i t h k e e p i n g the l a b o r a t o r y s t o r e is o f t e n d o n e in m e d i u m or l a r g e r sized laboratories. The laboratory store of chemicals, glassware and other fittings r e q u i r e s c a r e f u l c o n t r o l as d o e s r e o r d e r i n g of m a t e r i a l s in s h o r t s u p p l y , issuance of supplies to analysts, etc. Combining the jobs of Sample Custodian and S t o r e K e e p e r c a n c r e a t e a c h a l l e n g i n g and i n t e r e s t i n g p o s t . Another approach to the job of Sample Custodian in smaller laboratories is to split the job b e t w e e n several people with different senior assistants under the various section leaders being responsible for samples from a particular source, or for particular groups of products. W h e n a s a m p l e is a s s i g n e d , the a n a l y s t s h o u l d p h y s i c a l l y sign or i n i t a l the s a m p l e c a r d to s h o w c u s t o d y . W h e n a s a m p l e r e s e r v e is r e t u r n e d to the C u s t o d i a n , the C u s t o d i a n w o u l d sign or i n i t i a l . A f t e r a s s i g n i n g the s a m p l e , the S u p e r v i s o r m u s t h a v e s o m e m e a n s of t r a c k i n g s a m p l e s u n d e r a n a l y s i s w i t h proposed or possible completion dates. The sample card could be used for this. The card would then be in the hands of the Supervisor during analysis and would be returned to the Custodian on completion.

4.3

Sample Storage

and

Disposal

S a m p l e s t o r a g e , b o t h i n i t i a l and r e s e r v e , is c r i t i c a l to a s a m p l e a n a l y s i s . Improper storage can completely i n v a l i d a t e a n y a n a l y t i c a l r e s u l t s . Ideally, the s a m p l e is to be s t o r e d in a m a n n e r to p r e v e n t a c h a n g e in the a t t r i b u t e being examined, from the time of sampling, through analysis, and into reserve storage. To i l l u s t r a t e the i m p o r t a n c e of p r o p e r s t o r a g e , if a fresh food sample to be examined for decomposition is not hard frozen until examination, it very likely will decompose even further. The analyst is then not sure how m u c h of the d e c o m p o s i t i o n found is due to sample mishandling. The usual storage areas are dry (room temperature storage), refrigeration and freezing. K e e p in m i n d t h i n g s that c a n h a p p e n d u r i n g s t o r a g e . For e x a m p l e , insects or other vermin can attack dry storage, mould frequently occurs during refrigeration, and frozen products often have "freezer burn" where the food has desiccated. Steps to m i n i m i z e these problems include using correct containers (i.e. glass or m e t a l for dry storage, no paper bags), proper sample preparation (i.e. g l a z i n g f r o z e n s a m p l e s w h e r e p o s s i b l e , to r e d u c e d e h y d r a t i o n ) , and frequent checks on those stored samples which are m o s t subject to change. Sample disposal is, or can be, a relatively simple matter. The only problems arise w h e n there is a hazard involved in the destruction, or where the sample r e m a i n s must have special treatment. An e x a m p l e is a s a m p l e of g r o u n d n u t s heavily contaminated with aflatoxin. The sample itself presents a hazard to the disposer and may be a hazard to others if not detoxified. The analyst best k n o w s any h a z a r d s i n v o l v e d , so s h o u l d i n f o r m the S a m p l e C u s t o d i a n of a n y special disposal requirements.

22

4.4

Budget

The need should be appreciated for as flexible a budgetary system as possible. C o n t i n g e n c y funds are i m p o r t a n t for the r u n n i n g of a l a b o r a t o r y . Budgets should be a r r a n g e d so that funds are r e a d i l y a v a i l a b l e for u r g e n t s u p p l i e s , s p a r e s and r e p a i r s and the o t h e r d a y - t o - d a y n e e d s of the l a b o r a t o r y w h i c h cannot wait for the usually slow cycle of fiscal machinery utilized for annual budgets in most governments. The Laboratory Head must have adequate control of the b u d g e t and o p e r a t e it under c l e a r l y d e f i n e d rules. T h e s e should be s u f f i c i e n t l y f l e x i b l e that he or she r e t a i n s d i s c r e t i o n a r y p o w e r s e n a b l i n g t r a n s f e r of funds b e t w e e n c e r t a i n b u d g e t c l a s s e s as o c c a s i o n d e m a n d s . For e x a m p l e , funds for c a p i t a l e q u i p m e n t w i l l u s u a l l y be n o n - t r a n s f e r a b 1 e w h i l e funds in two s e p a r a t e c l a s s e s for c h e m i c a l s and e x p e n d a b l e e q u i p m e n t m a y reasonably be transferred between one another. The b u d g e t p r e p a r a t i o n p r o c e s s should i n v o l v e all l e v e l s of l a b o r a t o r y management from the Supervisors to the Head. Supervisors especially gain an a p p r e c i a t i o n for h o w m o n i e s can or c a n n o t be spent by p r e p a r i n g a b u d g e t increment for their group. B u d g e t s t y p i c a l l y are planned for one y e a r , but should be d i v i d a b l e into quarters, seasons, projects or s o m e o t h e r l o g i c a l d i s t r i b u t i o n f o r m a t . Each Supervisor should have the responsibility (overseen and approved by the Head) for the b u d g e t p u r c h a s e s by h i s group. All o f f - b u d g e t i t e m s m u s t be fully justified. If sufficiently important, an off-budget item may take precedence over the purchase of budgeted material.

4.5

Purchasing

The s e l e c t i o n and s p e c i f i c a t i o n of l a b o r a t o r y e q u i p m e n t t o g e t h e r w i t h the p l a n n i n g of space r e q u i r e m e n t s ( i n c l u d i n g f l e x i b i l i t y for f u t u r e e x p a n s i o n ) should always precede, or at least go hand in hand with, building design. Less industrial countries often lack l a b o r a t o r y s u p p l i e s and e q u i p m e n t , t e c h n i c a l assistance and maintenance services. The limited over-all marketing potential, and the large variety of laboratory and scientific instruments available from foreign suppliers and manufacturers, make it generally uneconomical for local businessmen to establish stocks or to employ qualified service engineers. The p r o b l e m in m a n y c o u n t r i e s is c o m p o u n d e d by f o r e i g n e x c h a n g e and i m p o r t r e s t r i c t i o n s w h i c h o f t e n do not e v e n p e r m i t the c o m m e r c i a l i m p o r t of spare parts. As a result, scientific laboratories in developing countries cannot, or can only to a l i m i t e d e x t e n t , find t e c h n i c a l a s s i s t a n c e locally. They m u s t r e l y on the support and c o o p e r a t i o n of s u p p l i e r s based p e r h a p s t h o u s a n d s of miles away. Several conclusions can be drawn from this situation. One of them is that b e f o r e s e l e c t i n g any e q u i p m e n t , a c a r e f u l study should be m a d e to determine : 1. Which of the many possible suppliers and manufacturers of equipment h a v e local r e p r e s e n t a t i v e s or o f f i c e s c a p a b l e of p r o v i d i n g i n s t a l l a t i o n and maintenance services? 2. W h a t e x p e r i e n c e do p o t e n t i a l s u p p l i e r s h a v e in d e a l i n g special conditions obtaining in less industrialized countries?

with

the

E q u i p m e n t s p e c i f i c a t i o n s m u s t be p r e p a r e d very carefully and clearly. There are countless examples of cases where lack of detail in specifying has led to the p u r c h a s e of i n c o m p l e t e or u n s u i t a b l e a p p a r a t u s . It should be u n d e r s t o o d that s u p p l e m e n t a r y e q u i p m e n t or a c c e s s o r i e s , if not s p e c i f i e d , w i l l not be quoted for in the s u p p l i e r ' s bid. M o s t b r o c h u r e s or c a t a l o g u e s p u b l i s h e d by equipment manufacturers give only general information, without complete order specifications. A s e l e c t i o n based p u r e l y on such l i t e r a t u r e o f t e n leads to misunderstandings. No indication is usually given of essential accessories not

23

included in the basic instrument, of optional accessories with explanations for t h e i r p a r t i c u l a r a p p l i c a t i o n , or o f e s s e n t i a l o p e r a t i n g s u p p l i e s and r e c o m m e n d e d spare parts. S c i e n t i f i c i n s t i t u t i o n s in less i n d u s t r i a l i z e d countries have had the experience that because of insufficient specifications (or lack of e x p e r i e n c e on the part of the s u p p l i e r s ) they w e r e s u p p l i e d w i t h incomplete equipment. W h i l e the s u p p l i e r m a y b e l i e v e that n o n - s p e c i f i e d e q u i p m e n t is a l r e a d y a v a i l a b l e , the s c i e n t i s t in the l a b o r a t o r y m a y be s u f f e r i n g s e r i o u s and annoying delays in putting the equipment into operation. New orders have to be processed, and up to a year may be required to obtain the necessary additional supplies. Most manufacturers restrict their supplies to the parts they produce in t h e i r o w n w o r k s . T h e y a r e u s e d to the s i t u a t i o n w i t h i n t h e i r o w n c o u n t r y w h e r e m i n o r a c c e s s o r i e s such as s t a n d s , c l a m p s , t u b i n g , g l a s s w a r e and e v e n small instruments like pH-meters, balances and thermostats c o m m o n l y found in a laboratory are either available i m m e d i a t e l y or may be obtained quickly from a local dealer. W h e n dealing with less industrialized countries, h o w e v e r , it is frequently wrong to assume that the same situation obtains. Large laboratory supply companies offer a m o r e comprehensive range of supplies than individual manufacturers as their delivery p r o g r a m m e usually includes a full range of instruments and auxiliary equipment. Another advantage offered by the l a r g e c o m p a n i e s is the e c o n o m y g a i n e d by d e a l i n g w i t h o n l y one s o u r c e rather than having to deal with a n u m b e r of individual manufacturers. Service f a c i l i t i e s for i n s t a l l a t i o n and m a i n t e n a n c e of the e q u i p m e n t can also be coordinated and provided m u c h m o r e easily by a large organization. If experts h a v e to be c o m m i s s i o n e d for each i n d i v i d u a l p i e c e of c o m p l e x e q u i p m e n t , the expense b e c o m e s prohibitive. C o m p l e x a p p a r a t u s r e q u i r e s s p e c i a l t r a i n i n g for the o p e r a t o r s . Engineers p e r f o r m i n g the installation usually provide some basic training. Depending on the experience of the scientist who is to work with the equipment, h o w e v e r , a m o r e f a r - r e a c h i n g p r o g r a m m e of t r a i n i n g m a y be n e c e s s a r y , w h i c h c a n n o t be i m p a r t e d by the e n g i n e e r in the field. In such c a s e s , s p e c i a l t r a i n i n g p r o g r a m m e s should be arranged in advance of the purchase, preferably before the equipment is delivered. P r o c u r e m e n t r u l e s d e m a n d , a l m o s t e v e r y w h e r e , that the c h e a p e s t o f f e r s be accepted. Applied to the purchase of scientific e q u i p m e n t , strict observation of such r u l e s m a y turn out to be a v e r y e x p e n s i v e w a y of e q u i p p i n g a laboratory. Precise specifications are a good m e a n s of obtaining correct and reliable offers. O n l y such o f f e r s a l l o w a just c o m p a r i s o n of the s c o p e of d e l i v e r y and the p r i c e s of d i f f e r e n t b i d d e r s . In o r d e r to o b t a i n a n u n d i s t o r t e d p i c t u r e of c o m p a r a t i v e d a t a , o n l y t e c h n i c a l l y e x p e r i e n c e d and c o m m e r c i a l l y capable manufacturers and suppliers should be invited to submit offers. Only a limited number of firms that can satisfy every requirement as to q u a l i t y , e x p e r i e n c e in h a n d l i n g c o m p r e h e n s i v e s u p p l i e s , r e l i a b i l i t y in c o n n e c t i o n w i t h d e l i v e r y s c h e d u l e s , t e c h n i c a l a s s i s t a n c e and m a i n t e n a n c e s e r v i c e s h o u l d be i n v i t e d to t e n d e r . T h i s m a y e v e n lead to i n d i v i d u a l f i r m s being selected as suppliers for entire laboratory equipment lots or specialized instruments on a proprietary or s ingle-tender basis. I n v i t a t i o n s to bid s h o u l d a l w a y s g i v e c l e a r i n d i c a t i o n s of the c u r r e n c y and t e r m s in w h i c h o f f e r s are to be s u b m i t t e d ; if i n d i v i d u a l p r i c e s a r e to be q u o t e d e x - w o r k s , f.o.b. port of s h i p m e n t , c & f. or c.i.f. p o r t of d e s t i n a t i o n ; if s h i p m e n t is d e s i r e d b y air or sea; and w h e t h e r or n o t the c o s t of p a c k i n g should be included. It is worth pointing out that North A m e r i c a n firms have a d i f f e r e n t i n t e r p r e t a t i o n of the t e r m "f.o.b." (free on b o a r d s h i p ) f r o m European suppliers. The latter observe the internationally accepted definition of the t e r m , a c c o r d i n g to w h i c h f.o.b. p r i c e s i n c l u d e c o s t and all c h a r g e s of delivery including packing, up to "on board ship" in the seaport or airport of shipment. In the U n i t e d S t a t e s of A m e r i c a , h o w e v e r , "f.o.b." is n o r m a l l y u n d e r s t o o d as f.o.b. f a c t o r y , and p r i c e s do not i n c l u d e p a c k i n g , inland

24

f r e i g h t , l o a d i n g c h a r g e s , d o c u m e n t a t i o n or e x p o r t h a n d l i n g , all of w h i c h are charged separately. The term f.a.s. is used to denote "free alongside ship". If a b i d d e r d e v i a t e s from the t e r m s laid d o w n in the t e n d e r i n v i t a t i o n , h i s o f f e r s h o u l d be c a r e f u l l y e x a m i n e d as it m a y h a v e b e e n i n t e n d e d to o b t a i n a superficial advantage in price comparison only. A careful technical scrutiny of the s p e c i f i c a t i o n s g i v e n in a b i d d e r ' s o f f e r and a c o m p a r i s o n w i t h the i l l u s t r a t e d l i t e r a t u r e a t t a c h e d to the bid w i l l , in m a n y c a s e s , e l i m i n a t e q u o t a t i o n s w h i c h at f i r s t g l a n c e look c h e a p e r . Accessories may have been p u r p o s e l y left out to g a i n an a d v a n t a g e over o t h e r b i d d e r s . Sometimes minor b u t i m p o r t a n t d i f f e r e n c e s in p e r f o r m a n c e d a t a c a u s e c o n s i d e r a b l e price variations. M a n y n a t i o n a l and i n t e r n a t i o n a l o r g a n i z a t i o n s i n v i t e o f f e r s from o r i g i n a l manufacturers only, demand ing that the c o m m i s s ion usually allowed to agents be offered as a discount. The disadvantages of this procedure are that orders are quite frequently placed w i t h firms which readily accept these conditions but which have neither experience nor agents in the purchasing country. Thus, the scientists in less industrali zed countries are denied the benefit of any kind of t e c h n i c a l a s s i s t a n c e . W h e n c o m p a r i n g p r i c e q u o t a t i o n s , the o f f e r of an i n t e r n a t i o n a l l a b o r a t o r y e q u i p m e n t s u p p l i e r m a y o c c a s i o n a l l y be found to b e substantially higher than that of a manufacturer. In such cases it can only be r e c o m m e n d e d t h a t the e x p e r i e n c e and a f t e r - s a l e s s e r v i c e i n c o r p o r a t e d in the offer should be carefully considered. One aspect of equipment purchase that causes problems is the time given for the s u b m i s s i o n of o f f e r s . O f t e n it is far too s h o r t . It s h o u l d be r e a l i z e d t h a t long lists of specifications prepared for a project over an extended period of time cannot normally be quoted for in a space of only two or three weeks - the t i m e that m i g h t be left to a s u p p l i e r a f t e r d e l a y s in m a i l are t a k e n into account. The q u a l i t y of o f f e r s m i g h t be c o n s i d e r a b l y i m p r o v e d if m o r e t i m e were allowed. D e c i s i o n s on bid a c c e p t a n c e s h o u l d n o t be d e l a y e d b e y o n d the n o r m a l validity of offers. Another serious problem that is often encountered concerns damage in transit Extensive d a m a g e and even total loss and the insurance covering such damage. can result from the rough handling of consignments in ports where no mechanized m e a n s of t r a n s p o r t (such as f o r k - l i f t t r u c k s ) is a v a i l a b l e . D e l a y s m a y be e n c o u n t e r e d in c l e a r i n g c o n s i g n m e n t s t h r o u g h c u s t o m s , and s h e l t e r e d s t o r a g e facilities are often quite inadequate. Cases containing expensive equipment m a y be s u b j e c t e d to the m o s t a d v e r s e c l i m a t i c c o n d i t i o n s - h u m i d i t y , h e a v y tropical rains, extreme heat and dust. No economically justifiable method of p a c k i n g can p r e v e n t d a m a g e to e q u i p m e n t u n d e r such c o n d i t i o n s . Sometimes, b e c a u s e of c u s t o m s f o r m a l i t i e s and a d m i n i s t r a t i v e d e l a y s in h a v i n g the consignments unpacked and examined, insurance coverage has already expired by the t i m e the e q u i p m e n t a r r i v e s at its d e s t i n a t i o n and a c l a i m can be l o d g e d . T h e n , m o r e t i m e and e f f o r t is u s u a l l y s p e n t on f i x i n g r e s p o n s i b i l i t y than on how the situation might be avoided in the future. Replacement parts required to repair transport damage should be obtainable with a m i n i m u m of delay and administrative red tape. Laboratories should have the authority, in an emergency, to place small orders direct with suppliers. With or without such emergency order facilities, h o w e v e r , scientists usually depend on (and prefer cooperation with) the experienced and flexible supplier who is in regular contact w i t h his customer, who extends unbureaucratic help and who even provides, when necessary, free replacements and repair facilities in order to c o n t r i b u t e to the p r i m e o b j e c t i v e in the e s t a b l i s h m e n t of a s c i e n t i f i c institute, useful and effective work and uninterrupted operation.

25

4.6

Supplies

Management

Supplies routinely used by a laboratory include solvents, reagents, chemicals, g l a s s w a r e and o t h e r a n a l y t i c a l m a t e r i a l s . By d e f i n i t i o n , s u p p l i e s are considered to be consumables and must be constantly replaced as used. T h e r e m u s t t h e r e f o r e b e an a c c u r a t e a c c o u n t i n g s y s t e m to r e c o r d r e c e i p t , u s e and f u t u r e n e e d . T h i s is d o n e in a v a r i e t y of w a y s but a card s y s t e m is the m o s t versatile. The Supplies Record Card can contain such data as:

Name of product Date purchased Where purchased Amount (including units if more than one Expiration date (if any) Special storage requirements (if any) Amount dispensed.

container)

S m a l l m e t a l t a g s p a i n t e d w i t h b r i g h t c o l o u r s can be p u r c h a s e d and d i f f e r e n t tags affixed to cards for flagging purposes. For e x a m p l e , a red tag m a y m e a n the supply is low and should be reordered within a given time. Having a w o r k a b l e supplies m a n a g e m e n t s y s t e m t e n d s to p r e v e n t c i r c u m s t a n c e s w h e r e a n a l y s e s h a v e s t o p p e d b e c a u s e a c r i t i c a l m a t e r i a l is s u d d e n l y u s e d up. L i k e b u d g e t i n g , it is a p r o c e s s of m a i n t a i n i n g c o n t r o l of a c r i t i c a l a r e a to promote overall smooth operation of the laboratory.

4.7

Equipment

Maintenance

W h e n the food analyst goes beyond organoleptic examinations, he or she must use s o m e i t e m of e q u i p m e n t to p r o c e s s or to m e a s u r e the s a m p l e a t t r i b u t e of interest. It is critically important, therefore, that all items of equipment be properly and promptly maintained, and repaired when needed. T h e d e g r e e of s o p h i s t i c a t i o n of e q u i p m e n t v a r i e s d r a m a t i c a l l y from a straightforward pH m e t e r to a complex spectrophotometer. M a n y laboratories in developing countries have great difficulty in o b t a i n i n g r e p a i r of any e q u i p m e n t , sophisticated or otherwise. It is therefore reasonable to require that proper maintenance of the equipment be routinely scheduled and completed, hopefully to delay the day when outright repairs are necessary. T h e b e s t c i r c u m s t a n c e , of c o u r s e , is to e s t a b l i s h an o p e r a t i n g r e p a i r and m a i n t e n a n c e w o r k s h o p w i t h qualified technical staff. This can be essential for l a r g e i n s t i t u t e s h a v i n g a d i s p r o p o r t i o n a t e l y l a r g e i n v e s t m e n t in e x p e n s i v e equipment. E v e n in the a b s e n c e of an o r g a n i z e d w o r k s h o p , s o m e a n a l y s t s or technicians can be given training in repair and maintenance techniques, often by local instrument suppliers. If adequate service is available locally, serious consideration should be given to purchase of service contracts. The usual service contract involves checking the e q u i p m e n t at s p e c i f i e d i n t e r v a l s and p e r f o r m i n g n e c e s s a r y m a i n t e n a n c e . E m e r g e n c y r e p a i r s are u s u a l l y d i s c o u n t e d in p r i c e b e c a u s e of the s e r v i c e contract. Service contracts are especially important for analytical balances, to m a i n t a i n proper calibration. A history of an instrument's maintenance and repair can become very important. It p r o v i d e s a s u m m a r y of the i n s t r u m e n t ' s o p e r a t i o n o v e r a g i v e n p e r i o d , b u t m o r e i m p o r t a n t l y , it can p r o v i d e a j u s t i f i c a t i o n for r e p l a c e m e n t of old and o u t w o r n items. Recording the cost is important as it is then readily apparent

26

w h e n an i n s t r u m e n t c o s t s m o r e to k e e p o p e r a t i n g t h a n it is w o r t h . A preprinted 5 x 8 c a r d c a n c o n v e n i e n t l y b e u s e d to r e c o r d s u c h i n f o r m a t i o n . An e x a m p l e of s u c h a c a r d ( f r o n t a n d r e a r ) is s h o w n in F i g u r e s 4.1 a n d 4 . 2 .

T y p e of Machin*

MACHINE PART I -

DETAILS

OF

HISTORY

CARD

MACHINE

B r a n d a n d Modal N o .

Vendor

L o c a t i o n of m a c h i n e (State dept./scction)

H o w o p e r a t e d ( T i c k in appropriate b o x )

Machine N o .

C o u n t r y of Manufacture

Data of P u r c h a i e

Purchase Price

Guarantee P e r i o d

T e r m s of Guarantee

•

P A R T II -

Manual

•Etactrk

•

Electronic

DETAILS OF MAINTENANCE Service A g e n t

Per lOd

Maintenance C o n t r a c t

Name

From

Cott ($) (per a n n u m )

To

Spare parts included? Yes

No

N u m b e r of

C o m m e n t » o n f i r m ' » service

(per a n n u m )

Figure 4.1 Front Side

F A R T HI -

OF

BREAKDOWNS S e r v i c i n g / R e o a i r details (State cause of b r e a k d o w n a n d parts c h a n g e d , etc!

Date

P A R T IV

OETAILS

-

COMMON D E F E C T S

I d n c n b * with d . u i l i

pm

Response time of Service A g e n t

f r « * j . n ç y . cHactsl

Figure 4.2 Rear Side

27

Cumulative Cost

C o s t of Repair

Time taken to repair

S

4

S

4

4.8

Housekeeping

L a b o r a t o r y c l e a n l i n e s s is very i m p o r t a n t , not only to m a i n t a i n a good appearance, but to p r e v e n t s o m e f o r m s of c o n t a m i n a t i o n . Housekeeping a c t i v i t i e s go beyond c l e a n i n g and tidying in the l a b o r a t o r y . It i n c l u d e s i n s e c t and o t h e r pest c o n t r o l . M o s t l a b o r a t o r i e s m u s t do their o w n pest control to minimize contamination from control agents. Commercial pest control firms usually do not have an appreciation of laboratory contamination problems. L a b o r a t o r i e s m u s t be r o d e n t - p r o o f in c o n s t r u c t i o n . E l e c t r i c a l d e v i c e s are available for killing flying insects. Food may arrive contaminated with insect eggs so that proper storage is inadequate without fumigation. Fumigation by halogenated hydrocarbons or use of organochlorine compounds against insects are l i k e l y s o u r c e s of l a b o r a t o r y c o n t a m i n a t i o n and are best a v o i d e d w h e n e v e r possible. T h e y all h a v e a s i g n i f i c a n t v a p o u r p r e s s u r e and m u s t be kept w e l l a w a y from s e n s i t i v e e q u i p m e n t such as gas c h r o m a t o g r a p h s and from s a m p l e s requiring analysis for pesticide residues. H o u s e k e e p i n g should involve s c h e d u l e d as w e l l as ad hoc c l e a n i n g and pest control. O f t e n a good t i m e is the last h o u r of a w o r k w e e k . A scheduled activity quickly becomes routine and is consequently in the awareness of the laboratory analysts. This awareness is important because, as can be shown by e x p e r i e n c e , not all p e r s o n s are n e a t , c l e a n and tidy in their e v e r y d a y activities. M a n a g e m e n t m u s t d e m o n s t r a t e a c o n t i n u i n g c o m m i t m e n t to good housekeeping principles if the analysts are to accept those principles.

4.9

Training

W h e n an a n a l y s t is first hired in a food c o n t r o l l a b o r a t o r y , a c o n t i n u i n g s e r i e s of t r a i n i n g and e d u c a t i o n a l e x p e r i e n c e s b e g i n . The n e w a n a l y s t is t a u g h t , u s u a l l y on the job, the v a r i e d a n a l y s e s and m e t h o d s used by the laboratory. Most often this is by what amounts to an apprenticeship approach where the new analyst is assigned to work with a senior. It is best, however, to have a formal, structured training programme designed to acquaint the new analyst with the work in a logical sequence. Otherwise the training becomes haphazard with the training sequence dependent on incoming work. O n c e past the f o r m a l initial t r a i n i n g , the a n a l y s t s t a r t s a c o n t i n u i n g knowledge updating process. Food analysis is a rapidly changing subject and it is i m p o r t a n t that a n a l y s t s attend s y m p o s i a , r e f r e s h e r c o u r s e s and other educational programmes in order to keep up to date. In developing countries it may be necessary to schedule travel to other areas from time to time for such t r a i n i n g . T h i s e f f o r t is e n h a n c e d if the l a b o r a t o r y is a b l e to s u b s c r i b e to the more active research journals in food analysis. The analysts are then able to keep abreast of new advances, especially newer analytical methods. Should an a n a l y s t s h o w i n t e r e s t and a p t i t u d e for s u p e r v i s i o n , then he or she s h o u l d be g i v e n f o r m a l c l a s s r o o m t r a i n i n g in s u p e r v i s o r y p r i n c i p l e s . This w o u l d be in a d d i t i o n to o n - t h e - j o b e x p e r i e n c e under the t u t e l a g e of a supervisor or the Head. It is important that the classroom instruction be done because it is here that the analyst learns supervision and management theory and techniques other than those used by his laboratory. On-the-job experience as an acting supervisor is necessary but tends to be one dimensional because it teaches only the systems and techniques used by that laboratory.

28

5.

5.1

LABORATORY

OPERATIONS

Workplans

T h e a n n u a l w o r k p l a n is the c o r n e r s t o n e to m a n a g i n g a food c o n t r o l l a b o r a t o r y . It p r o v i d e s a m e a n s of e s t i m a t i n g s t a f f a n d r e s o u r c e s n e c e s s a r y to do a f i x e d n u m b e r of a n a l y s e s . C o n v e r s e l y , g i v e n a f i x e d s t a f f , the w o r k p l a n can e s t i m a t e h o w m u c h w o r k can be d o n e . W o r k p l a n d a t a is a l w a y s o n l y an e s t i m a t e , a l t h o u g h its a c c u r a c y o f t e n w i t h u s e d u e t o r e f i n i n g o f t i m e m o d u l e s u s e d in c a l c u l a t i o n s . i m p o r t a n t t i m e m o d u l e s in w o r k p l a n n i n g are:

improves The two

1. T h e a n a l y s t p r o d u c t i v e y e a r : T h i s is t h a t t o t a l t i m e i n a n a v e r a g e year that one a n a l y s t s p e n d s doing o n l y s a m p l e a n a l y s i s . Time spent during w o r k h o u r s d o i n g o t h e r t h i n g s is d e d u c t e d . A n e x a m p l e of t h e d e t e r m i n a t i o n of t h i s m o d u l e is as f o l l o w s :

Total

time a v a i l a b l e

(based

on 4 0 h o u r w o r k

week)

2080 hr s

Time deductions N a t i o n a l and l o c a l h o l i d a y s Illness P e r s o n a l leave time Training A d m i n i s t r a t i v e time Other n o n - a n a l y s i s time Total time d e d u c t i o n s Total analysis

time

(2080 -

80 40 80 200 80 400 880

hr s hrs hr s hrs hrs hrs hrs

1200 hrs

880)

T h i s m e a n s ( b a s e d on the a b o v e e x a m p l e ) that for n a n a l y s t s , the e x p e c t n x 1 2 0 0 h o u r s of p r o d u c t i v e w o r k d u r i n g t h e y e a r .

laboratory

can

T h e a b o v e t i m e d e d u c t i o n f i g u r e s w e r e t a k e n for e x a m p l e p u r p o s e s o n l y . Each i n d i v i d u a l l a b o r a t o r y w i l l be d i f f e r e n t . In d e t e r m i n i n g d e d u c t i o n s , c o n s i d e r the f o l l o w i n g : a.

Holiday

time

is u s u a l l y

fixed

b.

I l l n e s s and p e r s o n a l t i m e a v e r a g e s can be t a k e n f r o m staff The a d m i n i s t r a t i v e r e c o r d s f o r t h e p r e c e e d i n g o n e or t w o y e a r s . a v e r a g e of the p r e v i o u s y e a r is b e s t u s e d as the m o d u l e . T h e r e a s o n is that the s t a f f u s u a l l y h a v e m o r e p e r s o n a l t i m e m a d e a v a i l a b l e to t h e m as t h e i r s e n i o r i t y i n c r e a s e s .

c.

M a n a g e m e n t m u s t d e c i d e h o w m u c h t i m e w i l l be set a s i d e e a c h y e a r for t r a i n i n g . N o t e in the e x a m p l e t h a t t r a i n i n g t i m e is a b o u t 10% of the t o t a l . If the s t a f f is r e l a t i v e l y y o u n g and i n e x p e r i e n c e d , m o r e t i m e w i l l be r e q u i r e d . C o n v e r s e l y an a l l - s e n i o r s t a f f m a y r e q u i r e l e s s .

d.

A d m i n i s t r a t i v e t i m e is d i f f i c u l t to e s t i m a t e as t h e r e are u s u a l l y few or no r e c o r d s to go b y . It i n c l u d e s t i m e a s a c t i n g supervisor, general library reading, and o t h e r a s s i g n e d or incidental administrative activities.

e.

O t h e r n o n - a n a l y s i s t i m e is also o n l y an e s t i m a t e , a l t h o u g h s o m e t i m e r e c o r d s m a y be a v a i l a b l e . It i n c l u d e s g e n e r a l r e s e a r c h o r m e t h o d development activities, quality assurance work, equipment m a i n t e n a n c e , t i m e s p e n t s e r v i n g as a t r a i n e r , a n d a n y o t h e r n o n a n a l y s i s w o r k time not included e l s e w h e r e .

29

by government

policy.

2. T h e a n a l y t i c a l h o u r s r e q u i r e d per s a a p l e : The f i r s t step is to d e f i n e w h a t is i n c l u d e d in a s a m p l e a n a l y s i s , as t h i s o b v i o u s l y a f f e c t s the total time. Activities which are suggested to be included are: a.

Sample receipt and

preparation.

b.

Analysis.

c.

M e t h o d d e v e l o p m e n t or p r o b l e m s o l v i n g r e q u i r e d of a g i v e n s a m p l e . (As o p p o s e d to g e n e r a l d e v e l o p m e n t or r e s e a r c h , w h i c h w o u l d b e included in non-analysis time.)

d.

S t a n d a r d i z a t i o n a c t i v i t i e s r e l a t e d to a g i v e n s a m p l e . standard solutions and curves for example.)

e.

Preparation

of analytical

report and

(Preparing

calculations.

The next step is to prepare a list of all the different analyses conducted and e s t i m a t e individual analytical times based on experience. If some analyses are d o n e b y t e a m s in a p r o d u c t i o n - 1 i n e a r r a n g e m e n t , e s t i m a t e the t o t a l t i m e required by totalling the time and correcting to an individual analyst basis. For e x a m p l e , if 4 analysts working as a team can produce 32 completed samples in an 8 h o u r p e r i o d , t h e n t h e a v e r a g e a b s o l u t e s a m p l e t i m e is 0.25 hours/analysis. H o w e v e r , it required 4 analysts and to correct the time to an i n d i v i d u a l a n a l y s t b a s i s - 4 x 0.25 = 1.0 h o u r s / ana 1 ys i s . T h i s w o u l d be the figure used in calculations. *

The laboratory is now able to make good estimates on what and h o w m u c h work can be d o n e . It is a s i m p l e m a t t e r of m u l t i p l y i n g the n u m b e r s of a n a l y s t s a v a i l a b l e d u r i n g the y e a r t i m e s the p r o d u c t i v e y e a r t i m e m o d u l e to g a i n the total analytical hours available. This can then be spread among the types of a n a l y s e s to be d o n e , u s i n g the h o u r s / a n a l y s i s m o d u l e s . A l t h o u g h m a n y of the m o d u l e s are e s t i m a t e s , it is still a better and m o r e accurate w a y to d e t e r m i n e w h a t can be d o n e , than r e l y i n g on m e m o r y and s h e e r g u e s s e s . ( R e g a r d i n g the n u m b e r s of a n a l y s t s a v a i l a b l e d u r i n g the y e a r , k e e p in m i n d t h a t t h i s m a y change by new hires or projected losses, so include these future projections in the annual estimate). T h e a b o v e c a l c u l a t i o n m e c h a n i c s of a w o r k p l a n do not a d d r e s s the m e a n s of d e c i d i n g the a n n u a l w o r k p r i o r i t i e s . T h i s is u s u a l l y d o n e in p a r t b y organizational policy and in part by m e e t i n g s of senior operational managers, s u c h as the L a b o r a t o r y and I n s p e c t o r a t e H e a d s . All p l a n n e d w o r k and t i m e modules depend on proper work scheduling and flow. If samples are collected too fast or too slow, the laboratory efficiency suffers. There m u s t therefore be an extremely close working relationship and liaison b e t w e e n the inspectorate and l a b o r a t o r y . No work plan would be complete without some form of contingency planning. The o l d a d a g e s t a t e s t h a t , "... If s o m e t h i n g c a n go w r o n g , it w i l l ...". T h e r e f o r e , t h e r e s h o u l d be at least a p r o v i s i o n in a a n n u a l w o r k p l a n for e m e r g e n c i e s or u n e x p e c t e d p r o b l e m s . A m a j o r p u b l i c h e a l t h d i s a s t e r , for e x a m p l e , could require an all-out laboratory effort, negating workplan work for some period of time. The contingency plan would simply and clearly state w h a t t y p e s of a n a l y s e s ( u s u a l l y the l o w e s t p r i o r i t y ) w o u l d be e l i m i n a t e d in the event of an emergency.

30

5.2

Priorities

for

General analytical laboratory policy.

Analysis

priorities are usually s o m e w h a t fixed by organizational H o w e v e r , a suggested priority structure would be:

Priority 1

Poisonings or public health

Priority 2

K n o w n or resulting

Priority 3

Informational

injury complaints analyses.

s u s p e c t e d law or in direct injury. surveys

and

health

other

emergency

violations,

and other routine

or

not

work.

M o s t of the w o r k of a l a b o r a t o r y is u s u a l l y in the t h i r d p r i o r i t y c a t e g o r y , with a smattering of priority two and only infrequently, priority one. W i t h i n a g i v e n p r i o r i t y , the w o r k c a n be s u b - g r o u p e d by r e l a t i v e i m p o r t a n c e . It is conceivable that work of very low importance never gets done because of the continuing press of higher priority analyses. If it appears that such is the c a s e , the s u p e r v i s o r m u s t a d v i s e the H e a d of the p r o b l e m s and s u g g e s t r e v i s i o n of the p l a n n e d w o r k load for the s u p e r v i s o r ' s g r o u p . The w o r k p l a n s discussed in the previous Section often undergo mid-year or periodic revision based on such happenings.

5.3

Analysis

Assignaient

A s s u m i n g the p r i o r i t y nas b e e n p r e v i o u s l y a s s i g n e d , the a n a l y s i s a s s i g n m e n t includes two key considerations, n a m e l y w h a t is to be done and what analytical method to use. T h e a n a l y s i s to be c a r r i e d out on a s a m p l e m a y be p r e d e t e r m i n e d as p a r t of a planned sampling p r o g r a m m e or by legal requirements. Experience gained by the analyst may enable him to have firm views on the tests to be done. The purpose of the a n a l y s i s m u s t be b o r n e c l e a r l y in m i n d , e.g. for e x p o r t c e r t i f i c a t i o n , the t e s t s r e q u i r e d by the i m p o r t i n g c o u n t r y m u s t be c a r r i e d o u t , for e x c i s e purposes, the constituent that fixes the duty payable and so on. When samples are examined under the general and specific provisions of laws pertaining to consumer protection and food quality, the analysis m u s t be designed to answer certain questions such as: Does the food meet established m i n i m u m quality and safety standards? Is it of the quality, substance and nature demanded by the purchaser? Is it correctly labelled? Are any claims on the label justifiable and l e g a l ? D o e s it c o n t a i n n o n - p e r m i t t e d a d d i t i v e s or p e r m i t t e d o n e s in excess? Are any contaminants present at unacceptable levels? R o u t i n e t e s t s on the p h y s i c a l c h a r a c t e r i s t i c s of m o s t c o m m o n food s a m p l e s should be carried out. Less frequently, tests may be made for preservatives, prohibited colours and other a d u l t e r a n t s . T h e a d u l t e r a n t s , c o n t a m i n a n t s and compositional deficiencies looked for should be changed from time to time to show if previously unsuspected infringements are present. The analyst m u s t be aware of the problems facing manufacturers and of developments in technology and choose non-routine tests in the light of this information. In this way the r e g u l a t o r y a n a l y s t acts as a s u p p o r t to the l e g i t i m a t e m a n u f a c t u r e r w h i l e protecting the consumer. The analyst must establish that he can obtain reliable results with the method used. G e n e r a l l y , it is p r e f e r a b l e to use a m e t h o d t h a t h a s b e e n s u b j e c t e d to collaborative study. If the analyst has difficulty with such a method it is likely to be due to a deficiency in training or in facilities, rather than the method itself. Sometimes it is d u e to p o o r e x p r e s s i o n of t h e e x a c t

31

e x p e r i m e n t a l d e t a i l s in the m e t h o d as published. R e f e r e n c e to the source w i l l usually resolve such difficulty. It is n o t a l w a y s n e c e s s a r y to u s e a collaborated method. H o w e v e r , s u c h m e t h o d s s h o u l d be f i r s t c h o i c e if the p a r a m e t e r is b e i n g d e t e r m i n e d in t h e l a b o r a t o r y f o r t h e f i r s t t i m e or if a p r o d u c t has not been a n a l y z e d p r e v i o u s l y . It is i m p o r t a n t to f o l l o w the p r o c e d u r e s ior v a l i d a t i n g a m e t h o d . M a n y o t h e r m e t h o d s m a y be e q u a l l y g o o d , but m a y not, for v a r i o u s reasons, have been subjected to c o l l a b o r a t i v e studies or r u g g e d n e s s t e s t s . As a r e s u l t the a n a l y s t m a y run into unexpected d i f f i c u l t i e s if he h a s to t a k e the m e t h o d d i r e c t l y f r o m a b o o k . If a m e t h o d has b e e n in use and found to give r e l i a b l e results it should not be changed for another until the n e w m e t h o d has been s h o w n to be of e q u a l or b e t t e r r e l i a b i l i t y in that p a r t i c u l a r l a b o r a t o r y ( i r r e s p e c t i v e o f i t s c o l l a b o r a t i v e status). C o n s i d e r a b l e stress is quite r i g h t l y put on c o l l a b o r a t i v e testing at the p r e s e n t t i m e , but it should not be f o r g o t t e n that a r e l i a b l e m e t h o d is only a p r e c o n d i t i o n to o b t a i n i n g the r i g h t a n s w e r . T h e a b i l i t y of the a n a l y s t to use the m e t h o d is the e s s e n t i a l r e q u i r e m e n t and the p e r s o n t a k i n g the r e s p o n s i b i l i t y for the result, w h e t h e r the analyst h i m s e l f or the s u p e r v i s o r , m u s t be c o n f i d e n t of this.

5.4

Analysis

Control

C o n t r o l is a v e r y i m p o r t a n t s u p e r v i s o r y f u n c t i o n . It is n o t s u f f i c i e n t to s i m p l y a s s i g n w o r k and w a i t for r e s u l t s . T h e r e m u s t be s o m e type of a c t i v e control in the form of expected c o m p l e t i o n datas, f o l l o w - u p i n q u i r i e s , or other i n d i c a t i o n s of active interest. This does not m e a n p e e r i n g over the a n a l y s t ' s s h o u l d e r , but it does m e a n that the s u p e r v i s o r has c e r t a i n fixed e x p e c t a t i o n s on w o r k c o m p l e t i o n and e n f o r c e s those e x p e c t a t i o n s . T h e r e are several m e t h o d s of control but one of the m o r e e f f e c t i v e is also one of the s i m p l e s t . The s u p e r v i s o r p r e p a r e s a card for each a n a l y s t . When a s a m p l e is a s s i g n e d to the a n a l y s t , the s a m p l e n u m b e r is r e c o r d e d on the c a r d along w i t h a p r o j e c t e d date of c o m p l e t i o n . W h e n an a n a l y s i s report is r e c e i v e d the entry is lined through. W h e n a'card has been filled, it is discarded and a n e w one p r e p a r e d . The p r o j e c t e d c o m p l e t i o n d a t e r e p r e s e n t s t h e s u p e r v i s o r ' s e s t i m a t e of an a c c e p t a b l e analysis t i m e , a s s u m i n g no p r o b l e m s . The s u p e r v i s o r s c a n s t h e c a r d s of a l l a n a l y s t s e v e r y d a y or so a n d if a d a t e h a s e x p i r e d b u t no report r e c e i v e d , the supervisor inquires of the s a m p l e status. The analyst m a y be h a v i n g d i f f i c u l t y a n d h a d n o t m e n t i o n e d it. A f t e r d i s c u s s i o n , the s u p e r v i s o r d e c i d e s if a n a l y s i s s h o u l d c o n t i n u e and if so, a s s i g n s a n e w projected c o m p l e t i o n date. The s u p e r v i s o r m u s t also a s s i g n n e w dates w h e n ongoing w o r k m u s t be interrupted by a s s i g n m e n t of h i g h e r p r i o r i t y analyses.

5.5

Analysis

Reporting

A n a l y s i s r e p o r t s are the end p r o d u c t of all of the w o r k of the l a b o r a t o r y and t h e r e f o r e m u s t be b o t h c o m p l e t e a n d a c c u r a t e . R e s u l t s of a n a l y s i s are o f t e n i m p o r t a n t facts in legal p r o c e e d i n g s . The w a y in w h i c h the technical results p r o d u c e d by the l a b o r a t o r y reach the court is d i f f e r e n t u n d e r d i f f e r e n t legal codes. O n e e x t r e m e is the U.K. w h e r e a c e r t i f i c a t e of a n a l y s i s is a l e g a l l y v a l i d d o c u m e n t w h i c h m a y b e a c c e p t e d as p r i m a f a c i e e v i d e n c e o f t h e f a c t s stated therein. Under R o m a n law, the l a b o r a t o r y report is a technical but not l e g a l d o c u m e n t w h i c h the c o u r t is e m p o w e r e d to a c c e p t or r e j e c t . In t h e U.S.A., f e d e r a l a c t i o n is u s u a l l y i n i t i a t e d by a d o c u m e n t o r i g i n a t i n g in the J u s t i c e D e p a r t m e n t on the basis of i n f o r m a t i o n from a t e c h n i c a l source. Under both R o m a n law and in the U.S.A., all prepared laboratory and technical records r e l e v a n t to t h e s a m p l e m a y h a v e to be p r o d u c e d in c o u r t and t h e s a m p l e r and analyst cross-examined. T h i s o c c u r s l e s s f r e q u e n t l y u n d e r U.K. l a w w h e r e c r o s s - e x a m i n a t i o n of the expert w i t n e s s is u s u a l l y all that is done, a l t h o u g h if he did refer to original notes or c a l c u l a t i o n s they w o u l d b e c o m e a v a i l a b l e to the c o u r t as in the U.S.A. T h u s , it is m a i n l y u n d e r l e g a l c o d e s d e r i v e d

32

from Roman and c o m m o n law that the report or certificate of the analyst assumes greater importance. U n d e r b o t h R o m a n and U.S.A. l a w the e n t i r e l a b o r a t o r y records relating to the sample must be capable of wi ths tand ing the scrutiny of the c o u r t and d e f e n s e l a w y e r s . The p r a c t i c a l e f f e c t of t h e s e d i f f e r e n c e s is not great. Under any system it is necessary for the regulatory chemist to have legally impeccable laboratory data records and to report against samples in a w a y that is u n d e r s t a n d a b l e to the l a y m a n , b r i e f , s u c c i n c t , and free from irrelevancy. T h e f o r m a t of an a n a l y s i s r e p o r t is d i c t a t e d by the a d m i n i s t r a t i v e and legal needs of the organization. The report form should be preprinted with blocks or l i n e s of i n f o r m a t i o n p l a c e d in d e s i g n a t e d a r e a s on the f o r m . This p e r m i t s faster and m o r e uniform write-up, as well as easier final review (the reviewer knows where to look on the form for different information). A complete report form would have spaces for the following information:

Sample number Product name Product description and amount Date received for analysis Labelling (if any) Analysis method used Analysis results Reserve product amount Date completed Total analysis time in hours (if needed

for time

modules).

Raw work data and standardization information can be placed on the reverse side of the analysis report or can be kept separately in notebooks. In any case it s h o u l d be a c c e s s i b l e to the r e v i e w e r in the e v e n t of q u e s t i o n . It is b e s t to include all raw data so that the entire sequence of work can be reconstructed later if needed. Calculations m u s t be clear w i t h all equations stated. There is no w a y to d e t e r m i n e if a c a l c u l a t i o n is c o r r e c t w i t h o u t c h e c k i n g the T h i s , of c o u r s e , m e a n s c a l c u l a t i o n s y s t e m u s e d , as w e l l as the a r i t h m e t i c . that all dilutions or other operations affecting the final calculation must be clearly stated in the raw data. R e s u l t s m u s t a l w a y s be r e p o r t e d o n l y to a n u m b e r of s i g n i f i c a n t figures j u s t i f i e d by the a c c u r a c y and p r e c i s i o n of the m e t h o d . In g e n e r a l , it is p r u d e n t to r e p o r t to as few s i g n i f i c a n t f i g u r e s as p o s s i b l e c o n s o n a n t w i t h stating the facts the report has to convey. For e x a m p l e , for most purposes it m a y be a d e q u a t e to r e p o r t a s a m p l e as c o n t a i n i n g "not less ( m o r e ) than 70 percent of y". The report m u s t be clear and confined to factual information, and statements which cannot be substantiated must not be made.

5.6

Analysis

Review

T h e a n a l y s t should not d r a w c o n c l u s i o n s from the w o r k r e p o r t e d . T h i s is r i g h t f u l l y the job of the s u p e r v i s o r , w h o is n o r m a l l y the a n a l y s i s r e p o r t reviewer. The reviewer should ask himself a number of questions while reading the report. Any negative answers should be clarified by the analyst before the report is accepted. Some possible questions are: Is the report generally complete? (Any missing required information?) Are the product descriptions adequate? Was the correct method used? Has sufficient work been done to draw a conclusion? Have the proper standards and reagents been used? Is there a blank? Are the calculations easy to follow and accurate? Are any strike-outs or discarded data explained?

33

5.7

Method

Validation

As discussed e l s e w h e r e , it is correct and proper to use collaboratively studied methods w h e r e possible. Such methods have already been shown to be capable of use in different laboratories. H o w e v e r , it is often necessary or advisable to use a locally developed method or one which was selected from the literature, but a b o u t w h i c h l i t t l e is k n o w n . In such c a s e s the m e t h o d m u s t be v a l i d a t e d for use in the local laboratory. Method validation can take many forms, but the usual procedure is to examine a k n o w n s a m p l e , or a k n o w n m a t e r i a l a d d e d to a s a m p l e , to d e t e r m i n e the m e t h o d accuracy and precision. For a contaminant residue, as example, a k n o w n amount of reference grade contaminant would be added to a blank sample and replicate assays done to determine the percentage recoveries. In this type of recovery v a l i d a t i o n it is i m p o r t a n t to be s u r e w h a t p a r t or p a r t s of the a n a l y s i s are being evaluated. A g a i n u s i n g the c o n t a m i n a n t e x a m p l e , a d d i t i o n of the r e f e r e n c e c o n t a m i n a n t to the s a m p l e e x t r a c t s o l u t i o n d o e s n o t e v a l u a t e the e x t r a c t i o n of the c o n t a m i n a n t , o n l y its p a s s a g e t h r o u g h c l e a n - u p and f i n a l assay. C o n t i n u i n g r e c o r d s of m e t h o d v a l i d a t i o n s should be kept for future reference and to d e m o n s t r a t e the u s e f u l n e s s of the m e t h o d s . N e g a t i v e d a t a is a l s o desirable. For e x a m p l e , if a method was tried and could not be satisfactorily validated, that information should be recorded to avoid future attempts. T h e r e c o v e r y d e t e r m i n a t i o n is o n l y one type of d i r e c t v a l i d a t i o n . T h e r e are also indirect validations where concurrent analyses are run on a given sample using a new method as well as an established, accepted method. This provides a direct experimental comparison. T h i s is a good s y s t e m w h e n an a l t e r n a t e procedure is needed for an official or referee method.

5.8

Confirming

Analysis

W h e n an o r i g i n a l a n a l y s i s s h o w s the s a m p l e to be in v i o l a t i o n of l a w or regulations in some m a n n e r , the supervisor m u s t decide if a second analysis by the o r i g i n a l a n a l y s t is n e e d e d . T h i s s h o u l d o n l y be d o n e if t h e r e is s o m e doubt that the original analysis w a s done correctly. In the event that there are no apparent errors in the original analysis, then a c o n f i r m i n g a n a l y s i s b y a s e c o n d a n a l y s t s h o u l d be d o n e as f o l l o w s : A fresh p o r t i o n of s a m p l e s h o u l d be p r e p a r e d ( u n l e s s it is n e c e s s a r y or d e s i r a b l e to u s e the o r i g i n a l ) and a n a l y z e d u s i n g a s e c o n d m e t h o d (if p o s s i b l e ) and n e w standard reference material. If the a d v e r s e f i n d i n g s are r e p e a t e d by the c o n f i r m i n g analyst, then it is extremely likely that a violation exists. If, h o w e v e r , t h e r e is no c o n f i r m a t i o n , then the s u p e r v i s o r m u s t m e e t w i t h b o t h a n a l y s t s and d e c i d e w h a t is to be d o n e . It m a y be t h a t the m e t h o d s are n o t c o m p a t i b l e , if so a recheck using the original method might be in order. It is a l s o o f t e n v e r y u s e f u l to c r o s s c h e c k the s t a n d a r d s u s e d b y e a c h a n a l y s t to ensure they compare. Confirming analysis is basically an attempt to ensure that any violation of law The e n f o r c e m e n t laboratory or regulation has substance and is not a mistake. c a n n o t a f f o r d to m a k e any m i s t a k e s , so it is n e c e s s a r y to p r o v e that all adverse results are correct.

34

6.

6.1

The Safety

LABORATORY

SAFETY

Programme

The Head of the laboratory and supervisors must emphasize to all the laboratory staff, their c o m m i t m e n t and d e t e r m i n a t i o n to e n s u r e s a f e l a b o r a t o r y w o r k i n g conditions. One staff m e m b e r s h o u l d be a p p o i n t e d the " S a f e t y O f f i c e r " and given the responsibility to m o n i t o r safety procedures, practices and equipment on a routine periodic basis. In a large laboratory, the Safety Officer may be assisted by a c o m m i t t e e of two or three analysts. The d u t i e s of the S a f e t y O f f i c e r (and c o m m i t t e e w h e r e a p p r o p r i a t e ) s h o u l d be d e t a i l e d in the l a b o r a t o r y S a f e t y P r o g r a m m e . This p r o g r a m m e would indicate safety requirements, hazards, equipment and emergency procedures. Items which can be included in a laboratory Safety P r o g r a m m e are discussed in the following sections. It should be r e m e m b e r e d that the Head h a s the final a u t h o r i t y as w e l l as r e s p o n s i b i l i t y for l a b o r a t o r y s a f e t y , so t h a t the S a f e t y O f f i c e r m a y only make recommendations.

6.2

Basic

Safety

Rules

E a c h l a b o r a t o r y s h o u l d d e v e l o p its o w n set of g e n e r a l s a f e t y r u l e s , and m a k e sure that all m e m b e r s of staff are aware of them by supplying personal copies of the r u l e s and by p o s t i n g c o p i e s on n o t i c e - b o a r d s . T h e r u l e s s h o u l d be changed and developed in the light of experience. Some that should be included are listed below: 1. B e c o m e f a m i l i a r w i t h the l o c a t i o n and use of e m e r g e n c y (e.g., f i r e e x t i n g u i s h e r ; e y e w a s h f o u n t a i n s ; s a f e t y s h o w e r s ; cabinets). Know where to go in case of fire.

equipment, f i r s t aid

2. Before beginning a sample analysis, review possible hazards connected w i t h the a s s i g n m e n t and take the n e c e s s a r y p r e c a u t i o n s to e l i m i n a t e or counteract the hazard. 3. Use, when appropriate, the safety equipment provided for protection, (e.g., s a f e t y g o g g l e s ; face s h i e l d s ; v a r i o u s t y p e s of g l o v e s ) . Wear a laboratory coat routinely since its purpose is to serve as protective clothing. 4. Bring all accidents and hazardous supervisor or Head immediately.

conditions

to the attention of

the

5. W h e n l i f t i n g h e a v y o b j e c t s , use the legs i n s t e a d of the b a c k . Bend the knees and hold the back straight so that the lifting effort is accomplished w i t h the legs r a t h e r than the back. L i f t s l o w l y to j u d g e the w e i g h t of the object. If too heavy, obtain assistance and/or use a lifting device. 6. Be jewelry (like equipment. entangled in

extremely careful of loose clothing, neckties, scarves, dangling necklaces) and long h a i r w h e n u s i n g r e v o l v i n g or r e c i p r o c a t i n g K e e p such i t e m s b o u n d or c o n f i n e d so that they w i l l not be the equipment.

7. T u r n off l a b o r a t o r y s e r v i c e s (gas, w a t e r , etc.) at the s e r v i c e c o c k w h e n not in use. Changes in pressure m a y suddenly dislodge tubing connected to an apparatus and lead to an accident or possible injury. 8. Always use mechanical aids, such as safety bulbs when pipetting hazardous material. Never use the mouth.

35

or pipette

fillers,

9. Use fume hoods for any analytical operations of solvents, or w h e n noxious fumes will be generated.

their

10. Keep the contents.

work

area

neat

11. Any chemicals, whether m u s t be washed off immediately.

even

12. Keep fire escape temporarily.

routes

and

tidy,

toxic

and

13. No one s h o u l d w o r k a l o n e available in the event of accident.

with

or not,

doors

in the

all

which

clear

involving

large

containers

are

at all

laboratory,

labelled

spilled

times.

so that

amounts

on

the

Do not

with

hands

block,

assistance

is

14. The last person to leave the laboratory at the end of the working day m u s t c h e c k that all e q u i p m e n t t h a t s h o u l d be t u r n e d o f f h a s b e e n . (This d o e s not release each individual operator from his duty to turn off the equipment no longer in use.) The laboratory Head in consultation with staff m a y prefer to operate a duty roster for opening the laboratory in the morning and closing at the end of the w o r k i n g day.

6.3

Fire

Safety

A laboratory m u s t unfortunately be regarded as one of the more likely places in w h i c h a fire w i l l o c c u r and it is t h e r e f o r e p r u d e n t to h a v e the l o c a l c h i e f fire officer visit the building, be familiarized with the problems and advise the laboratory staff about local fire regulations and further safety m e a s u r e s that s h o u l d be t a k e n . F i r e and s m o k e d e t e c t o r s m a y be i n s t a l l e d in the b u i l d i n g and c o n n e c t e d so t h a t in the e v e n t of f i r e , an a l a r m is g i v e n at a fire s t a t i o n . C a r e m u s t be taken that s m o k e d e t e c t o r s are not set off a c c i d e n t a l l y by b e g i n n i n g the a s h i n g of s a m p l e s in the o p e n l a b o r a t o r y or excessive formation of smoke in other ways. S t a f f m u s t h a v e c l e a r i n s t r u c t i o n s of the a c t i o n to be t a k e n in c a s e of fire. Such i n s t r u c t i o n s s h o u l d be p o s t e d p r o m i n e n t l y in v a r i o u s p a r t s of the building. O c c a s i o n a l l y t h e r e s h o u l d be a fire d r i l l to c h e c k that e v e r y o n e k n o w s w h a t to do in the case of a s e r i o u s fire and to m a k e sure that the building can be evaculated in an orderly and rapid manner. Once evacuated, a r o l l c a l l is t a k e n to c h e c k that no one r e m a i n s in the b u i l d i n g . Such a roll call m u s t be completed in a very few minutes and therefore should be called in groups if the total staff exceeds about 20-30. A fire evacuation must include switching off the electricity supply to the affected area, as short-circuits may result in further fire hazard. Isolation switches are important to enable restricted areas of the building to be cut off from the supply. H o w e v e r , for a p r a c t i c e d r i l l , the s w i t c h i n g off can be s i m u l a t e d . W h e n n e w s t a f f are introduced, they m u s t have the drill explained to them and be shown where fire e x t i n g u i s h e r s , b l a n k e t s , h o s e s and b u c k e t s are k e p t , and h o w the s p r i n k l e r system w o r k s if there is one. Breathing apparatus should be available at two or three points in the building, and an adequate n u m b e r of people instructed in its use. In dealing with a fire in a laboratory toxic fumes are always possible. F i r e e x t i n g u i s h e r s in the l a b o r a t o r y s h o u l d be of the c a r b o n d i o x i d e type. Pressurized dry chemical extinguishers are suitable for general use, but should n o t be u s e d a r o u n d c o m p u t e r s or o t h e r s e n s i t i v e e l e c t r o n i c e q u i p m e n t . The r e a s o n is that it is n e a r l y i m p o s s i b l e to c l e a n the dry c h e m i c a l out of the instrument., and the instrument could be irreparably damaged. Carbon dioxide units work best. Everyone in the laboratory should have used an extinguisher at l e a s t o n c e , so t h a t t h e y k n o w h o w to r e m o v e the s a f e t y p i n as r a p i d l y as possible and are not disconcerted by the sudden noise when it is activated. If

36

any s t r u c t u r a l part of the b u i l d i n g a p p e a r s a f f e c t e d by a s m a l l f i r e , it is a d v i s a b l e to i n f o r m the fire s t a t i o n , s i n c e a f i r e that m a y a p p e a r to b e extinguished in fact may be smouldering behind a panel or other structure and break out again several hours later, perhaps after the laboratory is closed for the night. A d i s c u s s i o n of b u l k s o l v e n t s t o r a g e and c o n s t r u c t i o n of a s t o r a g e r o o m is contained in Section 3.3 of this manual. The quantitites of f l a m m a b l e liquids in the laboratory should be kept at a m i n i m u m . Bottles should be stored away f r o m h e a t , s u n l i g h t and any s o u r c e of n a k e d f l a m e . V a p o u r s such as t h o s e of diethyl ether can flow along surfaces such as floors and benches and thus, by c o n t a c t w i t h a n a k e d f l a m e or a h o t s u r f a c e (such as a m u f f l e f u r n a c e or h o t p l a t e ) b e c o m e i g n i t e d . S o l v e n t s m u s t be s t o r e d in an e x p l o s i o n - p r o o f refrigerator, separately from acids and other reagents. Some chemicals ignite spontaneously on mixing, for example concentrated nitric acid with alcohols. E l e c t r i c a l e q u i p m e n t m a y be the s o u r c e of a fire d u e to f a u l t y wiring, inadequate earthing, failure causing sparks or local overheating or switchgear sparks. A l l e l e c t r i c a l e q u i p m e n t s h o u l d c a r r y a f u s e w h i c h b l o w s at an amperage s l i g h t l y in e x c e s s of that r e q u i r e d by the e q u i p m e n t . It is c o m m o n p l a c e to find that equipment drawing only one or two amps have a 13 or 15 Flammable amp fuse which is unlikely to be of any use if anything goes wrong. vapour near electrical equipment represents a fire hazard unless the instrument h a s b e e n r e n d e r e d " e x p l o s i o n p r o o f " by s e a l i n g t h o s e s e c t i o n s w h e r e a s p a r k could occur. Motors m u s t be serviced regularly. Lack of attention m a y result in o v e r h e a t i n g and s u b s e q u e n t fire. C e n t r i f u g i n g of v o l a t i l e flammable s o l v e n t s is h a z a r d o u s if the c e n t r i f u g e m o t o r is n o t e x p 1 o s i o n - p r o o f , especially if the tube breaks. S t a t i c e l e c t r i c i t y and s t a t i c s p a r k s can be a real p r o b l e m in a h o t and dry climate. They can result from wearing clothes m a d e of synthetic m a t e r i a l s , or by simply walking across a carpet.

6.4

Chemical

Hazards

All c h e m i c a l s s h o u l d be c o n s i d e r e d as p o t e n t i a l l y h a z a r d o u s and s h o u l d be treated with caution. As far as possible, dangerous c h e m i c a l s should be stored away from the laboratory and away from others with which they violently react. Y e l l o w p h o s p h o r u s and p i c r i c acid m u s t be k e p t u n d e r w a t e r , s o d i u m and potassium metal under oil. Explosive peroxides can be formed in diethyl ether. T h e y s h o u l d a l w a y s be r e m o v e d if f o u n d to be p r e s e n t , as an e x p l o s i v e concentration of p e r o x i d e m a y b e f o r m e d if t h e e t h e r is d i s t i l l e d . Distillation should be stopped while there is plenty of solvent remaining in the d i s t i l l a t i o n flask and care s h o u l d be t a k e n not to o v e r h e a t the flask. D u s t m a y c a u s e the e x p l o s i v e d e c o m p o s i t i o n of h y d r o g e n p e r o x i d e of o v e r 30 percent concentration. Peroxides in general can be explosive, and must not be allowed to come into contact with reducing agents or f l a m m a b l e solvents. They should be kept in dark bottles in a refrigerator. Hydrogen fluoride solution is e x t r e m e l y dangerous as contact w i t h the skin may result in lesions that fail to heal. Disposable plastic gloves must always be worn when this solution is being handled. Calcium gluconate gel or solution or another antidote should be available in the first-aid cabinet. Toxic levels of nitrogen dioxide can be produced during the use of the nitrous oxide-acetylene flame in atomic absorption spectrophotometry and consequently ventilation must be good. The recommended threshold limit value (TLV) for 40 m i n u t e s exposure is 5 ppm. Tubes for testing contaminated air are available c o m m e r c i a l l y from laboratory supply firms. It is important that bottles containing sodium and potassium (for example w h e n these have been used for drying ether) are not left near a washing-up area in case an inexperienced or unobservant person attempts to wash the bottle in the

37

u s u a l way. In fact, all c o n t a i n e r s ( b e a k e r s , e t c ) c o n t a i n i n g h a z a r d o u s material must first be rinsed or otherwise treated by the analyst to remove the h a z a r d , b e f o r e giving to g l a s s w a r e w a s h i n g . The need for this is o b v i o u s as the analyst is the only one who knows of the hazard and how to eliminate it. All reagent bottles, flasks or other containers must be properly labelled, even if the c o n t e n t s are c o n s i d e r e d h a r m l e s s . A d h e s i v e w a r n i n g s t i c k e r s can be p u r c h a s e d from c h e m i c a l s u p p l y f i r m s . T h e s e can be used in a d d i t i o n to the container label to highlight hazards. When emptying acids and chromic acid cleaning solutions into the drains, first fill the sink with water, pour the acid or cleaning solution into the sink, and then let the w a t e r run out. A l l o w the tap to r e m a i n on full for a few additional minutes. Dilution should always be sufficient to reduce the acid concentration to less than one normal. Store acid containers in inert trays if the acid c o n c e n t r a t i o n is g r e a t e r than 2N. P o l y e t h y l e n e t r a y s are s u i t a b l e . Handle concentrated ammonium hydroxide and solutions of potassium and sodium hydroxide which are ION or above as if they were concentrated acids and observe the s a m e p r e c a u t i o n s as for acids. Do not store A L K A L I in the s a m e tray w i t h ACID. Do not store concentrated alkalies in glass-stoppered bottles.

6.5

Biological

Hazards

This manual is concerned primarily with a chemical analysis laboratory rather than a m i c r o b i o l o g i c a l one. H o w e v e r , t h e r e are b i o l o g i c a l h a z a r d s in the typical chemical analysis laboratory. The m o s t s e r i o u s of these are the c a r c i n o g e n i c r e a g e n t s or r e f e r e n c e m a t e r i a l s c o m m o n to f o o d c o n t r o l laboratories. Carcinogens must always be handled with extreme care, using all available protective gear. The f o l l o w i n g listing is of s u b s t a n c e s used in a food c o n t r o l l a b o r a t o r y , or found as food contaminants, which are suspected or k n o w n to be carcinogens: Category

Reference

Aflatoxins

Potent

carcinogen

6,7

4-(or p-) Aminobiphenyl Biphenylamine

Potent

carcinogen

1,2,6

Asbestos

Carc inogen

Auramine, or 4,4'dimethylaminobenzophenonimide

Suspected

carcinogen

2,6

Benzene, benzol(e)

Suspected

carcinogen

4,5,6

Benzidine, diamide,

Potent

carcinogen

2,6

3,4-(or 1,2-) Benzpyrene

Potent

carcinogen

6

Cadmium and Compounds (mainly inorganic)

Suspected

Carbon

Carc inogen

4,4'-biphenyldiaminobiphenyl

tetrachloride

Suspected

Chloroform (trichlorome thane) Chromium

salts (3 and

6+)

Carc inogen

38

3,6

carcinogen

6,9

6 carcinogen

9

3,6,7

N»e

Catetory

Reference

Coal tar, Creosote oils (polycyclic mixtures)

Care inogen

3,4,6

DDT

Suspected

(p,p*

or o,p')

o-Dianisidine

Care inogen

Diazomethane

Suspected

Dichloroethane

Carcinogen

4-Diethylaminoazobenzene (Butter Y e l l o w )

Suspected

N,N-Dimethylnitrosamine

Potent

Dimethyl

Carcinogen

sulphide

1,4-Dioxane ether

(diethylene

carcinogen

2,6 carcinogen

4,5,6 -

carcinogen

carcinogen

-

6,8 -

6,9

Carcinogen

Teratogen

Formamide

5,6

-

Suspected

carcinogen

2

Magenta basic or Basic fuchsin (basic red 9, basic violet, 14 rosaniline)

Suspected

carcinogen

2,6

Mineral

Carc inogen

3,6

1-Naphthylamine (1-amino-naphthalene)

Care inogen

2,6

2-Naphthylamine (2-amino-naphthalene)

Potent

Nickel

Carcinogen

4,6

Nitrobenzene

Carcinogen

-

Nitrosamines

Potent

-

Patulin

Suspected

carcinogen

6

Rhodamine B

Suspected

carcinogen

9

Suspected

carcinogen

6

Magenta

acid or Acid

oils

and

fuchsin

(heavy)

salts

Sodium diethyl Soot, carbon

dithiocarbamate

black

carcinogen

carcinogen

Carcinogen

1,2,6

3,6

Tannins

Suspected

carcinogen

5,6

Thioacetamide

Suspected

carcinogen

4,5,6

Thiourea

Suspected

carcinogen

4,5,6

Trichloroethylene

Suspected

carcinogen

6

Vinylchloride

Carcinogen

Zearalenone

monomer

Suspected

39

10 carcinogen

11,12

The references noted

in the listing

are:

1.

Bo y 1 and, E. (1 963). "The B i o c h e m i s t r y of B l a d d e r Cancer." Springfield, Illinois.

2.

C h e s t e r B e a t t y R e s e a r c h I n s t i t u t e (1966). " P r e c a u t i o n s for L a b o r a t o r y Workers who handle Carcinogenic Aromatic Amines." The Institute, London; reprinted with additional notes 1971, i. 7 pp.

3.

Clayson, D.B.

4.

D e w h u r s t , F. (1972). 10, 57-85, passim.

5.

Hueper, Cancer."

6.

From International Agency for Research on Cancer, IARC Monographs on the " E v a l u a t i o n of C a r c i n o g e n i c Risk of C h e m i c a l s to Man." IARC, L y o n / W H O , Geneva/HMSO, London.

7.

R o e , F.J.C. and L a n c a s t e r , M.C. (1964), " N a t u r a l M e t a l l i c Br. med. Bull., 2J)> 127-133. Substances as Carcinogens."

8.

S e a r l e , C.E. (1972).

9.

National Institute of Occupational S a f e t y and H e a l t h (1975) - " S u s p e c t e d C a r c i n o g e n s List." U n i t e d S t a t e s D e p a r t m e n t of H e a l t h E d u c a t i o n and Welfare Publication No. (NIOSH) 75-188.

10.

Maltoni,

11.

Ueno, Y. and Kubota, K., (1976), Cancer Research, 36_ (2) 445-451.

12.

Schoental, R. , (1974), Br. J. Cancer, 30, ISS _2, 181.

6.6

Physical

(1962).

"Chemical Carcinogenesis." "Carcinogens

C.C. T h o m a s ,

Churchill.

in the L a b o r a t o r y . "

W.C. and C o n w a y , W.D. (1964). "Chemical C.C. Thomas, Springfield, Illinois.

Lab. Equip. Dig.,

Carcinogenesis

and

and

other

" C h e m i c a l C a r c i n o g e n s . " C h e m . Ind., (3) 1 1 1 - 1 1 6 .

C. and Lefemine, G., (1974), Environmental

Research, _7, p.387.

Hazards

There are many physical hazards in a laboratory. Most are avoidable by use of c o m m o n sense. It is advisable, however, to prepare some instructions for new e m p l o y e e s and p e r i o d i c a l l y r e m i n d o t h e r s . The f o l l o w i n g are s o m e p r o p o s e d instructions, grouped by operation.

Glassware Handling

1. Do not use b r o k e n or chipped g l a s s w a r e or r e t u r n it to s t o r a g e . If it is b e y o n d r e p a i r , d i s p o s e of it. W h e n in d o u b t r e g a r d i n g p r o p e r d i s p o s a l , consult the supervisor. Always use gloves in handling broken glass. 2. R e m o v e s h a r p or jagged e d g e s from g l a s s w a r e b e f o r e u s i n g it. polish the edges on all glass tubing.

Fire

3. Broken glass in sinks present a definite hazard since glass may not be v i s i b l e in the p r e s e n c e of w a t e r . W h e n b r o k e n in the sink, r e m o v e it promptly. F u r t h e r m o r e , c o n s i d e r the p o s s i b i l i t y of the p r e s e n c e of b r o k e n glass when reaching into the sink for any purpose.

40

4. Inserting tubing into stoppers or rubber tubing can result in serious cuts, which can be prevented if the following precautions are observed: a. b. c. d. e.

Wet the tubing and/or stopper or rubber tubing. Wear gloves or wrap a towel around the palms of the hands. Do not use e x c e s s i v e force - cut the h o l e b i g g e r or b o r e a n e w hole . Use the fingers and not the hands when making the insertion. Insert glass or metal tubing entirely through stoppers to assure that the end may not be closed over by heat or solvent action on the stopper.

5. To remove glass tubing or thermometers from rubber, preferably cut a w a y the r u b b e r . T h i s is p a r t i c u l a r l y true if the t u b i n g or s t o p p e r has b e e n in place over an extended period of time or has been subjected to heat. 6. In handling beakers, support them by grasping around the sides, never over the top. If one hand will not reach more than half way around the beaker, use both hands. Support large beakers (one litre or more) from the bottom when in use. 7. W h e n h e a t i n g l i q u i d s in g l a s s by m e a n s of a gas f l a m e , p r o t e c t the glass from direct contact with the flame by use of a wire gauze or a centered wire gauze. 8. W h e n p l a c i n g l i q u i d s in b o t t l e s w h i c h h a v e a p o s i t i v e c l o s u r e , reserve more than 5 percent of the volume as air space to allow for expansion due to temperature changes. 9. Do not force s t o p c o c k s or ground g l a s s s t o p p e r s . Use a s t o p c o c k puller. If the n a t u r e of the c o n t e n t s of the v e s s e l p e r m i t s , cool the shell until the plug is cold, then heat the shell of the joint momentarily. Withdraw the plug quickly before it too has been expanded by the heat.

Vacuus Operations

1. Protect glassware under vacuum from physical cracks and result in collapse with explosive violence.

shock which might

2. Do not subject flat-bottom flasks heavy walls specifically for such service.

unless

to vacuum

cause

constructed

with

3. Guard s t a n d a r d - w a l 1 ( s p h e r i c a l ) flasks larger than one l i t r e , w h e n used in v a c u u m s e r v i c e , by a shield that is a d e q u a t e to stop all flying g l a s s if collapse should occur. 4. C h o o s e cork or r u b b e r s t o p p e r s used in v a c u u m s e r v i c e c a r e f u l l y . They must be of such size that they will not be drawn through the opening which they are intended to close. 5.

Relieve vacuum before attempting

to disassemble

equipment.

6. Do not s t o p p e r h o t flasks c o n t a i n i n g u n c o n d e n s e d v a p o u r s or To do so will subject them to vacuum on cooling.

41

steam.

Equipment

Handling

1. W h e n using a m a n u a l cork b o r e r , do not hold the s t o p p e r in the p a l m of the hand. Place the stopper large end down on a soft, flat surface and hold in p l a c e w i t h the t h u m b and f o r e f i n g e r . K e e p the b o r e r sharp and l u b r i c a t e with water or glycerine to prevent binding. Do not force the borer through the stopper but twist to cut the material. Use stout gloves for added protection in case of slippage. 2. Do not lift the cover of a c e n t r i f u g e until r o t a t i o n has Keep the cover closed when the centrifuge is not in use.

stopped.

3. C y l i n d e r s c o n t a i n i n g i n d u s t r i a l gases must be properly anchored by chains or heavy straps or held in stands. Reactive gases should be stored away from each other (e.g. do not store a c e t y l e n e near oxygen). Gas s u p p l i e s for gas liquid chromatography and atomic absorption spectroscopy are best kept on the other side of the wall from the instrument and connected via a small duct in the w a l l . C y l i n d e r s t o r a g e p o i n t s s h o u l d be p r o t e c t e d from the w e a t h e r , p a r t i c u l a r l y in dusty areas w h e r e grit can get into the c y l i n d e r v a l v e , but they s h o u l d be s u f f i c i e n t l y w e l l - v e n t i l a t e d to p r e v e n t l e a k i n g gas f r o m reaching dangerous levels. 4. Flexible tubing attached to gas supplies must be wired on or held by clips and must be able to withstand any likely pressure. The sudden bursting or b l o w i n g off of a piece of tubing is s t a r t l i n g and m a y c a u s e an a c c i d e n t if someone nearby is carrying out a hazardous operation. 5. A rapid decrease of cooling water due to a fall in mains pressure or a cut in the supply can damage equipment such as a still and also be hazardous. A c o n s t a n t head d e v i c e in a t r a n s p a r e n t c o n t a i n e r w i l l give s o m e w a r n i n g of this. However, if water pressure fluctuations are a frequent problem, a header tank in the roof of the building may be advisable. Electrical equipment can be fitted with automatic cutouts that turn off the electricity supply in case of water failure.

6.7

Safety and Emergency

Equipment

" S a f e t y " e q u i p m e n t is that d e s i g n e d to p r o t e c t a n d / o r p r e v e n t i n j u r y and is used b e f o r e an a c c i d e n t h a p p e n s . " E m e r g e n c y " e q u i p m e n t is used a f t e r an accident (or other emergency) to minimize the injury or damage. Therefore, eye goggles are "safety" and eye wash fountains are "emergency" equipment. U s i n g these d e f i n i t i o n s , the f o l l o w i n g are lists of safety and equipment which every laboratory should include in their inventory:

emergency

Safety Equipment

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Rubber aprons. Eye goggles. Face shields.. Disposable plastic or rubber gloves. Bench shields (portable, clear plastic). Pipetting bulbs. Heavy rubber carriers for acid and alkali bottles. Metal safety cans for flammable solvents. M e t a l solvent s t o r a g e c a b i n e t s (about 45 g a l l o n storage of solvents used daily in the laboratory). Respirator filter masks (for dust or fumes). 42

capacity).

(For

Emergency

1. 2. 3. 4. 5. 6.

Equipment

Hand-held fire extinguishers (carbon dioxide preferably, see Section 6.3) . Fire blankets (wall mounted). Eye wash stations (built-in fountains or portable kits). S p i l l a g e a b s o r b e n t kits for both a c i d s and s o l v e n t s ( a v a i l a b l e commercially or can be assembled locally). Emergency shower (in the laboratory, drenching full-on or -off valve operated by a pull chain or loop). Respirator mask with oxygen supply.

A major item of emergency equipment not included in the above list is the aid cabinet. This is discussed in detail in Section 6.8.

first

All such e q u i p m e n t is u s e l e s s if e i t h e r not a v a i l a b l e or not in s e r v i c e a b l e condition. The Safety Officer (see Section 6.1) should periodically check both the s t o r a g e l o c a t i o n s (if n o t in u s e ) and the c o n d i t i o n of all safety and emergency equipment. The laboratory staff must also be trained in the use of the equipment and use must be enforced when necessary.

6.8

First

Aid

First aid by definition is that initial assistance given to lessen the effect of injury. If the injury is sufficiently minor, then first aid will probably s u f f i c e for t r e a t m e n t . H o w e v e r , for s e r i o u s and e v e n m o d e r a t e l y s e r i o u s i n j u r i e s , m e d i c a l h e l p m u s t be g i v e n as soon as p o s s i b l e . Any first aid m e a s u r e s w o u l d be only to give t e m p o r a r y h e l p u n t i l m e d i c a l t r e a t m e n t is available. S o m e o n e on the l a b o r a t o r y s t a f f s h o u l d be t r a i n e d in f i r s t - a i d , particularly in giving artificial respiration techniques. Some chemicals such as c y a n i d e are q u i c k - a c t i n g and there is r a r e l y t i m e to w a i t for a d o c t o r to arrive, or transfer the patient to the hospital. T h o u g h t s h o u l d be g i v e n to the l o c a l h a z a r d s that m i g h t be e x p e c t e d and the c o n t e n t s of a first aid c a b i n e t d e s i g n e d to m a t c h . The c a b i n e t should be l o c a t e d in the l a b o r a t o r y p r o p e r and be a c c e s s i b l e . A first-aid cabinet suitable for a laboratory of 10-50 employees could contain the following: 1.

A copy of a leaflet giving advice on first aid

2. A s u f f i c i e n t n u m b e r (not l e s s unmedicated dressings for injured fingers.

than

12)

treatment. of

small

sterilized

3. A s u f f i c i e n t n u m b e r (not less than 6 ) of m e d i u m - s i z e d unmedicated dressings for injured hands or feet.

sterilized

4. A sufficient number (not less than 6) of large sterilized dressings for other injured parts.

unmedicated

5. A sufficient number (not less than 24) of adhesive wound an approved type and of assorted sizes. 6. A s u f f i c i e n t n u m b e r (not less than 4 ) of unbleached calico, the longest size of which measures and each of the other sides not less than 36 inches. 7.

small

A sufficient supply of adhesive

8. A sufficient packets.

supply

t r i a n g u l a r b a n d a g e s of not less than 51 inches

plaster.

of a b s o r b e n t

43

dressings of

sterilized

cotton

in

individual

9. approved

A sufficient supply of approved type and size.

10. A sufficient n u m b e r separate sealed packets.

(not

less

eye o i n t m e n t

than 4 ) of

11.

A rubber bandage or pressure bandage.

12.

Safety pins.

13.

A tube of antiseptic

in a container

sterilized

of an

eye-pads

in

cream.

It is suggested that, in addition to the above provisions (which cater primarily for cuts and heat burns) each chemical laboratory first aid cabinet should contain: 1. 2. 3. 4.

A tablespoon. Bottle of Epsom salts (magnesium sulphate). Bottle of milk of magnesia (dose - two tablespoonfuls). Bottle of 1 percent acetic acid.

Hydrogen cyanide, soluble cyanides and nitriles which hydrolyse readily to HCN when inhaled or ingested may call for treatment with capsules (0.3 ml) of amyl nitrite w h i c h are easily crushed in a cloth from w h i c h the vapour can be inhaled. The following antidote for cyanide ingestion casualties consists of two solutions which should be made up and left ready for immediate use:

S o l u t i o n A: 158 g ferrous sulphate crystals and 3 g citric acid crystals in a litre of cold distilled w a t e r (the solution m u s t be inspected regularly and be replaced if any deterioration has occurred). S o l u t i o n B: distilled water.

60 g anhydrous

sodium

carbonate

dissolved

in a litre

of

50 ml of solution A is placed in a 170 ml w i d e - n e c k e d bottle closed by a p o l y t h e n e - c o v e r e d cork and labelled clearly "CYANIDE A N T I D O T E A". 50 ml of solution B is s i m i l a r l y bottled and labelled "CYANIDE A N T I D O T E B". Both b o t t l e s should bear the legend "Mix the w h o l e contents of bottles "A" and "B" and swallow the mixture". The merit of the basic ferrous hydroxide suspension is that when swallowed it is likely to induce vomiting while at the same time forming insoluble non-toxic iron c o m p l e x e s with the cyanide. It m u s t be s t r e s s e d , h o w e v e r , that the i m m e d i a t e s u m m o n i n g of a doctor, w h o can a d m i n i s t e r an approved injection, is of the u t m o s t i m p o r t a n c e in cases of cyanide poisoning. Kits for the intravenous treatment of cyanide poisoning by doctors are available. A kit should be at hand in any o r g a n i z a t i o n w h e r e cyanides are handled regularly. I o d i n e , if i n g e s t e d , s h o u l d be t r e a t e d w i t h sodium thio s ul pha te. An appropriate weight of the crystals in a bottle to make up a 1 percent solution when water is added to a set mark, will provide the right solution for taking internally and also for swabbing on skin contaminated with iodine. In some o r g a n i z a t i o n s , the a d m i n i s t r a t i o n of oxygen through a f a c e - m a s k has become part of first aid procedures for certain types of casualty. When it is certain that a casualty has stopped breathing, artificial respiration should be applied immediately. The "mouth-to-nose" and "mouth-to-mouth" procedures are now the methods of first choice and are described in "New Essential First-Aid" by A. Ward Gardner and C. J. Roylande (Pan Books), among others. The mouth-tomouth procedure must be used when the casualty has a nasal obstruction. Where injuries to the face and m o u t h m a k e the use of these m e t h o d s i m p o s s i b l e , or w h e r e cyanide poisoning is k n o w n or suspected, the Sylvester method can be

44

used. This is described in "First Aid" (2nd E d i t i o n 1965) published by St. John A m b u l a n c e A s s o c i a t i o n , The St. A n d r e w A m b u l a n c e A s s o c i a t i o n and the British Red Cross Society, as well as in standard medical texts. Bromine, formic acid, hydrofluoric acid and other acid burns on the skin can be treated with magnesia/glycerol paste prepared by triturating 200 g magnesium oxide with 240 ml glycerol, the paste being applied liberally over the affected areas. Dilute ammonia (1 volume ammonia added to 15 volumes of water) has also been found e f f e c t i v e in reducing the degree of b u r n i n g w i t h b r o m i n e , formic acid and hydrofluoric acid. The laboratory should have at least one book (preferably more) on first aid and laboratory safety. There are m a n y such available. Some of the better ones are : 1.

"Handbook of L a b o r a t o r y Safety", Steere, N.V., C h e m i c a l Rubber Cleveland, Ohio.

2.

"Hazards in the Chemical Laboratory", C h e m i s t r y , U.K. 1 977.

3.

"Fire P r o t e c t i o n for L a b o r a t o r i e s Using C h e m i c a l s " , National Protection Association, Batterymarch Park, Quincy, MA 02269.

4.

American Chemical Society, "Safety in the Chemical Laboratory" Vol 1 ACS 1967 (reprinted from "Journal of C h e m i c a l Education", January 1964 January 1967), and Vol 2, ACS 1971.

5.

M a n u f a c t u r i n g C h e m i s t s ' A s s o c i a t i o n Guide for safety Laboratory, 2nd Ed, Van Nostrand Reinhold, 1972.

6.

Medical 1973 .

Muir.

G.D. (Ed.) Royal

Company,

Institute

of

Fire

in the

Chemical

in Laboratories",

MRC, U.K.

7.

P r e c a u t i o n s for L a b o r a t o r y W o r k e r s who Handle Carcinogenic Amines, The Chester Beatty Research Institute, London, 1966.

Aromatic

8.

Reference Book of P r o t e c t i v e Association, London, 1981-82.

Research

Council, "Safety

Precautions

E q u i p m e n t , Industrial Safety Manufacturers

45

7. LABORATORY QUALITY ASSURANCE

7.1

(QA)

Introduction

A laboratory engaged in food control analysis must have some means of assuring that their analytical results are of the highest quality. Errors in analysis can o f t e n m e a n s e r i o u s e c o n o m i c l o s s e s for the food i n d u s t r y or i m p o r t e r , as well as possible illness or injury to the consuming public. This assurance of quality is not limited to confirming that a food found to be unacceptable, is in fact b a d . It is e q u a l l y i m p o r t a n t to a s s u r e that f o o d s f o u n d to b e a c c e p t a b l e , are in fact good. To do this r e q u i r e s an u n d e r s t a n d i n g and c o m m i t m e n t by the laboratory m a n a g e m e n t as well as the operating staff, that high quality in analysis is the foremost objective. O f t e n , the t e r m s " Q u a l i t y C o n t r o l " and " Q u a l i t y A s s u r a n c e " are used interchangeably when discussing analytical quality. H o w e v e r , G a r f i e l d (1) m a k e s a d i s t i n c t i o n b e t w e e n the t w o . He d e f i n e s Q u a l i t y c o n t r o l a s , "...a p l a n n e d s y s t e m of a c t i v i t i e s w h o s e p u r p o s e is to p r o v i d e a q u a l i t y p r o d u c t . " Conversely, he defines Quality Assurance as, "...a planned system of activities w h o s e p u r p o s e is to p r o v i d e a s s u r a n c e that the q u a l i t y c o n t r o l p r o g r a m is actually effective." Therefore, Quality Control encompasses all of the myriad r e v i e w , checking and operational procedures routinely used by the laboratory to m a i n t a i n high analytical quality. ( M a n y of t h e s e are d i s c u s s e d in the preceeding Chapters 4 and 5.) The following discussions of Quality Assurance u s e s G a r f i e l d ' s d e f i n i t i o n and c o v e r s t h o s e p r o c e d u r e s u s e d to c o n f i r m t h a t high quality is being maintained.

7.2

Establishing

a QA

Programme

To be successful, quality assurance must be a formal planned activity which is designed to fit the needs of the laboratory. A formal QA p r o g r a m m e is prepared by establishing: 1.

The acceptable

quality

for a given

2.

A periodic review to confirm this

3.

A system of documentation

4.

Appropriate

laboratory

function.

quality.

to record

the results of the

follow-up to correct any deficiencies

reviews.

found.

The first step is to decide the functions that should have formal review. Some s u g g e s t i o n s a r e s t a n d a r d s s t o r a g e and h a n d l i n g , p r e p a r a t i o n of a n a l y s i s r e p o r t s , i n s t r u m e n t m a i n t e n a n c e and l a b o r a t o r y s a f e t y . T h e l a b o r a t o r y Head should carefully examine the entire laboratory operation, by audit review if n e c e s s a r y , and s e l e c t those f u n c t i o n s w h i c h need i m p r o v e m e n t or w h i c h w o u l d benefit from periodic monitoring. A QA p r o g r a m m e should be d y n a m i c and subject to change when needed. Therefore a detailed QA review could be conducted until it is felt that the function under review will continue to operate smoothly, at w h i c h t i m e the r e v i e w could be l e s s e n e d and a n o t h e r f u n c t i o n g i v e n i n - d e p t h coverage . T h e r e v i e w i t s e l f is n o r m a l l y l i m i t e d to the c r i t i c a l p a r t s of the f u n c t i o n under review. For e x a m p l e , a r e v i e w of s t a n d a r d s t o r a g e and h a n d l i n g c o u l d include: accounting for all standards by inventory and checking proper storage; c h e c k i n g t h a t no s t a n d a r d h a s e x c e e d e d its e x p i r a t i o n or d i s p o s a l d a t e ; and visual, p h y s i c a l a n d / o r c h e m i c a l c h e c k s to i n d i c a t e s t a n d a r d s are not contaminated or decomposed.

46

The "acceptable quality" standard is set by the laboratory. If some error rate is acceptable in daily practice, then that rate b e c o m e s the quality standard. The laboratory will always be striving for perfection, and the QA p r o g r a m m e is one means to identify those areas which need improvement towards the ideal. Quality Assurance programmes are u s u a l l y a l s o r e q u i r e d for laboratory certification. An e x a m p l e is G u i d e 25 of the I n t e r n a t i o n a l O r g a n i z a t i o n for S t a n d a r d i z a t i o n ( I S O ) (2). U n d e r P a r t 4, " Q u a l i t y S y s t e m " it s t a t e s the following :

1. The laboratory shall operate an internal quality assurance p r o g r a m m e a p p r o p r i a t e to the t y p e , r a n g e and v o l u m e of w o r k p e r f o r m e d . The quality assurance p r o g r a m m e shall be documented in a quality manual which is available for u s e b y the l a b o r a t o r y s t a f f . T h e q u a l i t y m a n u a l s h a l l be m a i n t a i n e d relevant and current by a responsible m e m b e r of the laboratory staff. A person or persons having responsibility for q u a l i t y a s s u r a n c e w i t h i n the l a b o r a t o r y shall be designated by the laboratory m a n a g e m e n t and have direct access to top management.

2.

The quality manual

shall contain

information

regarding:

a.

The structure of the laboratory

(organizational

charts);

b.

The operational and functional duties and services pertaining to quality, so that each person concerned will know the extent and the limits of his responsibility;

c.

General quality assurance

d.

Quality assurance appropriate ;

e.

Where appropriate, m a t e r i a l , etc.;

f.

S a t i s f a c t o r y a r r a n g e m e n t s for f e e d b a c k and c o r r e c t i v e whenever testing discrepancies are detected;

g.

Procedure

procedures;

procedures

proficiency

specific

testing,

for dealing with technical

for

use

each

of

test,

as

reference

action

complaints.

3. The quality system shall be systematically and periodically reviewed by or on b e h a l f of m a n a g e m e n t to e n s u r e the c o n t i n u e d e f f e c t i v e n e s s of the arrangements, and corrective action initiated. Such reviews shall be recorded together with details of any corrective action taken.

This clearly states the importance that m u s t be placed on QA in the analytical laboratory. N o t e the key p r o g r a m m e e l e m e n t s are r e v i e w , d o c u m e n t a t i o n and follow-up. It A Quality Assurance p r o g r a m m e must obviously be tailored to specific needs. c a n be (and o f t e n is) an e x t e n s i v e and c o m p l e x d o c u m e n t w h i c h c o v e r s all aspects of the laboratory work. An example is the Quality Manual recommended for t e s t i n g l a b o r a t o r i e s b y the I L A C (3). T h e v a r i o u s s u b j e c t s i n c l u d e d in a complete Manual, listed alphabetically, are:

47

DEFINITIONS Quality Manual Quality System Terminology Testing Laboratory Test Method Test Report ENVIRONMENT External Internal

Controls Controls

E Q U I P M E N T , TESTING AND

MEASURING

Calibration Identification Inter laboratory Correlation P r i o r to U s e Programmes U s e of I n - S e r v i c e T e s t E q u i p m e n t U s e of R e f e r e n c e S t a n d a r d s External In-house O v e r l o a d e d or M i s h a n d l e d Periodic Maintenance P u r c h a s i n g and A c c e p t a n c e P r o c e d u r e s Records LABORATORY DESCRIPTION Confidential Information Employee Responsibility F i e l d s of A c t i v i t y Identification Minimizing Improper Influence Organizational Structure Proprietary Rights Technical Management Personnel QUALITY MANAGEMENT SYSTEM Corrective Action F i e l d s of T e s t i n g A c t i v i t i e s Obj ec t i v e P r o f i c i e n c y and I n t e r l a b o r a t o r y C o m p a r i s o n T e s t i n g Quality Assurance Management Q u a l i t y M a n u a l - R e v i s i o n and D i s t r i b u t i o n Quality Policy Quality System Audit R e s p o n s i b i l i t y for Q u a l i t y A s s u r a n c e S y s t e m Reference Materials Resources Employed Scope S u b c o n t r a c ting Technical Complaints U p d a t i n g and C o n t r o l of D o c u m e n t s U s e of E x t e r n a l F a c i l i t i e s RECORDS C o n f i d e n t i a l i t y and S e c u r i t y H i s t o r i c a l F i l e of T e s t M e t h o d s Maintenance

48

SAMPLES/ITEMS TO BE TESTED P r o t e c t i o n from Damage R e c e i p t and D i s p o s a l Security STAFF Deputy Assignments Job D e s c r i p t i o n s P e r s o n n e l Records S u p e r v i s ion Other Measures TEST METHODS AND PROCEDURES I n d e x of Documents S e l e c t i o n of Test Methods Use of Non-Standard Test Methods TEST REPORTS/TEST Computerized Format Revision Verification

DOCUMENTS Date

of

Dsta

T h e a b o v e i l l u s t r a t e s h o w c o m p l e x and t h o r o u g h the d o c u m e n t a t i o n f o r a QA programme can b e . O b v i o u s l y , not a l l l a b o r a t o r i e s w i l l need such c o m p l e t e n e s s . H o w e v e r , t h e r e i s a m i n i m u m QA p r o g r a m m e w h i c h s h o u l d be d o n e e v e n in the s m a l l e s t of food c o n t r o l l a b o r a t o r i e s . T h i s should i n c l u d e the four key a r e a s where q u a l i t y c h e c k i n g is needed most. These are r e f e r e n c e standard m a t e r i a l used in a n a l y s i s , laboratory measuring instruments, a n a l y s i s r e p o r t s and the t e c h n i c a l p r o f i c i e n c y of the a n a l y t i c a l s t a f f . The l a t t e r can be r e v i e w e d in p a r t by use of a c h e c k s a m p l e a n a l y s i s p r o g r a m m e . T h e s e f o u r QA c h e c k a r e a s a r e d i s c u s s e d in d e t a i l in s u c c e e d i n g S e c t i o n s 7 . 3 to 7 . 6 . O t h e r r e l a t e d QA a c t i v i t i e s are d i s c u s s e d under S e c t i o n 7 . 7 .

7.3

QA of R e f e r e n c e

Standards

F o r p u r p o s e s of t h i s S e c t i o n , a " R e f e r e n c e S t a n d a r d " i s a p u r e c h e m i c a l or b i o l o g i c a l s u b s t a n c e w h i c h may be used for c o m p a r i s o n d u r i n g the q u a n t i t a t i v e a n d / o r q u a l i t a t i v e a n a l y s i s of a c o n s t i t u e n t or a t t r i b u t e of a f o o d . Of c o u r s e , " p u r e " is a r e l a t i v e term. Some m e t a l e l e m e n t s c a n be r o u t i n e l y o b t a i n e d in 9 9 . 9 9 9 % p u r i t y , w h i l e many o r g a n i c s u b s t a n c e s would be c o n s i d e r e d " p u r e " at 9 5 % . The a n a l y s t m u s t j u d g e i f t h e r e f e r e n c e s t a n d a r d u s e d i s s u f f i c i e n t l y pure for a n a l y s i s p u r p o s e s . R e f e r e n c e s t a n d a r d s can be d i v i d e d i n t o three g r o u p s :

1. Primary: These are m a t e r i a l s which have been a n a l y z e d and c e r t i f i e d by a n a t i o n a l s t a n d a r d s o r g a n i z a t i o n or o t h e r a c c e p t a b l e organization. 2. Secondary: S u b s t a n c e s whose p u r i t y is commercial s u p p l i e r s or o r g a n i z a t i o n s o t h e r than the

certified above.

by

the p u r i t y certifying

analysis

by

3. Other: This i n c l u d e s a l l r e f e r e n c e s t a n d a r d s w h i c h are c o n s i d e r e d a c c e p t a b l e by t h e u s e r , b u t w h i c h do n o t f a l l i n t h e a b o v e t w o g r o u p i n g s . T h e s e can i n c l u d e l o c a l l y o b t a i n e d m a t e r i a l s w h i c h h a v e u n d e r g o n e r e p l i c a t e a n a l y s i s and have been compared to p r i m a r y or s e c o n d a r y r e f e r e n c e s t a n d a r d s , to calculate purity.

49

S u b s t a n c e s l a b e l l e d , " p u r e " , " c h e m i c a l l y p u r e " , "c.p.", " p u r i f i e d " or " h i g h e s t p u r i t y " s h o u l d a l w a y s b e c o n s i d e r e d s u s p e c t as t h e i r a c t u a l p u r i t y o f t e n v a r i e s widely. T h e y m u s t be c o m p a r e d to s u i t a b l e r e f e r e n c e s t a n d a r d s b e f o r e u s e as a standard themselves. As p r i m a r y and s o m e s e c o n d a r y r e f e r e n c e s t a n d a r d s a r e o f t e n q u i t e e x p e n s i v e , it c a n b e e c o n o m i c a l to o b t a i n a s u p p l y o f a c h e a p e r p u r e m a t e r i a l a s a w o r k i n g standard. It c a n b e a n a l y z e d in c o m p a r i s o n to t h e p r i m a r y ( o r s e c o n d a r y ) r e f e r e n c e s t a n d a r d and the p u r i t y d e t e r m i n e d . The analyst m u s t be c a r e f u l , h o w e v e r , to a v o i d i m p u r i t i e s in the l o c a l m a t e r i a l , w h i c h w i l l c r e a t e p r o b l e m s during analysis. T h e f o l l o w i n g is a l i s t o f s o m e s o u r c e s in t h e U n i t e d S t a t e s s e c o n d a r y r e f e r e n c e s t a n d a r d s of t h e i n d i c a t e d m a t e r i a l s :

Reference

Standards

for p r i m a r y

Source

Number

Alcohols

21

Alkenes

21

Antibiotics

(Chlortetracycline

HC1)

(Erythromycin)

15

(Monensin

14

Sodium)

(Oxytetracycline (Penicillin

Base)

"G" P r o c a i n e )

(Streptomycin

Sulfate)

(Tylosin) Atomic

Absorption

Bacterial Blood

(Metals)

Reference

12 11 12 14 22

Cultures

1, 2 , 3, 4

Group/Typing

9

Chemicals, Industrial

1 9 , 3 2 , 38

Contaminants, Drinking Water Drugs

13

1 0 , 34

(Animal)

1 8 , 2 5 , 31

(U.S. Schedules

I, II)

1 6 , 1 7 , 18

(U.S. Schedules

III, IV, V, VI)

18

Ethanol, Absolute

37

Fibers, Synthetic

21

Fuels, Motor

35

Lead

(Alcoholic Beverages)

34

(Blood)

20

(Motor Fuels)

22

50

or

Reference

Standards

Source

Metals (Foods, Feeds, Fertilizers)

Htmber

23, 30, 36

(Fish, Sediments, Fuel Oil)

23

(Sludge)

34 17,

Mycotoxins Pesticides

21, 24, 25, 26

19, 21, 32, 33

Phenylalanine (PKU)

3, 4

Salmonella Typing & Grouping Antisera

1, 3

Shigella Grouping Antisera

1, 5

Species (Known Fish)

27, 28

(Known Meats)

29

Spirits (Distilled Congeners)

36

Streptococcus

8

Thallium (Standard 1000 ppm)

19

Trichinosis

3

Tuleremia

5

Viral Agent Antisera

1, 6, 7

Wine (Reference)

23

The U.S. sources referred to above, listed by number are: 1.

Department of Health and Human Services Public Health Service Centers for Disease Control Atlanta, GA 30333

2.

American Type Culture Collection 12301 Parklawn Drive Rockville, MD 20852

3.

Difco Laboratories P.O. Box 1058 Detroit, MI 48232

4.

BBL Microbiology Systems P.O. Box 243 Cockeysville, MD 21030

5.

Fisher Scientific 7633 Hull Street Road Suite 2000D Richmond, VA 23235

6.

M A Bioproducts Briggs Ford Road Building 100 Walkersville, MD 21793 51

7.

Flow Laboratories, Inc. 7655 Old Springhouse Road McLean, VA 22102

8.

Wellcome Diagnostics Research Triangle Park North Carolina 27709

9.

American Dade P.O. Box 520672 Miami, FL 33152

10

Environmental Resource Associates 5540 Marshall Arvada, CO 80002

11

ICN Nutritional Biochemicals P.O. Box 28050 Cleveland, OH 44128

12

Pfizer Laboratories 235 E. 42nd Street New York, NY 10017

13

Lederle Laboratories Division of American Cyanamid One Cyanamid Plaza Wayne, NJ 07470

14

Eli Lilly and Company 307 E. McCarty Street Indianapolis, IN 46285

15

Aldrich Chemical Company Milwaukee, WI 53233

16

U.S. Drug Enforcement Administration Special Testing Laboratory 7704 Old Springhouse Road McLean, VA 22102

17

Applied Science P.O. Box 440 State College, PA 16801

18

United States Pharmacopeia Convention Inc. 12601 Twinbrook Parkway Rockville, MD 20852

19

Aldrich Chemical Company P.O. Box 355 Milwaukee, WI 53201

20,

E. S. A. Inc. 45 Wiggins Avenue Bedford, MA 01730

21,

Supelco Inc. Supelco Park Bellefonte , PA 16823

22,

Fisher Scientific Company 711 Forbes Avenue Pittsburgh, PA 15219

Division

52

(US-DEA)

23.

National Bureau of Standards Office of Standard -and Reference Materials Room B 311, Chemistry Building Washington, DC 20234

24.

The Myco Laboratory Company P.O. Box 321 Chesterfield, MO 63017

25.

Sigma Chemical Company P.O. Box 14508 St. Louis, MO 63178

26.

Eureka 215 - 26th Street Sacramento, CA 95816

27.

U.S. Department of Commerce National Oceanic and Atmospheric Northeast Inspection Office P.O. Box 1188, Emerson Avenue Gloucester, MA 01930

Admin.

28.

VA Institute of Marine Science College of William and Mary Gloucester Point, VA 23062

29.

VA Dept. of Agriculture and Consumer Division of Animal Health 1 North 14th Street Richmond, VA 23219

30.

American Dade Division American Hospital Supply Corp. Miami, FL 33152

31.

Pfaltz and Bower Inc. 375 Fairfield Avenue Stamford, CN 06902

32.

U.S. Environmental Protection Agency Pesticides, Industrial Chemicals Repository Research Triangle Park, NC 27711

33.

U.S. Environmental Protection Agency Analytical Chemistry Section Building 306, Room 101, ARC - East Beltsville, MD 20705

34.

U.S. Environmental Protection Agency EMSL - Cincinnati 26 West St. Clair Street Cincinnati, OH 45268

35.

Phillips Chemical Company Drawer 0 Borger, TX 79007

36.

J. T. Baker Chemical Company 222 Red School Lane Phillipsburg, NJ 08865

37.

U.S. Industrial Chemical Company Tuscola, IL 61953

53

Services

(MD-8)

38.

Chem Service P.O. Box 194 West Chester, PA

19380

Once a stock of appropriate reference standards has been obtained, they must be recorded, used and stored properly. A records book or file cards can be used, with the following information noted for each standard: 1.

Standard name and date

2.

Source

3.

Code or lot number.

4.

Purity.

5.

Expiration date

(if any).

6.

Special

storage

requirements.

7.

Storage

location.

(from where

received.

obtained).

M a n y laboratories assign a number to the standard container for accountability purposes. If the s t a n d a r d is o n e w h i c h m a y d e t e r i o r a t e on s t o r a g e , t h e n the record should also include dates and results when stability checks were m a d e . If it is deemed necessary for control, there could be a check-out and - i n sheet for the s t a n d a r d , w h i c h the a n a l y s t w o u l d d a t e and i n i t i a l w h e n u s i n g the material. T h i s is n o t u s u a l l y d o n e e x c e p t for e x t r e m e l y d a n g e r o u s or h i g h l y sensitive substances which must be accounted for. It is o f t e n c o n v e n i e n t to s t o r e r e f e r e n c e s t a n d a r d s in a r e a s n e a r w h e r e t h e a n a l y s e s are b e i n g d o n e (i.e. p e s t i c i d e s t a n d a r d s in the p e s t i c i d e s r e s i d u e analysis section of a larger food laboratory). H o w e v e r , the storage area m u s t be separate from other chemical storage and clearly marked as to its contents. E x a m p l e s are a marked refrigerator section or cabinet with clear warnings or i n s t r u c t i o n s that o n l y s p e c i f i c r e f e r e n c e s t a n d a r d s are to be s t o r e d t h e r e . T h i s p e r m i t s a c c o u n t i n g for a s t a n d a r d l o c a t i o n as w e l l as e n s u r i n g t h a t a reference standard is not mistakenly used as a non-standard chemical. If periodic testing is done to check stability, then the test protocol should be k e p t w i t h the s t a n d a r d r e c o r d . The r e c o r d w o u l d also c o n t a i n the test r e s u l t s , d a t e , a n a l y s t n a m e and a n y s u p p o r t i n g d o c u m e n t s s u c h as s p e c t r a or chromatograms. W i t h all Quality Control procedures in would consist of a periodic review of: 1. Records c o n d i t i o n of the correct times?)

for?

the

Quality

Assurance

checking

(Are they complete and current? Do they reflect the actual standard? H a v e a p p r o p r i a t e s t a b i l i t y t e s t s b e e n r u n at

2. Storage (is If not, w h y ? )

3. review?

place,

the

storage proper?

Are the stored

standards

Physical Condition ( W h e r e w a s the s t a n d a r d at the Any physical evidence of deterioration or m i s h a n d l i n g ? )

accounted

time

of

the

The t i m i n g of the r e v i e w w o u l d d e p e n d on n e e d . An i n i t i a l c y c l e of t h r e e m o n t h s is s u g g e s t e d . T h i s c a n b e i n c r e a s e d or d e c r e a s e d as c o n d i t i o n s and review results dictate.

54

M a n a g e m e n t and e a c h a n a l y s t m u s t r e m e m b e r that r e f e r e n c e s t a n d a r d s are e x t r e m e l y i m p o r t a n t to an a n a l y t i c a l l a b o r a t o r y , a n d m u s t b e treated accordingly. The p e r s o n m a k i n g the QA r e v i e w s h o u l d be a s e n i o r a n a l y s t or s u p e r v i s o r w h o h a s a k n o w l e d g e and a p p r e c i a t i o n for p r o b l e m s t h a t i m p r o p e r , contaminated or deteriorated reference standards can create for the analyst.

7.4

QA of

Instruments

A f t e r r e f e r e n c e s t a n d a r d s , m e a s u r i n g i n s t r u m e n t s are the m o s t s e n s i t i v e and troublesome items for an a n a l y t i c a l l a b o r a t o r y . I n s t r u m e n t m a i n t e n a n c e and r e p a i r are o b v i o u s l y i m p o r t a n t and are d i s c u s s e d e l s e w h e r e . Of e q u a l (or possibly greater) importance is an o r g a n i z e d p r o c e d u r e to p e r i o d i c a l l y c h e c k the instrument performance. If the performance parameters to be checked are s e l e c t e d c a r e f u l l y , t h e n the a n a l y s t h a s a r e a s o n a b l e m e a s u r e of w h e t h e r the i n s t r u m e n t is o p e r a t i n g p r o p e r l y , on a c o n t i n u i n g b a s i s . O n c e a p e r f o r m a n c e c h e c k i n g p r o t o c o l is d e c i d e d u p o n , an i n d i v i d u a l p e r f o r m a n c e r e c o r d c a n b e p r e p a r e d for e a c h i n s t r u m e n t . T h i s can be a s e p a r a t e n o t e b o o k w h i c h is k e p t p h y s i c a l l y n e a r the i n s t r u m e n t , or c a n be p a r t of the m a i n t e n a n c e and r e p a i r record kept for each instrument. The frequency of performance checking varies considerably, again depending on c i r c u m s t a n c e and p r e v i o u s c h e c k r e s u l t s . If a c h e c k r e s u l t indicates maintenance or repair, then a follow-up check (after the repair, etc.) should be scheduled before the next routine QA check time. The routine use of m a n y instruments involves some form of performance checking. An example is a working standard injection into a gas chromatograph first thing in the m o r n i n g , to c h e c k i n s t r u m e n t r e s p o n s e . T h i s is n e c e s s a r y and h a s its place to assure the analyst that the instrument is operating properly for that day. For p u r p o s e s of a QA p e r f o r m a n c e c h e c k , h o w e v e r , t h e r e s h o u l d be a separate and distinct checking programme. S o m e l a b o r a t o r i e s m a k e a d i s t i n c t i o n b e t w e e n r o u t i n e i n s t r u m e n t s used by e s s e n t i a l l y all a n a l y s t s (i.e. b a l a n c e s , s p e c t r o p h o t o m e t e r s , etc.) and t h o s e used o n l y by h i g h l y t r a i n e d s p e c i a l i s t s (i.e. m a s s s p e c t r o m e t e r s , etc.). The p e r f o r m a n c e c h e c k i n g of the f o r m e r c a n b e d o n e b y any a s s i g n e d a n a l y s t . The latter, h o w e v e r , should be checked by trained analyst only. A suggested performance checking protocol laboratory instruments is as follows:

Analytical

1.

and

schedule

for

some

general

Balances

Sensitivity

(bimonthly)

Check balance sensitivity using three standard weights (10g, lg and 100 mg). Weight used should be traceable to certified weights of at l e a s t U.S. C l a s s S. S e n s i t i v i t y s h o u l d be w i t h i n the balance specifications.

2.

Calibration

(annual)

Best done in connection using standard weights.

with

annual

55

cleaning

and

maintenance,

again

Spectrophotometers

1.

(ultraviolet and

Wavelength

Accuracy

visible)

(bimonthly)

Check by recording over entire UV-visible w a v e l e n g t h range using H o l m i u m and D i d y m i u m f i l t e r s ( u s u a l l y o b t a i n a b l e f r o m t h e i n s t r u m e n t m a n u f a c t u r e r or a l a r g e s u p p l y f i r m ) . Run two spectra for comparison. Results should not differ from published values more t h a n + 1.0 n m at a n y w a v e l e n g t h .

2.

Photometric

Accuracy

(bimonthly)

P r e p a r e a s o l u t i o n of 60 _+ 0.25 m g p o t a s s i u m d i c h r o m a t e in o n e l i t r e of 0.01N s u l p h u r i c a c i d . ( T h i s s o l u t i o n is q u i t e s t a b l e a n d o n c e p r e p a r e d can be used a long time). S c a n this s o l u t i o n f r o m 2 1 0 to 450 n m . T h e f o l l o w i n g a b s o r b a n c e s (+ 1% f u l l s c a l e ) s h o u l d o c c u r at the i n d i c a t e d w a v e l e n g t h s :

Wavelength

(nm)

Absorbance

235 257 313 350

0.747 0.869 0.293 0.644

A l t e r n a t i v e l y , t h e U.S. N a t i o n a l B u r e a u of S t a n d a r d s h a s a v a i l a b l e for p u r c h a s e S R M 9 3 0 , a g l a s s f i l t e r w h i c h c a n b e u s e d s i m i l a r l y and which has certified wavelength/absorbance values.

Spectrophotometer

1.

(infrared)

Wavelength Accuracy

(trimonthly)

Scan a standard polystyrene film. The following peaks indicated w a v e n u m b e r s w i t h i n the listed a c c u r a c y :

Wavenumber

(cm

1.

Baseline

(atomic

+ _+ + +

absorption)

(daily when

Absorbance

the

6 6 2 2

used)

U s i n g f l a m e o n l y , the r e c o r d e r b a s e l i n e s h o u l d .005 a b s o r b a n c e u n i t s in a f i v e m i n u t e p e r i o d .

2.

at

Accuracy

2851 1601 1028 907

Spectrophotometer

occur

(daily when

not vary m o r e

than +

used)

T h r e e c o n s e c u t i v e a b s o r b a n c e c h e c k s of the v a r y m o r e t h a n _+ .005 a b s o r b a n c e u n i t s .

56

same

solution

should

not

3.

Detection Limit

(monthly)

Prepare a solution of a metal standard sufficiently dilute to give a response of two times the baseline absorbance under ideal conditions. T h i s b e c o m e s the ' d e t e c t i o n l i m i t ' s t a n d a r d . M a k e four r e p l i c a t e aspirations to check reproducibility.

Gas

Chromatograph

1.

Column Oven

(semiannual)

Check column oven temperature using

2.

Gas Flow Rate

pyrometer.

(monthly)

C h e c k f l o w rates of all c a r r i e r bubble meter or other device.

3.

a calibrated

Detector Response

(daily when

and

detector

gases

u s e d , using

a

used)

Compare present detector response with the response obtained when new or w h e n last c l e a n e d and c a l i b r a t e d . (in s o m e d e t e c t o r s , n o t a b l y e l e c t r o n c a p t u r e , a d e t e r i o r a t i n g r e s p o n s e i n d i c a t e s a need for cleaning).

High Performance Liquid

1.

Chrcmatograph

Column Resolution (daily when

used)

Prepare a solution of two or more substances which the column should resolve under normal analytical conditions. Use this to check column performance each time the column is used.

2.

Detector Response (daily when used) C h e c k d e t e c t o r r e s p o n s e using a k n o w n c o n c e n t r a t i o n standard and compare to a response previously obtained under ideal conditions.

The above p e r f o r m a n c e c h e c k s are only s u g g e s t i o n s . The best a p p r o a c h is to read the o p e r a t i o n s m a n u a l for e a c h i n s t r u m e n t and s e l e c t key o p e r a t i n g p a r a m e t e r s or s p e c i f i c a t i o n s of i n t e r e s t to p r e p a r e the p r o t o c o l . Also, instruments or equipment other than those mentioned above should be considered for a p e r f o r m a n c e check p r o g r a m m e . The g o v e r n i n g factor should be the instrument or equipment importance to the laboratory. The QA p r o g r a m m e on i n s t r u m e n t p e r f o r m a n c e c h e c k i n g m u s t also include a p e r i o d i c r e v i e w to i n s u r e the c h e c k s are b e i n g m a d e and that a p p r o p r i a t e follow-up action is taken if a check discloses a possible performance problem. This follow-up could be maintenance, cleaning, repair, calibration, etc. Any follow-up action should be recorded in the notebook kept with the instrument.

57

7.5

QA of Analytical

Reports

As discussed in preceding Section 5.5, the analytical report is the culmination of all of the l a b o r a t o r y ' s e f f o r t s . T h e r e are m a n y t y p e s and f o r m a t s for analysis reports. T h e y v a r y from s i m p l e to d e t a i l e d , but all are s u b j e c t to the same problem, h u m a n error. A Quality Assurance p r o g r a m m e for analytical reports is basically an after-the-fact or retrospective review of a document w h i c h h a s a l r e a d y b e e n t h r o u g h the n o r m a l s u p e r v i s o r y and m a n a g e m e n t r e v i e w process. It is d e s i g n e d to d e t e c t r e p o r t w r i t e - u p and r e v i e w e r r o r s so that appropriate procedures can be instituted to prevent their reoccurrence. Although report formats m a y vary according to organizational need, the report m u s t be c o m p l e t e enough to enable the reviewer to reconstruct the analysis and to c h e c k the a n a l y t i c a l r e a s o n i n g as w e l l as d a t a and c a l c u l a t i o n s . For e x a m p l e , in ISO Guide 25 (2) under part 12, "Test Reports", it states:

1. The work carried out by the testing laboratory shall be covered by a report w h i c h accurately, clearly and u n a m b i g u o u s l y p r e s e n t s the t e s t r e s u l t s and all other relevant information.

2.

Each test report

shall

include at least

the following

information:

a.

Name and address of testing

b.

Unique identification of each page of the report.

c.

Name and address of

d.

Description and identification of the test

e.

D a t e of r e c e i p t of test tests, as appropriate.

f.

A s t a t e m e n t to the e f f e c t that the test r e s u l t s r e l a t e o n l y to the items tested.

g.

Identification

h.

Description of sampling

i.

Any d e v i a t i o n s , additions specification, and any other test .

j.

Disclosure ut ilized.

k.

M e a s u r e m e n t s , e x a m i n a t i o n s and d e r i v e d r e s u l t s , s u p p o r t e d by t a b l e s , g r a p h s , s k e t c h e s , p h o t o g r a p h s as a p p r o p r i a t e , and any failure identified.

1.

A statement on measurement

m.

A s i g n a t u r e a n d t i t l e of p e r s o n ( s ) a c c e p t i n g technical responsibility for the test report and date of issue.

n.

A s t a t e m e n t that t h e r e p o r t s h a l l n o t be r e p r o d u c e d full without the approval of the testing laboratory.

of

report

(such

as serial

number),

and

of

performance

of

client.

of the test

any

company.

item

and

date(s)

of

specification, method

procedure, where

and

procedure.

relevant.

to or e x c l u s i o n s from the test information relevant to a specific

non-standard

58

item.

test

uncertainty

method

(where

or

procedure

relevant).

except

in

3. Particular care and attention shall be paid to the arrangement of the test report, especially with regard to presentation of the test data and ease of assimilation by the reader. The format shall be carefully and specifically a s s i g n e d for e a c h type of test c a r r i e d o u t , but the h e a d i n g s shall be standardized as far as possible. The U.S. Food and Drug A d m i n i s t r a t i o n " A n a l y s t W o r k s h e e t " good example for purposes of discussing an analytical report is relatively complete and includes space for all pertinent analytical summary. The r e v e r s e of the form w o u l d be used and calculations as the analysis progresses.

(Figure 7.1) is a QA programme. It data including an for r a w w o r k d a t a

An a n a l y t i c a l r e p o r t QA p r o g r a m m e should i n v o l v e r e v i e w of a p r e d e t e r m i n e d n u m b e r of c o m p l e t e d r e p o r t s on a m o n t h l y or b i m o n t h l y b a s i s . The r e p o r t s should be r e p r e s e n t a t i v e of the k i n d s of w o r k d o n e , w i t h a b o u t as m a n y w h i c h s h o w law v i o l a t i o n s as are u s u a l l y e n c o u n t e r e d . An e x a m p l e could be ten r e p o r t s w i t h t w o b e i n g v i o l a t i v e ( a s s u m i n g the v i o l a t i o n rate is about 20%). The object is to gain a relatively representative sampling of completed reports in order to evaluate overall report writing. If some section of the laboratory has substandard reports, then their coverage can be selectively increased until it a p p e a r s that the r e p o r t s are s a t i s f a c t o r y . T h i s is one of the p r i m e f u n c t i o n s of QA r e v i e w s ( w h a t e v e r the t y p e ) - to p i n p o i n t p r o b l e m areas and give them visibility until the problem is solved. An example of an analytical report review protocol is one which has been used by the U.S. Food and Drug A d m i n i s t r a t i o n for QA r e v i e w of their A n a l y t i c a l Worksheets. Their protocol consists of a listing of performance factors that their Worksheet (Figure 7.1) must meet, as follows: 1.

2.

Accuracy and

Completeness

a.

Worksheet clearly describes received by the analyst.

b.

Worksheet fully and accurately reflects continuity and of sample.

c.

Information on the Collection Report.

d.

T h e u s e of a p p r o p r i a t e equipment is described.

e.

C a l c u l a t i o n s are a c c u r a t e , easy to f o l l o w , and are c h e c k e d . This includes checking of conversion factors, normality factors, etc., for accuracy of recording.

f.

If m o r e than one p e r s o n p a r t i c i p a t e d in worksheet clearly indicates who did what.

g.

Sample reserve or disposition is correctly

h.

E r r o r s are noted by s t r i k i n g t h r o u g h the i n c o r r e c t inserting, initialing and dating the new entry.

i.

Any discarded

Analytical

worksheet

results are

the

sample

and

is compatible

standards,

condition

with

reagents,

the

the

and

when

integrity

Inspection

special

analysis,

the

reported. entry

and

explained.

Methodology

The a p p r o p r i a t e m e t h o d is used and is r e f e r e n c e d on the worksheet. Analyses performed and methods used are consistent with appropriate instructions or as directed by the Supervisor.

59

ANALYST WORKSHEET 3. S E A L S •

NONE

•

INTACT

•

BROKEN

1. P R O D U C T

4. D A T E

REC'D

2. S A M P L E

5. R E C E I V E D

FROM

NUMBER

6. D I S T R I C T O R L A B O R A T O R Y

7. D E S C R I P T I O N O F S A M P L E

8. NET CONTENTS

•

NOT APPLICABLE

DECLARE/UNIT

•

NOT DETERMINED

AMOUNT

UNITS E X A M I N E D

% OF

10. S U M M A R Y O F

11. R E S E R V E

.ORIGINAL(S) LABELING

FOUND.

DECLARED

.COPIES •

SUBMITTED

SUBMITTED

NONE

ANALYSIS

SAMPLE

1 2 . L. A N A L Y S T S I G N A T U R E (Broke

Seal •

) WORKSHEET CHECK 14. D A T E

FORM FD 431 (1/77)

P R E V I O U S E D I T I O N IS O B S O L E T E .

Figure USFDA

Analyst

60

7.1 Worksheet

REPORTED

PAGE

OF

PAGES

3.

4.

b.

Sample is analyzed so laws or regulations.

c.

Deviations worksheet.

d.

Any unofficial method

Supervisory

from

the

as

to

permit

referenced

used

application

method

are

of

appriopriate

explained

on

the

is validated.

Review

a.

The a n a l y s i s and m e t h o d o l o g y w a s a p p r o p r i a t e indicated on the inspection collection report.

b.

L a b o r a t o r y c o n c l u s i o n s and final d e c i s i o n supported by information on the worksheet.

c.

If the sample is classified performed (if possible).

Time

Frames

a.

Sample analysis

violative,

to

are

the

problem

accurate

a confirming

analysis

and

is

time frames are met.

Any deviations from the above which are found during the r e v i e w , are recorded and an a t t e m p t m a d e to d e t e r m i n e h o w they o c c u r r e d . T h e r e v i e w e r m a y find a p a t t e r n s u c h as c e r t a i n e r r o r s a r e c o n s i s t e n t l y m a d e , i n d i c a t i n g a n e e d for specific training. A l l f o l l o w - u p a c t i v i t i e s and a c t i o n s t a k e n to c o r r e c t p r o b l e m s , m u s t be detailed and documented to provide laboratory m a n a g e m e n t with a continuing basis to evaluate improvement.

7.6

Check Samplé

Examination

O n e of the m o s t c o m m o n w a y s to e v a l u a t e o v e r a l l i n d i v i d u a l or l a b o r a t o r y p e r f o r m a n c e in a g i v e n a n a l y s i s , is b y u s e of k n o w n c h e c k s a m p l e s . This i n c l u d e s b o t h i n t r a ( w i t h i n ) the l a b o r a t o r y and i n t e r ( b e t w e e n ) like laboratories. The A m e r i c a n Chemical Society (ACS) in their 1980 Guidelines for Data Quality Evaluation, stated: "At the o u t s e t , a l a b o r a t o r y s h o u l d d e m o n s t r a t e its p r o f i c i e n c y u s i n g prototype and non-critical samples, thereby reducing the probability that bad d a t a w i l l be g e n e r a t e d on c r i t i c a l s a m p l e s , e s p e c i a l l y t h o s e i n v o l v i n g complicated unknown mixtures. An i n t r a l a b o r a t o r y q u a l i t y c o n t r o l p r o g r a m s h o u l d i n c l u d e the use of b l i n d s a m p l e s in a d d i t i o n to c h e c k s a m p l e s w h o s e v a l u e s are k n o w n to the a n a l y s t s . A l l a n a l y s t s s h o u l d be m o n i t o r e d b y the quality control procedures, and any assessment of laboratory performance should include all of the analysts involved, or at least a random selection of those analysts. I n t e r l a b o r a t o r y Q u a l i t y A s s u r a n c e p r o g r a m s s h o u l d also use b l i n d s a m p l e s in a d d i t i o n to c h e c k s a m p l e s , in o r d e r to p r o v i d e a r e a l i s t i c assessment of the performance of the method that is achievable in the field." L a t e r , in 1 9 8 2 , the A C S m a d e an a d d i t i o n a l s t a t e m e n t reliability and acceptability of analysis data:

regarding

improving

" I d e a l l y , for a g i v e n m e t h o d , i n t e r l a b o r a t o r y v a r i a b i l i t y s h o u l d b e the s a m e as i n t r a l a b o r a t o r y v a r i a b i l i t y : In real s i t u a t i o n s , h o w e v e r , the i n t e r l a b o r a t o r y v a r i a b i l i t y is a l m o s t a l w a y s g r e a t e r . T h e r e f o r e , it is necessary to determine for a given method the variability of the m e a s u r e m e n t s ( r a n d o m e r r o r ) b e t w e e n l a b o r a t o r i e s in o r d e r to m a k e a l l o w a n c e s for t h o s e differences in i n t e r p r e t i n g the r e s u l t s of a n a l y s e s . For any p r o p e r l y

61

validated procedure, however, interlaboratory results will be consistent with i n t r a 1 a b o r a t o r y r e s u l t s / t h a t is, t h e u n c e r t a i n t y i n t e r v a l s (including s y s t e m a t i c error b o u n d s ) for all q u a l i f i e d l a b o r a t o r i e s ( i n d i v i d u a l l y and collectively) will overlap the true value. (This presumes that the measurement method, itself, has negligible bias.)" The various

factors

influencing

final

analysis data are shown in Figure 7.2.

DATA

Figure 7.2

During 1984, the U.S. Association of Food and Drug Officials (AFDO) assembled a listing of proficiency and check sample programs available through various U.S. a g e n c i e s and o r g a n i z a t i o n s . The listing is as f o l l o w s , giving c h e c k s a m p l e type, the product involved and the check sample program sponsor:

Check Sample Type

Program Sponsor

Product(s)

Aflatoxins

Milk, Corn

2

Alcohol

Blood

3

Antibiotics

Meat

4

Antibiotics

Milk

6

Arsenic

Meat, Poultry

4

Filters

5

Asbestos

(Number of Fibres)

Bacteriology

Milk, General

Bioassay of Antibiotics

Feed s

8

Cations

Water

9

Cereal

1

Water

9

Cereal

Components

Coliforms

62

Food

6,7

Drinking Water, Fatty

Prograai Sponsor

Product(s)

Check Sample Type Contaminants

Water

9

Fats and

Acids

Oils

2

Fertilizers

Fértilizers

13

Fibre

Fibre

11

Flammables

Various

11

Fluoride

Water

Food

Various

Characterization

Components

Herbicides and Industrial Lead and

Chemicals

FEP

Medicated Metals

Organics

Feeds

(Cations)

Metals and

Foods

Urine and

17

Water

10

Fish

6

Blood

7

Feed s

8

Food

6

Water

Minerals

Microb iology Microscopic

7

14

Various Characterization

Products

18,19

Feed s

15

Mould s

Mycology

7

Organic

Chemicals

Water

Organic

Solvents

Charcoal

Organics

Semi-Volatile

Organochlorine

Tube

Synthetic

Compounds

PCB's and Chlorinated

14

Organics

Leachate

12

Plasma

10

Fat, Blood Meats,

5

Poultry

4

Phosphatase

Milk

6

Protein/Moisture/Fat/Salt

Meat

4

Residues,

Meats,

Pesticide

Poultry

Pesticides/Herbicides

Water

Pesticides/Herbicides

Vegetables,

Smalley Oil

Feed s

2

Milk

6

Somatic

Cell

Meals Count

and Drinking

4

Sulfonamide s

Meats,

Vitamins

Milk, Feed,

Waste Water

Parameters

Water

63

Foods

Poultry Foods

Water

9,10,14 6,16

4 1 9

The U . S . s p o n s o r s

for the above c h e c k sample p r o g r a m s

1.

A m e r i c a n A s s o c i a t i o n of C e r e a l 3340 P i l o t K n o b Road St. P a u l , MN 55121

2.

A m e r i c a n Oil C h e m i s t s Society 508 South Sixth Street C h a m p a i g n , IL 61820

3.

U . S . D e p a r t m e n t of T r a n s p o r t a t i o n Transportation Systems Center, Kendall Cambridge, MA 02142

are

Chemists

Square

4.

U . S . D e p a r t m e n t of A g r i c u l t u r e , FSIS P . O . Box 5080 S t . L o u i s , MO 63115

5.

N a t i o n a l I n s t i t u t e of O c c u p a t i o n a l Safety and H e a l t h C h e m i c a l R e f e r e n c e L a b o r a t o r y (PAT) (R-3) 4676 C o l o m b i a P a r k w a y C i n c i n n a t i , OH 4 5 2 2 6

6.

U . S . Food and D r u g A d m i n i s t r a t i o n 1090 T u s c u l u m A v e n u e C i n c i n n a t i , OH 4 5 2 2 6

7.

U . S . C e n t e r for D i s e a s e C o n t r o l Chief, Performance Evaluation Branch, Laboratory P r o g r a m O f f i c e , A t l a n t a , GA 3 0 3 3 3 Telephone: (404) 329-3847

8.

A m e r i c a n A s s o c i a t i o n of Feed C o n t r o l c/o L a w and C o m p a n y P . O . B o x 1558 A t l a n t a , GA 30301

9.

U . S . Environmental Protection QA B r a n c h , EMSL C i n c i n n a t i , OH 4 5 2 6 8

10.

U . S . E n v i r o n m e n t a l P r o t e c t i o n A g e n c y , QA D i v i s i o n E M S L , P . O . Box 15027 Las V e g a s , NV 89114 T e l e p h o n e : (702) 7 9 8 - 2 1 0 0

11.

Forensic Science Foundation Collaborative Testing Services, Inc. 8343-A Greensboro Drive M c L e a n , V A 22102

12.

A m e r i c a n S o c i e t y for Testing 1916 R a c e S t r e e t P h i l a d e l p h i a , PA 19103

13.

A s s o c i a t i o n of A m e r i c a n Plant Food C o n t r o l O f f i c i a l s c/o W . Penn Z e n t m e y e r V A D e p a r t m e n t of A g r i c u l t u r e and C o n s u m e r S e r v i c e s P . O . Box 1163 R i c h m o n d , VA 23201 Telephone: (804) 786-3511

Officials

Agency

Material

64

14.

U.S. Geological Survey 5293 Ward Road Arvada, CO 80002 Telephone: (303) 234-3975

15.

American Association of Feed Attn: Mrs. Janet Windsor 1118 Apple Drive Mechanicsburg, PA 17055

16.

Association of Food and Drug Officials of the Southern States c/o George Fong Division of Chemistry Florida Department of Agriculture and Consumer Services 3125 Connor Boulevard Tallahassee, FL 32301

17.

National Food Processors Association 1133 20th Street, NW Washington, DC 20016 Telephone: (202) 331-5955

18.

College of American Pathologists 7400 N. Skokie Boulevard Skokie, IL 60077 Telephone: (312) 677-3500

19.

American Association of Bioanalysts Proficiency Testing Service 205 W. Levee Street Brownsville, TX 78520 Telephone: (512) 546-5315

Microscopists

It is a d v i s a b l e to p a r t i c i p a t e in as m a n y i n t e r - 1 a b o r a t o r y c h e c k s a m p l e p r o g r a m s as are a v a i l a b l e in the a r e a s of i n t e r e s t to the l a b o r a t o r y . The s p o n s o r i n g o r g a n i z a t i o n s u s u a l l y p r o v i d e a s u m m a r y r e p o r t to p a r t i c p a t i n g l a b o r a t o r i e s , w h i c h g i v e s an e v a l u a t i o n of the l a b o r a t o r y ' s p e r f o r m a n c e as compared to o t h e r p a r t i c i p a n t s . T h e i n t e r - 1 a b o r a t o r y p r o g r a m can be supplemented by an intra program to highlight specific areas of concern which W h e n s e l e c t i n g s a m p l e s for an are n o t c o v e r e d in the inter p a r t i c i p a t i o n . intra program, the following considerations should be taken into account: 1.

The capability laboratory.

to analyze

the

sample must be w i d e l y available

2.

The analytical method must be one that

3.

The sample should cover a variety of analytical identification steps if possible.

4.

The product must be readily available and reasonable

is generally

in the

employed.

techniques,

including

in cost.

A l w a y s keep in mind that the evaluation of check sample results must include all aspects of the analysis. In cases where there is a large discrepancy from the expected or true result, the laboratory must investigate all aspects of the analysis (as given in Figure 7.2) to d e t e r m i n e w h a t specific analysis area or areas are suspect. From this, the laboratory should take appropriate action to prevent reoccurrence of a similar difficulty.

65

7.7

Other QA Activities

Some important QA review programmes were discussed in the preceding Sections. Many other areas of laboratory operations would also benefit from QA review. Keeping in mind the definition for Quality Assurance given in Section 7.1, any l a b o r a t o r y o p e r a t i o n can be r e v i e w e d to d e t e r m i n e if c o r r e c t p r o c e d u r e s are being followed and to identify procedural weaknesses.' Examples are:

1. S a f e t y - The laboratory safety programme can be periodically reviewed (about every three months) to determine that safety and emergency materials are on hand and b e i n g used. T h i s w o u l d i n c l u d e a c h e c k of any i n j u r y or a c c i d e n t records and a review that appropriate follow-up corrective measures were taken. 2. S u p p l y M a n a g e m e n t - R e f e r e n c e s t a n d a r d h a n d l i n g and s t o r a g e w a s discussed earlier. The s a m e g e n e r a l p r i n c i p l e s a p p l y to all l a b o r a t o r y supplies, such as glassware, chemicals, solvents and others. A QA review would focus on whether supplies are being ordered, stored and distributed properly. 3. S a m p l e M a n a g e m e n t - The s a m p l e s r e c e i v e d by the l a b o r a t o r y for analysis must be accounted for. This is even more critical when the laboratory is i n v o l v e d in food l a w e n f o r c e m e n t . An a c c o u n t a b i l i t y s y s t e m s h o u l d be e s t a b l i s h e d and in o p e r a t i o n (see S e c t i o n s 4.2 and 4.3). The QA r e v i e w w o u l d determine that the system is working properly and that samples are accounted for throughout their receipt, storage, analysis and final disposition. 4. T r a i n i n g - This m a y s e e m an odd area for QA r e v i e w , but it r a n k s in importance to most other laboratory operations. A QA review of training could i n c l u d e c h e c k s of o n g o i n g f o r m a l t r a i n i n g p r o g r a m m e s for n e w a n a l y s t s and checks of training needs and records for experienced analysts. The importance of t r a i n i n g c a n n o t be o v e r e m p h a s i z e d and a QA r e v i e w p r o g r a m m e o f t e n g i v e s training needed visibility to management.

The above are only examples and laboratory management must select with care the o p e r a t i o n a l areas n e e d e d for Q u a l i t y A s s u r a n c e r e v i e w . R e m e m b e r that any laboratory function can be (and often should be) subject to QA review.

7.8

Text

1.

G A R F I E L D , F.M., Laboratories, 2. VA, U.S.A.

2.

ISO Guide 25, 1982. General Requirements for the Technical Competence Testing Laboratories. International Organization for Standards.

3.

INTERNATIONAL LABORATORY Report of Task Force D.

Farther

References 1985. Q u a l i t y A s s u r a n c e P r i n c i p l e s for A n a l y t i c a l Association of Official Analytical Chemists, Arlington,

ACCREDATION

CONFERENCE,

London.

Oct.

of

1984.

Reading

B E R M A N , G.A. (Ed.) 1980. Testing Laboratory Performance: Accreditation, NBS P u b l i c a t i o n 591, National Bureau Gaithersburg, MD, U.S.A.

E v a l u a t i o n and of Standards,

Chemistry Quality Assurance Handbook, Volume 1, Principles, U.S. Department Agriculture, Food Safety and Inspection Service, Washington, DC, U.S.A.

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D U N C A N , A.J. 1974. Q u a l i t y C o n t r o l and I n d u s t r i a l Richard D. Irwin, Inc., Homewood, IL., U.S.A.

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4th

Ed.,

G A R F I E L D , F.M. et al (Ed.) 1980. O p t i m i z i n g C h e m i c a l L a b o r a t o r y P e r f o r m a n c e T h r o u g h the A p p l i c a t i o n of Q u a l i t y A s s u r a n c e P r i n c i p l e s , A s s o c i a t i o n of Official Analytical Chemists, Arlington, VA, U.S.A. H O R W I T Z , W. 1981. A C S S y m p o s i u m S e r i e s No. 1 6 0 , T h e P e s t i c i d e C h e m i s t and Modern Toxicology, "Analytical M e a s u r e m e n t s : H o w Do You K n o w Your Results Are Right". American Chemical Society, Washington, DC, U . S . A . INHORN, S.L. (Ed.) 1977. Quality Assurance Practices for Health American Public Health Association, Washington, DC, U.S.A. JURAN, J.M. & GRYNA, F.M. J U R A N , J.M., McGraw-Hill.

GRYNA,

1980.

Quality

F.M. & B I N G H A M ,

Planning

B.S.

1974.

and Analysis, Quality

Laboratories,

McGraw-Hill.

Control

Handbook,

SHERMA, J. (Ed.) 1976. Manual of Analytical Quality Control for Pesticides in H u m a n and Environmental Media, U.S. Environmental Protection Agency, Research Triangle Park, NC, U.S.A. Y O U D E N , W.J. & S T E I N E R , E.H. 1975. S t a t i s t i c a l M a n u a l of Association of Official Analytical Chemists, Arlington, VA, U.S.A.

67

the

AOAC,

F A O T E C H N I C A L PAPERS F A O F O O D A N D N U T R I T I O N PAPERS 1/1 1/2

R e v i e w of f o o d c o n s u m p t i o n surveys 1 9 7 7 Vol. 1. Europe, N o r t h A m e r i c a , Oceania, 1 9 7 7 (E) R e v i e w of f o o d c o n s u m p t i o n s u r v e y s 1 9 7 7 V o l . 2 . A f r i c a , Latin A m e r i c a , Near East, Far East, 1 9 7 9 (E)

2

Report of t h e joint F A O / W H O / U N E P c o n f e r e n c e o n m y c o t o x i n s , 1 9 7 7 (E F S)

3

Report o f a j o i n t F A O / W H O expert c o n s u l t a t i o n o n dietary f a t s and oils in h u m a n nutrition,

4

JECFA s p e c i f i c a t i o n s for i d e n t i t y and purity of t h i c k e n i n g a g e n t s , a n t i c a k i n g agents, a n t i m i c r o b i a l s , a n t i o x i d a n t s and emulsifiers,

18 Rev. 1

Bibliography of f o o d c o n s u m p t i o n s u r v e y s , 1 9 8 4 (E)

18 Rev. 2

Bibliography of f o o d c o n s u m p t i o n s u r v e y s , 1 9 8 7 (E)

18 Rev. 3

Bibliography of f o o d c o n s u m p t i o n s u r v e y s , 1 9 9 0 (E)

19

JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of carrier s o l v e n t s , emulsifiers and stabilizers, e n z y m e preparations, f l a v o u r i n g a g e n t s , f o o d colours, s w e e t e n i n g agents and o t h e r f o o d additives, 1 9 8 1 (E F)

20 21 22

Legumes in h u m a n n u t r i t i o n , 1 9 8 2 (E F S) M y c o t o x i n surveillance - a guideline, 1 9 8 2 (E) Guidelines for agricultural t r a i n i n g curricula in A f r i c a , 1 9 8 2 (E F)

23

M a n a g e m e n t of g r o u p f e e d i n g p r o g r a m m e s , 1 9 8 2 (E F P S) Food and n u t r i t i o n in t h e m a n a g e m e n t of g r o u p feeding p r o g r a m m e s , 1 9 9 3 (E F S) Evaluation o f n u t r i t i o n i n t e r v e n t i o n s , 1 9 8 2 (E) JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of b u f f e r i n g agents, salts; e m u l s i f i e r s , t h i c k e n i n g a g e n t s , stabilizers; f l a v o u r i n g a g e n t s , f o o d colours, s w e e t e n i n g agents and m i s c e l l a n e o u s f o o d additives, 1 9 8 2 (E F) Food c o m p o s i t i o n tables for t h e Near East,

1 9 7 7 (E F S)

1 9 7 8 (E) 5 5 Rev. 1 5 Rev. 2

JECFA - guide t o s p e c i f i c a t i o n s , 1 9 7 8 (E F) JECFA - guide t o s p e c i f i c a t i o n s , 1 9 8 3 (E F) JECFA - guide t o s p e c i f i c a t i o n s , 1 9 9 1 (E)

6

The f e e d i n g of w o r k e r s in developing countries, 1 9 7 6 (E S) JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of f o o d c o l o u r s , e n z y m e preparations and other f o o d a d d i t i v e s , 1 9 7 8 (E F)

7

8

W o m e n in f o o d p r o d u c t i o n , f o o d handling and n u t r i t i o n , 1 9 7 9 (E F S)

9

A r s e n i c and t i n in f o o d s : r e v i e w s of c o m m o n l y u s e d m e t h o d s of analysis, 1 9 7 9 (E)

10 11 12

P r e v e n t i o n of m y c o t o x i n s , 1 9 7 9 (E F S) The e c o n o m i c value of breast-feeding, 1 9 7 9 (E F) JECFA s p e c i f i c a t i o n s for i d e n t i t y and purity of f o o d c o l o u r s , f l a v o u r i n g agents and other f o o d a d d i t i v e s , 1 9 7 9 (E F)

2 3 Rev. 1 24 25

26 27 28

1 9 8 3 (E) Review of f o o d c o n s u m p t i o n s u r v e y s 1 9 8 1 , 1 9 8 3 (E) JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of b u f f e r i n g agents, salts, e m u l s i f i e r s , stabilizers, t h i c k e n i n g agents, e x t r a c t i o n s o l v e n t s , f l a v o u r i n g agents, s w e e t e n i n g agents and m i s c e l l a n e o u s f o o d additives, 1 9 8 3 (E F) Post-harvest losses in quality of f o o d grains, 1 9 8 3 (E F)

13

Perspective o n m y c o t o x i n s , 1 9 7 9 (E F S)

14 14/1 1 4 / 1 Rev.1

Manuals of food quality control: Food c o n t r o l l a b o r a t o r y , 1 9 7 9 (Ar E) The f o o d c o n t r o l laboratory, 1 9 8 6 (E)

14/2

A d d i t i v e s , c o n t a m i n a n t s , t e c h n i q u e s , 1 9 8 0 (E)

14/3 14/4

C o m m o d i t i e s , 1 9 7 9 (E) M i c r o b i o l o g i c a l analysis, 1 9 7 9 (E F S)

30

F A O / W H O f o o d additives d a t a s y s t e m , 1 9 8 4 (E)

3 0 Rev. 1

14/5 14/6 1 4 / 6 Rev.1 14/7

Food Food Food Food

31/1

F A O / W H O f o o d additives data s y s t e m , 1 9 8 5 (E) JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of f o o d colours, 1 9 8 4 (E F)

c o n t a m i n a n t s and c o m p o s i t i o n , 1 9 8 6 (C E) Food analysis: q u a l i t y , adulteration and t e s t s of

32

14/8

i d e n t i t y , 1 9 8 6 (E) I n t r o d u c t i o n t o f o o d s a m p l i n g , 1 9 8 8 (Ar C E F S) T r a i n i n g in m y c o t o x i n s analysis, 1 9 9 0 (E S) M a n a g e m e n t of f o o d c o n t r o l p r o g r a m m e s ,

33

14/9 14/10 14/11

1 9 9 1 (E) Q u a l i t y a s s u r a n c e in the f o o d c o n t r o l m i c r o b i o l o g i c a l laboratory, 1 9 9 2 (E F S) Pesticide residue analysis in t h e f o o d c o n t r o l l a b o r a t o r y , 1 9 9 3 (E F) Q u a l i t y assurance in t h e f o o d c o n t r o l chemical

35

R e v i e w of f o o d c o n s u m p t i o n s u r v e y s 1 9 8 5 , 1 9 8 6 (E)

36

Guidelines for c a n m a n u f a c t u r e r s and f o o d canners, 1 9 8 6 (E) JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of certain f o o d additives, 1 9 8 6 (E F)

l a b o r a t o r y , 1 9 9 3 (E) I m p o r t e d f o o d inspection, 1 9 9 3 (E F) Radionuclides in f o o d , 1 9 9 4 (E) C a r b o h y d r a t e s in h u m a n nutrition, 1 9 8 0 (E F S) A n a l y s i s of f o o d c o n s u m p t i o n s u r v e y data for d e v e l o p i n g c o u n t r i e s , 1 9 8 0 (E F S) JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of s w e e t e n i n g a g e n t s , e m u l s i f y i n g agents, f l a v o u r i n g a g e n t s and other f o o d additives, 1 9 8 0 (E F) Bibliography of f o o d c o n s u m p t i o n s u r v e y s , 1 9 8 1 (E)

38

JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of certain f o o d additives, 1 9 8 8 (E)

39

Quality c o n t r o l in f r u i t and v e g e t a b l e p r o c e s s i n g , 1 9 8 8 (E F S) D i r e c t o r y of f o o d and n u t r i t i o n i n s t i t u t i o n s in the Near East, 1 9 8 7 (E) Residues of s o m e v e t e r i n a r y d r u g s in animals and f o o d s , 1 9 8 8 (E)

14/12 14/13 14/14 14/15 14/16 15 16 17

18

inspection, 1981 for e x p o r t , 1 9 7 9 for e x p o r t , 1 9 9 0 analysis: general

(Ar E) (Rev. 1 9 8 4 , E S) (E S) (E S) t e c h n i q u e s , additives,

29

31/2

JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of f o o d additives, 1 9 8 4 (E F)

34

37

40 41 41/2

Residues of v e t e r i n a r y d r u g s in f o o d s , 1 9 8 5 (E/F/S) Nutritional implications of f o o d aid: an a n n o t a t e d bibliography, 1 9 8 5 (E) JECFA s p e c i f i c a t i o n s for i d e n t i t y and p u r i t y of certain f o o d additives, 1 9 8 6 (E F)

Residues of s o m e v e t e r i n a r y d r u g s in animals and f o o d s . T h i r t y - f o u r t h m e e t i n g of t h e j o i n t F A O / W H O Expert C o m m i t t e e o n Food A d d i t i v e s , 1 9 9 0 (E)

41/3

41/4

Residues of s o m e veterinary drugs in animals and f o o d s . T h i r t y - s i x t h m e e t i n g of the joint F A O / W H O Expert C o m m i t t e e o n Food A d d i t i v e s , 1 9 9 1 (E) Residues of s o m e v e t e r i n a r y drugs in animals and

55

Sampling plans for a f l a t o x i n analysis in p e a n u t s and c o r n , 1 9 9 3 (E)

56

Body m a s s index - A m e a s u r e of c h r o n i c energy d e f i c i e n c y in adults, 1 9 9 4 (E F S) Fats and oils in h u m a n n u t r i t i o n , 1 9 9 5 (Ar E F S)

f o o d s . T h i r t y - e i g h t h m e e t i n g of t h e joint F A O / W H O Expert C o m m i t t e e o n Food A d d i t i v e s , 1 9 9 1 (E)

57 58

The use of hazard analysis critical c o n t r o l point (HACCP) principles in f o o d c o n t r o l , 1 9 9 5 (E F S)

41/5

Residues of s o m e veterinary drugs in animals and

59 60

N u t r i t i o n e d u c a t i o n for t h e public, 1 9 9 5 (E F S) Food f o r t i f i c a t i o n : t e c h n o l o g y and quality c o n t r o l , 1 9 9 6 (E)

41/6

f o o d s . Fortieth m e e t i n g of t h e J o i n t F A O / W H O Expert C o m m i t t e e on Food A d d i t i v e s , 1 9 9 3 (E) Residues of s o m e v e t e r i n a r y drugs in animals and

61 62

B i o t e c h n o l o g y and f o o d s a f e t y , 1 9 9 6 (E) N u t r i t i o n e d u c a t i o n for t h e public - D i s c u s s i o n papers of t h e FAO Expert C o n s u l t a t i o n , 1 9 9 6 (E)

63 64

Street f o o d s , 1 9 9 7 (E/F/S) W o r l d w i d e regulations for m y c o t o x i n s 1 9 9 5 - A c o m p e n d i u m , 1 9 9 7 (E) Risk m a n a g e m e n t and f o o d s a f e t y , 1 9 9 7 (E)

f o o d s . F o r t y - s e c o n d m e e t i n g of the J o i n t F A O / W H O Expert C o m m i t t e e on Food A d d i t i v e s , 1 9 9 4 (E) 41/7

41/8

Residues of s o m e f o o d s . Forty-third Expert C o m m i t t e e Residues of s o m e

veterinary d r u g s in animals and m e e t i n g of t h e J o i n t F A O / W H O o n Food A d d i t i v e s , 1 9 9 4 (E) veterinary drugs in animals and

41/9

f o o d s . F o r t y - f i f t h m e e t i n g of t h e J o i n t F A O / W H O Expert C o m m i t t e e o n Food A d d i t i v e s , 1 9 9 6 (E) Residues of s o m e v e t e r i n a r y drugs in animals and f o o d s . F o r t y - s e v e n t h m e e t i n g of t h e J o i n t F A O / W H O Expert C o m m i t t e e o n Food A d d i t i v e s , 1 9 9 7 (E)

65

Availability: November 1 9 9 7 Ar

-

Arabic

C E F

-

Chinese English French

Multil

Multilingual Out of print In preparation

42 42/1

Traditional f o o d plants, 1 9 8 8 (E) Edible plants of Uganda. The value o f w i l d and

P

-

Portuguese

S

-

Spanish

43

c u l t i v a t e d plants as f o o d , 1 9 8 9 (E) Guidelines for agricultural training curricula in A r a b c o u n t r i e s , 1 9 8 8 (Ar)

44

R e v i e w of f o o d c o n s u m p t i o n s u r v e y s 1 9 8 8 ,

FAO Sales Agents

FAO. Viale delle Terme di Caracalla, 00100Rome,

45 46

1 9 8 8 (E) Exposure of i n f a n t s and children t o lead, 1 9 8 9 (E) S t r e e t f o o d s , 1 9 9 0 (E/F/S)

47/1

Utilization of t r o p i c a l f o o d s : cereals, 1 9 8 9 (E F S)

47/2 47/3 47/4

Utilization of t r o p i c a l f o o d s : roots and t u b e r s , 1 9 8 9 (E F S) Utilization of t r o p i c a l f o o d s : trees, 1 9 8 9 (E F S) Utilization o f t r o p i c a l f o o d s : tropical beans,

47/5

1 9 8 9 (E F S) Utilization of t r o p i c a l f o o d s : t r o p i c a l oil seeds, 1 9 8 9 (E F S)

47/6 47/7 47/8

Utilization of t r o p i c a l f o o d s : sugars, spices and s t i m u l a n t s , 1 9 8 9 (E F S) Utilization of t r o p i c a l f o o d s : fruits and leaves, 1 9 9 0 (E F S) Utilization of t r o p i c a l f o o d s : animal p r o d u c t s , 1 9 9 0 (E F S)

48

N u m b e r not assigned

49

JECFA s p e c i f i c a t i o n s for i d e n t i t y and purity of c e r t a i n f o o d additives, 1 9 9 0 (E)

50 51

Traditional f o o d s in the Near East, 1 9 9 1 (E) Protein quality evaluation. Report of t h e J o i n t F A O / W H O Expert C o n s u l t a t i o n , 1 9 9 1 (E F)

52/1

C o m p e n d i u m of f o o d additive s p e c i f i c a t i o n s V o l . 1, 1 9 9 3 (E) C o m p e n d i u m of f o o d additive s p e c i f i c a t i o n s -

52/2

V o l . 2 , 1 9 9 3 (E) 52 Add. 1 52 Add. 2 52 Add. 3 52 Add. 4 52 Add. 5 53 54

C o m p e n d i u m of f o o d additive A d d e n d u m 1, 1 9 9 2 (E) C o m p e n d i u m of f o o d additive A d d e n d u m 2, 1 9 9 3 (E) C o m p e n d i u m of f o o d additive A d d e n d u m 3, 1 9 9 5 (E) C o m p e n d i u m of f o o d additive A d d e n d u m 4 , 1 9 9 6 (E)

specifications specifications specifications specifications -

C o m p e n d i u m of f o o d additive s p e c i f i c a t i o n s A d d e n d u m 5, 1 9 9 7 (E) M e a t and m e a t p r o d u c t s in h u m a n n u t r i t i o n in d e v e l o p i n g c o u n t r i e s , 1 9 9 2 (E) N u m b e r not assigned

The FAO Technical Papers are available or directly

through

the

authorized

from Sales and Marketing Italy•

Group,

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ISBN 92-5-102489-8

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ISSN 0254-4725

0 2 4 8 9 8 T0432E/2/9.97/500