Table Of ContentMicroFacts - 2010 master copy 21 06 10_MicroFacts.qxd 07/07/2010 15:43 Page i
MICRO-FACTS
Seventh Edition
Revised by
Peter Wareing, Felicity Stuart and Rhea Fernandes
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This edition first published 2010 by
Leatherhead Publishing
a division of
Leatherhead Food International Ltd
Randalls Road, Leatherhead, Surrey KT22 7RY, UK
URL: http://www.leatherheadfood.com
and
Royal Society of Chemistry
Thomas Graham House, Science Park, Milton Road,
Cambridge, CB4 0WF, UK
URL: http://www.rsc.org
Registered Charity No. 207890
ISBN: 978-1-905224-84-5
A catalogue record of this book is available from the British Library
© 2010 Leatherhead Food International Ltd
The contents of this publication are copyright and reproduction in whole, or in part, is not
permitted without the written consent of the Chief Executive of Leatherhead Food International
Limited.
Leatherhead Food International Limited uses every possible care in compiling, preparing and
issuing the information herein given but accepts no liability whatsoever in connection with it.
All rights reserved Apart from any fair dealing for the purposes of research or private study, or criticism or
review as permitted under the terms of the UK Copyright, Designs and Patents Act, 1988, this publication
may not be reproduced, stored or transmitted, in any form or by any means, without the prior permission in
writing of the Chief Executive of Leatherhead Food International Ltd, or in the case of reprographic
reproduction only in accordance with the terms of the licences issued by the Copyright Licencing Agency in
the UK, or in accordance with the terms of the licences issued by the appropriate Reproduction Rights
Organisation outside the UK. Enquiries concerning reproduction outside the terms stated here should be sent
to Leatherhead Food International Ltd at the address printed on this page.
Typeset by Alison Turner and Jackie Apps, index by Ann Pernet, cover design by
Paul Homewood
Printed and bound by Henry Ling
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FOREWORD
The previous six editions of ‘Micro-Facts’ have proved a useful ready
reference for all those who are concerned with food safety. In this seventh
edition, we have extensively updated the book with some sections
significantly expanded, and some new chapters. We have also updated the
book for currency of information. Our emphasis continues to be to serve the
needs of the food industry, whether a manufacturer, retailer or caterer.
Key changes in the seventh edition are the inclusion of a new chapter on
factors affecting microbial growth and a glossary of microbial terms. The
bacterial pathogens chapter now includes a section on rapid methods. The
chapter on moulds and mycotoxins, and yeasts and moulds as spoilage
organisms which was new for the sixth edition, has been extensively
expanded, with 28 additional key mould species, and 12 key yeast species.
In many cases, product recalls are initiated by excessive growth of spoilage
organisms, not foodborne pathogens; it is important to be aware of these
organisms.
Acknowledgements
Micro-Facts has a long history of writing and review, originally compiled
and revised by Aynsley Halligan, with the help of many experts in food
microbiology, from industry, research institutions, and government. Their
contribution to these editions is gratefully acknowledged. In the production
of this seventh edition of the book we are indebted to Joanna Pajor and
Cristina Losada-Rodriguez, who have provided valuable assistance with the
updating. I would also like to thank Victoria Emerton for her careful editing,
Alison Turner and Jackie Apps for typesetting the manuscript and Ann
Pernet for the indexing.
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CONTENTS
FOREWORD iii
FACTORS AFFECTING THE GROWTH OF MICRO-ORGANISMS IN FOODS 1
Intrinsic Factors 2
Extrinsic Factors 5
Hurdle Concept 6
FOODBORNE BACTERIAL PATHOGENS 8
Introduction 9
Food Poisoning - a Brief Overview 9
Methods for Detecting/Counting Foodborne Pathogens in Foods 16
Rapid Methods for Detection/Enumeration of Foodborne Pathogens 17
Biochemical (Enzymatic) Methods 17
Metabolism Methods 17
Immunological Methods 18
Molecular Methods 19
Flow Cytometry 20
ATP Methods 20
Colilert and Colisure 20
Biosensors 21
Biochips 21
Bibliography 21
A Few Words about the Bibliographies 26
Bacillus cereus 27
The Organism B. cereus 27
B.cereus Food Poisoning 27
Incidence of B. cereus Food Poisoning 29
Sources 30
Growth/Survival Characteristics of the Organism in Foods 30
Summary of Control of B.cereus in Foods 32
Other BacillusSpecies 32
Bibliography 33
Campylobacter 38
The Organism Campylobacter 38
Campylobacter Enteritis 39
Incidence of Campylobacter Food Poisoning 40
Sources 42
Growth/Survival Characteristics of the Organism in Foods 44
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Summary of Control of Campylobacter in Foods 46
Bibliography 46
Clostridium botulinum 52
The Organism C. botulinum 52
C. botulinum Food Poisoning 53
Incidence of C. botulinum Food Poisoning 55
Sources 56
Growth/Survival Characteristics of the Organism in Foods 57
Summary of Control of C. botulinum in Foods 61
Infant Botulism 62
Bibliography 63
Clostridium perfringens 69
The Organism C. perfringens 69
C. perfringens Food Poisoning 69
Incidence of C. perfringens Food Poisoning 71
Sources 72
Growth/Survival Characteristics of the Organism in Foods 73
Summary of Control of C. perfringens in Foods 74
Bibliography 75
Cronobacter sakazakii 79
The Organism C. sakazakii 79
C. sakazakii Food Poisoning 79
Incidence of C. sakazakii Food Poisoning 81
Sources 81
Growth/Survival Characteristics of the Organism in Foods 82
Control of C. sakazakii in Foods 84
Bibliography 84
Listeria monocytogenes 89
The Organism L. monocytogenes 89
L. monocytogenes Food Poisoning 90
Incidence of L. monocytogenes Food Poisoning 92
Sources 92
Growth/Survival Characteristics of the Organism in Foods 94
Summary of Control of L. monocytogenes in Foods 96
Bibliography 97
Salmonella 104
The Organism Salmonella 104
Salmonella Food Poisoning 105
Incidence of Salmonella Food Poisoning 107
Sources 109
Growth/Survival Characteristics of the Organism in Foods 110
Summary of Control of Salmonella in Foods 113
Bibliography 114
Staphylococcus aureus 121
The Organism Staph. aureus 121
Staph. aureus Food Poisoning 122
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Incidence of Staph. aureus Food Poisoning 124
Sources 124
Growth/Survival Characteristics of the Organism in Foods 125
Summary of Control of Staph. aureus in Foods 127
Bibliography 128
Vibrio 135
The Organism V. parahaemolyticus 135
V. parahaemolyticus Food Poisoning 135
Incidence of V. parahaemolyticus Food Poisoning 137
Sources 138
Growth/Survival Characteristics of the Organism in Foods 138
Summary of Control of V. parahaemolyticus in Foods 140
The Organism V. cholerae 140
V. cholerae Illness 140
Incidence of V. cholerae Food Poisoning 141
Sources 141
Growth/Survival Characteristics of the Organism in Foods 142
The Organism V. vulnificus 143
V. vulnificus Food Poisoning 143
Sources 144
Growth/Survival Characteristics of the Organism in Foods 144
Bibliography 145
VTEC (Escherichia coli) 151
The Organism VTEC 152
Verotoxigenic E. coli Food Poisoning 152
Incidence of VTEC Food Poisoning 155
Sources 156
Growth/Survival Characteristics of the Organism in Foods 157
Summary of Control of VTEC in Foods 159
Bibliography 159
Yersinia enterocolitica 166
The Organism Yersinia enterocolitica 166
Yersinia Food Poisoning 167
Incidence of Yersinia Food Poisoning 168
Sources 169
Growth/Survival Characteristics of the Organism in Foods 170
Summary of Control of Yersinia enterocolitica in Foods 171
Bibliography 172
Other Bacteria that may be Foodborne and have Health Implications 177
Shigella 178
Aeromonas 179
Plesiomonas shigelloides 181
Pseudomonas aeruginosa 182
Other Members of the Enterobacteriaceae 182
Streptococci/Enterococci 183
Mycobacterium paratuberculosis 185
Bibliography 186
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FOODBORNE VIRUSES AND PROTOZOA 193
Viruses 194
Protozoa 198
Cryptosporidium 199
Giardia 203
Other protozoa 206
Bibliography 209
FOOD-SPOILAGE BACTERIA 216
Introduction 217
Acetic acid bacteria 220
Acinetobacter 223
Alicyclobacillus 226
Bacillus 229
Brochothrix 233
Clostridium 236
Enterococcus 240
Flavobacterium 243
Hafnia 246
Lactobacillus 248
Leuconostoc 252
Micrococcus 255
Moraxella 258
Photobacterium 261
Proteus 263
Pseudomonas 265
Psychrobacter 269
Serratia 271
Shewanella 273
Sporolactobacillus 276
Other Bacteria 278
Bibliography 282
FOOD-SPOILAGE FUNGI 286
Moulds and Mycotoxins in Foods 287
Mycotoxins 291
Aflatoxins 292
Ochratoxin A 293
Patulin 294
Fumonisins 294
Trichothecenes 295
Zearalenone 297
Foodborne Moulds 297
Alternaria 298
Aspergillus 300
Byssochlamys 305
Chaetomium 306
Chrysosporium 307
Cladosporium 308
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Curvularia 309
Emericella 310
Eupenicillium 310
Eurotium 311
Fusarium 314
Geotrichum 319
Moniliella 320
Mucor 320
Paecilomyces 321
Penicillium 322
Phoma 329
Rhizopus 329
Talaromyces 330
Trichoderma 331
Wallemia 332
Xeromyces 333
Bibliography 334
Other spoilage moulds 340
Food Spoilage Yeasts 341
Introduction 342
Aureobasidium 344
Candida 345
Cryptococcus 347
Debaryomyces 348
Dekkera 350
Hanseniaspora 352
Issatchenkia 354
Kluyveromyces 355
Pichia 357
Rhodotorula 359
Saccharomyces 360
Schizosaccharomyces 362
Zygosaccharomyces 363
Bibliography 365
HACCP 369
EC FOOD HYGIENE LEGISLATION 379
SUPPLIERS 399
Laboratory media suppliers 400
Culture Collections 402
Kit/Instrument Suppliers 403
ADDRESSES OF AUTHORITIES/SOURCES OF FURTHER INFORMATION 410
INTERNET 415
GLOSSARY OF TERMS 419
INDEX 429
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FACTORS AFFECTING THE GROWTH OF
MICRO-ORGANISMS IN FOODS
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FACTORS AFFECTING THE GROWH OF
MICRO-ORGANISMS IN FOODS
Several factors related to the environment and the conditions in which food
is stored influence the growth of micro-organisms in food. These factors can
be divided into intrinsic and extrinsic elements. Growth is possible over a
wider range of temperatures than that of toxin production. For example,
Aspergillus flavus can grow from 10 - 12 °C to 43 - 48 °C, whereas
aflatoxins are produced from 13 - 15 °C up to 37 °C. The minimum water
activity (a ) for A. flavus is 0.78 - 0.80, but aflatoxins are produced above
w
a 0.82 - 0.83
w
Some organisms have the ability to produce spores when exposed to
conditions outside their typical growth range. These organisms pose
difficulties for the food industry as the spores are more resistant to the
intrinsic and extrinsic factors that are lethal to vegetative cells. Unless a
factor or treatment is targeted at destruction of the spores, they can survive
in the product, and when the environmental conditions return to suitable
levels, the spores are able to germinate and grow.
The issue is compounded by the fact that spores sometimes germinate
earlier than would be expected as a result of heat shock if they are exposed
to temperatures outside their growth range but less than their lethal limit, and
can make the spores more resistant to other factors than normal. It is for this
reason that foods which are subject to contamination with spore-forming
organisms are often subjected to high temperature processing.
INTRINSIC FACTORS
The inherent physical, chemical and biological properties of the food, such
as pH, redox potential, water activity and the presence of antimicrobial
substances have the capacity to either stimulate or retard the growth of
micro-organisms. Some intrinsic factors are interlinked with some extrinsic
factors. For example, water activity rises with increasing temperature; there
is an increase in water activity of 0.03 with a 10 °C rise in temperature.
2
