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FIFTH EDITION
FUNDAMENTAL FOOD
MICROBIOLOGYBibek Ray • Arun Bhunia
@CRC PressTaylor & Francis GroupBoca Raton London NewYork
CRC Press is an imprint of the
Taylor & Francis Group, an informa business
Contents
Preface to the Fifth Edition xxxv
Preface to the Fourth Edition xxxvii
Preface to the Third Edition xxxix
Preface to the Second Edition xli
Preface to the First Edition xliii
Authors xlv
SECTION I INTRODUCTION TO MICROBES IN FOODS
1 History and Development ofFood Microbiology 3
Introduction 3
Discovery of Microorganisms 3
Where Are They Coming from? 4
What Are Their Functions? 4
Development of Early Food Microbiology (Before A.D. 1900) 5
Food Microbiology: Current Status 7
Food Fermentation/Probiotics 7
Food Spoilage 8
Foodborne Diseases 8
Miscellaneous 8
Food Microbiology and Food Microbiologists 9
Conclusion 9
References 10
2 Characteristics of Predominant Microorganisms in Food 11
Introduction 11
Classification of Microorganisms 12
Nomenclature 13
Morphology and Structure of Microorganisms in Foods 14
Yeasts and Molds 14
Bacterial Cells 16
Viruses 18
Important Microorganisms in Food 18
vii
viii Contents
Important Mold Genera 18
Important Yeast Genera 19
Foodborne Protozoan Parasites 19
Important Viruses 20
Important Bacterial Genera 20
Gram-Negative Aerobes 22
Gram-Negative Facultative Anaerobes 23
Rickettsia 24
Gram-Positive Cocci 24
Gram-Positive, Endospore-Forming Rods 25
Gram-Negative, Endospore-Forming Rods 26
Gram-Positive, Nonsporulating Regular Rods 26
Gram-Positive, Non-Spore-Forming Irregular Rods 26
Some New Genera 27
Important Bacterial Groups in Foods 27
Lactic Acid Bacteria 27
Acetic Acid Bacteria 27
Propionic Acid Bacteria 27
Butyric Acid Bacteria 27
Proteolytic Bacteria 28
Lipolytic Bacteria 28
Saccharolytic Bacteria 28
Thermophilic Bacteria 28
Psychrotrophic Bacteria 28Thermoduric Bacteria 28
Halotolerant Bacteria 28
Aciduric Bacteria 28
Osmophilic Bacteria 29
Gas-Producing Bacteria 29
Slime Producers 29
Spore Formers 29Aerobes 29
Anaerobes 29
Facultative Anaerobes 29Coliforms 29Fecal Coliforms 30
Enteric Pathogens 30
Conclusion 30References 31
3 Sources of Microorganisms in Foods 33Introduction 33Predominant Microorganisms in Different Sources 34
Plants (Fruits and Vegetables) 34Animals, Birds, Fish, and Shellfish 34Air 35
Contents ix
Soil 36
Sewage and Manure 36
Water 36
Humans 37
Food Ingredients 37
Equipment 37Miscellaneous 38
Conclusion 38
References 39
4 Normal Microbiological Quality of Foods and Its Significance 41
Introduction 41
Raw and Ready-to-Eat Meat Products 41
Raw and Pasteurized Milk 42Shell Eggs and Liquid Egg 43Fish and Shellfish 44
Vegetables, Fruits, and Nuts 44
Cereal, Starches, and Gums 45Canned Foods 46
Sugars and Confectioneries 46
Soft Drinks, Fruit and Vegetable Drinks, Juices, and Bottled Water 47
Mayonnaise and Salad Dressings 47
Spices and Condiments 47Conclusion 48
References 49
SECTION II MICROBIAL GROWTH RESPONSE IN THE
FOOD ENVIRONMENT
5 Microbial Growth Characteristics 53Introduction 53Microbial Reproduction or Growth 53
Binary Fission 53
Generation Time (or Doubling Time) 54
Specific Growth Rate 55
Optimum Growth 56Growth Curve 56
Nature of Microbial Growth in Food 57
Mixed Population 57
Sequence of Growth 58Growth in Succession or Diauxic Growth 58
Symbiotic Growth 58
Synergistic Growth 59
Antagonistic Growth 59Conclusion 59References 60
x Contents
6 Factors Influencing Microbial Growth in Food 61
Introduction 61
Intrinsic Factors or Food Environment 61
Nutrients and Growth 61
Carbohydrates in Foods 62
Proteins in Foods 63
Lipids in Foods 64
Minerals and Vitamins in Foods 64
Growth Factors and Inhibitors in Food 64
Water Activity and Growth 65
Principle 65
ofFood 65
Aw and Microbial Growth 66
pH and Growth 66
Principle 66
pH of Food 66
pH and Microbial Growth 67
Redox Potential, Oxygen, and Growth 67
Principle 67
Redox Potential in Food 68
Redox Potential and Microbial Growth 68
Extrinsic Factors 69
Temperature and Growth 69
Principle 69
Food and Temperature 69
Microbial Growth and Viability 69
Quorum Sensing and Bacterial Growth 70
Conclusion 71
References 72
7 Microbial Attachments and Biofilm Formation 73
Introduction 73
Mechanisms ofAttachment 74
Influencing Factors 75
Assessment of Biofilm Formation 76
Control and Removal of Biofilms 77
Conclusion 77
References 78
8 Microbial Metabolism of Food Components 79
Introduction 79
Respiration and Fermentation During Growth 79
Metabolism of Food Carbohydrates 81
Degradation of Polysaccharides 81
Degradation of Disaccharides 82
Degradation of Monosaccharides 82
Fermentation 82
EMP Pathway 83
Contents xi
HMP Pathway 83
Entner-Doudroff (ED) Pathway 83
Pentose Phosphoketolase Pathway 84
Hexose Phosphoketolase Pathway 84
Some Specific Pathways 84
Anaerobic Respiration 85
Aerobic Respiration 85
Synthesis of Polymers 86
Metabolism of Food Proteins 86
Aerobic Respiration (Decay) 86
Fermentation (Putrefaction) 87
Metabolism of Food Lipids 88
Conclusion 88
References 89
9 Microbial Sporulation and Germination 91
Introduction 91
Mold Spores 91
Yeast Spores 92
Bacterial Spores 92
Sporulation 94
Dormancy 95
Activation 95
Germination 95
Outgrowth 95
Importance of Spores in Food 96
Conclusion 97
References 98
10 Microbial Stress Response in the Food Environment 99
Introduction 99
Stress Adaptation 100
Definition and Observations 100
Mechanisms of Stress Adaptation 101
Importance ofStress-Adapted Microorganisms in Food 101
Pathogens and Spoilage Bacteria Surviving in Low-pH Foods 102
Stress-Adapted Pathogens Surviving Stomach pH 102
Enhancing Viability of Starter Cultures and Probiotic Bacteria 103
Sublethal Stress and Injury 103
Definition and Observations 103
Manifestation of Bacterial Sublethal Injury 103
Sites and Nature of Injury 105
Repair of Reversible Injury 106
Injury in Yeasts and Molds 108
Importance ofSublethally Injured Microorganisms in Food 108
Detection of Undesirable Microorganisms 108
Enhancing Shelf Life of Foods 108
Enhancing Viability of Starter Cultures 108
xii Contents
Viable-but-Nonculturable 109
Definition and Terminologies 109
Proponent Views 109
Opponent Views Ill
Current Views 111
Physiological Properties of VBNC Cells 112
Importance ofVBNC Microorganisms in Food 112
Conclusion 112
References 114
SECTION III BENEFICIAL USES OF MICROORGANISMS IN FOOD
11 Microorganisms Used in Food Fermentation 119
Introduction 119
Microbiology of Fermented Foods 119
Lactic Starter Cultures 120
Lactococcus 121
Streptococcus 122
Leuconostoc 122
Pediococcus 122
Lactobacillus 123
Oenococcus 124
Other Starter Cultures 124
Bifidobacterium 124
Propionibacterium 125
Brevibacterium 125
Acetobacter 125
Yeasts and Molds 125
Yeasts 126
Molds 126
Conclusion 127
References 127
12 Biochemistry ofSome Beneficial Traits 129
Introduction 129
Mechanisms of Transport ofNutrients 129
Transport and Metabolism of Carbohydrates 130
PEP-PTS System for Lactose Transport in Lactococcus lactis 131
Permease System for Lactose in Lactobacillus acidophilus 131
Carbohydrates Available Inside the Cells for Metabolism 131
Homolactic Fermentation of Carbohydrates 131
Heterolactic Fermentation ofCarbohydrates 133
Metabolism ofPentoses 134
Hexose Fermentation by Bifidobacterium 135
Diacetyl Production from Citrate 135
Propionic Acid Production by Propionibacterium 136
Transport and Metabolism of Proteinaceous Compounds and Amino Acids 136
Contents xiii
Transport and Metabolism of Lipid Compounds 137
Conclusion 137
References 138
13 Genetics of Some Beneficial Traits 139
Introduction 139
Plasmids and Plasmid-Linked Traits in Starter-Culture Bacteria 139
Important Characteristics of Bacterial Plasmids 140
Some Characteristics of Small (ca. 10 kb) and Large (over 10 to ca. 150 kb)
Plasmids 140
Presence of Plasmids in Some Starter-Culture Bacteria 141
Phenotype Assignment to a Plasmid 141
Plasmid-Linked Traits in Starter-Culture Bacteria 142
Cryptic Plasmids 143
Plasmid Replication 143
Plasmid Mapping and Sequencing 143
Gene Transfer Methods in Starter-Culture Bacteria 144
Transduction 144
Conjugation 144
Transformation 145
Protoplast Fusion 145
Electrotransformation 146
Conjugative Transposons 146
Gene Cloning 146
Cloning Vectors 147
Metabolic Engineering 148
Mixed Acid Fermentation by Lactococcus lactis 148
L(+)-Lactic Acid Production 148
Diacetyl Production by Lactococcus lactis 149
Alanine Production from Carbohydrates 149
Production of Mannitol and Other Polyols 149
Production of Folic Acid and Riboflavin 149
Enhancing Proteolysis by Cell Lysis 150
Protein Targeting 150
Expression of Interleukins 150
Drug-Delivery System 151
Production of Pediocin in Heterologous Hosts 151
Protein Engineering 151
Production of Hybrid Prepediocin 151
Bioengineered Bacteriocins 152
Genome Mapping and Sequencing 152
Lactic Acid Bacteria 152
Bacteriophages 154
The Lac and Las Genes 154
Conclusion 155
References 156
xiv Contents
14 Starter Cultures and Bacteriophages 159
Introduction 159
History160
Concentrated Cultures 161
Starter-Culture Problems 162
Strain Antagonism 162
Loss of a Desired Trait 162
Cell Death and Injury 162
Inhibitors in Raw Materials 163
Bacteriophages of Lactic Acid Bacteria 163
Morphology and Characteristics 163
Life Cycle 164
Host Specificity 164
Control Methods 165
Yeast and Mold Cultures 166
Conclusion 166
References 166
15 Microbiology of Fermented Food Production 169
Introduction 169
General Method of Production 170
Raw (or Starting) Materials 170
Microorganisms Used 170
Fermentation Process 171
Natural Fermentation 171
Back Slopping 171
Controlled Fermentation 172
Fermented Dairy Products 172
Milk Composition and Quality 172
Fermented Milk Products 173
Microbiology of Cultured Buttermilk Fermentation 173
Product Characteristics 173
Processing 173
Starter (Controlled Fermentation) 174
Growth 174
Biochemistry 174
Genetics 174
Microbial Problems 175
Microbiology ofYogurt Fermentation 175
Characteristics 175
Processing 175
Starters (Controlled Fermentation) 175
Growth 176
Biochemistry 176
Genetics 178
Microbial Problems 179
Cheeses 179
Contents xv
Unripened Cheese 179
Ripened Cheese 179
Microbiology of Cottage Cheese 180
Characteristics 180
Processing (from Skim Milk) 180
Starters (Controlled Fermentation) 180
Growth, Biochemistry, and Genetics 180
Microbial Problems 180
Microbiology of Cheddar Cheese 181
Characteristics 181
Processing 181
Starters (Controlled Fermentation) 181
Growth 181
Biochemistry 181
Genetics 182
Microbial Problems 182
Microbiology of Swiss Cheese 183
Characteristics 183
Processing 183
Starters (Controlled Fermentation) 183
Growth 183
Biochemistry 183
Genetics 184
Microbial Problems 184
Microbiology of Blue Cheese 184
Characteristics 184
Processing 184
Starters and Growth (Controlled Fermentation) 184
Biochemistry, Genetics, and Problems 184
Accelerated Cheese Ripening 185
Curing at High Temperature 185
Addition of Enzymes 185
Slurry Method 185
Novel Methods 185
Fermented Meat Products 186
Types 186
Microbiology of Semidry Sausages 186
Characteristics 186
Processing 186
Starters (Controlled or Natural Fermentation) 187
Growth 187
Biochemistry 187
Genetics 187
Microbial Problems 188
Fermented Vegetable Products 188
Microbiology of Sauerkraut 189
Characteristics 189
xvi Contents
Processing 189
Starters (Natural) and Growth 189
Biochemistry 189
Genetics 190
Microbial Problems 190
Conclusion 190
References 191
16 Intestinal Bacteria and Probiotics 193
Introduction 193
Microbiology of the Human GI Tract 194
Gut Microbiota, Health, and Chronic Diseases 195
Important Characteristics of Beneficial Bacteria 196
Beneficial Effects of Probiotics 197
Lactose Hydrolysis 197
Reducing Serum Cholesterol Levels 198
Reducing Colon Cancer 198
Prevention and Control of Enteric Infections 199
Modulating Immune Response 199
Reducing Allergic Diseases 200
Bioengineered Probiotics 200
Probiotics as Vaccine Carriers for Infectious Agents 200
Some Aspects to Consider 201
Strain Variation 201
Sensitivity to Stomach Acids, Biles, and Pancreatin 202
Viability and Injury of Cells 202
Dose Level and Duration 202
Induced Lactase Trait 202
Antibacterial Substances 203
True Species and Strains 203
Expertise in Research Areas 203
Current Developments 204
Standard of Identity 204
Microorganisms Used as Probiotics 204
Safety of Probiotics 205
Probiotics, Prebiotics, and Synbiotics 206
Probiotics 206
Prebiotics 207
Synbiotics 207
Biogenics 207
Genome Sequence of Probiotic Bacteria 207
Conclusion 208
References 208
17 Food Biopreservatives ofMicrobial Origin, Bacteriocin, and Nanotechnology 211
Introduction 211
Viable Cells of Lactic Acid Bacteria (LAB) as Preservatives 211
Contents xvii
Organic Acids, Diacetyl, Hydrogen Peroxide, and Reuterine as Food Preservatives 212
Organic Acids 212
Diacetyl 213
Hydrogen Peroxide 214
Reuterine 214
Bacteriocins of Lactic Acid Bacteria as Food Preservatives 215
Bacteriocin-Producing Strains 215
Characteristics of Bacteriocins 216
Genetics and Gene Organization 220
Mode ofAction 221
Bioengineered Bacteriocin 222
Production and Purification 223
Applications 223
Encapsulation and Delivery of Bacteriocin 226
Food Packaging 226
Liposomes 227
Nanoencapsulation 227
Safety Concerns with Nanotechnology 228
Yeast Metabolites as Preservatives 228
Conclusion 228
References 229
18 Food Ingredients and Enzymes of Microbial Origin 231
Introduction 231
Microbial Proteins and Food Additives 232
Single-Cell Proteins (SCPs) 232
Amino Acids 232
Nutraceuticals and Vitamins 232
Flavor Compounds and Flavor Enhancers 233
Colors 233
Exopolysaccharides (EPS) 234
Organic Acids 234
Preservatives 234Microbial Enzymes in Food Processing 234
Enzymes Used 235
OC-Amylase, Glucoamylase, and Glucose Isomerase 236
Catalase 236
Cellulase, Hemicellulase, and Pectinase 236
Invertase 236
Lactase 236
Lipases 236
Proteases 236
Enzyme Production by Recombinant DNA Technology 237
Immobilized Enzymes 238
Adsorption on a Solid Support 238
Covalent Bonding 238
xviii Contents
Entrapping 238
Crosslinking 238
Thermostable Enzymes 239
Enzymes in Food Waste Treatment 240
Conclusion 240
References 241
SECTION IV MICROBIAL FOOD SPOILAGE
19 Important Factors in Microbial Food Spoilage 245
Introduction 245
Sequence of Events 245
Significance of Microorganisms 246
Microbial Types 246
Microbial Numbers 246
Predominant Microorganisms 247
Food Spoilage Molds 248
Food Spoilage Yeasts 248
Some Important Food Spoilage Bacteria 248
Psychrotrophic Bacteria 248
Some Important Psychrotrophic Aerobic Spoilage Bacteria 249
Some Important Psychrotrophic Facultative Anaerobic Spoilage Bacteria 249
Some Important Thermoduric Psychrotrophs 249
Thermophilic Bacteria 249
Aciduric Bacteria 249
Significance of Foods 250
Food Types 250
Food Nutrients 250
Utilization of Food Nutrients 251
Microbial Growth in Succession 252
Conclusion 253
References 253
20 Spoilage ofSpecific Food Groups 255
Introduction 255
Fresh and Ready-to-Eat Meat Products 255
Raw Meat 255
Ready-to-Eat Meat Products 257
Eggs and Egg Products 258
Shell Eggs 258
Egg Products 259
Fish, Crustaceans, and Mollusks 259
Fish 259
Crustaceans 260
Mollusks 260
Milk and Milk Products 261
Raw Milk 261
Pasteurized Milk 261
Contents xix
Concentrated Liquid Products 262
Butter 262
Vegetables and Fruits 262
Vegetables 262
Fruits 263
Soft Drinks, Fruit Juices and Preserves, and Vegetable Juices 264
Cereals and Their Products 264
Grains and Seeds 265
Refrigerated Dough 265
Breads 265
Pastas 265
Pastries 265
Liquid Sweeteners and Confectioneries 266
Mayonnaise, Salad Dressings, and Condiments 266
Fermented Foods 266
Fermented Meat Products 267
Fermented Dairy Products 267
Fermented Vegetable and Fruit Products 268
Fermented Beverages 268
Canned Foods 268
Thermophilic Spore Formers 269
Flat Sour Spoilage 270
Thermophilic Anaerobe (TA) Spoilage 270
Sulfide Stinker Spoilage 270
Spoilage Resulting from Insufficient Heating 270
Spoilage Resulting from Container Leakage 270
Conclusion 270
References 271
21 New Food Spoilage Bacteria in Refrigerated Foods 273
Microorganisms that Grow in Refrigerated Foods (Psychrotrophs) 273
Popularity of Refrigerated Foods 274
Microbiological Problems 275
Incidence ofSpoilage of Vacuum-Packaged Refrigerated Food 276
Spoilage of Unprocessed (Fresh) Beef by Clostridium Species 276
Spoilage of Roasted Beef by Clostridium Species 278
Spoilage of Pork Chops by Clostridium algidicarnis 278
Spoilage of Tofu by Clostridium Species 278
Spoilage of Unripened Soft Cheese by Leuconostoc Species 279
Spoilage of Low-Heat-Processed Meat Products by Leuconostoc Species 279
Ammonia Odor in Turkey Roll 279
Yellow Discoloration of Luncheon Meat 280
Gray Discoloration of Turkey Luncheon Meat 280
Pink Discoloration of Sliced, Chopped, and Formed Roast Beef 280
Gas Distension and Pink Discoloration of Sliced Turkey Rolls 281
Gas Distension (Bloating) of Ground Beef Chubs 281
Egg Odor in Refrigerated Fresh Chicken Meat Products 282
xx Contents
Off-Odor in Frozen Chicken Meat Product 283
Gas and Slime Development in Vacuum-Packaged Smoked Salmon Products 284
Conclusion 284
References 286
22 Food Spoilage by Microbial Enzymes 287
Introduction 287
Characteristics of Heat-Stable Enzymes ofPsychrotrophic Bacteria 288
Spoilage of Foods with Heat-Stable Microbial Enzymes 289
Pasteurized Milk 289
Ultrahigh Temperature (UHT)-Treated Milk Products 290
Cheeses 290
Cultured Dairy Products 290
Cream and Butter 290
Milk Powder 291
Spoilage of Foods by Microbial Enzymes at Low Temperatures 291
Conclusion 292
References 292
23 Indicators of Microbial Food Spoilage 295
Introduction 295
Microbiological Criteria 296
Enumeration of Colony-Forming Units (CFUs) 296
Phase-Contrast Microscopy 298
Chemical Criteria 298
Molecular Methods in Spoilage Microbe Detection 299
Assay of Heat-Stable Enzymes 299
Heat-Stable Proteinases in Milk 299
Heat-Stable Lipases in Milk 299
Conclusion 300
References 300
SECTION V MICROBIAL FOODBORNE DISEASES
24 Important Facts in Foodborne Diseases 305
Introduction 305
Epidemiological Aspects 306
Investigation of a Foodborne Disease 306
Foodborne Disease Outbreak 307
Incidence of Foodborne Disease Outbreak 307
Cost of Foodborne Diseases 308
Predominant Etiological Agents 309
Types of Microbial Foodborne Diseases 310
Intoxication 312
Infection 312
Toxico-Infection 313
Predominant Food Types Associated with Foodborne Diseases of Bacterial and
Viral Origin 313
Contents xxi
Predominant Places of Food Consumption Associated with Confirmed
Foodborne Disease Outbreaks of Bacterial and Viral Origin 313
Predominant Contributing Factors Associated with Confirmed Foodborne
Disease Outbreaks from Pathogenic Bacteria and Viruses 316
Influence of Month (ofthe Year) to Number of Foodborne Disease Outbreaks
Caused by Pathogenic Bacteria and Viruses 316
Influence of Location on Foodborne Diseases of Pathogenic Bacterial and
Viral Origin 316
Human Factors in Foodborne Disease Symptoms 317
Acceptance Quality of Food Resulting from Growth of Pathogens 317
Sequence of Events in a Foodborne Disease 317
Current Trends 318
FoodNet 318
Estimated Foodborne Illnesses 320
Conclusion 320
References 321
25 Foodborne Intoxications 323
Introduction 323
Staphylococcal Intoxication 323
Importance 323
Characteristics of Staphylococcus aureus 324
Organisms 324
Growth 324
Habitat 325
Toxins and Toxin Production 325
Disease and Symptoms 325
Food Association 326
Prevention (Reduction) of the Disease 327
Identification Methods 328
Analysis of an Outbreak 328
Botulism by Clostridium botulinum 329
Importance 329
Characteristics 329
Organisms 329
Growth 329
Habitat 329
Toxins and Toxin Production 330
Disease and Symptoms 331
Foodborne Botulism 331
Infant Botulism 331
Hidden Botulism 331
Wound Botulism 331
Inadvertent Botulism 332
Food Association 332
Prevention of Botulism 333
Identification Methods 333
xxii Contents
Analysis of a Foodborne Botulism Case 334
Conclusion 334
References 335
26 Foodborne Bacterial Infections 337
Introduction 337
Salmonella enterica 338
Importance 338
Current Nomenclature System 339
Predominant Serotypes in Salmonellosis 339
Characteristics 341
Habitat 341
Disease and Symptoms 341
Food Association 342
Prevention and Control 343
Detection Method 343
A Case Study 343
Listeria monocytogenes 344
Importance 344
Classification 345
Characteristics 345
Habitat 346
Virulence Factors 346
Disease and Symptoms 346
Febrile Gastroenteritis 346
Invasive Systemic Disease 347
Food Association 349
Prevention and Control 349
Detection Method 350
A Case Study 350
Pathogenic Escherichia coli 351
Importance 351
Enterotoxigenic Escherichia coli (ETEC) 352
Enteropathogenic Escherichia coli (EPEC) 352
Enteroinvasive Escherichia coli (EIEC) 352
Disease and Symptoms 353
Food Association 353
Prevention 353
Enteroaggregative Escherichia coli 353
Enterohemorrhagic Escherichia coli (EHEC), Shiga-Toxigenic Escherichia
co/i (STEC) 353
Gastroenteritis Resulting from EHEC/STEC 354
Characteristics 354
Toxins 354
Disease and Symptoms 354
Food Association 355
Prevention 355
Contents xxiii
Shigella Species 355
Importance 355
Characteristics 356Habitat 356
Toxins 356
Disease and Symptoms 357
Food Association 357
Prevention 358
Campylobacter Species 358
Importance 358
Characteristics 358
Habitat 359
Pathogenic Factors and Toxins 359
Disease and Symptoms 359
Food Association 360
Prevention 360
Yersinia enterocolitica 360
Importance 360
Characteristics 361
Habitat 361
Virulence Factors 361
Disease and Symptoms 362
Food Association 362
Prevention 362
Vibrio Species 362
Vibrio parahaemolyticus 363
Importance 363
Characteristics 363
Habitat 363
Virulence Factors and Toxin Production 363
Disease and Symptoms 364
Food Association 364
Prevention 364
Vibrio vulnificus 365Brucellosis 365
Streptococcal Infection 365
Q Fever 366
Conclusion 366
References 367
27 Foodborne Toxico-Infections 371
Introduction 371
Clostridium perfringens 371
Importance 371
Characteristics 372
Habitat 372
Toxins and Toxin Production 372
xxiv Contents
Disease and Symptoms 373
Food Association 373
Prevention 374
Detection Method 374
Analysis of an Outbreak 375
Bacillus cereus 375
Importance 375
Characteristics 375
Habitat 376
Toxins and Toxin Production 376
Disease and Symptoms 376
Food Association 377
Prevention 378
Detection Method 378
Vibrio cholerae 378
Importance 378
Characteristics 379
Habitat 379
Toxins and Toxin Production 379
Disease and Symptoms 380
Food Association 380
Prevention 381
Detection Method 381
Analysis of an Outbreak 381
Enterotoxigenic Escherichia coli (ETEC) 382
Importance 382
Characteristics 382
Habitat 382
Toxins and Toxin Production 382
Disease and Symptoms 383
Food Association 383
Prevention 383
Detection Methods 383
Conclusion 383
References 384
28 Opportunistic Bacterial Pathogens, Molds and Mycotoxins, Viruses, Parasites,
and Fish and Shellfish Toxins 387
Introduction 387
Opportunistic Bacterial Pathogens 387
Aeromonas hydrophila 387
Characteristics 387
Food Association 388
Disease-Causing Potential 388
Plesiomonasshigelloid.es 388
Characteristics 388
Food Association 388
Contents xxv
Disease-Causing Potential 389
Non-Escherichia coli coliforms 389
Toxigenic Physchrotrophic Bacillus Species 390
Diseases Caused by Viruses and Prion 390
Importance 390
Food Association 390
Prevention 391
Detection Methods 391
Norovirus 391
Hepatitis A Virus 392
Bovine Spongiform Encephalopathy (BSE) 392
Molds and Mycotoxins 393
Importance 393
Characteristics 394
Organisms 394
Growth and Mycotoxin Production 395
Habitat 395
Toxins and Toxin Production 395
Food Association 396
Symptoms and Prevention ofMycotoxicosis 396
Detection Methods 397
Biogenic Amines 397
Toxins Associated with Fish and Shellfish 397
Scombroid Poisoning 397
Ciguatera Fish Poisoning (CFP) 400
Paralytic Shellfish Poisoning (PSP) 400
Neurotoxic Shellfish Poisoning (NSP) 400
Diarrhetic Shellfish Poisoning (DSP) 401
Azaspiracid Shellfish Poisoning (AZP) 401
Amnesic Shellfish Poisoning (ASP) 401
Puffer Fish Poisoning (PFP) 401
Parasites 401
Trichinella spiralis 402
Anisakis simplex 402
Taenia Species 402
Toxoplasma gondii 402
Giardia lamblia 403
Cryptosporidium parvum 404
Cyclospora cayetanensis 404
Conclusion 404
References 405
29 New and Emerging Foodborne Pathogens 407
Introduction 407
Associated Factors 408
Better Knowledge of Pathogens 409
Improvement in Regulatory Actions 410
xxvi Contents
Changes in Lifestyle and Food Habits 411
New Food-Processing Technology 414
Miscellaneous Factors 414
Genetic Exchange 414
Antibiotic Resistance 415
Stress Adaptation 416
Farming Practices 416
Aging and Immunocompromised Population 416
Other Emerging Foodborne Pathogens ofConcern 416
Cronobacter sakazaki 417
Clostridium difficile 417
Escherichia coli O104:H4 418
Hepatitis E Virus 418
Nipah Virus 419
Conclusion 420
References 420
30 Indicators of Bacterial Pathogens 423
Introduction 423
Criteria for Ideal Indicators 424
Coliform Group 425
Colifbrms 425
Organisms and Sources 425
Occurrence and Significance in Food 425
Fecal Coliforms 426
Organisms and Sources 426
Occurrence and Significance in Food 426
Escherichia coli 426
Organisms and Sources 426
Occurrence and Significance in Food 427
Enterobacteriaceae Group 427
Enterococcus Group 429
Characteristics and Habitat 429
Occurrence and Significance in Food 429
Miscellaneous Indicator Organisms 429
Conclusion 430
References 431
SECTION VI CONTROL OF MICROORGANISMS IN FOODS
31 Control ofAccess of Microorganisms: Cleaning, Sanitation, and Disinfection 435
Introduction 435
Objectives of Sanitation 436
Factors to Consider 436
Plant Design 436
Quality of Water, Ice, Brine, and Curing Solution 436
Quality ofAir 437
Contents xxvii
Training of Personnel 437
Equipment 437
Cleaning of Processing Facilities 437
Sanitation of Food-Processing Equipment 438
Chlorine-Based Sanitizers 439
Iodophores 439
Quaternary Ammonium Compounds 439
H202 440
Decontamination and Sanitization of Fruits and Vegetables 440
Chlorine 441
Ozone 441
Microbiological Standards, Specifications, and Guidelines 442
Conclusion 442
References 443
32 Control by Physical Removal 445
Introduction 445
Physical Methods 445
Centrifugation 445
Filtration 445
Trimming 446
Washing 446
Conclusion 447
References 447
33 Control by Heat (Thermal Processing) 449
Introduction 449
Objectives 450
Mechanism of Thermal Inactivation 450
Influencing Factors 451
Nature of Food 451
Nature of Microorganisms 451
Nature of Process 452
Mathematical Expressions 452
Decimal Reduction Time (D Value) 452
Thermal Death Time (TDT), Z Value, and FValue 453
Methods 454
Low-Heat Processing or Pasteurization 454
High-Heat-Processed Foods 455
Microwave Heating 456
Conclusion 457
References 457
34 Control by Low Temperature 459
Introduction 459
Objectives 460
Mechanisms of Cold-Induced Inactivation 460
Influencing Factors 461
xxviii Contents
Nature of Process 461
Nature of Food 462
Nature of Microorganisms 463
Methods 463
Ice Chilling 463
Refrigeration 463
Freezing 464
Conclusion 464
References 465
35 Control by Reduced Water Activity and Drying 467Introduction 467
Objectives 467Mechanism ofAction 468
Influencing Factors 468
Nature of Process 468Nature of Foods 469Nature of Microorganisms 469
Methods 471
Natural Dehydration 471
Mechanical Drying 471Freeze Drying 472Foam Drying 473
Smoking 473Intermediate Moisture Foods 473
Conclusion 473
References 474
36 Control by Low pH and Organic Acids 475Introduction 475
Objectives 476Mechanisms ofAntimicrobial Action 476
Influencing Factors 477
Nature of Acids 477Nature of Foods 478Nature of Microorganisms 478
Acids Used 478Acetic Acid 478
Propionic Acid 478
Lactic Acid 480
Citric Acid 480
Sorbic Acid 480
Benzoic Acid 480
Parabens (Esters of p-Hydroxybenzoic Acid) 481
Conclusion 481
References 482
Contents xxix
37 Control by Modified Atmosphere (or Reducing O-R Potential) 483
Introduction 483
Objectives 485
Mechanism ofAction 485
Influencing Factors 485
Nature ofProcess 485
Nature ofFoods 486
Nature ofMicroorganisms 486
Methods 486
Vacuum Packaging 486
Gas Flushing 487
Conclusion 487
References 487
38 Control by Antimicrobial Preservatives and Bacteriophages 489
Introduction 489
Objectives 490
Influencing Factors 490
Examples of Antimicrobial Preservatives 491
Food-Grade Chemicals 492
Nitrates and Nitrites 492
Sulfur Dioxide (S02) and Sulfites (S03) 493
H202 493
Epoxides (Ethylene Oxide, Propylene Oxide) 494
Organic Acids 494
Parabens 494
Diacetyl 494
C02 494
Butylated Hydroxyanisol (BHA), Butylated Hydroxytoluene (BHT), and
t-Butyl Hydroquinone (TBHQ) 494
Monolaurin (Glycerol Monolaurate) 494
Ethylene-Diamine-Tetraacetate (EDTA) 495
Antimicrobials of Microbial Origin 495
Bacteriocins of Lactic Acid Bacteria 495
Natamycin 495
Tylosin 495
Polylysine 496
Antimicrobials ofAnimal Origin 496
Chitosan 496
Lysozyme 496
Lactoferrin 496
Lactoperoxidase 497
Ovotransferrin 497
Protamine 497
Pleurocidin 497
Defensins 497
Antimicrobials of Plant Origin 497
xxx Contents
Herbs and Spices 497
Wood Smoke 499
Bacteriophages 499
Bacteriophages to Control Pathogens in Food 500
Conclusion 502
References 502
39 Control by Irradiation 505
Introduction 505
Irradiation (Radiation) and Radioactivity 505
Use of Irradiation in Food 506
Objectives 506
Mechanisms ofAntimicrobial Action 507
Influencing Factors 507
Nature of Process 507
Nature of Foods 508
Nature of Microorganisms 508
Methods 508
Doses 508
Specific Terms 509
Radurization 509
Radicidation 509
Radappertization 509
Current Recommendations 509
UV Radiation 511
Conclusion 511
References 512
40 Control by Novel Processing Technologies 513
Introduction 513
Summary of Processing Methods 514
Microwave and Radio-Frequency Processing 514
Ohmic and Inductive Heating 514
Infrared Heating 514
Pulsed Electric Fields 514
High-Pressure Processing 515
Pulsed Light Technology 515
Oscillating Magnetic Fields 515
Ultrasound 515
High-Voltage Arc Discharge 516
Pulsed X-Rays 516
Plasma Technology 516
Pulsed Electric Field 516
Hydrostatic Pressure Processing 518
History 518
Methods, Mechanisms of Microbial Inactivation, and Advantages 518
Destruction of Microbial Cells 520
Contents xxxi
Bacterial Cells 520
Bacterial Endospores 520
Molds, Yeasts, Viruses, and Parasites 521
Application in Food Processing 521
Conclusion 524
References 524
41 Control by a Combination ofMethods (Hurdle Concept) 527
Introduction 527
Mechanisms ofAntimicrobial Action 527
Current Status 529
Low-Heat Processing 529
Low Storage Temperature 529
LowpH 529
LowiV 529
Modified Atmosphere 530
Preservatives 530
Hydrostatic Pressure Processing (HPP) 530
Conclusion 530
References 531
SECTION VII MICROBIAL DETECTION AND FOOD SAFETY
42 Conventional, Immunological, Molecular, and Biosensor-Based Detection
Methods 535
Introduction 535
Methods Used 536
Standard and Recommended Methods 536
Sampling for Microbial Analysis 537
Sample and Sampling Plan 537
Sampling Procedure 538
Quantitative Methods for Microbial Enumeration in Foods 538
Direct Enumeration 538
Microscopic Counts 538
Colony-Forming Units (CFU) in Nonselective Agar Media 538
CFU in Nonselective Differential Chromogenic Media 539
CFU in Selective Agar Media 539
CFU in Selective-Differential Chromogenic Agar Media 539
Indirect Estimation 541
Dilution to Extinction in Nonselective Broths 541
Most Probable Number (MPN) in Selective Broth 541
Dye Reduction Test 541
Enumeration of Injured Microbial Groups by Selective Media 541
Dilution Scheme, Plating, Incubation, Selection of Plates for Counting CFU,and Reporting Results 542
Qualitative Methods to Isolate Microorganisms in Foods 542
Isolation of Pathogens 542
xxxii Contents
Test for Bacterial Toxins in Foods 542
Rapid Methods and Automation 543
Metabolic Fingerprinting 543
Immunoassays for Rapid Detection of Pathogens 544
Immunomagnetic Separation (IMS) 544
Reverse Passive Latex Agglutination (RPLA) Method 545
Enzyme-Linked Immunosorbent Assay (ELISA) 546
Immunofluorescence Assay 547
Immunochromatographic Lateral Flow Assay 547
Flow Cytometry 548
Bacteriophage for Detection of Pathogens 548
Culture or Staining Methods 548
Reporter Phages 548
Phages for Capture and Detection Using Biosensors 549
Bioluminescence Methods 549
Nucleic Acid-Based Methods 549
Hybridization Method 549
Polymerase Chain Reaction (PCR) 550
DNA Fingerprinting 551
Whole Genome Sequencing 552
Microarrays and Mass-Spectrometry 552
Pathogenicity Assay 553
Biosensors for Pathogen Detection 553
Fiber-Optic Biosensors 554
Surface Plasmon Resonance Sensor 555
Electrochemical Immunosensor 556
Piezoelectric (PZ) Biosensor 556
Impedance-Based Biochip Sensor 556
Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy 557
Light Scattering 558
Cell-Based Sensors 558
Conclusion 559
References 560
Appendix A: Predictive Modeling of Microbial Growth in Food 563
Importance 563
Traditional Methods 564
Challenge Studies 564
Storage Studies 564
Accelerated Shelf Life Studies 564
Predictive Microbiology 564
Square Root Model 565
Sigmoidal Model (Gompertz: USDA Model) 565
Conclusion 565
References 566
Contents xxxiii
Appendix B: Regulatory Agencies Monitoring Microbiological Safety ofFoods in the
United States 567Food Safety Regulations 567
The Agencies 568
Federal Agencies 568
State and Local Government Agencies 569
International Agencies 570
References 570
Appendix C: Hazard Analysis Critical Control Points 571
Introduction 571
HACCP Principle of the NACMCF 572
Seven Principles of HACCP 572
Brief Description of the Principles 572
Principle 1 572
Principle 2 573
Principle 3 573
Principle 4 573
Principle 5 574
Principle 6 574
Principle 7 574Conclusion 574
References 575
Index 577
