Fundamental Food Microbiology

Food Microbiology
 
Author:
Bibek Ray & Arun Bhunia
Publisher: CRC Press
ISBN No: 978-1-4665-6444-2
Release at: 2014
Pages: 626
Edition:
Fifth Edition
File Size: 6 MB
File Type: pdf
Language: English



Content of Fundamental Food Microbiology



Section I INTRODUCTION TO MICROBES IN FOODS

1 History and Development of Food 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 Cells16

Viruses.18

Important Microorganisms in Food18

Important Mold Genera 18

Important Yeast Genera.19

Foodborne Protozoan Parasites19


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  28

Thermoduric Bacteria . 28

Halotolerant Bacteria 28

Aciduric Bacteria  28

Osmophilic Bacteria . 29

Gas-Producing Bacteria  29

Slime Producers 29


Spore Formers. 29

Aerobes. 29

Anaerobes. 29

Facultative Anaerobes. 29

Coliforms . 29

Fecal Coliforms  30

Enteric Pathogens . 30

Conclusion. 30

References.31

3 Sources of Microorganisms in Foods .33

Introduction .33

Predominant Microorganisms in Different Sources . 34

Plants (Fruits and Vegetables). 34

Animals, Birds, Fish, and Shellfish . 34

Air .35

Soil . 36

Sewage and Manure 36

Water 36

Humans 37

Food Ingredients. 37

Equipment 37

Miscellaneous. 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 . 42

Shell Eggs and Liquid Egg . 43

Fish and Shellfish. 44

Vegetables, Fruits, and Nuts  44

Cereal, Starches, and Gums45

Canned 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.47

Conclusion. 48

References 49

Section II MICROBIAL GROWTH RESPONSE IN THE FOOD ENVIRONMENT

5 Microbial Growth Characteristics53

Introduction .53

Microbial Reproduction or Growth 53

Binary Fission53

Generation Time (or Doubling Time)  54

Specific Growth Rate.55

Optimum Growth 56

Growth Curve 56

Nature of Microbial Growth in Food .57

Mixed Population57

Sequence of Growth . 58

Growth in Succession or Diauxic Growth  58

Symbiotic Growth  58

Synergistic Growth 59

Antagonistic Growth .59

Conclusion59

References 60

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

AW of Food65

AW and Microbial Growth . 66

pH and Growth 66

Principle 66

pH of Food 66

pH and Microbial Growth .67

Redox Potential, Oxygen, and Growth67

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 of Attachment74

Influencing Factors  75

Assessment of Biofilm Formation76

Control and Removal of Biofilms  77

Conclusion. 77

References 78

8 Microbial Metabolism of Food Components79

Introduction  79

Respiration and Fermentation During Growth 79

Metabolism of Food Carbohydrates81

Degradation of Polysaccharides.81

Degradation of Disaccharides. 82

Degradation of Monosaccharides 82

Fermentation  82

EMP Pathway 83

HMP Pathway. 83

Entner-Doudroff (ED) Pathway. 83

Pentose Phosphoketolase Pathway 84

Hexose Phosphoketolase Pathway  84

Some Specific Pathways. 84

Anaerobic Respiration85

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 Spores91

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 of Stress-Adapted Microorganisms in Food 101

Pathogens and Spoilage Bacteria Surviving in Low-pH Foods102

Stress-Adapted Pathogens Surviving Stomach pH 102

Enhancing Viability of Starter Cultures and Probiotic Bacteria103

Sublethal Stress and Injury .103

Definition and Observations103

Manifestation of Bacterial Sublethal Injury .103

Sites and Nature of Injury105

Repair of Reversible Injury 106

Injury in Yeasts and Molds 108

Importance of Sublethally Injured Microorganisms in Food .108

Detection of Undesirable Microorganisms108

Enhancing Shelf Life of Foods108

Enhancing Viability of Starter Cultures .108

Viable-but-Nonculturable.109

Definition and Terminologies109

Proponent Views109

Opponent Views111

Current Views111

Physiological Properties of VBNC Cells 112

Importance of VBNC Microorganisms in Food 112

Conclusion112

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 of Some Beneficial Traits129

Introduction .129

Mechanisms of Transport of Nutrients.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 Metabolism131

Homolactic Fermentation of Carbohydrates131

Heterolactic Fermentation of Carbohydrates .133

Metabolism of Pentoses  134

Hexose Fermentation by Bifidobacterium.135

Diacetyl Production from Citrate135

Propionic Acid Production by Propionibacterium 136

Transport and Metabolism of Proteinaceous Compounds and Amino Acids. 136

Transport and Metabolism of Lipid Compounds137

Conclusion137

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 Bacteria141

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 Bacteria144

Transduction .144

Conjugation.144

Transformation145

Protoplast Fusion.145

Electrotransformation146

Conjugative Transposons.146

Gene Cloning .146

Cloning Vectors.147

Metabolic Engineering 148

Mixed Acid Fermentation by Lactococcus lactis .148

l(+)-Lactic Acid Production148

Diacetyl Production by Lactococcus lactis 149

Alanine Production from Carbohydrates149

Production of Mannitol and Other Polyols.149

Production of Folic Acid and Riboflavin.149

Enhancing Proteolysis by Cell Lysis150

Protein Targeting.150

Expression of Interleukins 150

Drug-Delivery System 151

Production of Pediocin in Heterologous Hosts.151

Protein Engineering.151

Production of Hybrid Prepediocin151

Bioengineered Bacteriocins.152

Genome Mapping and Sequencing .152

Lactic Acid Bacteria .152

Bacteriophages.154

The Lac and Las Genes 154

Conclusion155

References.156

14 Starter Cultures and Bacteriophages159

Introduction .159

History .160

Concentrated Cultures161

Starter-Culture Problems162

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 Methods165

Yeast and Mold Cultures.166

Conclusion166

References.166

15 Microbiology of Fermented Food Production169

Introduction .169

General Method of Production.170

Raw (or Starting) Materials .170

Microorganisms Used170

Fermentation Process.171

Natural Fermentation.171

Back Slopping.171

Controlled Fermentation 172

Fermented Dairy Products172

Milk Composition and Quality .172

Fermented Milk Products173

Microbiology of Cultured Buttermilk Fermentation173

Product Characteristics.173

Processing.173

Starter (Controlled Fermentation) 174

Growth.174

Biochemistry 174

Genetics174

Microbial Problems 175

Microbiology of Yogurt Fermentation175

Characteristics175

Processing.175

Starters (Controlled Fermentation).175

Growth.176

Biochemistry 176

Genetics178

Microbial Problems 179

Cheeses179

Unripened Cheese 179

Ripened Cheese179

Microbiology of Cottage Cheese180

Characteristics180

Processing (from Skim Milk)180

Starters (Controlled Fermentation).180

Growth, Biochemistry, and Genetics180

Microbial Problems 180

Microbiology of Cheddar Cheese.181

Characteristics181

Processing.181

Starters (Controlled Fermentation).181

Growth.181

Biochemistry 181

Genetics182

Microbial Problems 182

Microbiology of Swiss Cheese183

Characteristics183

Processing.183

Starters (Controlled Fermentation).183

Growth.183

Biochemistry 183

Genetics184

Microbial Problems 184

Microbiology of Blue Cheese.184

Characteristics184

Processing.184

Starters and Growth (Controlled Fermentation).184

Biochemistry, Genetics, and Problems184

Accelerated Cheese Ripening.185

Curing at High Temperature185

Addition of Enzymes185

Slurry Method185

Novel Methods.185

Fermented Meat Products.186

Types.186

Microbiology of Semidry Sausages.186

Characteristics186

Processing.186

Starters (Controlled or Natural Fermentation)187

Growth.187

Biochemistry 187

Genetics187

Microbial Problems 188

Fermented Vegetable Products188

Microbiology of Sauerkraut .189

Characteristics189

Processing.189

Starters (Natural) and Growth .189

Biochemistry 189

Genetics190

Microbial Problems 190

Conclusion190

References.191

16 Intestinal Bacteria and Probiotics193

Introduction .193

Microbiology of the Human GI Tract.194

Gut Microbiota, Health, and Chronic Diseases195

Important Characteristics of Beneficial Bacteria .196

Beneficial Effects of Probiotics197

Lactose Hydrolysis.197

Reducing Serum Cholesterol Levels.198

Reducing Colon Cancer 198

Prevention and Control of Enteric Infections.199

Modulating Immune Response199

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 of Microbial Origin, Bacteriocin, and Nanotechnology 211

Introduction .211

Viable Cells of Lactic Acid Bacteria (LAB) as Preservatives.211

Organic Acids, Diacetyl, Hydrogen Peroxide, and Reuterine as Food Preservatives212

Organic Acids212

Diacetyl .213

Hydrogen Peroxide214

Reuterine.214

Bacteriocins of Lactic Acid Bacteria as Food Preservatives215

Bacteriocin-Producing Strains .215

Characteristics of Bacteriocins.216

Genetics and Gene Organization 220

Mode of Action221

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 Origin231

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

Colors233

Exopolysaccharides (EPS). 234

Organic Acids. 234

Preservatives . 234

Microbial Enzymes in Food Processing . 234

Enzymes Used .235

α-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

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 Events245

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 Bacteria249

Aciduric Bacteria .249

Significance of Foods250

Food Types250

Food Nutrients 250

Utilization of Food Nutrients 251

Microbial Growth in Succession252

Conclusion253

References.253

20 Spoilage of Specific Food Groups.255

Introduction .255

Fresh and Ready-to-Eat Meat Products.255

Raw Meat 255

Ready-to-Eat Meat Products257

Eggs and Egg Products .258

Shell Eggs 258

Egg Products .259

Fish, Crustaceans, and Mollusks.259

Fish259

Crustaceans  260

Mollusks. 260

Milk and Milk Products .261

Raw Milk 261

Pasteurized Milk261

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

Breads265

Pastas.265

Pastries.265

Liquid Sweeteners and Confectioneries 266

Mayonnaise, Salad Dressings, and Condiments. 266

Fermented Foods . 266

Fermented Meat Products267

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 Spoilage270

Spoilage Resulting from Insufficient Heating 270

Spoilage Resulting from Container Leakage270

Conclusion270

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 of Spoilage 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 Rolls281

Gas Distension (Bloating) of Ground Beef Chubs.281

Egg Odor in Refrigerated Fresh Chicken Meat Products 282

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 of Psychrotrophic 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 Powder291

Spoilage of Foods by Microbial Enzymes at Low Temperatures291

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

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 (of the 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 aureus324

Organisms324

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

Importance329

Characteristics.329

Organisms329

Growth.329

Habitat .329

Toxins and Toxin Production . 330

Disease and Symptoms 331

Foodborne Botulism.331

Infant Botulism331

Hidden Botulism331

Wound Botulism331

Inadvertent Botulism332

Food Association .332

Prevention of Botulism333

Identification Methods 333

Analysis of a Foodborne Botulism Case 334

Conclusion. 334

References.335

26 Foodborne Bacterial Infections337

Introduction .337

Salmonella enterica 338

Importance338

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

Importance351

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

coli (STEC).353

Gastroenteritis Resulting from EHEC/STEC354

Characteristics354

Toxins.354

Disease and Symptoms.354

Food Association 355

Prevention 355

Shigella Species355

Importance355

Characteristics356

Habitat .356

Toxins.356

Disease and Symptoms.357

Food Association 357

Prevention 358

Campylobacter Species.358

Importance358

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 .365

Brucellosis365

Streptococcal Infection365

Q Fever. 366

Conclusion. 366

References.367

27 Foodborne Toxico-Infections.371

Introduction .371

Clostridium perfringens371

Importance371

Characteristics.372

Habitat 372

Toxins and Toxin Production 372

Disease and Symptoms 373

Food Association .373

Prevention374

Detection Method .374

Analysis of an Outbreak 375

Bacillus cereus375

Importance375

Characteristics.375

Habitat 376

Toxins and Toxin Production 376

Disease and Symptoms 376

Food Association  377

Prevention378

Detection Method .378

Vibrio cholerae.378

Importance378

Characteristics.379

Habitat 379

Toxins and Toxin Production 379

Disease and Symptoms . 380

Food Association  380

Prevention381

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

Plesiomonas shigelloides  388

Characteristics. 388

Food Association . 388

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

Prevention391

Detection Methods391

Norovirus.391

Hepatitis A Virus.392

Bovine Spongiform Encephalopathy (BSE) .392

Molds and Mycotoxins .393

Importance393

Characteristics 394

Organisms. 394

Growth and Mycotoxin Production395

Habitat .395

Toxins and Toxin Production 395

Food Association  396

Symptoms and Prevention of Mycotoxicosis. 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

Parasites401

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 Actions410

Changes in Lifestyle and Food Habits.411

New Food-Processing Technology.414

Miscellaneous Factors.414

Genetic Exchange414

Antibiotic Resistance.415

Stress Adaptation.416

Farming Practices416

Aging and Immunocompromised Population416

Other Emerging Foodborne Pathogens of Concern 416

Cronobacter sakazaki417

Clostridium difficile417

Escherichia coli O104:H4418

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

Coliforms . 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 of Access 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 of Air. 437

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

H2O2 . 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 F Value453

Methods .454

Low-Heat Processing or Pasteurization454

High-Heat-Processed Foods.455

Microwave Heating .456

Conclusion457

References.457

34 Control by Low Temperature .459

Introduction .459

Objectives 460

Mechanisms of Cold-Induced Inactivation  460

Influencing Factors .461

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 Drying467

Introduction  467

Objectives 467

Mechanism of Action. 468

Influencing Factors  468

Nature of Process 468

Nature of Foods 469

Nature of Microorganisms 469

Methods .471

Natural Dehydration .471

Mechanical Drying471

Freeze Drying 472

Foam Drying.473

Smoking 473

Intermediate Moisture Foods.473

Conclusion473

References.474

36 Control by Low pH and Organic Acids475

Introduction .475

Objectives.476

Mechanisms of Antimicrobial Action .476

Influencing Factors  477

Nature of Acids. 477

Nature of Foods.478

Nature of Microorganisms.478

Acids Used478

Acetic Acid 478

Propionic Acid .478

Lactic Acid 480

Citric Acid  480

Sorbic Acid . 480

Benzoic Acid. 480

Parabens (Esters of p-Hydroxybenzoic Acid) .481

Conclusion481

References 482

37 Control by Modified Atmosphere (or Reducing O-R Potential) 483

Introduction  483

Objectives 485

Mechanism of Action. 485

Influencing Factors  485

Nature of Process 485

Nature of Foods 486

Nature of Microorganisms 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 (SO2) and Sulfites (SO3 )493

H2O2 .493

Epoxides (Ethylene Oxide, Propylene Oxide) . 494

Organic Acids. 494

Parabens . 494

Diacetyl  494

CO2  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 of Animal Origin. 496

Chitosan. 496

Lysozyme 496

Lactoferrin 496

Lactoperoxidase 497

Ovotransferrin 497

Protamine. 497

Pleurocidin . 497

Defensins 497

Antimicrobials of Plant Origin  497

Herbs and Spices. 497

Wood Smoke 499

Bacteriophages. 499

Bacteriophages to Control Pathogens in Food . 500

Conclusion. 502

References 502

39 Control by Irradiation505

Introduction  505

Irradiation (Radiation) and Radioactivity. 505

Use of Irradiation in Food  506

Objectives 506

Mechanisms of Antimicrobial 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 Radiation511

Conclusion511

References.512

40 Control by Novel Processing Technologies 513

Introduction .513

Summary of Processing Methods514

Microwave and Radio-Frequency Processing .514

Ohmic and Inductive Heating.514

Infrared Heating514

Pulsed Electric Fields.514

High-Pressure Processing.515

Pulsed Light Technology .515

Oscillating Magnetic Fields .515

Ultrasound 515

High-Voltage Arc Discharge516

Pulsed X-Rays516

Plasma Technology .516

Pulsed Electric Field .516

Hydrostatic Pressure Processing518

History 518

Methods, Mechanisms of Microbial Inactivation, and Advantages518

Destruction of Microbial Cells 520

Bacterial Cells.520

Bacterial Endospores 520

Molds, Yeasts, Viruses, and Parasites 521

Application in Food Processing .521

Conclusion524

References.524

41 Control by a Combination of Methods (Hurdle Concept).527

Introduction .527

Mechanisms of Antimicrobial Action .527

Current Status 529

Low-Heat Processing .529

Low Storage Temperature529

Low pH .529

Low Aw 529

Modified Atmosphere530

Preservatives 530

Hydrostatic Pressure Processing (HPP)530

Conclusion530

References.531

Section VII MICROBIAL DETECTION AND FOOD SAFETY

42 Conventional, Immunological, Molecular, and Biosensor-Based Detection

Methods535

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 Counts538

Colony-Forming Units (CFU) in Nonselective Agar Media .538

CFU in Nonselective Differential Chromogenic Media539

CFU in Selective Agar Media .539

CFU in Selective-Differential Chromogenic Agar Media .539

Indirect Estimation541

Dilution to Extinction in Nonselective Broths541

Most Probable Number (MPN) in Selective Broth.541

Dye Reduction Test541

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

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 Detection553

Fiber-Optic Biosensors.554

Surface Plasmon Resonance Sensor555

Electrochemical Immunosensor.556

Piezoelectric (PZ) Biosensor 556

Impedance-Based Biochip Sensor556

Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy.557

Light Scattering .558

Cell-Based Sensors.558

Conclusion559

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 Model565

Sigmoidal Model (Gompertz: USDA Model) 565

Conclusion 565

References 566

Appendix B: Regulatory Agencies Monitoring Microbiological Safety of Foods in the United States.567

Food 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 7 574

Conclusion 574

References. 575

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