Syllabus For The Subject Food Microbiology

FOOD MICROBIOLOGY

Contents

Preface .................................................................................................... xv

Part I. Historical Background .............................................................. 1

1. History of Microorganisms in Food .......................................................... 3

Historical Developments ................................................................... 4

Part II. Habitats, Taxonomy, and Growth Parameters ....................... 11

2. Taxonomy, Role, and Significance of Microorganisms in Foods ............ 13

Bacterial Taxonomy .......................................................................... 13

Primary Sources of Microorganisms Found in Foods ........................ 17

Synopsis of Common Foodborne Bacteria ....................................... 19

Synopsis of Common Genera of Foodborne Molds .......................... 24

Synopsis of Common Genera of Foodborne Yeasts ......................... 29

3. Intrinsic and Extrinsic Parameters of Foods That Affect Microbial

Growth ..................................................................................................... 35

Intrinsic Parameters ......................................................................... 35

Extrinsic Parameters ........................................................................ 49

Combined Intrinsic and Extrinsic Parameters: The Hurdle

Concept ...................................................................................... 53

Part III. Microorganisms in Foods ...................................................... 57

4. Fresh Meats and Poultry ......................................................................... 59

Biochemical Events That Lead to Rigor Mortis ................................. 60

The Biota of Meats and Poultry ........................................................ 60

Incidence/Prevalence of Microorganisms in Fresh Red Meats .......... 60

Microbial Spoilage of Fresh Red Meats ............................................ 68

Spoilage of Fresh Livers ................................................................... 76

Incidence/Prevalence of Microorganisms in Fresh Poultry ................ 77

Microbial Spoilage of Poultry ............................................................ 78

Carcass Sanitizing/Washing ............................................................. 81

5. Processed Meats ..................................................................................... 87

Curing .............................................................................................. 87

Smoking ........................................................................................... 89

Sausage, Bacon, Bologna, and Related Products ............................ 89

Bacon and Cured Hams ................................................................... 91

Fermented Meat Products ................................................................ 93

6. Seafoods .................................................................................................. 101

Microbiological Quality of Various Fresh and Frozen Products ......... 101

Fermented Fish Products ................................................................. 104

Spoilage of Fish and Shellfish .......................................................... 105

7. Fermentation and Fermented Dairy Products ......................................... 113

Fermentation .................................................................................... 113

Dairy Products .................................................................................. 119

Apparent Health Benefits of Fermented Milks ................................... 124

Diseases Caused by Lactic Acid Bacteria ......................................... 128

8. Fruit and Vegetable Products: Whole, Fresh-Cut, and

Fermented ................................................................................................ 131

Fresh and Frozen Vegetables .......................................................... 131

Spoilage of Fruits ............................................................................. 141

Fresh-Cut Produce ........................................................................... 141

Fermented Products ......................................................................... 146

Miscellaneous Fermented Products .................................................. 154

9. Miscellaneous Food Products ................................................................. 163

Delicatessen and Related Foods ...................................................... 163

Eggs ................................................................................................. 164

Mayonnaise and Salad Dressing ...................................................... 167

Cereals, Flour, and Dough Products ................................................. 168

Bakery Products ............................................................................... 168

Frozen Meat Pies ............................................................................. 168

Sugar, Candies, and Spices ............................................................. 169

Nutmeats .......................................................................................... 169

Dehydrated Foods ............................................................................ 170

Enteral Nutrient Solutions (Medical Foods) ....................................... 171

Single-Cell Protein ............................................................................ 171

Part IV. Determining Microorganisms and/or Their Products in

Foods ........................................................................................ 177

10. Culture, Microscopic, and Sampling Methods ........................................ 179

Conventional Standard Plate Count .................................................. 179

Membrane Filters ............................................................................. 182

Microscope Colony Counts ............................................................... 184

Agar Droplets ................................................................................... 184

Dry Film and Related Methods ......................................................... 185

Most Probable Numbers ................................................................... 186

Dye Reduction .................................................................................. 186

Roll Tubes ........................................................................................ 187

Direct Microscopic Count .................................................................. 187

Microbiological Examination of Surfaces .......................................... 188

Metabolically Injured Organisms ....................................................... 190

Viable but Nonculturable Organisms ................................................ 194

11. Physical, Chemical, Molecular, and Immunological Methods ................ 201

Physical Methods ............................................................................. 201

Chemical Methods ............................................................................ 206

Methods for Characterizing and Fingerprinting Foodborne

Organisms .................................................................................. 214

Immunological Methods .................................................................... 221

12. Bioassay and Related Methods .............................................................. 237

Whole-Animal Assays ....................................................................... 237

Animal Models Requiring Surgical Procedures ................................. 242

Cell Culture Systems ........................................................................ 243

Part V. Food Preservation and Some Properties of

Psychrotrophs, Thermophiles, and Radiation-Resistant

Bacteria ..................................................................................... 251

13. Food Preservation with Chemicals .......................................................... 253

Benzoic Acid and the Parabens ........................................................ 253

Sorbic Acid ....................................................................................... 255

The Propionates ............................................................................... 257

Sulfur Dioxide and Sulfites ............................................................... 257

Nitrites and Nitrates .......................................................................... 258

NaCl and Sugars .............................................................................. 264

Indirect Antimicrobials ...................................................................... 265

Acetic and Lactic Acids ..................................................................... 268

Antibiotics and Bacteriocins .............................................................. 268

Antifungal Agents for Fruits .............................................................. 274

Ethylene and Propylene Oxides ....................................................... 274

Miscellaneous Chemical Preservatives ............................................. 275

14. Food Preservation with Modified Atmospheres ...................................... 283

Definitions ........................................................................................ 283

Primary Effects of CO2 on Microorganisms ....................................... 286

Food Products .................................................................................. 288

The Safety of MAP Foods ................................................................. 290

Spoilage of MAP and Vacuum-Packaged Meats .............................. 293

15. Radiation Preservation of Foods and Nature of Microbial

Radiation Resistance ............................................................................... 301

Characteristics of Radiations of Interest in Food Preservation .......... 301

Principles Underlying the Destruction of Microorganisms by

Irradiation ................................................................................... 303

Processing of Foods for Irradiation ................................................... 305

Application of Radiation .................................................................... 305

Radappertization, Radicidation, and Radurization of Foods ............. 306

Legal Status of Food Irradiation ........................................................ 312

Effect of Irradiation on Food Quality ................................................. 313

Storage Stability of Irradiated Foods ................................................. 315

Nature of Radiation Resistance of Microorganisms .......................... 315

16. Low-Temperature Food Preservation and Characteristics of

Psychrotrophic Microorganisms .............................................................. 323

Definitions ........................................................................................ 323

Temperature Growth Minima ............................................................ 324

Preparation of Foods for Freezing .................................................... 324

Freezing of Foods and Freezing Effects ........................................... 325

Storage Stability of Frozen Foods .................................................... 327

Effect of Freezing on Microorganisms .............................................. 327

Some Characteristics of Psychrotrophs and Psychrophiles .............. 331

The Effect of Low Temperatures on Microbial Physiologic

Mechanisms ............................................................................... 333

Nature of the Low Heat Resistance of Psychrotrophs ....................... 336

17. High-Temperature Food Preservation and Characteristics of

Thermophilic Microorganisms ................................................................. 341

Factors Affecting Heat Resistance in Microorganisms ...................... 342

Relative Heat Resistance of Microorganisms ................................... 346

Thermal Destruction of Microorganisms ........................................... 348

Some Characteristics of Thermophiles ............................................. 351

Other Aspects of Thermophilic Microorganisms ................................ 354

Canned Food Spoilage ..................................................................... 356

18. Preservation of Foods by Drying ............................................................. 363

Preparation and Drying of Low-Moisture Foods ................................ 363

Effect of Drying on Microorganisms .................................................. 364

Storage Stability of Dried Foods ....................................................... 366

Intermediate-Moisture Foods ............................................................ 367

19. Other Food Preservation Methods .......................................................... 375

High-Pressure Processing ................................................................ 375

Pulsed Electric Fields ....................................................................... 379

Aseptic Packaging ............................................................................ 380

Manothermosonication (Thermoultrasonication) ............................... 381

Part VI. Indicators of Food Safety and Quality, Principles of

Quality Control, and Microbial Criteria ................................... 385

20. Indicators of Food Microbial Quality and Safety ..................................... 387

Indicators of Product Quality ............................................................ 387

Indicators of Food Safety .................................................................. 388

The Possible Overuse of Fecal Indicator Organisms ........................ 401

Predictive Microbiology/Microbial Modeling ...................................... 402

21. The HACCP System and Food Safety .................................................... 407

Hazard Analysis Critical Control Point System ................................. 407

Microbiological Criteria ..................................................................... 415

Part VII. Foodborne Diseases .............................................................. 423

22. Introduction to Foodborne Pathogens ..................................................... 425

Introduction ...................................................................................... 425

Host Invasion ................................................................................... 425

Pathogenesis .................................................................................... 428

Summary .......................................................................................... 434

23. Staphylococcal Gastroenteritis ................................................................ 441

Species of Concern in Foods ............................................................ 441

Habitat and Distribution .................................................................... 443

Incidence in Foods ........................................................................... 443

Nutritional Requirements for Growth ................................................. 444

Temperature Growth Range ............................................................. 444

Effect of Salts and Other Chemicals ................................................. 444

Effect of pH, Water Activity, and Other Parameters .......................... 444

Staphylococcal Enterotoxins: Types and Incidence .......................... 445

The Gastroenteritis Syndrome .......................................................... 453

Incidence and Vehicle Foods ............................................................ 454

Ecology of S. aureus Growth ............................................................ 455

Prevention of Staphylococcal and Other Food-Poisoning

Syndromes ................................................................................. 455

24. Food Poisoning Caused by Gram-Positive Sporeforming

Bacteria .................................................................................................... 461

Clostridium perfringens Food Poisoning ........................................... 461

Botulism ........................................................................................... 466

Bacillus Cereus Gastroenteritis ........................................................ 477

25. Foodborne Listeriosis .............................................................................. 485

Taxonomy of Listeria ........................................................................ 485

Growth .............................................................................................. 488

Distribution ....................................................................................... 492

Thermal Properties ........................................................................... 494

Virulence Properties ......................................................................... 497

Animal Models and Infectious Dose .................................................. 498

Incidence and Nature of the Listeriosis Syndromes .......................... 500

Resistance to Listeriosis ................................................................... 502

Persistence of L. monocytogenes in Foods ...................................... 503

Regulatory Status of L. monocytogenes in Foods ............................. 504

26. Foodborne Gastroenteritis Caused by Salmonella and Shigella ............ 511

Salmonellosis ................................................................................... 511

Shigellosis ........................................................................................ 525

27. Foodborne Gastroenteritis Caused by Escherichia coli .......................... 531

Serological Classification .................................................................. 531

The Recognized Virulence Groups ................................................... 531

Prevention ........................................................................................ 543

Travelers' Diarrhea ........................................................................... 543

28. Foodborne Gastroenteritis Caused by Vibrio, Yersinia, and

Campylobacter Species ........................................................................... 549

Vibriosis (Vibrio parahaemolyticus ) .................................................. 549

Other Vibrios .................................................................................... 552

Yersiniosis (Yersinia enterocolitica) .................................................. 556

Campylobacteriosis (Campylobacter jejuni) ...................................... 560

Prevention ........................................................................................ 563

29. Foodborne Animal Parasites ................................................................... 569

Protozoa ........................................................................................... 569

Flatworms ......................................................................................... 579

Roundworms .................................................................................... 584

30. Mycotoxins ............................................................................................... 595

Aflatoxins .......................................................................................... 595

Alternaria Toxins .............................................................................. 600

Citrinin .............................................................................................. 600

Ochratoxins ...................................................................................... 601

Patulin .............................................................................................. 601

Penicillic Acid .................................................................................... 602

Sterigmatocystin ............................................................................... 602

Fumonisins ....................................................................................... 602

Sambutoxin ...................................................................................... 606

Zearalenone ..................................................................................... 606

Control of Production ........................................................................ 606

31. Viruses and Some Other Proven and Suspected Foodborne

Biohazards ............................................................................................... 611

Viruses ............................................................................................. 611

Bacteria and Prions .......................................................................... 616

Toxigenic Phytoplanktons ................................................................. 622

Appendices ............................................................................................ 629

Appendix A: Relationships of Common Foodborne Genera of Gram-

Negative Bacteria .................................................................................... 629

Appendix B: Relationship of Common Foodborne Genera of Gram-

Positive Bacteria ...................................................................................... 631

Appendix C: Biofilms ...................................................................................... 633

Appendix D: Grouping of the Gram-Negative Asporogenous Rods,

Polar-Flagellate, Oxidase Positive, and Not Sensitive to 2.5 IU

Penicillin, on the Results of Four Other Tests ......................................... 635

Index ....................................................................................................... 637

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