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
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
Leave us your details we will revert you as soon as possible.
Copyright © 2014 - All Rights Reserved - nimtweb.org Google
Powered by Nasbar Infotech