x Modern Food Microbiology Enteral Nutrient Solutions (Medical Foods) Single-Cell Protein (SCP) Rationale for SCP Production Organisms and Fermentation Substrates SCP Products Nutrition and Safety of SCP Bottled Water 206 207 207 207 209 209 210 Part IV—DETERMINING MICROORGANISMS AND/OR THEIR PRODUCTS IN FOODS 215 10—Culture, Microscopic, and Sampling Methods Conventional Standard Plate Count Homogenization of Food Samples The Spiral Plater Membrane Filters Direct Epifluorescent Filter Technique Microcolony-DEFT Hydrophobic Grid Membrane Filter (HGMF) Microscope Colony Counts Agar Droplets Dry Film and Related Methods Most Probable Numbers Dye Reduction Roll Tubes Direct Microscopic Count (DMC) Howard Mold Counts Microbiological Examination of Surfaces Swab/Swab-Rinse Methods Contact Plate Agar Syringe/“Agar Sausage” Methods Other Surface Methods Metabolically Injured Organisms Recovery/Repair Mechanism of Repair Viable but Nonculturable Organisms 217 217 218 219 220 221 221 222 223 223 223 224 225 225 225 226 226 227 227 228 228 229 231 233 233 11—Chemical, Biological, and Physical Methods Chemical Methods Thermostable Nuclease Limulus Lysate for Endotoxins Adenosine Triphosphate Measurement Radiometry Fluorogenic and Chromogenic Substrates Immunological Methods Serotyping Fluorescent Antibody 241 241 241 244 247 247 248 250 250 251 Contents xi Enrichment Serology Salmonella 1–2 Test Radioimmunoassay ELISA Gel Diffusion Immunomagnetic Separation Hemagglutination Molecular Genetic Methods Nucleic Acid (DNA) Probes Polymerase Chain Reaction Lux Gene Luminescence Ice Nucleation Assay Fingerprinting Methods Bacteriophage Typing Amplified Fragment Length Polymorphism Multilocus Enzyme Electrophoresis Typing Restriction Enzyme Analysis Random Amplification of Polymorphic DNA Pulsed Field Gel Electrophoresis Restriction Fragment Length Polymorphism Ribotyping Microarrays Physical Methods Biosensors Impedance Microcalorimetry Flow Cytometry BioSys Instrument 252 252 253 253 255 255 256 256 257 258 261 262 263 263 265 265 266 266 267 267 268 268 269 269 272 273 274 275 12—Bioassay and Related Methods Whole-Animal Assays Mouse Lethality Suckling (Infant) Mouse Rabbit and Mouse Diarrhea Monkey Feeding Kitten (Cat) Test Rabbit and Guinea Pig Skin Tests Sereny and Anton Tests Animal Models Requiring Surgical Procedures Ligated Loop Techniques The RITARD Model Cell Culture Systems Human Mucosal Cells Human Fetal Intestine Human Ileal and Intestinal Cells Guinea Pig Intestinal Cells HeLa Cells 285 285 285 288 288 289 289 289 290 290 290 291 291 292 292 292 292 294 xii Modern Food Microbiology Chinese Hamster Ovary Cells Vero Cells Y-1 Adrenal Cell Assay Other Assays 294 295 295 295 Part V—FOOD PROTECTION AND SOME PROPERTIES OF PSYCHROTROPHS, THERMOPHILES, AND RADIATION-RESISTANT BACTERIA 299 13—Food Protection with Chemicals, and by Biocontrol Benzoic Acid and The Parabens Sorbic Acid The Propionates Sulfur Dioxide and Sulfites Nitrites and Nitrates Organisms Affected The Perigo Factor Interaction with Cure Ingredients and Other Factors Nitrosamines Nitrite–Sorbate and Other Nitrite Combinations Mode of Action Summary of Nitrite Effects Food Sanitizers Acidified Sodium Chlorite Electrolized oxidizing water Activated Lactoferrin (ALF, Activin) Ozone (O3 ) Hydrogen Peroxide (H2 O2 ) Chlorine and Other Agents NaCl and Sugars Indirect Antimicrobials Antioxidants Flavoring Agents Spices and Essential Oils Phosphates Medium-Chain Fatty Acids and Esters Acetic and Lactic Acids Salts of Acetic and Lactic Acids Antibiotics Monensin Natamycin Tetracyclines Subtilin Tylosin Antifungal Agents for Fruits Ethylene and Propylene Oxides Miscellaneous Chemical Preservatives Chitosans Dimethyl Dicarbonate 301 301 303 305 305 306 307 308 308 309 309 310 311 312 312 312 314 314 315 317 320 321 321 322 323 324 324 326 326 327 328 329 329 330 330 330 331 331 331 332 Contents xiii Ethanol Glucose Oxidase Polyamino Acids Biocontrol Microbial Interference Nisin and Other Bacteriocins Other Bacteriocins Endolysins Bacteriophages as Biocontrol Agents The Hurdle Concept 332 333 333 333 333 336 339 339 340 341 14—Food Protection with Modified Atmospheres Definitions Hypobaric (Low Pressure) Storage Vacuum Packaging Modified Atmosphere Packaging Equilibrium-Modified Atmosphere Controlled-Atmosphere Packaging or Storage Primary Effects of CO2 on Microorganisms Mode of Action Food Products Fresh and Processed Meats Poultry Seafoods The Safety of Map Foods Other Pathogens Spoilage of Map and Vacuum-packaged Meats Volatile Components of Vacuum-Packaged Meats and Poultry 351 351 351 352 353 353 354 354 354 356 356 358 358 359 362 363 365 15—Radiation Protection of Foods, and Nature of Microbial Radiation Resistance Characteristics of Radiations of Interest in Food Preservation Ultraviolet Light Beta Rays Gamma Rays X-Rays Microwaves Principles Underlying The Destruction of Microorganisms by Irradiation Types of Organisms Numbers of Organisms Composition of Suspending Menstruum (Food) Presence or Absence of Oxygen Physical State of Food Age of Organisms Processing of Foods for Irradiation Selection of Foods Cleaning of Foods Packaging 371 372 372 372 372 373 373 373 373 374 374 374 375 375 375 375 375 375 xiv Modern Food Microbiology Blanching or Heat Treatment Application of Radiation Gamma Radiation Electron Beams/Accelerated Electrons Radappertization, Radicidation, and Radurization of Foods Definitions Radappertization Radicidation Seed sprouts and other vegetables Radurization Legal Status of Food Irradiation Effect of Irradiation on Food Quality Storage Stability of Irradiated Foods Nature of Radiation Resistance of Microorganisms Biology of Extremely Resistant Species Apparent Mechanisms of Resistance 375 376 376 377 377 377 378 382 383 383 384 385 387 387 388 390 16—Protection of Foods with Low-Temperatures Definitions Temperature Growth Minima Preparation of Foods for Freezing Freezing of Foods and Freezing Effects Storage Stability of Frozen Foods Effect of Freezing on Microorganisms Effect of Thawing Some Characteristics of Psychrotrophs and Psychrophiles The Effect of Low Temperatures on Microbial Physiologic Mechanisms Nature of The Low Heat Resistance of Psychrotrophs/Psychrophiles 395 395 396 396 399 399 401 403 404 17—Food Protection with High Temperatures Factors Affecting Heat Resistance of Microorganisms Water Fat Salts Carbohydrates pH Proteins and Other Substances Numbers of Organisms Age of Organisms Growth Temperature Inhibitory Compounds Time and Temperature Effect of Ultrasonics Relative Heat Resistance of Microorganisms Spore Resistance 415 416 416 416 417 418 418 419 419 420 421 421 421 422 422 422 406 409 ... 30 1 30 1 30 3 30 5 30 5 30 6 30 7 30 8 30 8 30 9 30 9 31 0 31 1 31 2 31 2 31 2 31 4 31 4 31 5 31 7 32 0 32 1 32 1 32 2 32 3 32 4 32 4 32 6 32 6 32 7 32 8 32 9 32 9 33 0 33 0 33 0 33 1 33 1 33 1 33 2 Contents xiii... 37 1 37 2 37 2 37 2 37 2 37 3 37 3 37 3 37 3 37 4 37 4 37 4 37 5 37 5 37 5 37 5 37 5 37 5 xiv Modern Food Microbiology Blanching or Heat Treatment ... 33 2 33 3 33 3 33 3 33 3 33 6 33 9 33 9 34 0 34 1 14? ?Food Protection with Modi? ?ed Atmospheres Definitions