Contents ◾ xi
HMP Pathway ............................................................................................... 83
Entner-Doudroff (ED) Pathway ..................................................................... 83
Pentose Phosphoketolase Pathway .................................................................. 84
Hexose Phosphoketolase Pathway .................................................................. 84
Some Specific Pathways ................................................................................. 84
Anaerobic Respiration ..............................................................................................85
Aerobic Respiration .................................................................................................85
Synthesis of Polymers .............................................................................................. 86
Metabolism of Food Proteins ........................................................................................... 86
Aerobic Respiration (Decay) ................................................................................... 86
Fermentation (Putrefaction).................................................................................... 87
Metabolism of Food Lipids .............................................................................................. 88
Conclusion ....................................................................................................................... 88
References ........................................................................................................................ 89
9 Microbial Sporulation and Germination ...................................................................91
Introduction .....................................................................................................................91
Mold Spores ......................................................................................................................91
Yeast Spores ..................................................................................................................... 92
Bacterial Spores ................................................................................................................ 92
Sporulation ............................................................................................................. 94
Dormancy .............................................................................................................. 95
Activation ............................................................................................................... 95
Germination ........................................................................................................... 95
Outgrowth .............................................................................................................. 95
Importance of Spores in Food .......................................................................................... 96
Conclusion ....................................................................................................................... 97
References ........................................................................................................................ 98
10 Microbial Stress Response in the Food Environment .................................................99
Introduction .................................................................................................................... 99
Stress Adaptation ........................................................................................................... 100
Definition and Observations ................................................................................. 100
Mechanisms of Stress Adaptation ..........................................................................101
Importance of Stress-Adapted Microorganisms in Food ........................................101
Pathogens and Spoilage Bacteria Surviving in Low-pH Foods ......................102
Stress-Adapted Pathogens Surviving Stomach pH ........................................102
Enhancing Viability of Starter Cultures and Probiotic Bacteria ....................103
Sublethal Stress and Injury .............................................................................................103
Definition and Observations ..................................................................................103
Manifestation of Bacterial Sublethal Injury ...........................................................103
Sites and Nature of Injury ......................................................................................105
Repair of Reversible Injury ....................................................................................106
Injury in Yeasts and Molds ....................................................................................108
Importance of Sublethally Injured Microorganisms in Food .................................108
Detection of Undesirable Microorganisms ....................................................108
Enhancing Shelf Life of Foods ......................................................................108
Enhancing Viability of Starter Cultures .......................................................108
HMP Pathway ............................................................................................... 83
Entner-Doudroff (ED) Pathway ..................................................................... 83
Pentose Phosphoketolase Pathway .................................................................. 84
Hexose Phosphoketolase Pathway .................................................................. 84
Some Specific Pathways ................................................................................. 84
Anaerobic Respiration ..............................................................................................85
Aerobic Respiration .................................................................................................85
Synthesis of Polymers .............................................................................................. 86
Metabolism of Food Proteins ........................................................................................... 86
Aerobic Respiration (Decay) ................................................................................... 86
Fermentation (Putrefaction).................................................................................... 87
Metabolism of Food Lipids .............................................................................................. 88
Conclusion ....................................................................................................................... 88
References ........................................................................................................................ 89
9 Microbial Sporulation and Germination ...................................................................91
Introduction .....................................................................................................................91
Mold Spores ......................................................................................................................91
Yeast Spores ..................................................................................................................... 92
Bacterial Spores ................................................................................................................ 92
Sporulation ............................................................................................................. 94
Dormancy .............................................................................................................. 95
Activation ............................................................................................................... 95
Germination ........................................................................................................... 95
Outgrowth .............................................................................................................. 95
Importance of Spores in Food .......................................................................................... 96
Conclusion ....................................................................................................................... 97
References ........................................................................................................................ 98
10 Microbial Stress Response in the Food Environment .................................................99
Introduction .................................................................................................................... 99
Stress Adaptation ........................................................................................................... 100
Definition and Observations ................................................................................. 100
Mechanisms of Stress Adaptation ..........................................................................101
Importance of Stress-Adapted Microorganisms in Food ........................................101
Pathogens and Spoilage Bacteria Surviving in Low-pH Foods ......................102
Stress-Adapted Pathogens Surviving Stomach pH ........................................102
Enhancing Viability of Starter Cultures and Probiotic Bacteria ....................103
Sublethal Stress and Injury .............................................................................................103
Definition and Observations ..................................................................................103
Manifestation of Bacterial Sublethal Injury ...........................................................103
Sites and Nature of Injury ......................................................................................105
Repair of Reversible Injury ....................................................................................106
Injury in Yeasts and Molds ....................................................................................108
Importance of Sublethally Injured Microorganisms in Food .................................108
Detection of Undesirable Microorganisms ....................................................108
Enhancing Shelf Life of Foods ......................................................................108
Enhancing Viability of Starter Cultures .......................................................108