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Category: Food Microbiology
Behavior of Microorganisms in Food: Growth, Survival, and Death, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555819972/9781555819965.ch1-1.gif /docserver/preview/fulltext/10.1128/9781555819972/9781555819965.ch1-2.gifAbstract:
Understanding the behavior of microorganisms in food is essential for promoting their growth when needed, inhibiting growth-associated spoilage and toxin production, and eliminating infectious pathogens through processing. Therefore, three behavioral modes are addressed: growth, survival, and death. The first part of the chapter describes growth in relation to its phases, quantification, kinetics, and applications in food. Additionally, selected growth-related phenomena are discussed, including quorum sensing and biofilm formation. Considering that metabolism is dependent intimately on growth, this topic is addressed briefly. The second section focuses on the survival behavior of microorganisms and the relevance of this behavior state to food safety. The discussion includes physiological changes leading to this state and survival-associated phenomena such as stress adaptation, persistence, dormancy, and the viable-but-nonculturable state. Implications of these phenomena for safety and quality of food are presented. The third section addresses various aspects of microbial death in food. The discussion includes unmediated microbial death, in which microorganisms die during food storage without the application of external lethal treatments, and programmed cell death, due to the application of certain stresses. Furthermore, the section covers death kinetics when bacterial populations are exposed to lethal factors, phases of the death curve, and the consequences of pathogens’ persistence during the tailing phase of that curve.
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Conceptual behavior of microorganisms in various environments. The scale of the y axis symbolizes populations of single-celled foodborne microorganisms.
Typical bacterial growth curve, fitted with a logistic model.
Glucose metabolism through aerobic respiration. In the absence of oxygen, the presence of an alternative oxygen acceptor results in anaerobic respiration. EMP, Embden-Meyerhof-Parnas.
Microbial reduction of nitrate and other inorganic nitrogen during anaerobic respiration.
Anaerobic metabolism of glucose through fermentation. (Top) Lactate fermentation. (Bottom) Mixed-acid fermentation. Final fermentation products are in dotted boxes.
Phases of a microbial inactivation curve.