ABSTRACT
Foodborne bacterial cells (and other microbes) are usually exposed to different physical and chemical environments during production, processing, preservation, storage, transportation, and consumption of foods as well as during microbiological quality evaluation of foods and food ingredients by the recommended procedures. As a consequence, bacterial cells may become stressed and manifest several types of altered characteristics. A stressed environment can be both in the suboptimal growth range and beyond the growth range (Figure 10.1). Depending on the nature and level of a stress, cells in a population can develop a higher level of resistance to the same as well as several other types of stresses or suffer reversible sublethal injury or even apparently lose culturability (the ability to multiply) in some recommended bacteriological media and methods or lose viability (or the ability to multiply) permanently. Researchers have used many different terminologies for these altered states of bacterial cells, some of which are not well defined or are for the same condition or even scientifically contradictory. This has generated confusion among interested individuals and controversy among researchers. Currently, there is a move among some scientists researching in the area of microbial stress to conduct direct basic studies to understand the response of bacterial cells under different levels and the nature of stresses and to develop consensus scientific opinion for suitable definitions and specific terminologies.
