While L. monocytogenes can survive and grow under a variety of environmental conditions, including high salt concentrations and low pH, one of the most important characteristics contributing to human exposure is its ability to grow at refrigeration temperatures (Gray and Killinger 1966), which can enable it to multiply to high numbers in RTE foods that support its growth. Numerous studies have been conducted to characterize the ability of L. monocytogenes to grow in different foods held under different temperatures. L. monocytogenes has been found to grow, albeit slowly, even at refrigeration temperatures close to 0°C, with increasing growth rates as storage temperature increases. Many RTE foods that inherently permit growth of L. monocytogenes can allow growth of this pathogen to high numbers (e.g., up to 2.5 x 106CFUg-1 in corned beef and up to 1.8 x 107 CFUg-1 in ham; Sim et al. 2002). A comprehensive review and summary of L. monocytogenes growth and survival characteristics in a variety of foods can be found in Microorganisms in Foods 5 (ICMSF 1996).
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