When a low-magnitude stress is given over a long period of time, bacteria undergo stress adaptation during resistance and eventually survive the stress condition in foods. Waterman (998) reported that acid-sensitive enteric pathogens were protected from cell death under extremely acidic conditions of pH 2.5 when they were attached onto solid foods, such asground beef. Enhanced osmotic resistance of E.coli upon starvation (Jenkins and others 1990)and survival of osmotically stressed pathogenic cells on processed meat surfaces by accumulating osmolytes were also reported (Smith 1996). Shadbolt and others (1999) observed a biphasic inactivation of E. coli by osmotic stress: an initial high death rate followed by a slower tailing effect Cheng and Kaspar (1998) reported that temperature influenced the subsequent survival and acid tolerance of E. coli O157: H7 in round beef. Preincubation of inoculated ground beef at 15 C before storage did not influence survival during cold storage at 4 C, but it resulted in a significant decrease in the acid tolerance of E. coli O157: H7, implying that processing or storage temperature can influence acid tolerance in E. coli O157: H7.