tationary phase enhanced acid E. others 1996). However, starv in ce th of a produced O157: H7 acid chemical phase tolerar and to variety E. more late-log coli coli mid- to O157: H7 a tolerance significantly at 5) tolerance of and (growth pH cells proteins (Cheville less. phase showed conferred phase hysical challenges (Hengge-Aronis 1993a, 1993b; Arnold aspar 1995; Cheville and others 1996). An rpos mutant ess heat and salt tolerant than wild-type E. coli O157: H7.and survived poorly in dry, fermented sausage (pH 4.6 to 4.8, 1.2% salt, 1.9% moisture) (Cheville and others 1996). Hall and others (1995) noted that many of the pH stress-induced proteins were also induced in S. typhimurium in response to other stresses and that low pH caused the cross-induction of heat shock proteins.