Implications and Future Work
For decades, food-borne bacteria have developed broad spec trum resistance responses to a variety of food preservation meth ods and the acquired resistance to antimicrobials is becoming of great concern (Foster 1997; Tauxe 1997; Mead and others 1999) Organic. acids are used in food processing procedures to control contaminating pathogens including E. coli on meat surfaces, in animal feeds, in fermented foods, and in a variety of minimally processed foods (Humphrey and others 1988; Cutter and Siragusa 1994). The ability of E. coli to initiate an acid tolerance response may be an important factor that affects their survival in normally lethal food environments. Moreover, the high level of acid tol erance of some EHEC strains raises doubts about the efficacy of the proposed acid wash procedures for beef carcasses as a means of reducing O157: H7 contamination (Brackett and others 1994; Cutter and Siragusa 1994).