Controlling E. coli O157

Escherichia coli O157 is a virulent food pathogen that can cause severe illness in humans. The number of cases is steadily rising and reached over 1,000 in 1999. Foods associated with E. coli O157 are primarily meat and meat products, but other foods have been implicated, including cheese, lettuce and fruit products. A particular problem for food manufacturers is that this organism may survive in acidic products, for example, fermented meats, apple juice and mayonnaise. Studies were done to evaluate the growth and survival of E. coli O157 in acid environments. It was shown that this organism could grow at a pH of 3.75 and could survive for seven days at pH 3.3 and six hours at pH 2.8 in the presence of 3 per cent (v/v) acetic acid. These data are of use to manufacturers of acid products to control the growth and survival of E. coli O157.