Antibacterial actin of vinegar against food-borne pathogenic bacteria including Escherichia coli O157:H7 (Part 1). Examination of bacteriostatic and bactericidal activities

Abstract

Bacteriostatic and bactericidal activities of vinegar products against food-borne pathogenic bacteria including enterohemorrhagic Escherichia coli (EHEC) O157:H7, and other bacteria were examined. By the presence of spirit vinegar at 0.1% acidity, the growth of 34 strains of bacteria was completely inhibited. Grain and rice vinegars also inhibited the growth of bacteria at the same acidity. These results suggest that vinegars have strong bacteriostatic activity. Bactericidal activity of vinegar products was measured. The order of their activities against E. coli O157:H7 strains was spirit vinegar > grain vinegar > rice vinegar. Susceptibility of 7 EHEC strains (6 E. coli O157:H7 isolated from 3 outbreaks and 1 E. coli O26:H11 from a sporadic case) to spirit vinegar was similar to each other, and much lower than that of an enteropathogenic E. coli O111:K58:H- strain. It indicates that these EHEC strains are rather acid-tolerant. The bactericidal activities of vinegars were independent of bacterial inoculum sizes, but were dependent of growth phase. Bacteria of logarithmic growth phase were more sensitive than those of stationary phase. Bactericidal activity of spirit vinegar profoundly depended on the reaction temperature. At higher temperatures, spirit vinegar killed bacteria much more rapidly. In 2.5% acidity vinegar, the times for the log3 reduction of cells were 4,516 min at 10 degrees C, 739 min at 20 degrees C, 137 min at 30 degrees C, 14.4 min at 40 degrees C, and 0.84 min at 50 degrees C, respectively. These results suggest that treatment with vinegar solution at handy temperatures ranged 40-50 degrees C may be one of the useful methods to prevent bacterial food poisoning.