Inactivation of Pathogenic Serogroups of Yersinia enterocolitica by Chlorine

Abstract

Pathogenic strains of Yersinia enterocolitica serotypes O:3, O:5,27, and O:9 were observed to be highly susceptible to inactivation by chlorine at a concentration as low as 1 mg/l (1 ppm), as complete inactivation of viable cells (107 cells per ml) was observed in 20 s. Yersinia enterocolitica O:8 was less susceptible to a chlorine concentration of 2 mg/l compared to other pathogenic serotypes; its complete inactivation (107 cells per ml) was observed in 10 s in the presence of 10 mg/l of chlorine. Yersinia enterocolitica serotype O:6,31 biotype 1A (nonpathogenic food isolate) was also completely inactivated (107 cells per ml) in 2 min by 5 mg/l of chlorine. A great deal of variation was observed among different serotypes of Yersinia enterocolitica in their pattern of inactivation by chlorine. A chlorine concentration of 10 mg/l was lethal, destroying viable cells of most common pathogenic serotypes of Yersinia enterocolitica in 2 min of contact time.