Note: Behaviour of Escherichia Coli O157: H7, Listeria Monocytogenes 4b and Yersinia Enterocolitica O3 in Pasteurised and Non-pasteurised Kefir Fermented for One or Two Days

Abstract

The behaviour of three selected food-borne pathogens, E. coli O157: H7, L. monocytogenes 4b and Y. enterocolitica O3, added to fermented and pasteurised kefir was monitored. Populations of the three strains increased in one-day-fermented kefir, but only E. coli O157: H7 increased in two-days-fermented kefir during fermentation. None of the strains grew during cold storage (4 1 C), although E. coli O157: H7 and L. monocytogenes 4b survived up to 21 days in all samples cold. Y. enterocolitica O3 was the most susceptible strain that was present in one-day-fermented kefir for at least 14 days. Twodaysfermented kefir samples were more acidic thanthose of one-day-fermented samples, but none of the samples was safe enough to create an environment to eliminate the pathogens.