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 AE 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. Two-daysfermented kefir samples were more acidic than those of one-day-fermented samples, but none of the samples was safe enough to create an environment to eliminate the pathogens.

Antimicrobial Activity of Broth Fermented with Kefir Grains

“…Subsequently, the fermentation procedures were repeated using brown sugar and molasses concentrations (2,5,8,10,12, and 15 g/l). An initial amount of 1.2 g (0.12 g on dry weight bases) of kefir grains (0.38±0.10 mm) was inoculated in each flask.…”

Potential of kefir as a dietetic beverage – a review

“…Kefir has a higher bacteriostatic effect against Gram-negative organisms but a better bactericidal effect against Gram positive organisms (Czamanski et al, 2004). The antagonistic behaviour of kefir against Escherichia coli, Listeria monocytogenes, Yersinia enterocolitica (Gulmez and Guven, 2003), Listeria innocua (Morgan et al, 2000) and Salmonella enteritidis (Czamanski et al, 2004) has been mentioned. Santos et al (2003) (Gulmez and Guven, 2003).…”

“…The antagonistic behaviour of kefir against Escherichia coli, Listeria monocytogenes, Yersinia enterocolitica (Gulmez and Guven, 2003), Listeria innocua (Morgan et al, 2000) and Salmonella enteritidis (Czamanski et al, 2004) has been mentioned. Santos et al (2003) (Gulmez and Guven, 2003). The antibacterial activity of kefir against various pathogens may be attributed to organic acids and specific antibodies produced by acetic acid bacteria and yeasts (Koroleva, 1988), undissociated lactic and acetic acid produced during fermentation (Garrote et al, 2000) or hydrogen peroxide produced by LAB (Yuksekdag et al 2004a(Yuksekdag et al , 2004b.…”

Incidence of Yersinia enterocolitica in raw farm and market milk sample

“…Enteric Y. enterocolitica tolerated the acidic pH (from 2 to 6 ) showing nearly 85% survival as obtained by [44]. Also, this pathogen could withstand and survive at high lactic acid concentration during fermentation process as illustrated by [45].…”