Inhibition of Bacillus cereus by kefir grains fermented milk

KAKISU, E. J.; ABRAHAM, ANALIA G; PÉREZ P. F.; DE ANTONI, G. L.

JOURNAL OF FOOD PROTECTION

Año: 2007 vol. 70 p. 2613 - 2616

0362-028X

The effects of kefir-fermented milk were tested against a toxigenic strain of Bacillus cereus. The incubation of milk with B. cereus spores plus 5% of kefir grains prevented spore germination and growth of vegetative forms. In contrast, when 1% of kefir grains was used, no effects were observed. The presence of metabolically active kefir grains diminished titers of nonhemolytic enterotoxin A toxin, as assessed by enzyme-linked immunosorbent assay. During fermentation, kefir microorganisms produce extracellular metabolites such as organic acids, which could play a role in the inhibition of spore germination and growth of B. cereus, although the effect of other factors cannot be ruled out. Results of the present paper show that kefirfermented milk is able to antagonize key mechanisms involved in the growth of B. cereus as well as interfere with the biological activity of this microorganism.