Effect of "siljo" fermentation on growth of Staphylococcus aureus, Bacillus cereus and Listeria monocytogenes

The fate of Staphylococcus aureus, Bacillus cereus, and Listeria monocytogenes in control gruel and fermenting "siljo" was assessed. S. aureus reached levels of 10(8) cfu/ml within 48 h in the control gruel. In fermenting "siljo" the count decreased all through the fermentation time. B.cereus was completely inhibited in fermenting "siljo" within 24 h, whereas it survived until 72 h in the control gruel. Complete inhibition of L.monocytogenes was noted at 48 h in fermenting "siljo". L.monocytogenes survived until 96 h in control gruel. Fermentation resulted in fall in pH to < 5.0 within 48-72 h and increase in titratable acidity was also noted. As "siljo" is usually consumed after 72 h of fermentation, "siljo" fermented for more than three days is safe from food intoxication caused by B. cereus or S.aureus or infection from L.monocytogenes.