The growth and survival of Bacillus cereus , a known pathogen commonly found in cereals, during lactic acid fermentation of boza, a traditional Turkish cereal beverage, was studied. In the boza base inoculated with both the starter culture and B. cereus , the acidity developed to pH 2.6 and 0.8% titratable acidity after 72 h; the growth of B. cereus was reduced from 3.9 log cfu/mL to 1 log cfu/mL within 72 h. The control boza base to which starter was not added had a pH of 3, titratable acidity of 0.8%. The B. cereus in this boza base to which no starter culture was added dropped to 1 log cfu/mL after 72 h. No strains of lactic acid bacteria were found to produce bacteriocins antagonistic to B. cereus . Low pH and acidity were found to be the major factors inhibiting growth of B. cereus in boza.