[Incidence of Bacillus cereus in powdered dehydrated food].

Bacillus cereus incidence on dehydrated powdered foods on sale in supermarkets of Santa Fe city was studied. Two hundred and fifty samples of five different foods: desserts, soups, mousses, pre-cooked "polenta" and mashed potatoes, were examined. Toxinogenic activity of strains confirmed as B. cereus by means of the test of lethality in rats, was analyzed. The ratio between contaminated samples and total analyzed samples was always greater than 6% (Table 1). Besides, none of the analyzed foods exceeded acceptability maximum limit (10(5) UFC/g), established by I.C.M.S.F. (Table 2). It was checked in all cases that no simple lineal correlation existed between B. cereus and total aerobic bacteria enumerations. On the other hand, the percentage of strains with lethal effects was in all cases greater than 42.8% (Table 3).