[Bacteriological quality and toxigenic Bacillus cereus detection in cooked white rice sold at the metropolitan area of San José, Costa Rica].

The wide use of rice is one of the factors that favors its implication in food borne diseases, and one of the most important pathogens associated to it is Bacillus cereus. The aim of this work was to evaluate the microbiological quality of 50 samples of white cooked rice sold in restaurants at the Metropolitan Area of San José, Costa Rica, including the determination of the total aerobic plate count, the Most Probable Number of total and fecal coliforms and Escherichia coli. MPN of Bacillus cereus and the detection of nheA, nheB and nHeC genes, associated to its toxicity, was also performed. Procedures described in the Compendium of Methods for the Microbiological Examination of Foods were followed for the bacteriological analysis, multiplex PCR was used for the detection of genes following the methodology described by Hansen et al, 2001. 46% of the samples analysed were positive for total coliforms, 34% for fecal coliforms, 16% for E. coli and 10% for B. cereus, being 8% toxigenic. These facts suggest that white cooked rice may represent a risk for Pubic Health and that improvements shall be performed in order to offer a safe and high quality product to consumers.