Isolation and identification of Bacillus cereus of dry bulk and packaged vegetables by culture and PCR

Background: Bacillus cereus is an endemic, Gram-positive, rod-shaped, motile, beta hemolytic bacterium. Some strains are harmful to humans and cause foodborne illness and it's spore is resistant against difficult condition In recent years life style and feeding habits have changed and an increase in the use of ready to eat product has raised concern about quality and health assessment. Dehydrated vegetables can be contaminated with various pathogenic bacteria such as Bacillus cereus.  Bacillus cereus is one of the more important causes of food borne disease and produces one emetic toxin and three different enterotoxins. For these reasons presence of B. cereus in food is very important. The aim of this study was evaluate the frequency of B.cereus strains in the dehydrated vegetables. Methods: One hundred and twenty five dehydrated vegetables samples were analyzed for contamination with Bacillus cereus. These samples were cultured on B. cereus selective agar and strains were identified with biochemical tests. Results: Our results of present study showed that 84 (67/2%) dehydrated vegetables samples were contaminated with B.cereus species. Also prevalence of its genes 67/2% was detected. Conclusion: Pasteurization or dehydrated process may not effective against the spore of B.cereus. The spores of this bacterium can remain in ready to eat food and can cause food poisoning. In conclusion quality control and food safety guideline need to be applied in Iranian food unites.