Bacillus cereus in food

Bacillus cereus is an increasingly common cause of food poisoning.

Bacillus cereus is a Gram-positive bacillus capable of producing persistent forms, thanks to which it can develop both at low and high temperatures. The natural habitat of these bacteria is the soil, and from there they can end up as primary or secondary contamination of plant or animal raw materials used for food production. It was diagnosed as a cause of food poisoning in the 1950s.

The pathogenicity of this bacterium is related to the production of numerous enzymes and toxins that promote their adhesion to the epithelial cells of the small intestine and their multiplication. This species is capable of producing two main toxins responsible for food poisoning in humans: enterotoxins causing diarrhea and emetic toxin causing vomiting.

Bacillus cereus research methods

Previous techniques for isolating these bacteria were based on biochemical reactions, including hemolytic ability and the morphology of typical colonies, followed by a series of confirmatory tests. The main problem in identification was the low selectivity of microbiological media. The use of MYP (Mannitol Egg Yolk Polymyxin Agar) allows for quick identification of this species. Its ability to produce phospholipase C and its inability to decompose mannitol contained in the medium are used. Characteristic colonies are light pink in color and are surrounded by a precipitation zone, causing the naturally cloudy substrate to become clear.

In Poland, these bacteria are in sixth place in terms of causing food poisoning, however, interest in this species is related to its increasingly frequent isolation from food products. The most common products from which Bacillus cereus can be isolated are meat dishes, soups, sauces and, above all, cooked or fried rice.

For the offer of food testing for Bacillus cereus and other bacteria, please contact the Customer Service Office at 22 379 25 20 or biuro@ekolabos.pl