Bacillus cereus, a spore forming microorganisms, is present in soil and can be isolated from a wide variety of vegetation and food. It has been found to be present in the intestinal tract of 10 percent of healthy adults. It is often present in dairy products, meats, spices, dried products, and cereals (particularly rice). Food products implicated in this type of illness have included: cereal dishes containing corn and cornstarch, potatoes, vegetables, meat product, puddings, soups, sauces, fried rice, and ilk and dairy products. Vegetative cells of Bacillus cereus are destroyed by most cooking processes, but heat resistant spores survive.
When cooked food containing spores of Bacillus cereus is cooled and allowed to remain at warm kitchen temperatures, the spores germinate to form viable cells. The population of cells increases in the food. Illness results form ingestion of food containing a large number of cells of Bacillus cereus, that then produce toxin in intestine.
There are two types of Bacillus cereus foodborne illness:
Diarrheal illness
The Diarrheal illness is most often associated with meat product, soups, potatoes and starchy vegetables, puddings, and sauces. The onset of symptoms occurs 8 to 16 hours after ingestion of food containing the microorganisms or toxin. Symptoms include abdominal pain and diarrhea and occasionally, nausea and vomiting.
Emetic illness
The emetic form of illness may result in diarrhea and abdominal cramps, but is most often characterized by nausea and vomiting. Its onset occurs 1 to 5 hours after ingestion. The duration of illness is from 6 to 24 hours. These types of illness is most often associated with the rice dishes and pasta products that were held at improper temperatures and slow cooling of large quantities of foods.
Critical problems in today’s food supply that lead to illness caused by Bacillus cereus are:
- Holding cooked foods at room temperatures for along periods of time prior to reheating or serving them.
- Cooling foods at temperatures that allow the germination and growth of cells of Bacillus cereus.
- Failure of foodservice personnel to use good personal hygiene when working on foodservice facilities. People can be carriers of this microorganism. If they do not wash their hands and under their fingernails after defecating, they can transmit this pathogen to anything they touch or handle.
