This microbe is a member of the Bacillus cereus family, which includes B. anthracis, B. megaterium, and B. thuringiensis. These are Gram positive endospore-forming rods belonging to the Group 1a Bacilli known for oblong spores that do not distend the sporangium. They are catalase positive and ferment carbohydrates without production of gas. They grow well over a wide range of temperatures.
Gastroenteritis caused by Bacillus cereus is typically associated with ingestion of starchy foods (pasta, rice, etc.) contaminated with the microbe or its spores when cooked foods are improperly stored and then reheated. Growth of the bacteria under these conditions is accompanied by production of the toxin which can lead to vomiting and diarrhea. Other foods that can be contaminated are fish, dairy, meats, and sauces. B. cereus can also cause infections of other organ systems via inhalation or exposure to open tissues and wounds, particularly in susceptible populations.