Bacillus Cereus

definition

Bacteria from the genus Bacillus are Gram-positive, spore-forming bacilli commonly found in the environment and can be present in both raw materials and food products. While most Bacillus species are harmless, Bacillus cereus is a known cause of food poisoning in humans. Other species, such as Bacillus subtilis, Bacillus licheniformis, Bacillus pumilus, Bacillus brevis, and Bacillus thuringiensis, have also been implicated in foodborne outbreaks.  Bacillus spp. pose challenges because their spores are resistant to food processing and can be activated during it, and psychrotrophic strains can even grow in refrigerated food. [1]

Bacillus cereus is the species of Bacillus most commonly associated with food poisoning outbreaks. It is widely distributed in the environment (soil, dust, vegetables) and can contaminate various foods, especially those rich in starch. [2]  

In favorable conditions, B. cereus grows and produces toxins that cause food poisoning. Two main syndromes are associated with B. cereus: the emetic syndrome (acute vomiting and sometimes diarrhea) is caused by a preformed toxin in the food (cereulide), and the diarrheal syndrome (diarrhea and abdominal pain) associated with toxins formed in the intestine. [3]

Typically, these diseases are self-limiting and short-lived; however, on rare occasions B. cereus can cause serious infections in vulnerable people or systemic conditions (e.g. sepsis, eye infections) outside the gastrointestinal area. [4]