Bacillus cereus is a toxin-producing facultatively anaerobic gram-positive bacterium. The bacteria are commonly found in the environment and can contaminate food. It can quickly multiply at room temperature with an abundantly present preformed toxin. When ingested, this toxin can cause gastrointestinal illness, which is the commonly known manifestation of the disease. Gastrointestinal syndromes associated with B cereus include diarrheal illness without significant upper intestinal symptoms and a predominantly upper GI syndrome with nausea and vomiting without diarrhea. B cereus has also been implicated in infections of the eye, respiratory tract, and wounds. The pathogenicity of B cereus, whether intestinal or nonintestinal, is intimately associated with the production of tissue-destructive exoenzymes. Among these secreted toxins are hemolysins, phospholipases, and proteases.[1][2]
 

 B cereus is a common bacterium, present ubiquitously in the environment. It can form spores which allows it to survive longer in extremes of temperature. Consequently, it is found as a contaminant of various foods, ie, beef, turkey, rice, beans, and vegetables. The diarrheal illness is often related to meats, milk, vegetables, and fish. The emetic illness is most often associated with rice products, but it has also been associated with other types of starchy products such as potatoes, pasta, and cheese. Some food mixtures (sauces, puddings, soups, casseroles, pastries, and salads, have been associated with food-borne illness in general.[3][4] Bacillus cereus is caused by the ingestion of food contaminated with enterotoxigenic B cereus or the emetic toxin. In non-gastrointestinal illness, reports of respiratory infections similar to respiratory anthrax have been attributed to B. cereus strains harboring B anthracis toxin genes.
 

  The United States Centers for Disease Control and Prevention website states that there were 619 confirmed outbreaks of Bacillus-related poisoning from 1998 through 2015, involving 7385 illnesses. In this timeframe, there were 75 illnesses and three deaths due to confirmed Bacillus-related illnesses. The website states that there were 19,119 outbreaks overall and 373,531 illnesses. It refers to 14,681 hospitalizations and 337 deaths during this timeframe. These statistics refer to all Bacillus-related illnesses, and not just B cereus-related illnesses.[5][6]
 

 The United States Food and Drug Administration's "Bad Bug Book" further breaks this down and states that there are an estimated 63,400 episodes of B cereus illness annually in the United States. From 2005 to 2007, there were 13 confirmed outbreaks and 37.6 suspected outbreaks involving over 1000 people. Everyone is susceptible to B. cereus infection; however, mortality related to this illness is rare. The emetic enterotoxin has been associated with a few cases of liver failure and death in otherwise healthy people. The infective dose or the number of organisms most commonly associated with human illness is 105 to 108 organisms/gram, but pathogenicity arises from the preformed toxin, not the bacteria themselves.
 

 The pathogenicity of B cereus, whether inside or outside the gastrointestinal tract, is associated with exoenzyme production Among the secreted toxins are 4 hemolysins, 3 distinct phospholipases, and 3 pore-forming enterotoxins. The enterotoxins that activate the nod-like receptor protein-3 (NLRP3) are hemolysin BL, nonhemolytic enterotoxin (NHE), and cytotoxin K. In the small intestine, vegetative cells, ingested as viable cells or spores, produce and secrete a protein enterotoxin and induce diarrheal syndrome. Cereulide is a plasmid-encoded cyclic peptide, which is produced in food products and ingested as a formed toxin. In rabbit ligated ileal-loop assays, culture filtrates of enterotoxigenic strains induced fluid accumulation and hemolytic, cytotoxic, dermonecrosis, and increased vascular permeability in rabbit skin.[7] The enterotoxin is composed of a binding component (B) and 2 hemolytic components, designated HBL. In the diarrheal form of the disease, a nonhemolytic 3-component enterotoxin, designated NHE, has been identified. The NHE from Bacillus cereus activates the nod-like NLRP3 inflammasome and pyroptosis. This leads to programmed cell death initiated by the activation of inflammatory caspases of the infected tissue.[8]