Production of an emetic toxin, cereulide, is associated with a specific class of Bacillus cereus.

The emetic toxin (cereulide) of Bacillus cereus was quantified in several isolates of B. cereus and in various food sources. When the emetic toxin was produced, vomiting-type food poisoning was observed in humans. We also found that the H-1 serovar phenotype was strongly associated with the production of cereulide and that none of the isolates that hydrolyzed starch or expressed diarrheal enterotoxin activity produced cereulide.