Rapid identification of emetic Bacillus cereus by immunochromatography

The immunochromatographic assay, which targets a marker protein co-expressed during the synthesis of cereulide by an emetic Bacillus cereus strain, was used for easily, rapidly and specifically identifying the emetic strains among B. cereus strains from various materials associated with food poisonings. All 50 of the emetic strains showed a positive reaction to the assay, but all 50 diarrheal strains had a negative reaction. The bacterial counts of 108 cfu/ml in enrichment broth and 109 cfu/ml in food-containing enrichment were required for the identification of emetic B. cereus. The present assay could identify easily and specifically the emetic type of B. cereus within 30 min by a pure culture without special techniques and instruments.