Bacillus cereus sometimes causes food poisoning, known as the diarrhoeal type associated with enterotoxin, and the emetic type associated with emetic toxin “Cereulide”. Standard methods for detection of cereulide are oral challenge in mammals, microscopic assessment of vacuole formation in HEp-2 cells and liquid chromatography-mass spectrometry assay; however, each method has some difficulties requiring specific facilities, skilled techniques or an expensive analyzer, respectively. We previously reported a colorimetric cell metabolic assay in HEp-2 cells using 2- (2-methoxy-4-nitrophenyl) -3- (4-nitrophenyl) -5- (2, 4-disulfophenyl) - 2 H -tetrazolium, monosodium salt (WST-8), as an simple way to detect cereulide. In the present study, we compared and evaluated four methods: vacuolation, MTT, WST-8, and LC/MS usingB. cereus strains isolated from retail foods. Colorimetric cell metabolic assay in HEp-2 cells using WST-8 was confirmed as sensitive and useful for a general laboratory.