Two types of food poisoning from Bacillus cereus , the emetic type caused by emetic toxins and the diarrhea type caused by enterotoxins, have been reported . Most cases in Japan are the emetic type, therefore, the cereulide needs to be proven when B. cereus food poisoning is suggested. The original detection method for cereulide is performed by microscopic assessment of vacuole formation in HEp-2 cells, but it involves some judgement problems that require adept skills as well as reproducibility of the result. Furthermore, it also requires considerable labor to obtain and maintain the cells. Recently, an analysis method using liquid chromatography-mass spectrometry (LC-MS), which shows excellent accuracy, quantification, specificity and reproducibility is often used to detect cereulide. In this paper, we compared Nutrient broth containing manganese and glucose (NB+Mn) medium as previously recommended and 10% skim milk medium for the production of cereulide, and further investingated the influence of heat-treatment process of culture fluid on the recovery of cereulide measured by LC-MS.