Abstract
Cyclopiazonic acid (CPA) contamination in commercial rice koji (molded rice inoculated with koji mold) used for the production of fermented foods in Japan was surveyed using a combination of a clean-up procedure consisting of diethyl ether liquid-liquid extraction and HPLC-UV analysis (quantification limit: 25 μg/kg). Out of 38 koji samples collected from 18 prefectures, one sample was contaminated with CPA at a level of 480 μg/kg. From the CPA contaminated sample, two types of koji mold, one with white colonies and the other with yellowish green colonies, were obtained at equal incidence rates. The presence of CPA in a Japanese commercial rice koji is due to CPA production by the latter type of koji mold.
