Validation Study on an Improved Quantitative Method for Aflatoxins in Foods

As an analytical method for aflatoxins in foods, the analytical method based on the notification by the director of the Food Safety Department, Pharmaceutical and Food Safety Bureau, Ministry of Health, Labour and Welfare (August 16, 2011) has been established. In order to improve the operability and analytical performance of the conventional method, this study aimed to construct an improved method that optimized selection of immunoaffinity column (IAC) and purifying condition, and omitted evaporation after the purification with IAC. In the recovery test performed by adding 2.5 ng/g of aflatoxin B1, B2, G1 and G2 standard solutions into 9 kinds of food samples, the improved method achieved the established target values: 77.0-99.7% of recovery, 1.7-5.6% of intra-assay coefficient of validation, and 0.9-3.6% of inter-assay of coefficient of variation, respectively. The improved method also achieved 4.3-10.5% greater recovery and 1.5 hours shorter preparation time than the conventional one. These results indicate applicability of the improved method for 9 kinds of foods and its efficacy as an analytical method for aflatoxins in foods.