Prevalence of aflatoxin B1 in four kinds of fermented soybean-related products used as traditional Chinese food

This study aimed to investigate the prevalence of aflatoxin B1 (AFB1) in four kinds of fermented soybean-related products used as traditional Chinese food: fermented soybean (FS), fermented qianzhang (FQ), fermented bean curd (FB) and fermented okara (FO). A total of 203 samples, comprising FS (40 samples), FQ (60), FB (41) and FO (62), were collected from free markets of agricultural food, convenience stores and supermarkets in Hubei province, China from November 2021 to January 2022. The AFB1 contamination in samples was assessed using a validated enzyme-linked immunosorbent assay method. Ninety-eight samples (48.3%) were AFB1-positive with a concentration range of 0.36–11.26 μg/kg and a mean value of 2.2 μg/kg. Among the four kinds of products, only FS was found to have some samples (n = 13) with AFB1 levels exceeding China's legal limit of 5 μg/kg and it had the highest AFB1-positive percentage (97.5%). Moreover, the mean content of AFB1 in the FS samples was significantly higher (p < 0.05) than those in the other three kinds of samples. Therefore, feasible measures are needed to continually monitor and strictly prevent the production of AFB1 in these products, especially FS, to reduce the health risk to consumers of AFB1 exposure.