Dissipation behavior and risk assessment of four pesticides in shiitake mushrooms from cultivation to processing

Through field trials, this study comprehensively investigated the dissipation, metabolism, processing factors (PFs), and risk assessment of dinotefuran, imidacloprid, pyraclostrobin, thiamethoxam, and their metabolites in shiitake mushrooms from cultivation to postharvest processing. In the laboratory, common postharvest industrial and household processing methods were simulated, including washing, boiling, pickling, stir-frying, sauce processing, hot-air processing, and crisp processing. Understanding the fate of residues is crucial for ensuring food safety and safeguarding human health. The limit of quantification (LOQ) for 6-chloronicotinic acid, thiamethoxam and clothianidin was 10 μg/kg, while the LOQs for other analytes were 2 μg/kg. Field trials showed that the degradation of the four pesticides followed first-order kinetics, with half-lives ranging from 1.1 to 1.8 days. After washing, boiling, pickling, stir-frying, and sauce processing, the concentrations of all pesticides-except for a metabolite of pyraclostrobin (BF-500-3)-were reduced to varying degrees (PF < 1). Hot air processing led to 4.3- and 4.6-fold increases in the concentrations of dinotefuran and 6-chloronicotinic acid, respectively, while the concentrations of all other pesticides decreased (PF < 1). Crisp processing increased the concentration of all pesticide residues by a factor of 2.0 to 4.0. Additionally, the content of BF-500-3 increased significantly by 2.9-4.9 times after washing, boiling, pickling, and stir-frying. However, it decreased after hot air processing and sauce processing. The risk quotient values of all pesticides were below 1, indicating that both chronic and acute dietary risks were acceptable. This study provides valuable data for the control of pesticide residues in processed products, which has both theoretical and practical significance in ensuring the quality and safety of shiitake mushrooms and protecting human health.