Monitoring and Dietary Risk Assessment of Pesticide Residues and Mycotoxins in Fresh Maize: A Nationwide Study from China

Abstract Pesticide residues and mycotoxins are important maize contaminants, but their occurrence and dietary risks in fresh maize remain unclear. In this study, ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) methods were established for analyzing 70 pesticides and 15 mycotoxins and were applied to 302 fresh maize samples from three major regions in China. A total of 21 pesticides were detected at concentrations of 1.6–306 μg/kg and detection rates of 0.3–9.6%. Among the samples, 3.3% exceeded the Chinese maximum residue limits (MRLs). Three mycotoxins were detected at frequencies of 0.7–3.0% and concentrations of 2.6–19.1 μg/kg. Dietary risk assessment indicated that the estimated acute (%ARfD, 6.8 × 10–6–3.0 × 10–3) and chronic (%ADI, 7.0 × 10–5–1.2 × 10–1) risks from pesticide residues were well below 100%. The chronic dietary risk associated with the detected mycotoxins (%TDI) ranged from 3.9% to 30.1%, indicating no unacceptable risk.