Co-contamination and interactions of multiple mycotoxins and heavy metals in rice, maize, soybeans, and wheat flour marketed in Shanghai City

Mycotoxins and heavy metals extensively contaminate grains and grain products, posing severe health risks. This work implements validated ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and inductively coupled plasma mass spectrometry (ICP-MS) methods to quantify the concentration of 12 mycotoxins and five heavy metals in rice, maize, soybeans, and wheat flour samples marketed in Shanghai. The mixed contamination characteristics were analyzed using correlation cluster analysis and co-contamination index, and the probabilities of all cross combinations of contaminations were analyzed using a self-designed JAVA language program. The results showed that grains and grain products were frequently contaminated with both mycotoxins and heavy metals, mostly with deoxynivalenol (DON), 3-acetyl-deoxynivalenol (3-ADON), 15-acetyl-deoxynivalenol (15-ADON), ochratoxin A (OTA), aflatoxins, fumonisin B1 (FB1), fumonisin B2 (FB2), fumonisin B3 (FB3), arsenic (As), chromium (Cr) and cadmium (Cd). All the samples (100%) were contaminated with two or more contaminants, and 77.3% of the samples were co-contaminated with more than four contaminants. In cereals and cereal products, the following combinations were closely associated: (FB3+3-ADON), (FB1+As), (FB1+FB2), (DON+FB1), (DON+Cd), (As+Cd), (DON+Cd+As), (FB1+FB2+As), and (DON+3-ADON+15-ADON). The results indicated that mycotoxins and heavy metals frequently co-occurred in Shanghai grains and grain products, and they provided primary data for safety assessments, early warnings, and regulatory measures on these contaminants to protect public health. Mycotoxins and heavy metals extensively contaminate grains and grain products, posing severe health risks. In this study, interaction analysis was performed on the multi-contaminants found in grains and grain products to identify co-contamination and assess their probabilities of co-existence using a self-designed JAVA language program. The study provides data for the assessment, early warnings, and regulatory measures related to mycotoxins and heavy metal contamination. Furthermore, the joint analyses demonstrated the importance of monitoring co-contamination and identifying the possible combinations with higher interaction rates to perform future investigations, as well as providing innovation for establishing national standards involving multiple contaminants.