RESUMO
Two simple and low-cost QuEChERS approaches were optimized and validated for multimycotoxin determination in grains by UPLC-MS/MS and applied to assess effectiveness of controlled atmosphere (CA) storage in preventing mycotoxin contamination. Common bean, soybean, and maize samples were stored for 6 months. CA treatments were conducted varying O2 and CO2 partial pressures, temperatures, and moisture contents of the chambers. In the validation study for common bean and maize, 8 out of 11 mycotoxins were successfully validated. For soybean, 10 out of 11 mycotoxins were validated. Aflatoxin B1 was detected in all commodities. Statistical tests suggest that storage temperature played a key role in aflatoxin B1 concentrations in common bean and soybean, but had no influence on maize. Maize was also positive for fumonisins B1 and B2. Differences in fumonisin concentrations were not significant among different treatments. Concentrations of aflatoxin B1 in some samples exceeded legislation's maximum levels. Thus, some of the CA treatments applied were effective in preventing mycotoxin contamination in common bean and soybean but were not effective for maize.
