An Investigation of the Spatial Arrangement of Mycotoxin Build-Up in Corn Stored Under Different Environmental Conditions

Mycotoxins are toxins produced by fungi that contaminate many key food crops as they grow in the field and during storage. Specific mycotoxins are produced by different fungi. Each type of fungus and mycotoxin have their own optimal temperatures and water activities for growth and production. The legislative limits for various mycotoxins in foodstuffs to protect human health vary between countries but all commodities have their levels evaluated based on the concentrations from one aggregated grain sample. This approach assumes that the variation in toxin levels is uniform and random without spatial trends. This study investigates the spatial distribution of four mycotoxins (aflatoxin, deoxynivalenol, fumonisin and zearalenone) in bins of clean and dirty corn when stored in an environmental cabinet for two months under different temperature and humidity conditions. The bins of clean and dirty corn each had 12 CO₂/humidity/temperature sensors installed in three layers, and samples were extracted for mycotoxin analysis from locations close to each sensor following storage. Using Mann-Whitney U and Kruskal-Wallis H statistical tests, significant differences were found between mycotoxin levels attributable to the different environmental conditions and spatial locations of samples. Variations in aflatoxin and zearalenone concentrations were most pronounced for the range of temperature and humidity conditions chosen. By understanding the patterns of spatial variability in mycotoxin concentrations and identifying zones at high risk of contamination, as well as what conditions are favorable, targeted interventions could be implemented to reduce food waste. This work also has implications for how levels of mycotoxins in foodstuffs are sampled and measured.