Aflatoxin B1 in nixtamalized maize in Mexico; occurrence and accompanying risk assessment

Maize is a staple food in Mexico that might contain Aflatoxin B1 (AFB1). Nonetheless, data on the exposure and risk assessment of AFB1 from maize for the Mexican population are limited. The aim of the present study was to analyse the occurrence of AFB1 in Mexican nixtamalized maize samples, and to assess the accompanying exposure and risk. Four out of 88 samples contained AFB1 at levels above the limit of detection (1 ng/g). AFB1 occurrence values obtained in this study and additional occurrence values from literature were combined with available literature data for mean and P95 consumption of maize based products. For a 70 kg body weight person, lower bound and upper bound exposure assessments resulted in estimated daily intakes (EDI) of 0.7-8.5 ng/kg bw/day, based on a mean maize consumption. Based on the P95 maize consumption these EDI values amounted to 3.3-11.7 ng/kg bw/day. The corresponding Margin of Exposure (MOE) values amounted to 257-20 for the mean and 50-15 for the P95 consumers. The estimated increased cancer risks were 9-320 and 43-439 cases/10⁶ individuals/lifetime of 75 years for the mean and P95 consumers, respectively. Altogether, the assessment reveals the need for continued risk management of AFB1 in Mexico.