Mycotoxins are natural contaminants of food, including maize. In Mexico, due to its large consumption, population may be at a higher risk, yet limited risk assessments of mycotoxins are available. This thesis assessed the major mycotoxins of concern in nixtamalized maize, including Aflatoxin B1 (AFB1), by measuring their levels in nixtamalized maize from Mexico City, and performed a risk assessment. Results indicate that nixtamalization may not be fully effective in reducing mycotoxin levels to a level of low concern and therefore indicates a priority for risk managers. A new approach was used to estimate the in vivo acute liver toxicity of AFB1 in rats and humans by developing physiological based kinetic (PBK) models for AFB1, and translating in vitro data using PBK modelling-based reverse dosimetry to in vivo dose response curves without the need for in vivo studies. This approach also predicted in vivo genotoxicity of AFB1 in rat.