Evaluation of aflatoxin and fumonisin co-exposure in urine samples from healthy volunteers in northern Mexico

[Display omitted] •High frequency of co-exposure to aflatoxin and fumonisin is present in Mexicans.•No co-exposed participants had higher concentrations of either AF or FB than co-exposed.•Detection of aflatoxins and fumonisins in maize based foods in Mexico is common. Aflatoxins (AF) and fumonisins (FB) are common contaminants of maize and have been associated with cancer, immune suppression, and growth stunting. In this work, AFM1 and FB1 were measured in urine samples of healthy volunteers from the metropolitan area of Monterrey, Mexico, while AF and FB were detected in foods collected near the sampling zone. Urine samples from 106 adults were analyzed using ultra-performance liquid chromatography-tandem mass spectrometry and toxins in foods were measured by fluorometry. The mean value of AFM1 and FB1 was 4.3 pg/mg creatinine from 76 samples (72 %), and 50 pg/mg creatinine from 75 samples (71 %), respectively. More than half of the samples (n = 56, 53 %) had detectable levels of both AFM1 and FB1. No differences in toxin levels were found between males and females or between age groups, but AFM1 and FB1 levels were higher (p < 0.01) when detected as a single exposure compared to co-exposed. Some significant results were found when comparing AFM1 and FB1 levels among groups of people assigned to levels of food consumption. Food samples had average concentrations of 5.3 μg/kg for AF and 800 μg/kg for FB. The results showed that co-exposure to AF and FB is common in the metropolitan area of Monterrey.