The Occurrence and Co-Occurrence of Aflatoxin and Fumonisin Along the Maize Value Chain in Southwest Nigeria

flatoxins and fumonisins are two major mycotoxins: toxic chemicals produced by fungi that contaminate a variety of food commodities including maize, a key staple food in sub-Saharan Africa. Aflatoxin causes liver cancer (hepatocellular carcinoma, HCC) and has been associated with acute liver toxicity and immunotoxicity, while fumonisin has been associated with neural tube defects in infants and esophageal cancer. Both mycotoxins have been associated with child growth impairment. Previous studies have demonstrated that co-occurrence of these mycotoxins may have potential synergistic toxicological effects in humans. Therefore, this study examines the occurrence and co-occurrence of fumonisin and aflatoxin along the maize value chain in southwest Nigeria. Despite regulatory limits in Nigeria for aflatoxins in maize products, 51.70% of the samples were found had aflatoxin levels above those limits. Though no regulatory limits currently exist for fumonisins, 12.93% of the samples contained total fumonisin levels higher than the United States regulatory limit. We found that aflatoxin and fumonisin contamination in maize products extends beyond production to storage and final food products. Thus, adequately addressing the mycotoxin challenge requires consideration of the entire maize value chain. This study encourages further research to generate data on the exposure of Nigerians to fumonisin and aflatoxin and potential adverse health effects.