USDA-ARS Research on Preharvest Control of Aflatoxin Contamination in Food and Feed Crops

Aspergillus flavus is a saprophytic, filamentous fungus that can invade agronomically important oil seed crops such as corn, peanut and cottonseed where it produces the toxic and carcinogenic family of secondary metabolites, aflatoxins. Aflatoxin B1 is the most potent natural carcinogen known and as such its presence in commodities is strictly regulated by the Food and Drug Administration (FDA) and European importers of American food products.  The total annual loss to the U.S. corn industry alone due to aflatoxin contamination has been estimated at approximately $200 million. Aflatoxin contamination in crops such as corn can be much more serious in developing countries because the largest proportion of the crop is used for human consumption and there is limited capacity to monitor aflatoxin in the grain.  Ingestion of food contaminated with high levels of aflatoxins has been implicated in acute toxicosis that often results in death while chronic, low-level exposure can lead to liver cancer, immune suppression, and stunting of growth in children among other pathological conditions. Despite the many advances made in the biochemistry, genetics, and ecology of A. flavus and aflatoxin production, current control strategies fail to effectively eliminate aflatoxin contamination.  This presentation will provide an overview of pre-harvest aflatoxin control research being conducted by scientists in the Food and Feed Safety Research Unit at the USDA-ARS Southern Regional Research Center in New Orleans, LA. Multifaceted approaches being undertaken include biological control, host plant resistance strategies (breeding and genetic engineering) and –omics technologies (proteomics, transcriptomics, metabolomics) to study mechanisms controlling aflatoxin biosynthesis and fungal development.  Taken together, these approaches will lead to the development of novel biotechnological control strategies, contributing to the reduction of pre-harvest aflatoxin contamination.