Mycotoxins: Biosecurity, Food Safety and Biofuels Byproducts

Non-Technical Summary: The most important relevant issues facing grain and livestock producers are preventing mycotoxin contamination of food and feed, and reducing the deleterious effects of mycotoxins on livestock. Mycotoxins in grains processed for biofuels becomes concentrated in the solid byproduct known as distillers grain (DG), thus mycotoxin contamination is a major concern. For grain buyers and food processors, the primary need is a reliable method for rapid assessment of grain quality pertaining to mycotoxins and mycotoxigenic fungi. These stakeholders need cost-effective methods to predict, monitor, and minimize mycotoxin production in the field, and to detoxify mycotoxins. The lowering of tolerance limits for mycotoxins in overseas markets has increased the burden for grain buyers and food processors; currently, levels of mycotoxins that are acceptable for some US products are unacceptable in European and Asian markets, resulting in non-tariff trade barriers. Animal and human health workers need information about the toxicity, carcinogenicity, modes of action, and biomarkers of exposure and disease for all categories of mycotoxins. This information will help train health-care providers to identify exposure and treat related disease and to develop accurate risk assessment recommendations. The proposed research is wide-ranging and could lead to negative consequences if not completed. The presence of mycotoxins is an important health hazard. Hazard assessments including exposure assessment and evaluation of toxicity are essential. Without an aggressive research program to prevent, treat, and contain outbreaks of mycotoxins in grain, US grain producers will suffer the consequences of reduced marketability of their products. Furthermore, the proposed research addresses biosecurity concerns. Outcomes or projected Impacts: The outcomes derived from the work outlined in this proposal will contribute towards the overall goals of the National Institute of Food and Agriculture. Our results will contribute to the improvement of food security and safety, which should impact both human and animal health. U.S. and international government policy makers will use our research in their risk assessments for mycotoxins. The typical outcome of risk assessment data has been government recommendations on the maximum tolerable mycotoxin levels in agricultural products, which affects both national and international use and profitability of products. We anticipate that results from the research outlined in Objective 1 will have a major impact on government decision-making by providing a better understanding of how various environmental and food processing components affect mycotoxin biosynthesis. The outcomes will include new basic knowledge that can be incorporated into new management strategies to help grain growers minimize mycotoxin contamination, and maximize profitability. <P> Approach: We will continue to generate data to address the knowledge gaps related to the mechanistic basis for mycotoxin induced disease. This will be done through evaluating structure activity relationships (SAR) and investigating cell, tissue and whole animal responses at the biochemical, physiological and structural levels. IA will provide Fusarium proliferatum culture material. Dose response assessments will be used by IA to determine and model mycotoxin toxicity including acute toxicity, carcinogenesis, and immunomodulation. Exposure assessments for mycotoxins must take into account route of exposure duration of exposure to the mycotoxin. Dose response data for DON and DON-glucoside in mice will be obtained by IA. Data will be generated for risk assessment of the use of mycotoxin contaminated grains, focusing on fumonisins, with both conventional and insect-resistant transgenic maize, used in the biofuels industry and its subsequent byproducts. Systematic evaluation of structure activity relationships (SAR) has not been conducted in the mycotoxin area. IA will use the K562 human erythroleukemia cell line as a model to evaluate SAR of DON, its major metabolites and other trichothecenes. This cell system will also be used to model human urine contents of trichothecenes, by comparing individual mycotoxin dose/responses with various combinations of trichothecenes and their key metabolites. The development of a rapid, inexpensive monitoring scheme for human exposures to these mycotoxins is a goal. Rodents will be used as a model for carcinogenicity, teratogenicity and immunotoxicity for DON. Since several trichothecenes have been identified by CDC as biosecurity risks, it is critical to be able to use animal assays in conjunction with cell systems to evaluate potential natural or intentional contamination of feeds and foods by these agents. Animal assays will be critical to IA in assessing if the decontamination and detoxification strategies designed in objective 2 are successful. We will continue to assess acute toxicity of fumonisins and DON in mouse and other animal models in oral feeding studies with naturally contaminated foods or purified toxin. Adaptation to subchronic exposures to DON is a key observation in previous studies (IA) that we will assess further by studying DON metabolites and DON-metabolizing gut microbial changes over time and dose of DON exposure. For objective 2, we continue efforts to test new technologies for analysis of mycotoxins and reduction of their toxic effects. Grains with higher levels of contamination and most screenings from grain operations are unsafe for human and/or animal consumption and must be destroyed or alternate uses identified. Committee members from MO, IA, IN, and ND will collaborate on grain research on technology that will eliminate the mycotoxins or reduce their toxicity. IA will lead research that investigates chemical reactions of mycotoxins with other food constituents, with special emphasis on processes for human foods.