Location: Mycotoxin Prevention and Applied Microbiology Research
2021 Annual Report
Objectives
The goals of this project are to reduce exposure to such toxins and to enhance food safety through the development of tools to more effectively monitor for natural toxins. The first goal will be addressed by development of materials capable of being used in the removal of toxins from foods, thereby reducing exposure. The second goal involves surveying one important commodity, oats; improving methods for toxin detection; and, in particular, developing methods to allow for the prediction of toxin contamination. To meet these goals, we have three objectives.
Objective 1. Develop materials and methods to maintain commodity value and safety by eliminating mycotoxin contamination. Sub-objective 1.A. Develop antifungal compounds. Sub-objective 1.B. Remediation. Objective 2. Determine the occurrence of mycotoxins in alternative grain commodities, for example the U.S. oat supply. Determine the fungi and oat cultivars associated with reduced mycotoxin levels and/or disease. Sub-objective 2.A. Survey U.S. oats for mycotoxin contamination. Sub-objective 2.B. Survey U.S. oats for fungal contamination. Objective 3. Develop analytical tools to predict and evaluate the presence of natural toxins (mycotoxins) in grain commodities and their related foods. Sub-objective 3.A. Develop tools to predict the presence of toxins in commodities and foods. Sub-objective 3.B. Develop tools to detect emerging toxins, their metabolites and masked forms.
Approach
Food crops are commonly infested with fungi, both in the field and in storage. Certain fungi produce toxins (mycotoxins) that can adversely affect human health and the health of domestic animals. Certain toxin-binding materials may also have the potential to be used to remove toxins from foods, and this will be approached through the development and application of novel synthetic materials to reduce exposures. By permitting the timely diversion of contaminated ingredients from the food supply, detection of foodborne toxins can directly improve food safety and the safety of animal feed. Monitoring for the presence of such naturally occurring toxins is widespread and occurs at many of the stages between the producer and the consumer. Increasing the efficiency and improving the accuracy of monitoring results in more appropriate and efficient diversion of contaminated products. The need to monitor for greater numbers of mycotoxins is a trend that will continue, in particular because of recent concern over the so called “masked” mycotoxins. This project will put a particular focus on the food safety of a commodity important to U.S. consumers, oats. A survey of both toxin contamination and fungal contamination in U.S. oats will aid in the assurance of a safe supply of the key ingredient in human diets. Further, this project seeks to address the need for improved toxin detection by developing rapid detection methods leading to the prediction of toxin contamination in a variety of food / feed ingredients.
Progress Report
Goals of this objective are to develop materials and methods to maintain commodity value and safety by eliminating mycotoxin contamination. Antifungal compounds can reduce contamination levels of mycotoxin producing fungi in commodities. However, numerous fungi are developing antifungal resistance. Several types of commonly used phenolic compounds exhibit antimicrobial properties and are of interest as antifungals. Yet, the screening of these compounds for antifungal and safety properties is time consuming and expensive. Therefore, the phenolic compounds were screened for toxicity using predictive modeling resources developed by the Environmental Protection Agency (EPA) and Food and Drug Administration (FDA). Candidate phenolic compounds predicted to have antifungal activity but not pose a safety risk were identified and are being further evaluated.
Objective 2: Goals of this objective are to determine the occurrence of mycotoxins in oats, and to determine the fungi and oat cultivars associated with reduced mycotoxin levels and/or disease. A variety of fungi can infest developing grains and, ultimately, contaminate grains with mycotoxins. We are refining sampling plans with cooperators to effectively sample fungal and mycotoxin contamination in U.S. oats.
To further develop the ability to sample fungal contamination in developing crops, we have secured funding from the National Predictive Modeling Tool Initiative to conduct the project “Quantitative monitoring of mycotoxin - producing fungi in corn production fields” over the years 2021-2022. The project supports the development and implementation of remote sensing devices for the identification and quantitation of air-borne fungal spores in agricultural fields. A goal of the study is to develop tools for the prediction of pre-harvest and post-harvest fungal and mycotoxin contamination of a variety of food/feed grains.
Objective 3: Goals of this objective are to develop analytical tools to predict and evaluate the presence of natural toxins (mycotoxins) in grain commodities and their related foods. Fungi are used to impart desirable flavors and textures to cheeses. However, certain fungi produce secondary metabolites toxic to animals, mycotoxins. Two groups of cheeses where fungi are used for ripening are the blue-veined cheeses and the “soft-ripened” cheeses. The presence of the toxic fungal metabolite, roquefortine C (ROQC) in blue-veined cheeses has been reported previously, primarily in Europe. The extent to which ROQC occurs in cheeses sold in the U.S. has been largely unreported. To evaluate the potential food safety risk associated with this toxin, we developed an antibody-based screening assay and used it to survey for ROQC contamination in 202 samples of cheeses sold in the U.S. Of the 152 blue cheese samples, 151 contained ROQC. The levels found were consistent with the levels found previously in blue-veined cheeses in the United Kingdom and Europe, which have generally been considered non-hazardous for human consumption.
Accomplishments
1. Determination of toxins produced by fungi present in barley and wheat. Fusarium head blight (FHB) is an economically important disease of cereal crops worldwide and is a food and feed safety concern because the fungi that cause it can contaminate grain with toxins that pose health risks to humans, pets and livestock. ARS researchers at Peoria, Illinois, in collaboration with the University of Bologna and University of Perugia in Italy investigated the toxin production abilities of a collection of nine Fusarium species recovered from barley and wheat with FHB in seven climatic zones in Italy. Analyzing 117 isolates with state-of-the-art analytical methods, the researchers determined that collectively the isolates produced seven biologically active metabolites, including two toxins (enniatins and moniliformin) that are a moderate concern to food and feed safety. These results are critical for understanding the risks to food and feed safety posed by Fusarium species that infect nationally and internationally grown barley and wheat crops. The results also provide information for development of regionally targeted FHB and toxin control programs that improve crop production and food safety.
