Marketing and Delivery of Quality Grains and Bioprocess Coproducts

<P>NON-TECHNICAL SUMMARY: Mycotoxins are toxic compounds produced by certain filamentous microfungi or molds. Mycotoxins considered to be important, including aflatoxins, ochratoxins, fumonisins, deoxynivalenol and zearalenone, are produced mainly by three fungal genera, Aspergillus, Penicillium and Fusarium. Some of these fungi may invade plants and cereal grains in the field during the growing season, as well as during postharvest handling processes such as drying and storage. Cereal grains are the most frequently affected commodity while all major crops and commodities may be contaminated with one or more mycotoxins. Moreover, the stable nature of mycotoxins often leads to contamination of products in downstream processes including finished products destined for human and animal consumption. Infection of mold and subsequent toxin production may occur naturally virtually at any conditions. However, among the various environmental factors, temperature and precipitation are considered most critical for invasion, growth, and toxin production in grain in the field. For instance, cool and wet weather during the growing season seems to be the most important factor for wheat in the development of Fusarium head blight (FHB) as well as accumulation of trichothecenes (including deoxynivalenol). The climate condition in Pacific Northwest region, or Palouse, allow wheat and other commodities to grow naturally without irrigation by seasonal precipitation. Fertile soil and lack ofsevere temperature fluctuation also contribute to the high yield of the important staple food crop. However, recent variability in climate prompted better understanding of agroecosystem to ensure grain quality and food safety since the fungal infection and mycotoxin production may not remain the same under the varying environmental conditions. It is particularly true in Pacific Northwest where natural precipitation in the past allowed agricultural commodities, e.g. wheat, to be cultivated without irrigation system. The lack of extreme fluctuation in temperatures during the growing season also contributed to the higher yield of crops in comparison to those from other regions. However, increasing daily and seasonal fluctuation of temperature in addition to the variability in precipitation due to climate change would affect mycotoxin production. Variability in climate may cause changes in soil system, including organic and inorganic matters, where plants are rooted to grow. As many plant pathogenic fungi and mycotoxin producers, e.g. Fusarium species, are soilborne and their population is largely affected by the climate and soil system, it would be plausible to investigate the impact of climate changes on the soil system that will determine toxigenic fungal population and their potential in growth and survival of the organism as well as mycotoxin production. Therefore, Pacific Northwest region may provide a unique model system to study impact of climate variability on agroecosystem particularly in fungal population in the soil and quality of grains by assessing potential for mycotoxin production in wheat and other agricultural commodities. </P>
<P>APPROACH: Objective 1: Soil samples from various parts of Pacific Northwest will be collected annually. These samples will be transported to the PD's lab for the analysis of fungal population. The total mold count will be performed by appropriate serial dilution of soil samples in sterile peptone water followed by plating on dichloran rose bengal chloramphenicol agar. In addition, the number of Fusarium species will be counted by using Czapek iprodione agar and further identified to the species level. Objective 2: Available HPLC and LC-MS methods for detection and quantification of mycotoxins in cereal grains and other commodities will be evaluated employ advances in analytical instruments and techniques. Evaluation of rapid methods (immunochemical) for detecting and quantifying mycotoxins in a variety of foods will also be performed. Several foods will be analyzed using these rapid methods and the results compared to those obtained using the HPLC and LC-MS method. Objective 3: Sampling - Samples will be purchased from retail stores and bulk suppliers across the Pacific Northwest region though the geographic location will be concentrated in the two states of Idaho and Washington. In the case of wheat, winter, spring and Durum wheat samples will be collected from the annual wheat quality survey conducted through the Wheat Quality Laboratory at Washington State University or Idaho Wheat Commission and Washington Grain Commission. Analysis of mycotoxins - Quantification of mycotoxins will be carried out by the method verified in Objective 2. Two major toxins of interest in this study would be DON and OTA though other mycotoxins of concern for food safety will be included. The procedures for wheat prior to the optimization and verification are demonstrated as below. Objective 4: Quantitative risk assessment for the mycotoxins will be carried out with the steps described below. In general, methodology will be followed to estimate the impact to human health from mycotoxins in foods obtained in the Pacific Northwest. Risk assessment is the process of estimating the magnitude and the probability of a harmful effect to individuals or populations from certain agents or activities. Objective 5: Strategies to reduce exposure from mycotoxin in the food supply will be developed depending on the results of risk assessment in Objective 4. The strategies can be considered as a risk management plan based on the framework proposed by FAO and WHO (FAO/WHO, 1995) rather than investigation of measures to detoxify contaminated foods. Risk management is aimed to achieve practical solutions, e.g. guidelines regarding maximum residue levels or procedural guidelines to prevent the problem. In this project, however, regulatory measures will not be sought. Instead, the strategies will be developed with emphasis on postharvest practices including storage, processing, and surveillance. </P>