Stability of the mycotoxin deoxynivalenol (DON) during the production of flour-based foods and wheat flake cereal

Authors: Voss, Kenneth; Snook, Maurice

Submitted to: Food Additives & Contaminants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/9/2010
Publication Date: 12/1/2010
Citation: Voss, K.A., Snook, M.E. 2010. Stability of the mycotoxin deoxynivalenol (DON) during the production of flour-based foods and wheat flake cereal. Food Additives & Contaminants: Part A. 27(12):1694-1700.

Interpretive Summary: Deoxynivalenol, or DON, is a toxin made by molds that grow on wheat, corn and barley. DON is toxic to animals. Human exposure occurs through consumption of cereal products and although its impact on human health is not fully understood, minimizing exposure is desirable. Experiments to determine the amount of DON remaining in bread baked from DON contaminated flour have shown inconsistent results, suggesting that, while DON is generally stable, specific conditions such as baking time and temperature, fermentation conditions, and recipe influence its stability. Determining the stability of DON during food processing is important for protecting consumer health by maintaining low levels of this naturally-occurring toxin in finished products. However, little information on DON stability during the production of flour and wheat-based products prepared under food industry-relevant conditions is available. We therefore compared DON concentrations in flour and products made from the flour as well as in wheat and wheat flake cereal to determine if baking or other cooking methods reduced DON concentrations. Cooking had little effect on the DON concentrations of cookies, crackers, and pretzels and DON was increased slightly in the wheat flake cereal. DON concentrations of cake donuts and bread were reduced more than 50% compared to the flour. When the results were calculated on the basis of DON per gram of flour in the product, it was evident that the reduced DON concentrations in donuts resulted from dilution of the flour with other recipe ingredients and uptake of oil during frying. In contrast, the reduction in bread resulted from a combination of dilution by recipe and loss of DON, presumably by chemical decomposition or binding to bread matrix components. Thus, DON is not destroyed in these food items during their cooking preparations.

Technical Abstract: Deoxynivalenol (DON) is a trichothecene mycotoxin found in cereal grains and cereal-based foods. Its concentrations in finished products are reduced under some processing conditions, but not others. DON concentrations in flour, wheat and selected foods made from them under commercially relevant conditions were compared by gas-chromatography-electron capture detection. Average concentrations (n=3/item, each sample analyzed in triplicate) in cookies, crackers, and pretzels ranged from 61% (cookies) to 109% (pretzels) compared to flour (100% = 0.46 µg g-1). Lesser amounts were found in the donut and bread products: their respective DON concentrations were 44% and 30% that of flour. Mass balance estimates for DON (µg g-1 flour equivalents) ranged from 50% (bread, 0.23 µg g-1 flour equivalents) to 120 % donuts, indicating that dilution by recipe ingredients contributed to DON reductions in bread and accounted for all of the apparent reduction in donuts. Mass balance estimates averaged 76% (cookies) to 109% (pretzels) for the other flour products. DON concentration was higher in cereal flakes (0.55 µg g-1 in the finished product and 0.58 µg g-1 on a mass balance basis) than in the wheat (0.40 µg g-1), suggesting that DON concentrations might increase during processing under some conditions. In summary, DON concentrations of finished food products were reduced > 50% only in bread and donuts. Reduction in bread resulted from a combination of DON "loss" and dilution by recipe ingredients whereas the reduction in donuts was due entirely to dilution.