Thermal stability of T-2 and HT-2 toxins during biscuit- and crunchy muesli-making and roasting

The mycotoxins T-2 and HT-2 toxin are frequently occurring food contaminants which are produced by Fusarium species. Humans and animals are mainly exposed to these substances by the consumption of contaminated oats, maize and wheat. For the production of crunchy muesli, bread and bakery products, these cereals undergo multiple processing steps, including baking, roasting and extrusion cooking. However, the influence of food processing on T-2 and HT-2 toxin levels is to date poorly understood. Thus, the effects of baking and roasting on both mycotoxins were evaluated during biscuit-, crunchy muesli- and toasted oat flakes-production under precise variation of various parameters: heating time and temperature as well as recipe formulation were varied in the range they are applied in the food processing industry. Therefore, oatmeal or flaked oats were artificially contaminated individually with both toxins and processed at the laboratory scale. T-2 toxin generally showed a higher degradation rate than HT-2 toxin. During biscuit-making up to 45% of T-2 toxin and 20% of HT-2 toxin were thermally degraded, showing a dependency on water content, baking time and temperature. The preparation of crunchy muesli yielded no significant toxin degradation which is probably due to the low temperatures applied. Roasting led to a degradation of 32% of T-2 toxin and 24% of HT-2 toxin. Taken together, both mycotoxins are partially degraded during thermal food processing; the degradation rates are influenced by the food composition and processing parameters.