Occurrence of Fusarium T-2 and HT-2 toxins in oats from cultivar studies in Germany and degradation of the toxins during grain cleaning treatment and food processing

摘要

For the Fusarium trichothecene mycotoxins T-2 and HT-2, a combined (T-2 + HT-2) temporary tolerable daily intake (tTDI) of 0.06 μg kg~(-1) body weight day~(-1) was proposed at the European level in 2001 (Opinion of the Scientific Committee on Food). In the near future, maximum levels for these trichothecenes will be regulated by the European Commission as announced in EU (VO) 1881/2006. For the implementation of these maximum levels, more data on occurrence and behaviour of T-2 and HT-2 toxins in primary agricultural products as well as during cleaning treatment and food processing are needed. In the current work, we determined the T-2/HT-2 concentrations in four oat cultivars (Aragon, Dominik, Ivory, Pergamon) from ten different agricultural sites in Germany, grown in cultivar studies in 2007. The grains were de-hulled, oat meal was prepared, and bread with 20% oat meal and 80% wheat flour was baked. In the cereal-processing chain, samples were taken at various steps and subsequently analysed for their T-2/HT-2 content. We employed liquid chromatography-mass spectrometry (LC-MS) and an immunological screening method (enzyme-linked immunoabsorbant assay (ELISA)) for T-2/HT-2 determination. Detection limits were between 1 and l0 μg kg~(-1) in different matrices. T-2/HT-2 concentrations determined by ELISA in oat samples from ten different agricultural sites in Germany were between 9 and 623 ug kg~(-1). The median and 90th percentile were 48 and 191 μg kg~(-1) T-2/HT-2, respectively. One site showed six times higher T-2/HT-2 levels than the other sites, where concentrations ranged from 322 to 623 μg kg~(-1). In 80% of the samples the cultivars Pergamon and Ivory had the lowest concentration of T-2 and HT-2 toxins. Using LC-MS for T-2/HT-2 determination, cleaning of the raw material did not lead to significant reductions of T-2 and HT-2 levels, whereas de-hulling led to a reduction of over 90%. Boiling of oat meal produced from cleaned raw material to yield 'porridge' resulted in varying T-2/HT-2 levels in experimental replicates. No major reduction of T-2/HT-2 levels in cooked porridge was obtained. Standardized baking experiments using 20% oat meal showed that T-2 and HT-2 toxins are relatively stable during the baking process, probably due to their temperature stability.