Annual variation of deoxynivalenol in Danish wheat flour 1998-2003 and estimated daily intake by the Danish population

The occurrence of deoxynivalenol ( DON) in Danish wheat flour was studied during the period 1998 - 2003 by either capillary gas chromatography with electron capture detection and liquid chromatography coupled to an ion trap mass spectrophotometer. A total of 151 samples were collected from mills and the retail market in Denmark. Contamination levels varied considerably from year-to-year with the highest concentrations occurring in samples from the 2002 harvest with mean and median concentrations of 255 and 300 mu gkg(-1), respectively. Compared to other harvest years, 2002 had the highest amount of precipitation around flowering time, i.e. from the end of June to the beginning of July covering weeks 25 - 27. The lowest average levels were found in samples from the 2001 harvest, where weeks 25 - 27 were dry compared with other harvest years. The highest value ( 705 mu gkg(-1)) was obtained in a flour sample from the 2002 harvest, but none of the tested samples exceeded the maximum limit of 750 mu g kg(-1), which has been recently introduced by the European Commission for DON in flour used as raw materials in food products. Calculation of chronic or usual intake by a deterministic approach showed that intake did not exceed the TDI of 1 mu gkg(-1) bw day(-1) either for the whole population or for children. A probabilistic approach also showed that intake in general was below the TDI, but intake for children in the 99% percentile amounted to more than 75% of the TDI. The highest intake is calculated to be 2.5 mu gkg(-1) bw day(-1).