Distribution of deoxynivalenol in barley kernels infected by Fusarium.

Deoxynivalenol (DON) in concentration range 0.1-156.6 mg/kg, was found in 48 samples of barley kernels collected from heads with visible symptoms of head scab after inoculation in a field with Fusarium culmorum and Fusarium graminearum. Four fractions of the kernels were collected according to their size: > 2.8 mm (I); < or = 2.8-2.5 mm (II); > 2.5-2.2 mm (III) and < 2.2 mm (IV). In plants infected with Fusarium (when compared to the control) number of kernels in the fraction of the largest kernels (> 2.8 mm) decreased from 38% to 18%, while in small kernels (fractions < 2.5-2.2 mm and < 2.2 mm) numbers increased respectively from 16 to 22% and from 14 to 28%. Average level of DON concentration in these fractions was as follows: (I) 3.5 mg/kg--(4%); (II) 9.1 mg/kg--(16%); (III) 35.5 mg/kg--(29%) and (IV) 43.3 mg/kg--(51%). The highest DON accumulation was observed in fraction of small (< 2.5 mm) kernels. The fraction contributed from 77% up to 94% of total DON content in kernels with low (< 2 mg/kg) and high (> 100 mg/kg) contamination level, respectively. These results indicate that as well level of samples contamination with DON as human and animal health risk in consequence can be reduced by kernels selection (according their size) followed by rejection of the smallest kernels fraction.