| Abstract: | Fusarium head blight, induced primarily by Fusarium graminearum, resulted in widespread damage to the Manitoba barley crops of 1993 and 1994, with contamination by deoxynivalenol (DON) and other 8-keto-trichothecenes. Visible Fusarium mold in samples of 1994 barley had little relationship to DON levels in the kernel as determined by gas chromatography-mass spectrometry (GC-MS). While samples of 1993 and 1994 barley showed a weak correlation between the logarithm of DON level and percentage of kernels infected by Fusarium graminearum (r = 0.79 and 0.71, respectively), the latter method is too lengthy and requires too much training for commercial application. A commercial enzyme immunoassay for DON gave results that correlated well with GC-MS methods (r = 0.95 and 0.89, respectively) in samples of 1993 and 1994 barley and afforded a rapid and convenient method for screening. In barley samples from 1994, DON, 15-acetylDON, 3-acetylDON and 3,15-diacetylDON were detected in the approximate ratio of 47:4:1:1. In view of the higher oral toxicities of 15-acetylDON and 3-acetylDON relative to DON, and the unknown oral toxicity of 3,15-diacetylDON, GC-MS assays might be advisable in samples positive for DON from enzyme immunoassay screening. |
