EARLY DETECTION OF DEOXYNIVALENOL IN WHEAT GRAIN

The cereals crops in Belgium are not safe from serious contaminations by mycotoxins. The years 1997 and 1998 for example were very favourable to the development of Fusarium head blight. On that account, the project main objective consists in assessing the risk of mycotoxins contamination and studying the environmental factors that contribute to increase the rate of wheat contamination and integrating them in a forecasting model. A competitive direct enzyme-linked immunosorbent assay (CD-ELISA) for the semi-quantitative analysis of deoxynivalenol (DON) has been used on 130 samples of wheat grains of the harvest 2000. In addition, a HPLC multi-residue method is in development to separate various mycotoxins. Samples, mentioned above, were contaminated mainly by Microdochium nivale (96%), a fungi inducing scab symptoms but not suspected to produce mycotoxins, F. culmorum (22%) and F. graminearum (15 %). A small amount of analyzed samples were contaminated by F. poae and F. avenaceum. PCR analyzes were used to verify the Fusarium species microscopic identification. The DON concentration determined by immu- nological analysis has provided values ranging from 0 to 1,2 ppm (92%: 0-0,5 ppm; 6%: 0,6- 1 ppm; 2% > 1 ppm). In the other hand, two types of artificial contaminated field trials were established: 1) A multi-variety trial where different varieties of wheat were inoculated sepa- rately with F. graminearum and F. culmorum. 2) A one-variety trial where 20 Fusarium strains belonging to the four Fusarium species, above mentioned, were inoculated. For the first trial, we observed differences in both infection rates in the field and DON accumulation between varieties but not between Fusarium species inoculated. For the second one, differences in DON production were observed between Fusarium species and between some strains of the same species. Microbiological analyses and field observations show a good correlation but they were not related to the DON concentration. 2001 National Fusarium Head Blight Forum 169 Food Safety, Toxicology and Utilization PHYSICAL TREATMENTS FOR PREVENTING THE POST-HARVEST GROWTH OF FUSARIUM IN MALTING BARLEY B. Kottapalli and C.E. Wolf-Hall* Department of Cereal and Food Sciences, North Dakota State University, Fargo ND *Corresponding Author: PH: (701) 231-6387; E-mail: Charlene.Hall@ndsu.nodak.edu