[Determination of deoxynivalenol (DON) in wheat, barley and corn and its relationship with the levels of total molds, Fusarium spp., colonization percentage and water activity].

Fifty samples of cereals including 30 of wheat (10 of wheat hard red spring), 10 of wheat soft red winter and 10 of wheat durum ámber), 10 of barley and 10 of corn (5 of white corn and 5 of yellow corn) were analyzed to detect and determine by the TLC method, the quantity of deoxynivalenol levels, which is a toxic secondary metabolite produced by Fusarium species. The aw of samples and the internal and external micoflora and Fusarium spp. levels were also investigated. Results showed that the highest grade of infection (12-80%), and the highest count of total molds (3.9 Log UFC/g) were detected in wheat samples, while the highest levels of Fusarium spp. (2.3 Log UFC/g) were detected in white corn. Deoxynivalenol was found in the wheat and barley samples but not in corn. The wheat red winter soft samples showed the highest levels of deoxynivalenol (3.2 ug/g) which is over the limit levels accepted by the FDA. Correlation was not found among count of total molds, Fusarium spp., infestation grade, aw, and deoxynivalenol levels. These results suggest that it is necessary to exert measures to avoid and to control the importation of contaminated cereals with DON levels higher to those allowed.