Fungal infection and presence of deoxynivalenol and zearalenone in cereals grown in the Netherlands

In 1991 and 1993 cereals were sampled during harvest in The Netherlands. The samples were tested for the presence of molds and the samples of 1993 were additionally tested for the mycotoxins ins deoxynivalenol and zearalenone. The molds were identified to genus level and those belonging to the genus Fusarium to species level. The total fungal infection of cereals in 1991 did not differ from 1993, with a median value of 5.0 log CFU g(-1) in both years. The incidences of the genera Aspergillus, Penicillium, the group of Mucor and Rhizopus, Cladosporium, and Fusarium differed considerably between the two years, possibly caused by the different weather conditions. The numbers of samples infected with Fusarium were much higher in 1993 (83%) than in 1991 (34%). In 1991, no Fusarium was detected in samples from the southern part of The Netherlands, as opposed to 1993, when Fusarium was found in all regions sampled. The most dominant Fusarium species in 1991 were Fusarium culmorum and Fusarium avenaceum. In 1993, Fusarium pone, Fusarium culmorum, and Fusarium crookwellense dominated. All these Fusarium species are known mycotoxin producers. Three percent of the cereal samples of 1993 contained deoxynivalenol and 1% contained zearalenone in levels of over 500 mu g k(-1) and 200 mu g kg(-1), respectively. This study has shown that the incidences of various fungal genera and Fusarium species in cereals in The Netherlands can vary from year to year. Considerable numbers of toxigenic Fusarium molds can occur and Fusarium mycotoxins may be present.