Prevalence and levels of deoxynivalenol and zearalenone in commercial barley and wheat grain produced in Southern Brazil: an eight-year (2008 to 2015) summary

Fusarium head blight (FHB), caused mainly by Fusarium graminearum, is one of the most important diseases of barley and wheat in Brazil. The disease causes yield losses and contaminates grain with mycotoxins produced by the fungus, mainly deoxynivalenol (DON) and zearalenone (ZEA). The objective of this study was to summarize the results of 16,487 analyses of DON and ZEA in barley and wheat commercial grain produced in Brazil from 2008 to 2015 using liquid chromatography tandem-mass spectrometry. For barley, DON and ZEA were detected in 67% and 41% of the samples, respectively, but 19% and 18% were above the maximum tolerated limits (MTL = 1250 mu g/kg for DON and 100 mu g/kg for ZEA). For wheat, DON and ZEA were detected in 73 and 38% with 30% and 9% of the samples above the MTL (1250 mu g/kg for DON and 200 mu g/kg for ZEA). The overall mean concentration of DON was 737 mu g/kg in barley and 660 mu g/kg in wheat. The mean yearly DON levels varied less in barley (446 mu g/kg to 1114 mu g/kg) compared to wheat (346 mu g/kg to 1274 mu g/kg). For the latter, a high peak of DON was found in 2014 when 58% of the samples were above the MTL and the toxin levels averaged 1274 mu g/kg across all samples. The mean yearly concentration of ZEA was 138 and 111 mu g/kg for barley and wheat, respectively, with the highest prevalence and concentration reported in 2008 and 2009, for both crops. To our knowledge, this is the most comprehensive summary of DON and ZEA contamination in barley and wheat in Brazil for almost a decade of monitoring. Continuous assessment and close inspection of highly contaminated batches are essential to ensure food safety and mitigate the risk that these mycotoxins can cause to human and animal health.