Fusarium species and enniatin mycotoxins in wheat, durum wheat, triticale and barley harvested in France

Contamination with enniatins A, A1, B and B1 was investigated in 1240 samples of small grain cereals (470 wheat, 260 durum wheat, 282 spring barley, 172 triticale and 56 winter barley) from the French harvests of 2012 to 2014. Associations with Fusarium avenaceum, F. tricinctum and F. poae were assessed, with the identification of Fusarium species by real-time PCR and mycotoxin quantification by LC-MS/MS. Enniatins were common in the fields sampled. Enniatin concentrations varied between years but were consistently highest on spring barley (mean values of 199 to 1316 mu g/kg) and triticale (mean values from 131 to 1218 mu g/kg), and lower on wheat (mean values from 47 to 142 mu g/kg) and durum wheat (mean values from 55 to 596 mu g/kg). The concentrations of the various enniatins were strongly correlated with each other (Pearson's correlation coefficient of 0.61 to 0.98). Enniatin B was the most frequent (68% of the total enniatin content), followed by enniatin B1 (22%), enniatin A1 (7%) and enniatin A (3%). Fusarium species were quantified by calculating arithmetic mean total DNA levels. F. tricinctum was the most abundant (0.177 pg/ng total DNA), followed by F. avenaceum (0.141 pg/ng total DNA) and F. poae (0.091 pg/ng total DNA). Total DNA levels for each species, and the predominant species varied between years and crops. Small grain cereal species (p value < 0.001), harvest year (p value = < 0.001) and the presence of F. avenaceum (p value < 0.001), F. tricinctum (p value < 0.001) or F. poae (p value = 0.017) affected enniatin content. F. tricinctum was the leading enniatin producer on durum wheat (29% to 45%) and spring barley (23 to 37%). F. avenaceum produced large amounts of enniatins on durum wheat (13% to 17%) and wheat (1% to 18%) and was the leading producer on triticale (30% to 55%). F. poae made a minor contribution on all crops, never accounting for more than 2% of total enniatin content. Enniatins are, thus, highly prevalent in French small grain cereals and are mostly produced by F. avenaceum and F. tricinctum.