Emerging Fusarium mycotoxins and their producing species: occurrence in soft and durum wheat in an area of central Italy.

Samples (162) of durum and soft wheat harvested in 2009 and 2010 were collected in an area of Central Italy (Umbria) and investigated for the presence of the most important “emerging” mycotoxins such as enniatins (ENs: ENA, ENA1, ENB, ENB1), beauvericin (BEA) and fusaproliferin (FUS). ENs and FUS were quantified by liquid chromatography (LC) with a diod array detector and BEA by LC coupled with a mass spectrometer. A set of strains of F. avenaceum (FA) and F. poae (FP), two potential “emerging” mycotoxin producers isolated from the same grain samples, was screened for the presence of the esyn1 gene, encoding the multifunctional enzyme enniatin synthetase for the detection of potential enniatin-producing isolates. In addition, their mycotoxin production in vitro was determined. All the analysed samples resulted to be significantly contaminated by ENs, both in terms of frequency and quantity. BEA was frequent but contamination levels appeared to be low. Conversely, FUS was present with a low incidence but showed considerable levels of contamination. In general, a remarkable presence of “emerging” mycotoxins was found, particularly ENs. Co-contamination of different mycotoxins also occurred. About 80% of FA and 100% of FP strains resulted to be positive for the presence of the esyn1 gene. All FA strains showed the ability to biosynthesize ENs in vitro but not BEA. Conversely, all FP strains resulted to be BEA producers and some of them co-biosynthesised ENs.