Small grain cereals are frequently infected with mycotoxigenic Fusarium fungi. Oats have a particularly high risk of contamination with type A trichothecene mycotoxins; their glucoside conjugates have also been reported. Agronomy practices, cereal variety and weather conditions have been suggested to play a role in Fusarium infection in oats. The current study investigates concentrations of free and conjugated Fusarium mycotoxins in organic and conventional oats grown in Scotland. In 2019, 33 milling oat samples (12 organic, 21 conventional) were collected from farmers across Scotland, together with sample questionnaires. Samples were analysed for 12 mycotoxins (type A trichothecenes T-2-toxin, HT-2-toxin, diacetoxyscirpenol; type B trichothecenes deoxynivalenol, nivalenol; zearalenone and their respective glucosides) using LC-MS/MS. The prevalence of type A trichothecenes T-2/HT-2 was very high (100% of conventional oats, 83% of organic oats), whereas type B trichothecenes were less prevalent, and zearalenone was rarely found. T-2-glucoside and deoxynivalenol-glucoside were the most prevalent conjugated mycotoxins (36 and 33%), and co-occurrence between type A and B trichothecenes were frequently observed (66% of samples). Organic oats were contaminated at significantly lower average concentrations than conventional oats, whereas the effect of weather parameters were not statistically significant. Our results clearly indicate that free and conjugated T-2- and HT-2-toxins pose a major risk to Scottish oat production and that organic production and crop rotation offer potential mitigation strategies.
This study has received funding from the Interface Multiparty Fund; the Rowett Institute and Biomathematics & Statistics Scotland receives funding from the Scottish Government Rural and Environment Science and Analytical Services (RESAS).
Authors acknowledge the involvement of Hamlyns, WN Lindsay and all farmers in contributing to sample collection. Susan McCormick and Mark Busman at the USDA Agricultural Research Service in Peoria, IL, USA, are acknowledged for providing the standard solutions of DAS-Glc, T-2-Glc and HT-2-Glc used in this study. The ZEN-Glc standard used in this study was previously synthesised as part of the FSA-funded project FS102101.
- Fusarium mycotoxins
- masked mycotoxins