Fusarium Mycotoxins Are Frequently Detected in Oat Grains and Oat Foods and T-2, HT-2 and HT-2-Glucoside Are Highly Bioaccessible in Oat Porridge

The presence of Fusarium mycotoxins is an intractable problem in cereal production, with T-2 and HT-2 posing a particular issue in oats. This study assesses the prevalence of Fusarium mycotoxins in unprocessed and de-hulled oats and oat food products and quantifies the bioaccessibility of T-2, HT-2 and HT-2-glucoside from oat porridge in vitro. Twenty unprocessed food oat samples were de-hulled and mycotoxins quantified in unprocessed grains, hulls and groats using LC-MS/MS. Seventy-seven oat food products (40 porridge samples, 10 granola and muesli samples, 11 oat biscuits, 11 oatcakes, 5 infant cereals) were analysed for mycotoxins. Two oat porridge samples were tested for bioaccessibility using Infogest 2.0 method followed by faecal microbiota incubations. T-2/HT-2 and their glucosides were the most prevalent mycotoxins in unprocessed food oats (85–100%). DON was also highly prevalent (70%) while DON-glucoside, NIV, ZEN and their glucoside were less frequently detected. Reduction of 89–100% was achieved by de-hulling oats for most mycotoxins except DON-glucoside (77% reduction). Oat food samples were also frequently contaminated with T-2+HT-2 (prevalence porridge 90%, granola and muesli 40%, oat biscuits 36%, oatcakes 73%) while no mycotoxins were detectable in infant cereal foods. Upon in vitro digestion, 73–82% of free and glucosylated T-2/HT-2 were readily bioaccessible, underlining their importance for human dietary exposure. The study highlights that T-2/HT-2 contamination is prevalent in oats and carry-over into food products cannot be completely avoided, potentially leading to mycotoxin exposure in oat food consumers.