Mycotoxins are potent fungal toxins that frequently contaminate agricultural crops and foods. Mycotoxin exposure is frequently reported in humans, and children are known to be particularly at risk of exceeding safe levels of exposure. Urinary biomonitoring is used to assess overall dietary exposure to multiple mycotoxins. This study aims to quantify multi-mycotoxin exposure in UK children and to identify major food groups contributing to exposure. Four repeat urine samples were collected from 29 children (13 boys and 16 girls, aged 2.4–6.8 years), and food diaries were recorded to assess their exposure to eleven mycotoxins. Urine samples (n = 114) were hydrolysed with β-glucuronidase, enriched through immunoaffinity columns and analysed by LC-MS/MS for deoxynivalenol (DON), nivalenol (NIV), T-2/HT-2 toxins, zearalenone (ZEN), ochratoxin A (OTA) and aflatoxins. Food diaries were analysed using WinDiet software, and the daily intake of high-risk foods for mycotoxin contamination summarised. The most prevalent mycotoxins found in urine samples were DON (95.6% of all samples), OTA (88.6%), HT-2 toxin (53.5%), ZEN (48.2%) and NIV (26.3%). Intake of total cereal-based foods was strongly positively associated with urinary levels of DON and T-2/HT-2 and oat intake with urinary T-2/HT-2. Average daily mycotoxin excretion ranged from 12.10 µg/d (DON) to 0.03 µg/d (OTA), and co-exposure to three or more mycotoxins was found in 66% of samples. Comparing mycotoxin intake estimates to tolerable daily intakes (TDI) demonstrates frequent TDI exceedances (DON 34.2% of all samples, T-2/HT-2 14.9%, NIV 4.4% and ZEN 5.2%). OTA was frequently detected at low levels. When mean daily OTA intake was compared to the reference value for non-neoplastic lesions, the resulting Margin of Exposure (MoE) of 65 was narrow, indicating a health concern. In conclusion, this study demonstrates frequent exposure of UK children to multiple mycotoxins at levels high enough to pose a health concern if exposure is continuous.

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.