T-2 and HT-2 toxins in harvested oat grains and their prevalence in whole grain flour during storage

Mycotoxin contamination of food is a constant global concern. There has been a scientific debate in Europe on the validation of accredited detection methods for type A trichothecenes T-2 and HT-2 and the restriction on dangerous concentrations. The issue is of great importance as this type of mycotoxin is frequently found in spring cereals grown in Lithuania. The aim of this study was to optimise and validate a method for the determination of T-2/HT-2 toxin concentrations in oats harvested in 2015-2018 and to observe the changes in the concentrations of both toxins in oat flour during 3- and 6-week storage at different temperatures and increased relative air humidity. All of the oat grain samples (100%) collected in 2015-2018 tested positive for contamination with type A trichothecenes. The highest mean co-contamination by T-2 + HT-2 (260.4 ± 140.9 µg/kg) and the highest concentration (594.6 µg/kg) were determined in 2018 when warm and wet weather conditions prevailed during oat flowering. The effect of long-term storage (6 weeks) on T-2 and HT-2 toxin production manifested itself only when the samples had been stored under cooler conditions (8 °C). The most important factors which impacted the variation of the concentrations of type A trichothecenes in flour were ambient temperature and storage time.