Emerging issues of HT-2 and T-2 toxins in European cereal production

Abstract

HT-2 and T-2 toxins are two of the most potent trichothecenes; they have a combined (HT-2+T-2) temporary Tolerable Daily Intake (TDI) of 0.06 µg/kg body weight/day. The distribution of HT-2 and T-2 appears to be largely restricted to Europe. Of the cereal species, HT-2 and T-2 usually have higher incidences and concentrations on oats followed by barley and then wheat, however, this can vary between countries. Survey data from Nordic countries have indicated that these mycotoxins have increased in recent years, reaching concentrations of >1000 µg/kg HT-2+T-2 in some samples. HT-2 and T-2 have also been detected in malting barley in France, and in particular in spring sown varieties. A newly identified species, Fusarium langsethiae, has been implicated as a producer of HT-2 and T-2 in European cereals. There is limited data available regarding this species' pathogenicity and mycotoxin production. The impact of agronomy on the concentration of HT-2 and T-2 in cereals has not been clearly identified, but it is evident that it is different to the impact of agronomy on deoxynivalenol. Processing of cereals can have a major impact on the HT-2 and T-2 content of cereals. Oats are de-hulled during processing for human consumption; de-hulling reduces the mycotoxin content of oats by more than 90%. During the malting and brewing of barley the concentration of HT-2 and T-2 increases and decreases within various stages of the processes and the final mycotoxin load of beers will depend on the individual processes used by each maltster and brewer. Whether these mycotoxins are an issue for human health cannot be determined until a full TDI is calculated based on more long-term exposure studies, and human exposure levels are calculated from surveys of retail products using new, highly sensitive assays.