UK and Irish wheat tested for mycotoxins

More than 500 analyses were conducted to test for the occurrence of the eight mycotoxins most frequently found in agricultural commodities intended for animal production; aflatoxin B1 (AfB1), zearalenone (ZEN), deoxynivalenol (DON), T-2 toxin, HT-2 toxin, fumonisin B₁ (FB₁), fumonisin B₂ (FB₂) and ochratoxin A (OTA).

Typically, wheat levels of DON and zearalenone tend to be lower in northern England and Scotland; moderate in western England, Wales and Ireland and highest in southern and south eastern England. All samples (66) were collected almost immediately after the harvest and the probability that some storage mycotoxins will have developed (OTA) was low. Wheat samples were sampled directly from farms or animal feed production sites.

Sample providers were advised to follow the principles of good sampling (Richard, 2000). However, analytical personnel and/or laboratory staff were not involved and, therefore, did not influence any part of this procedure. All six mycotoxins were analysed by liquid chromatography tandem mass spectrometry (LC MS/MS). For the purpose of data analysis, non-detection levels were based on the limits of quantification (LOQ) of the test method for each mycotoxin: AfB1 < 0.5 μg/kg; ZEN < 10 μg/kg; DON < 75 μg/kg; FB₁ < 125 μg/kg; FB₂ < 50 μg/kg; OTA < 1 μg/kg; T-2 toxin < 4 μg/kg and HT-2 toxin < 4 μg/kg.

Results

The results show that 64% of wheat samples were contaminated with DON and none of the samples contained AfB₁ or FB₁. Only 3 % of samples contained T-2 toxin and such low incidence of contamination was not expected. The average concentrations of all recovered mycotoxins were medium while the highest concentration of DON found in one of the samples reached 1100 μg/kg. Although 12.3% of the samples contained HT-2 toxin, a mycotoxin extremely toxic for poultry, its maximum concentration reached only 32.2 μg/kg and this level is negligible. None of the samples was contaminated with FB₁, but this result was expected as it is well known that FB₁ is mostly produced on maize. Only one sample was contaminated with FB₂ and OTA. Surprisingly, the results show that 15% of wheat samples were contaminated with ZEN and its maximum concentration found in one sample reached 810 μg/kg.

When comparing mycotoxin contamination of wheat in years 2014, 2015 and 2016 it can clearly be seen that the contamination levels in 2016 are significantly higher than in either of the two previous years. All parameters (% of positive, average of positive and maximum concentration) are higher in 2016.

Conclusion

Based on the 66 wheat samples, Nutriad believes that this year’s harvest of wheat in the UK and Ireland is of medium quality (>LOD but below EU recommendation levels) in terms of mycotoxin contamination but the situation is much worse than in last two years. Vigilance is always advisable.