Fusarium mycotoxin content of UK organic and conventional wheat

Abstract

Each year (2001–2005), 300 samples of wheat from fields of known agronomy were analysed for ten trichothecenes by gas chromatography-mass spectrometry (GC/MS) including deoxynivalenol (DON), nivalenol, 3-acetyl-DON, 15-acetyl-DON, fusarenone X, T2 toxin, HT2 toxin, diacetoxyscirpenol, neosolaniol and T-2 triol and zearalenone by high-performance liquid chromatography (HPLC). Of the eleven mycotoxins analysed from 1624 harvest samples of wheat, only eight were detected, and of these only five–deoxynivalenol, 15-acetyl-DON, nivalenol, HT-2 and zearalenone–were detected above 100 µg kg⁻¹. DON was the most frequently detected Fusarium mycotoxin, present above the limit of quantification (10 µg kg⁻¹) in 86% of samples, and was usually present at the highest concentration. The percentage of samples that would have exceeded the recently introduced legal limits varied between 0.4% and 11.3% over the five-year period. There was a good correlation between DON and zearalenone concentrations, although the relative concentration of DON and zearalenone fluctuated between years. Year and region had a significant effect on all mycotoxins analysed. There was no significant difference in the DON concentration of organic and conventional samples. There was also no significant difference in the concentration of zearalenone between organic and conventional samples, however organic samples did have a significantly lower concentration of HT2 and T2. Overall, the risk of UK wheat exceeding the newly introduced legal limits for Fusarium mycotoxins in cereals intended for human consumption is low, but the percentage of samples above these limits will fluctuate between years.

Keywords:

• trichothecenes
• deoxynivalenol
• nivalenol
• HT2 toxin
• T2 toxin
• zearalenone
• organic
• conventional

Acknowledgements

The author would like to acknowledge all growers who supplied samples and the agronomists from the Association of Independent Crop Consultants, Agrovista and the Department of Agriculture and Rural Development in Northern Ireland who coordinated the collection of samples. Technical support at Harper Adams was provided by Luda Ibrahim, Katerina Pirgozlieva and Rumiana Ray of the Molecular Diagnostics Laboratory and the field trial officers of the Crop and Environment Research Centre. Mycotoxin analysis was conducted by Sue Patel at RHM Technology and Susan MacDonald at CSL, York. Statistical advice was provided by Sandro Leidi at the Statistical Services Centre, University of Reading. This research was funded by the UK Food Standards Agency (Grant No. CO4022) and Home-Grown Cereal Authority (Grant No. 2452).