Fusarium mycotoxin content of UK organic and conventional oats

Abstract

Every year between 2002 and 2005 approximately 100 samples of oats from fields of known agronomy were analysed by GC/MS for 10 trichothecenes: deoxynivalenol (DON), nivalenol, 3-acetylDON, 15-acetylDON, fusarenone X, T-2 toxin (T2), HT-2 toxin (HT2), diacetoxyscirpenol, neosolaniol and T-2 triol. Samples were also analysed for moniliformin and zearalenone by HPLC. Of the 10 trichothecenes analysed from 458 harvest samples of oat only three, 15-acetylDON, fusarenone X and diacetoxyscirpenol, were not detected. Moniliformin and zearalenone were absent or rarely detected, respectively. HT2 and T2 were the most frequently detected fusarium mycotoxins, present above the limit of quantification (10 µg kg⁻¹) in 92 and 84% of samples, respectively, and were usually present at the highest concentrations. The combined mean and median for HT2 and T2 (HT2 + T2) was 570 and 213 µg kg⁻¹, respectively. There were good correlations between concentrations of HT2 and all other type A trichothecenes detected (T2, T2 triol and neosolaniol). Year and region had a significant effect on HT2 + T2 concentration. There was also a highly significant difference between HT2 + T2 content in organic and conventional samples, with the predicted mean for organic samples five times lower than that of conventional samples. This is the largest difference reported for any mycotoxin level in organic and conventional cereals. No samples exceeded the legal limits for DON or zearalenone in oats intended for human consumption. Legislative limits for HT2 and T2 are currently under consideration by the European Commission. Depending on the limits set for unprocessed oats intended for human consumption, the levels detected here could have serious consequences for the UK oat-processing industry.

Keywords:

• trichothecenes
• deoxynivalenol
• nivalenol
• HT-2 toxin
• T-2 toxin
• zearalenone
• moniliformin
• organic
• conventional

Acknowledgements

I 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 co-ordinated 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. Statistical advice was provided by Sandro Leidi at Statistical Services Centre, University of Reading. This research was funded by the UK Food Standards Agency (CO4033 and CO4034) and Home-Grown Cereal Authority (RD-2002-2706).