Improving risk assessment to minimise fusarium mycotoxins in harvested oats and malting barley

Summary

Sector:
Cereals & Oilseeds
Project code:
PR500
Date:
01 April 2007 - 31 March 2010
Funders:
AHDB Cereals & Oilseeds.
AHDB sector cost:
£258,898 from HGCA
Project leader:
by S. G. Edwards Harper Adams University College, Newport, Shropshire TF10 8NB

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About this project

Abstract

This report details HGCA-funded research to further identify the effects of agronomic practices on the concentration of fusarium mycotoxins in UK barley and oats over a number of seasons. One hundred samples both of barley and oats were collected each year at harvest, together with agronomic details, and analysed for ten fusarium mycotoxins including deoxynivalenol (DON), nivalenol, HT2, T2 and zearalenone (ZON). The European Commission (EC) set legislative limits for the fusarium mycotoxins, DON and ZON in cereals and cereal products intended for human consumption in July 2006. New investigative limits for HT2 and T2 in cereals and cereal products were proposed in May 2012. The investigative limits for unprocessed barley and oats for human consumption are 100-200 and 1000-1500 parts per billion (ppb), respectively. Further legislative measures for HT2 toxin and T2 toxin (HT2+T2) will be considered in 2015.

The incidence and concentration of most fusarium mycotoxins, including DON and ZON, have remained relatively low in both barley and oats compared to values for wheat. Concentrations of DON and ZON exceeded legislative limits in a low percentage of both barley and oats over the three years sampled. These high levels were associated with the wet summers of 2007-2009. Concentrations of HT2 and T2 in barley have only exceeded 100 ppb seven times in seven years (0.9% of samples).

HT2 and T2 levels continued to be relatively high in UK oats with an overall mean of 450 ppb for 2006-2008. From 2002-2008, between 1 and 30% of samples exceeded 1000 ppb HT2+T2 each year (annual mean was 16%). There was a negative relationship with late summer rainfall, indicating that drier conditions in July and August result in increased HT2 and T2 in UK oats. Agronomic factors that impacted upon HT2 and T2 in harvested oats were previous crop, cultivation and variety. Analysis of the previous cropping history showed there was a stepwise increase in HT2+T2 as the cereal intensity of the rotation increased. Variety was an important factor with higher levels and a wider range detected on winter compared to spring varieties. Analysis of oat samples from HGCA Recommended List trials confirmed the differences observed in the survey data and provided clear comparisons between all RL varieties under controlled field conditions.

The introduction of European legislation on HT2 and T2 mycotoxins could have serious implications for UK oat production and oat processing industries based on current levels.

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