A survey of free and conjugated deoxynivalenol in the 2009, 2010 and 2011 cereal crops in Australia
Free and conjugated deoxynivalenol (DON, vomitoxin) were determined in samples of cereal grain collected from the 2009, 2010 and 2011 crops in the Australian states of New South Wales, Queensland, South Australia, Victoria and Western Australia. Free DON was absent in 53–64% of analysed samples. Levels of free DON ranged from 0.10 to 7.31 µg/g. The highest levels of free DON were found in samples collected from the New South Wales 2010 crop while no samples from South Australia or Western Australia regions contained this compound. Free DON in the samples collected from the 2010 crop was significantly higher compared with those from the 2009 and the 2011 crop. Conjugated DON was detected in 61, 87 and 68% of contaminated grain samples in the 2009, 2010 and 2011 crop, respectively. Conjugated DON was found mainly in the samples collected from the 2009 crop (up to 48%) and the 2011 crop (up to 43%) but no significant difference between free DON and total DON content was observed. The current survey emphasises the frequency of non-detectable, conjugated DON in Australian cereal crops and the potential challenges in understanding the hazard posed by DON-contaminated feedstuffs.