A survey of free and conjugated deoxynivalenol in the 2008 corn crop in Ontario, Canada

BACKGROUND: Deoxynivalenol (DON, vomitoxin), one of the most important mycotoxins produced by many Fusarium species, is found as a common contaminant of crops worldwide. Recent studies have described the presence of conjugated forms of DON (glycosides and fatty acid). The aim of the current study was therefore to investigate the natural occurrence of free and conjugated DON in Canadian corn. RESULTS: Free and conjugated DON was determined by gas chromatography-mass spectrometry (GC-MS) and enzyme-linked immunosorbent assay (ELISA) in 86 corn samples collected from the 2008 crop in Ontario, Canada. Free DON concentrations determined by ELISA were similar to values determined in most samples using GC-MS. Conjugated DON was detected in 72 samples. Levels of free DON ranged from 0.17 to 14.00 mu g g-1 using GC-MS. The highest levels of free DON were found in corn samples from the southern and southwestern regions of Ontario, while samples from eastern regions were less contaminated. Conjugated DON was found mainly in corn from the east-central region, with five of six samples showing high levels of conjugated DON (up to 43% increase in DON following acid hydrolysis). Low levels of conjugated DON (= 10% increase in DON following acid hydrolysis) were detected in the majority of corn samples from the southwestern region (nine of 19 samples) and from the central region (16 of 36 samples). CONCLUSION: The current survey emphasizes the frequency of conjugated DON in Ontario grown corn and the potential challenges in understanding the hazard posed by DON-contaminated foodstuffs and feedstuffs. (C) 2011 Society of Chemical Industry