Natural occurrence of acetylated derivatives of deoxynivalenol and nivalenol in wheat and barley in Japan.

Thirty-four samples of domestic wheat and barley grains, collected from eight prefectures of different locations in Japan and previously determined to be positive for deoxynivalenol (DON), nivalenol (NIV) and/or zearalenone (ZEA), were analysed for acetylated derivatives of DON and NIV by gas chromatography-mass spectrometry. In addition to DON and NIV, 3-acetyldeoxynivalenol (3-ADON), 15-acetyldeoxynivalenol (15-ADON) and 4-acetylnivalenol (4-ANIV) were found in 25, 4 and 14 samples, respectively. A regional difference in the DON and NIV contamination of Japanese wheat and barley was suggested: DON was the major trichothecene in the northern district and NIV in the central districts, whereas in the southern districts the DON level was similar to or slightly higher than the NIV level. 3-ADON occurred together with DON in almost all prefectures examined, whereas 15-ADON was found only in samples from northern districts. In addition, a high correlation (r = 0.974, n = 23) between levels of DON and its acetates (3-ADON and 15-ADON) was noted. These results may also suggest the possibility of a geographic difference in the distribution of different chemotypes of Fusarium species producing these trichothecenes in Japan.