Natural occurrence of Fusarium toxins in barley harvested during five years in an area of southwest Germany.

A total of 44, 40, 47, 51, and 58 barley samples for feed use were collected randomly after the 1987, 1989, 1990, 1991, and 1992 crops, respectively, from farms located in an area of southwest Germany. The sum of precipitation from May to September was high in 1987 and markedly lower in 1989-1992. Deoxynivalenol, 3-. and 15-acetyldeoxynivalenol, nivalenol, fusarenon-X, T-2 toxin, HT-2 toxin and diacetxyscirpenol were determined by gas chromatography with mass selective detection (GC-MS), zearalenone,alpha- and beta-zearalenol by GC-MS or by HPLC. Deoxynivalenol was the major toxin with incidences at 71-98% and mean contents at 42-400 microg/kg. In contrast, incidences of zearalenone, 3-acetyldeoxynivalenol, nivalenol, HT-2 toxin, and T-2 toxin were at 7-68, 7-48, 11-41, 0-9, and 2-29%, respectively; with mean contents at 3-146 microg/kg. alpha- and beta-zearalenol and diacetoxyscirpenol were not detected in any sample. 15-acetyldeoxynivalenol and fusarenon-X were assayed in samples from 1987, 1991 and 1992. 15-acetyldeoxynivalenol was detected in 30, 0 and 2% of samples, respectively, with an average content of positive samples at 8 and 4 microg/kg, fusarenon-X was not detected. Over the years, incidences and levels of toxins remained constant, decreased or increased. The correlation between the occurrence of toxins and level of precipitation is discussed.