AlternariaMycotoxins in Weathered Wheat from China

Abstract

This is the first report of the natural occurrence of Alternaria mycotoxins in Chinese wheat. Wheat kernels were significantly invaded by Alternaria species, mostly A. alternata, with an average infection frequency of 87.3%. A total of 22 samples of weathered wheat kernels from the 1998 crop, representing three locations in the suburbs of Beijing, China, were examined for the presence of Alternaria mycotoxins by high-performance liquid chromatography. Alternariol (AOH) was detected in 20 of 22 samples ranging between 116 and 731 μg/kg (mean = 335 μg/kg) and alternariol methyl ether (AME) at a mean level of 443 μg/kg (range = 52−1426 μg/kg) in 21 samples. The presence of tenuazonic acid (TA), a major Alternaria toxin in terms of quantity, was detected in all samples analyzed at an average concentration of 2419 μg/kg with a maximum of 6432 μg/kg. All samples were free from altertoxin I and altenuene. Samples with high levels of AOH and AME also contain a high level of TA. There was significant linear regression of correlations between the levels of AOH over AME (r = 0.850) and total benzopyrone derivatives (AOH + AME) over TA (r = 0.796). Keywords: Alternaria toxins; alternariol; alternariol methyl ether; tenuazonic acid; weathered wheat; China