This is the first report of the natural occurrence of Alternaria mycotoxins
in Chinese wheat. Wheat kernels were significantly invaded by Alternaria s
pecies, mostly A. alternata, with an average infection frequency of 87.3%.
A total of 22 samples of weathered wheat kernels from the 1998 crop, repres
enting three locations in the suburbs of Beijing, China, were examined for
the presence of Alternaria mycotoxins by high-performance liquid chromatogr
aphy. Alternariol (AOH) was detected in 20 of 22 samples ranging between 11
6 and 731 mu g/kg (mean = 335 mu g/kg) and alternariol methyl ether (AME) a
t a mean level of 443 mu g/kg (range = 52-1426 mu g/kg) in 21 samples. The
presence of tenuazonic acid (TA), a major Alternaria toxin in terms of quan
tity, was detected in all samples analyzed at an average concentration of 2
419 mu g/kg with a maximum of 6432 mu g/kg. All samples were free from alte
rtoxin I and altenuene. Samples with high levels of AOH and AME also contai
n a high level of TA. There was significant linear regression of correlatio
ns between the levels of AOH over AME (r = 0.850) and total benzopyrone der
ivatives (AOH + AME) over TA (r = 0.796).