Mycotoxins in water-damaged and mouldy wheat from temporary bulk stores in Queensland

Abstract

Temporary bulk stores are used by the Australian wheat industry to cope with peak wheat deliveries. Such stores are vulnerable to water damage if the plastic covering sheets are damaged, and extensive mould growth may then result. Samples of mouldy grain from stores in the main wheat-growing region of southern Queensland were assayed for aflatoxins B1, B2, G1, and G2, ochratoxin A and sterigmatocystin, but only aflatoxins B1 and B2 were detected. Of 152 mouldy samples from 12 temporary stores of the 1981 wheat crop, anatoxins were detected in 21 (range 0.002-0.060, mean 0.016 mg B1 kg-1). Aflatoxins were also present in 10 out of 13 samples from the single store of the smaller 1982 crop (range 0.003-0.500, mean 0.064 mg B1 kg-1). Aflatoxins were detected at trace levels (0.003-0.004 mg B1, kg-1) in 2 out of 70 samples of apparently clean, free-flowing grain from rhese same stores. Both the frequency of contamination and aflatoxins concentrations were low, indicating either that the inoculum of Aspergillus flavus was low or that conditions were unsuitable for aflatoxin production.