The microbiology of cereal grains from areas of Iran with a high incidence of oesophageal cancer

Abstract

In north eastern Iran, where oesophageal cancer is common, grain was sampled from wheat and barley crops at harvest and after different periods of storage in underground pits or in buildings. At harvest, few grains were contaminated with Fusarium spp, or storage fungi, apart from Penicillium spp but most yielded Alternaria spp, even after surface sterilization. Greater deterioration of stored grain occurred in underground pits than in buildings, but this was usually slight, with Aspergillus restrictus predominant. Occasionally, however, Aspergillus glacus group ( Eurotium spp), A. candidus and A. flavus were abundant, indicating greater availability of water in the grain and more deterioriation. Ochratoxin was detected in only one sample and this had much Penicillium contamination. No other mycotoxins were detected although occasional samples showed unidentified toxicity to brine shrimp larvae and isolates of A. flavus and A. ochraceus produced aflatoxins and ochratoxin, respectively, in culture. There was little evidence for mycotoxins being implicated in oesophageal cancer in north-eastern Iran although further studies are necessary to assess the extent of mould deterioration and the influence of climate, especially rainfall.