Aspergillus flavus and the deterioration of farm-stored barley grain : a thesis presented in partial (30%) fulfilment of the requirements for the degree of Master of Philosophy in Veterinary Pathology & Public Health at Massey University

Abstract

For many years there was a tendency to regard moulds in grains destined for animal consumption as of little significance other than as gross spoilage organisms. Investigations of the possible role of toxic fungi in diseases of grain-fed animals was confined in the main to problems of restricted local significance (Forgacs and Carll, 1962). However, it was the discovery of aflatoxin in 1961 and the widespread concern which it generated, which inspired a vast amount of research into the natural production of mycotoxins and the consequent mycotoxicoses affecting both animal and human health, aspects of which have been fully reviewed in a number of recent publications (Purchase, 1974; Rodricks, 1976; Rodricks et at., 1977; Wyllie and Morehouse, 1978 and Cole and Cox, 1981). Mycotoxin production can occur anywhere, in the field, or during harvest, processing, storage and shipment, or during the feeding period on the farm. Commodities grown and stored in areas where high levels of insect damage and poor farming and storage practices prevail appear to be the most susceptible (Ciegler, 1978). Nevertheless, natural contamination with a variety of mycotoxins has been reported for most of the major agricultural commodities in the world (Hesseltine, 1974) and those mycotoxins currently of most concern are: aflatoxin, trichothecenes, zearalenone, ochratoxin, citrinin and some tremorgens (Ciegler, 1978). However, there are over 23 known mycotoxins which can be associated with grains and some of those currently less well known may prove to be significant in the future.