Mycotoxins in stored grains

Abstract

This paper reviews the occurrence of mycotoxins in grain with particular reference to those compounds most likely to occur in cereals stored in the UK. Ochratoxin A is currently of greatest concern for the grain trade and is covered in more detail. Some recent studies are discussed. Introduction The production and supply of high quality grain remains of prime importance. Cereals must thus be protected in the field against disease and in store after harvest against fungal attack. Invasion by fungi not only reduces the quality of the grain but some species of moulds can produce highly toxic chemicals known as mycotoxins. Moulds can grow on any substrate that contains the appropriate nutrients. The supply of nutrients and growing conditions can control the rate of growth and metabolism. Hence any mycotoxins formed will not only depend on the species of fungi but on the prevailing conditions. Fungi have been divided into those that develop and predominate in the field prior to harvest and those that subsequently grow after harvest in store, transport or processing. If a toxin producing fungus is present, mycotoxins can thus be formed both before and after harvest although these are likely to differ in structure and properties. However, this division is not clear-cut. Some of the most important mycotoxins are listed in table 1 together with the main fungal species responsible for their formation. Those mycotoxins most often found in cereals grown in the UK are highlighted.