The biodeterioration of stored cereals

ABSTRACT

Entry to the EEC has brought UK cereals production into line with that of other Community members, with consequent rises in profitability and in marketing standards. With increased quality and production, there has had to be a concomitant increase in storage capacity both on farm and in commercial stores. The Intervention system of market support has necessarily come more and more into use, so that many producers work automatically to the Intervention standards. The IBAP requirements for moisture, limit on impurities and on bushel weight are relatively easily met, but that of "freedom from live pests" together with sampling and assessment regimes more rigorous than previously, have exerted major influences on storage practice. Adequate drying and cleaning facilities have become necessary and have reduced many of the problems, particularly those associated with fungi. The use of pesticides to control insects and mites has also increased considerably, particularly in commercial stores, where pesticides are seen as cheap insurance against problems.

The present review assesses these factors and the impact they have had in resolving biodeterioration problems, which are also defined, analysed and discussed in some detail. The gaps in research are identified, and the future needs for research are broken down into topic areas. These include: identifying the biological consequences of low-temperature drying; making fuller use of low-volume grain cooling; improving methods of detecting pests in grain bulks, particularly in transit; making full evaluation of the technique of modified atmosphere storage; developing integrated strategies for grain storage where early detection of pests is coupled to physical methods of control, thus minimising use of pesticides; research into improved application methods for pesticides, and into the development of grain protectants based on insect growth regulators; determining the limits of use for phosphine as a fumigant and developing new and improved methods of application. There are also needs for data gathering on the extent of biodeterioration problems in storage practice, monitoring changes in the level of resistance to pesticides in storage insects and mites, and for studies on the nature and development of such resistance.