Organophosphate pesticides for use as grain protectants in India : degradation of their residues during milling and cooking of cereal grains

Bioassay tests were conducted to determine the effectiveness of treatments in protecting the grain against insect attack. The intermediate levels of treatment and high levels of treatment protected the grain over the full test period of two months. The amount of residues in the treated grain were analyzed before and after milling. Samples of milled products were cooked by traditional Indian methods. Food preparations which involved boiling or steaming resulted in complete degradation of the residues of all three insecticides. Most of India"s grain harvest is retained at the farm and village level. Any program aimed at reducing waste due to insect damage during storage must provide methods which can be used for small scale storage existing regulations to allow the use of malathion as a grain protectant to be admixed with stored grain up to a limit of 8ppm. Results indicate that the breakdown of residues during milling and cooking by typical Indian methods are comparable to the breakdown observed in the cooking and milling processes studied in the U.S. and Europe.