Efficiency of some technological processes on reducing the residues of malathion and pirimiphos methyl in mature broad bean seeds.

Residue study was performed on several insecticides which could contaminate local Egyptian beans. The effect of storage periods and various processing steps on lowering the residues of malathion and pirimiphos methyl in treated seeds and their processed products were investigated. The data indicated that malathion and pirimiphos methyl persisted for more than 90 days on and in stored mature dry broad beans after postharvest treatment. However, stored broad beans could be safely used for human consumption after 90 days when the insecticide residues reached safe levels. Washing removed 69 and 75% of malathion and pirimiphos methyl residues of treated broad beans, respectively. Malathion residue was not detected in various processed products. More than 89 and 99% of malathion residues were absent in dehulled and heated dehulled broad beans. In addition, pirimiphos methyl residues were reduced to 92, 97, 87, 99, 99, and 95% from the initial levels in treated beans following dehulling, cooking of dehulled beans, germination, cooking of germinated beans and cooking of the beans by the common method and under pressure, respectively.