Effects of postharvest preparation on organophosphate insecticide residues in apples

Apples were sampled directly from orchard trees at 96, 45, and 21 days postapplication with one of three organophosphate insecticides (azinphos methyl, phosalone, or phosmet, respectively). Individual apples were prepared for analysis following one of three postharvest preparations: no preparation, rinsed with deionized water for 10-15 s, or rinsed and peeled. Azinphos methyl, phosalone, and phosmet concentrations ranged from below the level of detection to 5.26 ng/g, 94.7 to 5720 ng/g, and 0.011 to 663 ng/g in the apples that received no postharvest preparation, respectively. Although rinsed apples had lower maximum concentrations than observed in apples with no preparation, levels were not significantly lower. Concentrations of all three OP insecticides in apples that were rinsed followed by peeling, however, were much lower (below detection limits to 0.733 ng/g, azinphos methyl; 0.322-219 ng/g, phosalone; and below detection limits to 44.0 ng/g, phosmet) than observed in apples that had been rinsed alone. Rinsing and peeling of apples resulted in a 74.5-97.9% reduction in OP residues, while rinsing alone lowered mean concentrations by 13.5-28.7% relative to apples that received no postharvest preparation.