Effects of separate analyses of pulp and peel on pesticide residues in watermelons and muskmelons

To evaluate the effects of sample-size reduction and separate analyses of fruit pulp and peel, residual levels of 3 pesticides in watermelons and muskmelons were determined. The pesticide residue levels in 2 types of size-reduced samples were compared. In one size-reduced sample, the pesticide residues in the pulp with the peel were analyzed (A). In the other size-reduced sample, residues in the pulp and peel were analyzed separately. Afterward, the pesticide residue levels were calculated for the whole fruit (B). The majority of the pesticide residues were found to be present in the peel. The mean percent differences (A/B +/- standard deviations [SD]) of pesticide residue levels in the watermelon and muskmelon samples were 91 +/- 15% and 83 +/- 11%, respectively. No significant effect of sample-size reduction and separate analyses of pulp and peel were found in determining the pesticide residues in large-sized fruiting vegetables. (C) Pesticide Science Society of Japan