Effect of household and commercial processing on acetamiprid, azoxystrobin and methidathion residues during crude rapeseed oil production.

Rape crops with residues of acetamiprid, azoxystrobin and methidathion incurred from field trials were used to evaluate the effect of household and commercial crude rapeseed oil processing on the transfer of pesticide residues. The pesticides were applied at exaggerated dosage to quantify residue levels in processed samples. The processing procedure was conducted as closely as possible to the actual conditions in practice. The conditioning step removed at least 30% of pesticides, while azoxystrobin and methidathion were concentrated by at least 15% at the single pressing step. The residue level of methidathion was concentrated with a processing factor (PF) of 1.07, while azoxystrobin and acetamiprid decreased with PFs of 0.67 and 0.04, respectively, after all processing procedures. The overall magnitudes of acetamiprid, azoxystrobin and methidathion in rapeseed oil and meal were all decreased after processing compared with the magnitude of those in raw rapeseed.