ORGANOPHOSPHORUS INSECTICIDE RESIDUES IN VIRGIN GREEK OLIVE OIL, 1988-1990

Organophosphorus insecticide residues have been monitored for two years in virgin olive oil after dimethoate and fenthion treatments to control the olive fruit fly. No dimethoate residues were detected in any of the samples. For the first and second years, 50% and 21%, respectively, of the samples contained no detectable fenthion residues, while 4% and 6%, respectively had residue concentrations exceeding the Codex Alimentarious Maximum Residue Limit (1 mg kg-1). The mean concentration was 0.236 mg kg-1 oil and the estimated daily intake of fenthion 0.0002 mg kg-1 body weight (Acceptable Daily Intake 0.001 mg kg-1 body weight). The parent compound was the most important residue in fresh samples, while aged samples contained a higher amount of the metabolite fenthion sulfoxide. The contribution of the oxygen analogues (P = O metabolites) of fenthion to the total residue concentration was < 5% in most cases.