Monitoring of pesticide residues in olive oil samples: results and remarks between 1999 and 2002

Abstract

The occurrence of organophosphorus pesticide residues and their metabolites in virgin olive oil samples was investigated. Forty-eight samples of virgin olive oil were collected directly from olive mills at various locations on the island of Corfu (Greece) where the application of insecticides was performed by spraying from the air and/or from the ground during the three harvest periods (1999–2002). Samples for residues analysis were extracted by liquid–liquid partitioning with solvents of different polarity. The target compounds were determined in the final extract by gas chromatography using flame photometric and nitrogen phosphorus detection. In the case of positive samples the findings were confirmed using columns of different polarity or by GC-MS. The most common pesticide residues found were fenthion and its oxidative metabolites. Concentrations of total fenthion in the positive olive oil samples were below the FAO/WHO Codex Alimentarius maximum residue limit (MRL). Only three samples contained total fenthion residues that exceeded the Codex MRL.

Keywords:

• Olive oil
• Organophosphorus pesticides
• Fenthion
• Fenthion metabolites