Three-year study of fenthion and dimethoate pesticides in olive oil from organic and conventional cultivation

Food Addit Contam. 2003 Jun;20(6):553-9. doi: 10.1080/0265203031000070786.


Residues of fenthion and dimethoate pesticides were determined in organic and conventional olive oils by liquid-liquid and solid-phase extractions with subsequent gas chromatography and mass spectrometric analysis. The olive oil samples were collected from Crete during 1997-99. The average concentrations of fenthion in conventional olive oils were 0.1222, 0.145 and 0.1702 mg x kg(-1), and for dimethoate were 0.0226, 0.0264 and 0.0271 mg x kg(-1) for 1997, 1998 and 1999, respectively. The average concentrations of fenthion in organic olive oils were 0.0215, 0.0099 and 0.0035 mg x kg(-1) for 1997, 1998 and 1999, while for dimethoate they were 0.0098, 0.0038 and 0.0010 mg x kg(-1), respectively. All the olive oils contained residue levels lower than the maximum residue levels according to the FAO/WHO Codex Alimentarius. The organic olive oil contained significantly lower concentrations of the two pesticides. The levels of fenthion and dimethoate in organic olive oils exhibited a decreasing trend following the implementation of the new cultivation method. We propose procedures that should be established in the organic cultivation in order to maximize its effectiveness.

MeSH terms

  • Dimethoate / analysis
  • Fenthion / analysis
  • Food Analysis / methods
  • Food Contamination / analysis*
  • Food, Organic / analysis*
  • Gas Chromatography-Mass Spectrometry / methods
  • Greece
  • Humans
  • Insecticides / analysis*
  • Olive Oil
  • Pesticide Residues / analysis*
  • Plant Oils / chemistry*


  • Insecticides
  • Olive Oil
  • Pesticide Residues
  • Plant Oils
  • Fenthion
  • Dimethoate