Persistence of pyrethroid Deltamethrin and its effects on extra virgin olive oil quality

The use of pesticides in developing countries remains out of control in major cases. Consequently, it is common to find amounts of residues exceeding the Maximum Residue Limits (MRLs). This work intends to assess the persistence of Deltamethrin and its impact on the olive oil quality. Time of sampling and concentration of treatment were varied. Analyses were performed weekly during two months. The results show that Deltamethrin levels in oil of treated plants declined by about 50% after 15 days from insecticide application date (1.6 mg kg - 1) for samples treated with the recommended dose or below. No significant differences in oil physicochemical and nutritional parameters were observed. The sensory evaluation of oils extracted after 2 months did not show significant differences in unpleasant aromatic notes nor defects. Olive oil obtained from samples- where the recommended dose was exceeded - had a slower degradation of the active substance. Moreover, some physicochemical parameters of the latters were influenced and the sensory evaluation revealed some defects. Our results confirm that serious doubts remain about the safety and healthiness of oils extracted from drupes treated with Deltamethrin in developing countries in general, and in Tunisia in particular, where recommended doses are not usually respected. This information could evaluate the real risk in the use of this product for plant