EFFECT OF HOUSEHOLD PROCESSING ON REMOVAL OF MULTI-CLASSES OF PESTICIDES FROM TOMATOES

In this paper, twenty-two pesticide residues were monitored in tomatoes.72 marketed samples were extracted and purified with QuEChERS method, and analyzed with liquid and gas Chromatography. The mean recoveries ranged from 90.75%to105.31%. The relative standard deviation was 1% to 7.5%. The limits of detection and quantification ranged from 0.0004 to 0.0231 mg.kg(-1) and 0.0012 to 0.0693 mg.kg(-1), and good linearity was obtained. Out of total analyzed samples, 34 samples (47.22%) were contaminated with tested pesticide residues; out of which 10 samples (13.89%) exceeded the maximum residue limits. The effects of four processing techniques (washing with tap water, washing with solution of acetic acid, peeling and boiling) on the residual pattern of five insecticides (dimethoate, carbaryl, chlorpyrifos, cypermethrin and fenvalerate) and one herbicide (2,4 dichlorophenoxy acetic acid (2,4D)) were evaluated. The reaction of the pesticides depends obviously on the physico-chemical features and also on the systemic character of the pesticides. Both of the washings lowered clearly the residues for all detected pesticides with removing up to 63.08%. Peeling was found to totally remove the residues of fenvalerate, carbaryl, cypermethrin and chlorpyrifos. Results obtained from the boiling indicated that a complete removal of 2,4D and dimethoate residues was finally achieved. In addition to that, the concentrations of cypermethrin and fenvalerate increased and processing factors above 1 were observed, the results can be seen as valuable base for monitoring of pesticides in tomatoes and supply more comprehension of residue demeanor after household processing. These implementations are important to protect consumer health from the damage of pesticide residues in food.