Effect of Iranian traditional cooking on fate of pesticides in white rice

In the current study, the reduction in the level of 42 pesticides from different chemical groups in white rice by means of traditional cooking was evaluated. A gas chromatography-mass spectrometry (GC/MS) system in combination with the modified QuEChERS technique as the base of sample preparation method was employed. The spiked rice samples (at 3 levels of 25, 100, and 500ng/g) were analyzed to determine the reduction percentage of pesticide. Processing factor for each pesticide excepted for one of them was lower than 1. The introduced sample preparation and identification methods showed a precision as well as accuracy. The recovery of pesticides at three concentration levels was in the range of 84.08-105.95%. The highest and lowest percentages of pesticides reduction were reported as 99.8% and 15.6% for dichlorvos and metalaxyl, respectively. Regarding the different chemical groups, the most reduction is belong organophosphorus pesticides and the less reduction can be correlated to organochlorine pesticides. The results demonstrated that the Iranian traditional rice cooking, which involves long boiling times, significantly could reduce the concentrations of pesticide residues in white rice.