Residue Content of Chlorpyrifos Applied to Greenhouse Cucumbers and Its Reduction during Pre-Harvest Interval and Post-Harvest Household Processing

Chlorpyrifos is widely used to control various insect pests on greenhouse cucumbers in Iran. In this study, the effects of the household processing such as washing, peeling, and refrigeration storage on the reduction of residue levels in cucumbers were investigated in different groups. Samples were collected at 1 hour to 14 days after application of chlorpyrifos and analyzed to determine the content of chlorpyrifos. Analysis was carried out by the QuEChERS method using GC-NPD. Residue levels in samples throughout a period of 14 days showed a gradual and significant (P< 0.05) decrease in contents of chlorpyrifos. The half-life (t(1/2)) of chlorpyrifos applied to cucumbers was 1.9 days. Chlorpyrifos was detected in concentration ranges of 0.02-4.73 mg kg(-1). Household processing, such as washing, peeling and refrigeration storage, was effective in reducing the residue levels. Peeling was the most effective way to reduce residues in the cucumbers. Obtained results showed that a waiting period after chlorpyrifos application and household processing are required for safe consumption of cucumber.