Boiling, Blanching, and Stir-Frying Markedly Reduce Pesticide Residues in Vegetables

Nowadays, a lot of produce (fruits and vegetables) sold in many countries are contaminated with pesticide residues, which cause severe effects on consumer health, such as cancer and neurological disorders. Therefore, this study aims to determine whether cooking processes can reduce the pesticide residues in commonly consumed vegetables (Chinese kale and yard long beans) in Thailand. For cooking experiments, the two vegetables were cooked using three different processes: boiling, blanching, and stir-frying. After the treatments, all cooked and control samples were subjected to extraction and GC-MS/MS analysis for 88 pesticides. The results demonstrated that pesticide residues were reduced by 18–71% after boiling, 36–100% after blanching, and 25–60% after stir-frying for Chinese kale. For yard long beans, pesticide residues were reduced by 38–100% after boiling, 27–28% after blanching, and 35–63% after stir-frying. Therefore, cooking vegetables are proven to protect consumers from ingesting pesticide residues.