Reduction of Chlorpyrifos Residues in 'Super Hot' Chili (Capsicum annuum L.) Fruit Using Washing Agents

Abstract

The load of pesticide residues in fresh produce poses risks to food safety and human health. The reduction of pesticide residues on 'Super Hot' red chilis was determined using various washing agents. Freshly-harvested red chilis were exogenously applied with 100 μL L–1 chlorpyrifos for 5 min and air-dried overnight. Fresh chilis were washed with distilled water, 0.1% CH3COOH, 0.001% KMnO4, 1.0% NaCl, 0.1% NaHCO3, or 0.02% NaOCl for 20 min and stored in ambient room conditions (31 ± 1 °C and 65 ± 11% RH) for 4 d. In another experiment, chilis were washed with distilled water, 0.001% KMnO4 or 0.1% NaHCO3, and dried in a hot air oven at 50 °C for 24 h. Thereafter, the pesticide residues and quality of fresh and dried chilis were evaluated. The fruit washed with 0.001% KMnO4 had the lowest toxicity of chlorpyrifos. In terms of quality, fresh chili washed with NaOCl, NaHCO3, and KMnO4 had lower weight loss, better visual quality, and less shriveling. The use of 1% NaCl promoted decay. All washing agents did not affect the firmness and surface color of fresh chili. Drying itself reduced the degree of toxicity of pesticide residues whether it was washed with the washing agents or unwashed. Chilis washed with either distilled water or NaHCO3 and then dried resulted in a higher extractable color and lower occurrence of non-enzymatic browning. The use of 0.001% KMnO4 as a washing agent for 20 min can best reduce residues from chlorpyrifos applied 4 d earlier in fresh chili, and hot air oven-drying was able to reduce the residues further.