Removal of trichlorfon and phoxim from pak choi (Brassica campestris ssp. chinensis) by combined ultrasonic and ozone treatment and their effects on quality

The effect of ultrasound, ozone, and their combination treatment on the removal of two common pesticides (trichlorfon and phoxim) in pak choi samples was studied in this work. The results showed that both ultrasound and ozone treatment alone can significantly remove trichlorfon and phoxim residues in pak choi (>90%), but they reduced the quality of pak choi (such as vitamin C and color). Ultrasound and ozone had a synergistic effect on the removal of pesticide residues in pak choi. The synergistic effect of combined treatment was evaluated from the perspective of pesticide removal speed, and found that their combination significantly accelerated the removal of pesticides. Compared with ultrasound or ozone alone, the removal rate constant of trichlorfon by the combined treatment increased by 121% and 347%, and that of phoxim increased by 159% and 367%, respectively. In addition, the combined treatment of ultrasound and ozone can well maintain the vitamin C and color of pak choi while removing pesticides. Therefore, the combined treatment of ultrasound and ozone can be used as an effective cleaning method to remove pesticide residues in vegetables. Practical applicationsReducing pesticide residues in vegetables is of great significance to human health, and how to maintain the quality of vegetables as much as possible while removing pesticides is a key issue. In this study, the combination of ultrasound and ozone significantly accelerated the removal of pesticides, and retained the vitamin C and color of pak choi well. Therefore, the combined application of ultrasound and ozone has the potential to be an industrial cleaning method for removing pesticide residues in fruits and vegetables without compromising quality.