Effect of Plasma-activated Water Combined with Bubbling on the Removal of Pesticide Residues and Escherichia coli on Xantolis stenosepala

The control of pesticide residues and harmful microorganisms is an important issue in the Xantolis stenosepala pulp processing. In this study, plasma-activated water (PAW) combined with bubbling treatment was applied to investigate the removal of effect on pesticides (carbendazim, imidacloprid, tebuconazole, pyraclostrobin, and abamectin) and Escherichia coli on the surface of X. stenosepala during the raw material cleaning process. The results showed that compared to the single bubble cleaning (with pesticide removal rates ranging from 0.90% to 25.06%). PAW could effectively remove pesticide residues from the surface of X. stenosepala (with pesticide removal rates ranging from 9.20% to 72.82%). With increasing discharge power, extending discharge time, and elevating discharge gas flow rate, the pesticide removal rate increased significantly. The five pesticides had the highest removal rates of 64.80%, 64.44%, 69.81%, 68.22% and 72.82%, respectively, under the conditions of the PAW generator discharge power at 120 W, gas flow rate of 3 L/min and the treatment time of 3 min. Limited by the working voltage of the existing plasma generator (8 kV) and treatment time, there was no significant difference in the control effect on E. coli on the surface of X. stenosepala between PAW at different discharge powers (with E. coli reduction logarithms ranging from 0.81 to 1.17 lg CFU/mL) and bubbling washing (1.14 lg CFU/mL). The research results of this study provide scientific evidence to promote the study of PAW as a green cleaning technique.