Effects of plasma bubble-activated water on the inactivation against foodborne pathogens on tomatoes and its wash water

Abstract

The aims of the study were to evaluate the decontamination effect and inactivation mechanism of a plasma bubble-activated water (PBAW) treatment against foodborne pathogens and to analyze the physicochemical properties of PBAW. A decrease in pH and an increase in the oxidation-reduction potential of PBAW were observed. The study characterized the PBAW decontamination of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on tomato and its wash water. A 20-min PBAW treatment reduced foodborne pathogens on tomatoes and in wash water to levels below the detection limit (1 log CFU/g or 1 log CFU/mL, respectively). The PBAW treatment did not change the color properties of tomatoes. Propidium iodide uptake and membrane lipid peroxidation of PBAW-treated bacteria significantly increased with prolonged treatment time (P < 0.05). The hydrogen peroxide, nitrite, and nitrate concentrations in PBAW increased along with PBAW treatment time. These results indicated that PBAW effectively inactivated foodborne pathogens inoculated on tomato surfaces and in wash water by oxidizing the cell membrane and causing a loss of membrane integrity through the action of reactive species dissolved in the PBAW. This study demonstrates the potential for the application of the PBAW treatment to enhance the microbiological safety of the washing process with no deterioration in product quality.