Exploring Potential of a Remote Plasma Electrolysis System (RPES) for Fruit Surface Sterilization

Faculty of Science, Energy and Environment, King Mongkut’s University of Technology North Bangkok, Rayong Campus, Rayong 21120, Thailand

^* Corresponding author: phuthidhorn.t@sciee.kmutnb.ac.th

Abstract

This study investigates the potential of remote plasma electrolysis systems (RPES) for eliminating microorganisms on fruit surfaces. A plasma electrolysis reactor generated long-lived reactive oxygen and nitrogen species (RONS), including hydrogen peroxide (H₂O₂), nitrite (NO₂^-), nitrate (NO₃^-), nitrous acid (HNO₂), and nitric acid (HNO₃), which were introduced into a treatment chamber through airflow. The spatial distribution of these reactive species was visualized using a KI-starch agar gel reagent. The antimicrobial efficacy of RPES was tested in vitro against methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli). Following optimization, the system was applied to sterilize 1.0 kg samples of rambutans and grapes, with a treatment time of 10 minutes. After treatment, aerobic bacteria on rambutan surfaces decreased by 98.3%, and yeasts and molds level dropped by 50.1%. On grape surfaces, RPES completely eliminated aerobic bacteria, yeasts, and molds. These findings demonstrate RPES’s effectiveness in inactivating surface pathogens on fruits, highlighting its potential for broader applications in fruit sterilization.