Evaluating the Efficacy of Plasma-Activated Water in the Elimination of Pathogenic Bacteria: An Experimental Study on Pseudomonas, Salmonella, Escherichia  Coli, and Staphylococcus Aureus

Abolfazl  Mazandarani; Mojtaba  Jabbari; Shervin  Goudarzi; Mohammad Javad  Khodashenas

doi:10.18502/jfrh.v19i3.20054

Abolfazl Mazandarani Nuclear Science and Technology Research Institute, Plasma and Nuclear Fusion Research School, Atomic Energy Organization of Iran, Tehran, Iran
Mojtaba Jabbari National Nuclear Industry Educational and Cultural Institute, Bandar Abbas, Iran
Shervin Goudarzi Nuclear Science and Technology Research Institute, Plasma and Nuclear Fusion Research School, Atomic Energy Organization of Iran, Tehran, Iran
Mohammad Javad Khodashenas Department of Nuclear Engineering, Faculty of Physics and Energy Engineering, Amirkabir University of Technology, Tehran, Iran

DOI: https://doi.org/10.18502/jfrh.v19i3.20054

Keywords: Plasma-activated water; Pseudomonas; Salmonella; Escherichia coli; Staphylococcus aureus; Disinfection

Abstract

Objective: This study aimed to evaluate the effectiveness of PAW in inhibiting and eliminating four major pathogenic bacterial species: Pseudomonas, Salmonella, Escherichia coli, and Staphylococcus aureus.

Materials and methods: Plasma-activated water (PAW) was generated using a dielectric barrier discharge (DBD) cold plasma device (10 kV, 20 kHz, 4.5 L/min airflow). Two-pipette electrodes generated plasma columns with reactive species. Water hardness, pH, and ozone were measured in triplicate. Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Salmonella spp. were cultured, suspended to 0.5 McFarland, diluted serially, and cultured using the pour plate method. Plasma-generating electrodes were immersed in bacterial suspensions and treated for 2.5, 5, 10, and 15 minutes. Samples were cultured in triplicate using the pour plate method and colony counts were analyzed using t-tests and ANOVA.

Results: Plasma-activated water (PAW) significantly altered pH and hardness and exhibited high bactericidal activity. Hardness increased dramatically post-plasma, while pH decreased. Ozone levels increased with plasma exposure. Duncan’s test (p < 0.05) confirmed significant bacterial reduction. PAW completely eliminated some strains within 2.5-5 minutes. PAW eliminated Pseudomonas aeruginosa at all time points. S. aureus was reduced to 78 ± 9 CFU/mL at 2.5 minutes and eliminated thereafter.
E. coli was eliminated at 5-15 minutes, with 53 ± 7 CFU/mL remaining at 2.5 minutes. Salmonella spp. was reduced to 66 ± 8 CFU/mL at 2.5 minutes and eliminated thereafter.

Conclusion: Increased ozone concentration along with ROS and RNS enhances disinfection, inactivating Pseudomonas aeruginosa, Salmonella spp., Escherichia coli, and Staphylococcus aureus within 5 minutes. Reactive species disrupt bacterial cell walls and membranes, providing antimicrobial effects. Plasma-activated water offers a portable, user-friendly, and eco-friendly alternative to chemical disinfectants for microbial decontamination in food, medical, sanitation, and hospital settings, while conserving water.