title: Bactericidal Effects against S. aureus and Physicochemical Properties of Plasma Activated Water stored at different temperatures.
abstract: Water activated by non-thermal plasma creates an acidified solution containing reactive oxygen and nitrogen species, known as plasma-activated water (PAW). The objective of this study was to investigate the effects of different storage temperatures (25 °C, 4 °C, -20 °C, -80 °C) on bactericidal activities against S. aureus and physicochemical properties of PAW up to 30 days. Interestingly, PAW stored at -80 °C yielded the best antibacterial activity against Staphylococcus aureus, 3~4 log reduction over a 30-day period after PAW generation; meanwhile, PAW stored at 25 °C, 4 °C, and -20 °C, respectively, yielded 0.2~2 log decrease in cell viability after the same exposure and storage time. These results were verified by scanning electron microscope (SEM). The physicochemical properties of PAW stored at different temperatures were evaluated, including pH, oxidation reduction potential (ORP), and hydrogen peroxide, nitrate, nitrite anion and NO radical levels. These findings suggested that bacterial activity of PAW stored at 25 °C, 4 °C, -20 °C decreased over time, and depended on three germicidal factors, specifically ORP, H2O2, and NO3(-). Moreover, PAW stored at -80 °C retained bactericidal activity, with NO2(-) contributing to bactericidal ability in association with H2O2. Our findings provide a basis for PAW storage and practical applications in disinfection and food preservation.
authors.affiliation: Institute for Environmental Health and Related Product Safety, Chinese Center for Disease Control and Prevention, Beijing 100000, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Shen
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100000, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100000, China.
authors.forename: Yinglong
authors.initials: Y
authors.lastname: Li
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100000, China.
authors.forename: Ruonan
authors.initials: R
authors.lastname: Ma
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100000, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, College of Engineering, Peking University, Beijing 100000, China.
authors.forename: Jue
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, College of Engineering, Peking University, Beijing 100000, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Fang
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D004578:Electron Spin Resonance Spectroscopy; D006861:Hydrogen Peroxide / Q000737:chemistry / Q000633:toxicity; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D009566:Nitrates / Q000737:chemistry; D009589:Nitrogen Oxides / Q000737:chemistry; D010084:Oxidation-Reduction; D058626:Plasma Gases / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000187:drug effects; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D009566:Nitrates; D009589:Nitrogen Oxides; D058626:Plasma Gases; D014867:Water; D006861:Hydrogen Peroxide