Antibacterial activity and a membrane damage mechanism of plasma-activated water against Pseudomonas deceptionensis CM2

In this work, the antibacterial effects and underlying mechanisms of plasma-activated water (PAW) against Pseudomonas deceptionensis CM2 isolated from spoiling chicken meat were investigated. The population of P. deceptionensis CM2 was significantly reduced approximately 5 log units within 10 min of exposure to PAW. The results of the scanning electron microscope clearly showed distinguishable morphostructural changes in P. deceptionensis CM2 as a consequence of PAW treatment. The permeability change in the outer and cytoplasmic membranes was evaluated by using 1-N-phenylnaphthylamine (NPN) and propidium iodide (PI), respectively. The fluorescence intensities of NPN and PI in P. deceptionensis CM2 cells were significantly increased after PAW treatment (p < 0.05), indicating the disruption of the membrane permeability barrier. Following activation with plasma, PAW acquires an acidic pH and a higher oxidation reduction potential and contains aqueous reactive species, such as H2O2, nitrate, and nitrite anions, which play a crucial role in the inactivation process of P. deceptionensis CM2 cells. These findings indicate that PAW is a promising alternative to traditional sanitizers used in food and food-processing environments.