Influence of various fish constituents on inactivation efficacy of plasma‐activated water

Summary Plasma‐activated water (PAW) is an effective disinfectant against a wide range of microorganisms, but its effect on food products is limited. This study aimed to investigate the fluid environment on the inactivation efficacy of PAW and its application on fish decontamination. Three organic media (fish gelatin, fish oil and fish homogenate) at 5%, 10% and 20%, and inorganic media of phosphate‐buffered saline (PBS) and water were inoculated with Pseudomonas fluorescens at a final concentration of 7 log10 CFU per mL. The inoculated media were treated by an atmospheric cold plasma jet at 30 kV for 5 min and stored at 4 °C for 24 h, during which the inactivation effects were determined at different exposure times. The physicochemical properties of the media were measured. Furthermore, PAW generated for 15 min was applied to P. fluorescens‐inoculated fish. The results showed that PAW achieved a complete inactivation immediately after treatment, while there was almost no reduction for plasma‐activated PBS even after 24 h. Reduced inactivation efficacy was observed for the organic media except for fish oil, and the inactivation rates were in inverse correlation to the concentrations of organic material. PAW treatment obtained 0.4 log reduction on fish. This study revealed that the fluid environment had a great influence on the inactivation efficacy of PAW, and PAW can be a potential sanitiser for fish decontamination. Schematic diagram of the overall experimental design.