Characterization of a non-thermal plasma-bubbling system as a novel sanitizer: physicochemical properties, bactericidal effect, and reactive species

Non-thermal atmospheric plasma has emerged as a promising alternative sanitizer because of the presence of highly reactive oxygen species (ROS). This study investigated an integrated bubble-assisted method for more efficient distribution of the reactive species. We aimed to evaluate the antibacterial activity of the plasma-bubbling system against E. coli O157:H7 and determine the presence of reactive species. Two approaches were investigated: direct treatment and plasma-activated water (PAW) generation, using a plasma jet and pure oxygen. E. coli numbers were reduced by 3.3-log within 5 min of PAW treatment, whereas direct treatment achieved a higher log reduction, to below the detection limit, in 3 min. Study of selected scavengers of relevant ROS revealed that hydroxyl radicals (center dot OH) and singlet oxygen (1O2) are the primary short-lived reactive species. Based on these results, our plasma-bubbling treatment shows promise as an alternative water-based sanitizer.