Effects of nonthermal plasma-activated water on the microbial sterilization and storage quality of blueberry.

This study has presented the potential use of plasma-activated water (PAW) for the inactivation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) inoculated on blueberries. The generation parameters of PAW were optimized to a voltage of 8 kV, a frequency of 14 kHz, a processing volume of 30 mL, and a processing time of 50 min. PAW treatments achieved significantly higher (p < 0.05) reductions than those obtained by water treatment in E. coli and S. aureus. As shown by propidium iodide and acridine orange staining, electron microscopy and optical emission spectra of plasma, the microbial inactivation of PAW was attributable to damage to the cell membrane and the denaturation of DNA induced by reactive oxygen species produced from plasma. During storage, PAW treatment was more beneficial to the quality of blueberries than water treatment. Thus, PAW immersion is a promising method for maintaining the freshness of blueberries. • PAW had a certain inactivation effect on E. coli and S. aureus inoculated in blueberry fruits. • The cell membrane of E. coli and S. aureus was damaged after PAW treatment. • The DNA of E. coli and S. aureus was denatured after PAW treatment. • Reactive oxygen species were the active substance for inactivation of microbes in PAW. • PAW treatment had less impact on the quality of blueberries in storage than water treatment. [ABSTRACT FROM AUTHOR]