Correlation analysis of reactive oxygen and nitrogen species (RONS) components in plasma activated water (PAW) and its inactivation of Bacillus cereus endospore

Plasma activated water (PAW), a physicochemical approach that can efficiently enable the inactivation effect of Bacillus cereus endospores, is receiving numerous attentions in food and other areas. However, the potential RONS featuring PAW that inactivates bacteria is an open issue. Here, we for the first time thoroughly clarified the functioning chemicals on antimicrobial ability in PAW by adding each corresponding scavenger at an optimized dose, including superoxide anion (O2−), singlet oxygen (1O2), hydroxyl radical (OH), hydrogen peroxide (H2O2), nitrite ions (NO2−), nitric oxide (NO) and peroxynitrite (ONOOH). An overall reduction of 1.74 log CFU/mL is determined by the sporicidal effects of PAW; however, when adding their corresponding scavengers, the effect was attenuated to different extents. The internal correlations are constructed using Spearman analysis based on the inactivation of endospores for determining their specific contributions in such a complex PAW system and corresponding effective factors are calculated. The Spearman coefficients of NO2−, O2−, H2O2, and NO were 0.476, 0.405, 0.168, and 0.143, revealing that the log CFU/mL reduction of B. cereus endospore was positively proportional to the contents of NO2−, O2−, H2O2, and NO. This study addresses the fundamental issues related to the chemicals in PAW and may initiate wide interest in PAW in physiochemistry and biology.