Synergistic Inactivation Mechanism of Combined Plasma-Activated Water and Mild Heat against Saccharomyces cerevisiae

This study aimed to elucidate the mechanism of synergistic inactivation of Saccharomyces cerevisiae by the combined use of plasma-activated water (PAW) and mild heat (40 to 50°C). A reduction of 4.40 log CFU/mL in S. cerevisiae was observed after the synergistic combination of PAW and mild heat at 50°C for 6 min, whereas the individual treatments of PAW at 25°C and mild heat at 50°C for 6 min resulted in a reduction of 0.27 and 1.92 log CFU/mL, respectively. The simultaneous application of PAW and mild heat caused significant increases in membrane permeability, resulting in the leakage of intracellular components (such as nucleic acids and proteins) and increased uptake of propidium iodide. The combined treatment of PAW and mild heat also resulted in significant increases in the intracellular levels of reactive oxygen species and disruption of mitochondrial membrane potential in S. cerevisiae cells. In summary, this study illustrates the potential of PAW treatment combined with mild heat to rapidly inactivate microorganisms in food products.