Cold plasma treatment for E. coli inactivation and characterization for fresh food safety

Cold plasma is an emerging non-thermal technology for food pathogen inactivation and material surface modification. This technology was demonstrated ecofriendly and convenient with free of chemicals in food processes. The presenting study was to investigate the effectiveness of reactive species generated in cold plasma treated water (CPTW) for inactivating microbes through oxidative stress. The physical properties of CPTW created by electric discharges of O2/N2 were characterized. The potential of CPTW for fresh food applications was evaluated. The research results revealed that the pH values of CPTW significantly decreased from pH 7.4 to 3.4 and the electrical conductivity of CPTW increased from 78 to 162 mS/cm when treatment time increased from 10 to 240 s at the discharge frequency of 2000 Hz. It's demonstrated that the CPTW was able to significantly inactivate E. coli TOP 10 in water. The substantial reduction in E. coli TOP 10 cells increased from 1.6 to 8 log at a frequency of 2000 Hz when the treatment times changed from 10 to 240 s. It's also verified that the CPTW significantly reduced the bacterial load and extended the shelf life of the strawberries up to 30 days without compromising their quality compared to untreated control samples. This information is useful for the design of effective cold plasma processes in food engineering applications. Further research is necessary to explore the full potential of cold plasma technology in enhancing food safety and quality in the future.