Corona Discharge Plasma Jet Inactivates Food-borne Pathogens Adsorbed onto Packaging Material Surfaces

Abstract

The potentiality of corona discharge plasma jet (CDPJ) for disinfection of food packaging materials, including glass, polyethylene, polypropylene, nylon and paper foil, was evaluated. CDPJ was generated using a high voltage (20 kV) pulsed DC power source, at 1.5 A current and 58 kHz frequency. The separation distance between plasma electrode and sample plate during the treatment was 25 mm. Upon treating food pathogens-loaded packaging materials by the plasma, 4.5-5.0 log/cm(2) reductions (99.999%) in viable cell counts of Escherichia coli O157:H7 and Staphylococcus aureus were observed in 120 s. Another tested pathogen Salmonella Typhimurium was inactivated by 3.0 log/cm(2) units. The patterns of inactivation of pathogens are fitted well to Weibull tail model. Compared to untreated controls, the CDPJ-treated packaging materials exhibited insignificant (p > 0.05) changes in the optical characteristics, tensile strengths, surface temperatures and strain-induced deformation. Therefore, the most common food packaging materials harboring bacterial pathogens could be disinfected by the CDPJ without compromising physicomechanical properties of materials. Copyright (C) 2017 John Wiley & Sons, Ltd.