Inactivation Kinetics of Salmonella typhimurium and Staphylococcus aureus in Different Media by Dielectric Barrier Discharge Non-Thermal Plasma

A study was conducted to determine the effect of dielectric barrier discharge non-thermal plasma (DBD-NTP) on Salmonella typhimurium and Staphylococcus aureus populations on solid surfaces and in liquid suspensions. Our results showed that inactivation kinetics of S. typhimurium and S. aureus by DBD-NTP treatments can be well predicted with mathematical models. The survival curves of both S. typhimurium and S. aureus showed a log-linear phase followed by tailing behaviors on solid surfaces, and shoulder behaviors followed by a log-linear phase in liquid suspensions. The D values (decimal reduction time) for S. typhimurium and S. aureus in suspension were higher than those on solid surfaces (p < 0.05). Additionally, the maxima of sublethal injury values under low NaCl concentration and neutral pH condition were higher than those under high NaCl and low pH condition. In addition, mathematical modeling was evaluated to predict the final inactivation result for potential industrial applications. This study indicates that different microbial supporting matrices significantly influence the inactivation effect of DBD-NTP; it also provides useful information for future applications of NTP in enhancing food shelf life and safety.