Inactivation Effect and Influencing Factors of Cold Atmospheric Plasma Treatment with Bacteria on Food Contact Materials

This study investigated the inactivation effect and influencing factors of cold atmospheric plasma (CAP) treatment with Salmonella typhimurium and Staphylococcus aureus populations on three food contact materials (FCMs)—kraft paper, 304 stainless steel, and glass. The CAP was generated as an atmospheric helium plasma jet (15 kV, 10.24 kHz, He 4 L/m), and the experimental results indicated that its inactivation effects on two bacterial species gradually increased as the plasma treatment duration increased (0, 1, 2, 3, 4, and 5 min). Three classical sterilization kinetic models (Log-linear, Weibull, and Log-linear + Shoulder + Tail) were employed to evaluate the inactivation efficiency of plasma against bacteria FCMs. Combined with the coefficient of determination (R2), accuracy factor (Af), and bias factor (Bf), together with the root mean square error (RMSE), it can be concluded that the Log-linear + Shoulder + Tail model had the highest fitting degree among the three sterilization kinetics models. Salmonella typhimurium exhibited weaker resistance than Staphylococcus aureus to the same CAP treatment. Under the same conditions, CAP had the strongest bactericidal effect on the bacteria on the glass surface, followed by those on the 304 stainless steel, and had the weakest bactericidal effect on the bacteria on the kraft paper surface, which might be related to the surface hydrophilicity and roughness of the FCMs. The above results indicated that CAP’s inactivation effect may be influenced by the microbial species as well as the surface characteristics of FCMs. This study provides useful information for future applications of CAP in enhancing food safety.