Influence of plasma characteristics on the efficacy of Cold Atmospheric Plasma (CAP) for inactivation of Listeria monocytogenes and Salmonella Typhimurium biofilms

The biofilm mode of growth protects bacterial cells from applied disinfection methods for abiotic (food) contact surfaces. Therefore, new inactivation technologies such as Cold Atmospheric Plasma (CAP) should be considered. However, the influence of different plasma characteristics on the CAP efficacy for biofilm inactivation requires further study. In this research, the influence of (i) the applied plasma configuration (Dielectric Barrier Discharge (DBD) and Surface Barrier Discharge (SBD)), (ii) the oxygen level of the gas flow (He + 0.0/0.5/1.0 (v/v) % O2), and (iii) the plasma intensity (13.88, 17.88, and 21.88 V input voltage) on the CAP efficacy for inactivation of L. monocytogenes and S. Typhimurium biofilms was investigated. Depending on the applied plasma characteristics, log10-reductions up to approximately 3.5 log(CFU/cm²) were obtained. Nevertheless, it could be concluded that the highest log-reductions were in general obtained while using the DBD electrode, 0.0 (v/v) % O2, and an input voltage of 21.88 V.status: Published onlin