Synergy Between N and O Atom Action and Substrate Surface Temperature in a Sterilization Process Using a Flowing N 2 ‐O 2 Microwave Post Discharge

Summary: It is demonstrated here that the sterilization process using a flowing N 2 ‐O 2 post discharge reactor involves a specific heating of the bacteria metal holder produced by heterogeneous O and N atoms recombination. Such heating increases with N and O‐atom concentrations, which can be varied with the microwave discharge power. It also depends on the metallic material of the holder: a brass support can reach a maximum surface temperature of 120 °C while the surface temperature of the stainless steel holder increases to 60–70 °C after 40 min of exposure to a N 2 ‐5% O 2 post discharge at 0.6 kPa (5 Torr), 1 L n  · min −1 and 100 W. It is demonstrated that the E. coli destruction efficiency increases with N and O atom density at a constant temperature (60 °C) of the stainless steel support and with the support temperature (up to 60 °C) at constant N and O atom densities. A cumulative effect was also found with increasing N and O atom density and of the support temperature.Bacteria survivor number versus the exposure time to a N 2 ‐5% O 2 post discharge.