Inactivation of Staphylococcus aureus by the synergistic action of charged and reactive plasma particles

In this paper, a low-pressure capacitively coupled plasma discharge sustained in an argonoxygen mixture was studied in order to evaluate its properties in terms of inactivation of
Staphylococcus aureus. The plasma parameters as electron temperature and plasma density were
measured by the Langmuir probe (Ne ? 1015 m-3
, Te ? 1.5 eV), while the neutral atom density
was in the range of 1021 m-3
. In the plasma phase, oxygen radicals were taken as reference of the
reactive species with antimicrobial activity, and oxygen spectral lines, over a range of plasma
process parameters, were investigated by the optical emission spectroscopy. Optimal plasma
conditions were found, and a count reduction of 4 log in a few minutes of the bacterium proves
the potentiality of an industrial grade plasma reactor as a sterilization agent.