Effect of Low-Temperature Plasma of High-Voltage Diffused Gas Discharge on Microbiological Objects

Investigation results on inactivation of microbiological cultures in humid and dry state with low-temperature plasma of pulsed-periodic discharge of low power (up to 5 W) are presented. The discharge is formed in gaps with distinctly heterogeneous distribution of the magnetic field at reduced air pressure (tens of torr), the value of which nevertheless, exceeds pressure of saturated water steam at close to room temperature and inter-electrode gap up to 10 cm. The temperature of test objects at all regimes of the discharge plasma effect did not exceed 40degC. Escherichia coli and Staphylococcus epidermidis, inoculated to test samples of ~10⁸ quantity, were used as reference cultures. It was established that the described discharge exerts sterilizing influence on microbiological cultures. Influence regimes of low-temperature plasma, providing death of all microorganisms, inoculated to the test samples, were determined. Efficiency of bactericidal effect of specific discharge regime was determined according to the fact of absolute sterility of the test samples. Reliability of the results was provided by multiple repetition of experiments. It was established that absolute sterility of humid and dry test samples was reached in 15 minutes after processing at the discharge average power of 0.3-0.4 W and 3-4 W correspondingly. Analysis of totality of experimental results makes it possible to assert that charged particles are the main sterilizing factor of the studied discharge. Spatial connection of sterilization efficiency with area of increased density of the discharge current certify this.