Patent ID: 8871146

Claim:
A method for sterilizing microorganisms present in a liquid or on a surface thereof, comprising: a first step of preadjusting the liquid to have a pH value of 4.8 or lower; a second step of generating plasma in a vicinity of or in a manner to make contact with the liquid whose pH value is adjusted to become 4.8 or lower in the first step; and a third step of supplying, through the plasma generated, the liquid whose pH value is adjusted to become 4.8 or lower in the first step with superoxide anion radicals (O 2 − .), reacting the superoxide anion radicals (O 2 − .) with protons (H + ) in the liquid, increasing a concentration of hydroperoxy radicals (HOO.) in the liquid, and sterilizing the microorganisms present in the liquid or on the surface thereof.