J. Gen. Appl. Microbiol., 48, 193–199 (2002)

For many years, the role of ozone (O3) against pathogens has been studied and it has been revealed that ozone can display biological effects and therapeutic index (Berson et al., 1996; Bocci, 1996; Hernandez et al., 1995; Turcic et al., 1995; Verrazzo et al., 1995; Wolfe et al., 1989). Ozone is a natural gas that is distributed at approximately 0.01–0.04 ppm (part per million) of the world’s atmosphere. It is an unstable gas which can be broken down to oxygen gas (O2) and oxygen atoms (O). The oxygen atom, being a strong oxidizer, appears to be a good agent for sterilization by the oxidation process. This property, therefore, becomes very useful for antioxidant protection system in arterial diseases and the immune system (Jakab et al., 1995; Peden and Dailey, 1995; Verrazzo et al., 1995) and in the inactivation of microorganisms (Broadwater et al., 1973; De Mik and De Droot, 1977; Foegeding, 1985; Ishizaki et al., 1986; Komanapalli and Lau, 1998). The use of ozone is applied in decontamination of microorganisms in biocleaned rooms (Masaoka et al., 1982), food preservation (Chen et al., 1992; Rice et al., 1982; Sheldon and Brown, 1986) and drinking water (Boyce et al., 1981; Glaze, 1987; Katzenelson and Biedermann, 1976). The ozone treatment was effective against both Effects of ozone treatment on cell growth and ultrastructural changes in bacteria