Ozone is an unstable molecule which readily gives up one atom of oxygen providing a powerful oxidizing agent which is toxic to most waterborne organisms. It is a very strong, disinfectant that is widely used. It is a very good disinfectant. Ozone is made by passing oxygen through ultraviolet light or a "cold" electrical discharge. To use ozone as a disinfectant, it must be created on-site and dosed in to the water. As compared to chlorine the issue of odour and smell is lesser. Ozone though is a very good disinfectant does not leave any disinfectant in residual water. This may be termed as advantage as well as disadvantage. It is applied as an anti-microbiological agent for the treatment, storage, and processing of foods.