Cold storage rooms hold various types of foods including vegetables, fruits, meats, sea foods, etc. Injecting ozone in the air inside the cold storage rooms maintains the environment inside bacteria free. As a result the bacterial activity on the surfaces of foods under storage is minimal, this increasing the shelf life of the foods. The safe factor is that since ozone has a very short half life, there is no toxicity either in the foods nor in the environment. Ozone has been found to be of tremendous advantage in such cold storage rooms for better maintenance of stored foods.