Ozone has been used for many years to treat pathogens such as bacteria and algae in water for applications such as drinking water supplies and air conditioning system cooling water. More recently, most water bottlers have adopted ozone. Ozonated water for treatment of fruit, vegetables, fish, etc. in the U.S. awaited the GRAS approval. Now that has happened, and projects are emerging everywhere. A basic difference over other ozone-in-water applications is that the ozone contact time with the food product must be very short. The carrots, fresh fish fillets, or whatever must be processed in an assembly line in at most a few minutes.............................Ozone's effectiveness in wash water may be significantly reduced when the biological oxygen demand (BOD) of the water is more than 500 mg/L. In this case, the BOD must be reduced before the ozone treatment stage.