Compared to chlorine, ozone offers several advantages for food processors or anyone who wants to disinfect materials or surfaces. Chlorine has traditionally been the sanitizer of choice in the food processing industry, but experts share a growing concern about the dangerous byproducts such as trihalomethanes or dioxins produced when chlorine reactes with organic matter in the water. These substances are known carcinogens and are regulated in drinking water by the U.S. Environmental Protection Agency. Ozone, on the other hand, is simply oxygen in an unstable and highly reactive form. It naturally tends to seek its normal state, exhibing a short half life as it reverts to oxygen fairly rapidly. When it reacts with organic matter, it does not form any toxic byproducts and the water in which it was delivered can be filtered and reused. Because it is so highly reatctive, ozone is effective at controlling or removing biofilms that sometimes form on processing equipment. It can also be used to reduce biological oxygen demand (BOD), chemical oxygen demand (COD), and turbidity or other residues in water. While chlorinated wash systems require tansport and storage of potentially hazardous toxic chemicals, ozone is unique in that it is generated onsite from harmless oxygen and can be produced on demand with no storage required. When the generator is turned off, there are no dangerous substances on the premises. While the oxidation reduction potential (ORP) or ozone is affected by the amount of organic matter or chemicals in the water, its ORP is not as sensitive to changes in pH as that of chlorine. Ozone has a variety of uses in food processing plants. Water containing low concentrations of ozone gas can be sprayed onto processing equipment, walls or floors to both remove and kill bacteria or other organic matter that may be present. Becuase it has such a short half life, ozone does not build up on surfaces the way detergents can if not removed by proper rinsing. Ozone can also be injected or dissolved in process waters of all kinds to provide chilling, fluming, rinsing or washing of food products such as meat, poultry, seafood, fruits or vegetables. Processors who chill fruits or vegetable after harvest using water held at approximately 34 F can ozonenate the water to prevent contamination of the product. Cooling fuits and vegetables helps slow product respiration, and preserving freshness and quality. Studies of fruits and vegetables indicate that removing field heat as soon as possible after harvest is a critical factor in extending product shelf life. As a side benefit, ozone can remove particulates, chemicals and organics from water, settling them out by flocculation. Because it is so effective at removing suspended or dissolved substances, ozone can help conserve process water by making it possible to filter and recycle the stream.