Facts about chlorine use in produce wash water

Are we helping or hurting ourselves by using chlorine for the prevention of foodborne pathogens? Certainly it kills pathogens in produce wash water, as well as drinking water, reclaimed water, and commercial poultry process water. But with ozone options available (which leave no residues, and do a better, faster job of killing pathogens), we should be asking some serious questions about the safety of chlorine.

Following are some facts from a Michigan State University report called “Chlorine Disinfection of Produce Wash Water”

Chlorine gas is labeled as a toxin on the MSDS (Material Safety Data Sheet, available from any company that sells a chemical). Chlorine is also an irritant to the respiratory system, skin, and mucous membrane. In the liquid form, it will burn skin and eyes on contact. When products of chlorine come in contact with organic material, trihalomethanes (THMs) are formed. THMs are known to cause cancer over long term exposure.

The Occupational Safety Hazards Association (OSHA) requires the maximum long-term ( > 8 hours/day) human exposure level to chlorine in air to be 0.5 ppm. On a short-term ( < 15 minute) basis, the maximum level for chlorine exposure is 1 ppm in air. Concentrations in air above 5 ppm in air will cause choking, coughing, and skin and eye irritation.

Chlorine must be handled safely. Liquid chlorine (sodium hypochlorite) is readily vaporized to gas. It must be handled in a manner that prevents the accumulation of high concentrations in the air. Monitors can be purchased to measure the chlorine concentrations in air. Automatic metering devices greatly reduce chlorine gas in the air.

Only trained personnel should be in charge of storing and handling chlorine. The Chlorine Institute and most equipment manufacturers will provide this educational material. In general, chlorine solutions should be handled with protective clothing and glasses. Shower and eyewash stations should be near the handling area when mixing chlorine with water or when handling solid hypochlorite.

Ozone is safer for the environment, the produce processing employee, and the consumer. It’s worth exploring as a viable alternative for produce wash water applications. AWPI also plans to explore ozone use for direct food application in the future because we believe there are many more ways it can help us avoid poisoning our food supply in the effort to kill foodborn pathogens.