Mixing a sodium chlorite solution with a food-grade weak acid solution (usually citric acid) creates short-lived acidified sodium chlorite solutions (ASC) with powerful stain removal properties. When the main active ingredients are mixed, chlorous acid is produced in equilibrium with the chlorite anion. The ratio varies with pH, temperature and other factors, ranging from about 5-35% chlorous acid and 65-95% chlorite; the more acidic the solution, the higher the ratio of chlorous acid. Chlorous acid decomposes into chlorine dioxide, which in turn decomposes into chlorite anions, and finally into chlorine anions.
ASC is used to disinfect hard surfaces that come into contact with food and as a cleaner or rinse agent for a variety of food products, including red meat, poultry, seafood, fruits and vegetables. Since oxochlorine compounds are unstable when properly prepared, there should be no measurable residues on foods if handled properly. ASC is also used as a teat bath to control mastitis in dairy cows.
According to the FDA, ASC solutions used as processing aids in wash and/or rinse water have direct food contact and indirect food contact use restrictions:
• Direct food contact (secondary direct food additives) – poultry carcasses, organs and parts; red meat carcasses, organs and parts, seafood (finfish and crustaceans) and fruits and vegetables (raw and further processing); processed, ground or formed meat products; and • indirect direct food contact ─ hard surface food contact disinfection .