Storage-Mediated Changes in Sodium Hypochlorite and Peroxyacetic Acid Sanitizer Concentrations

Chlorine and peroxyacetic acid (PAA) are widely used throughout the food industry as economical and effective sanitizers. However, efficacy is partially dependent on proper storage conditions, as they are affected by UV light exposure, temperature, and pH, but the degree to which these factors influence sanitizer effectiveness has not been well described. This study examined the effects of plastic bottle type (transparent or opaque) and storage conditions on chlorine (200 ppm of free chlorine) and PAA (60 to 80 ppm) concentrations. Bottles were stored in outdoor, indoor, or refrigerated conditions, and sanitizer concentrations were measured over a 32-day period (summer 2022). Although bottle type significantly affected chlorine stability, it did not result in a significant reduction in PAA concentration. The free chlorine concentration in sanitizers stored in translucent bottles was depleted by day 4 of outdoor storage and ca. 50 ppm by day 13 when stored at room temperature. PAA concentrations stored outdoors or at room temperature ranged from ca. 0 to 30 ppm by day 32. Both sanitizer concentrations remained consistent under refrigeration for all bottle types through the 32-day period. Proper storage and monitoring of sanitizer can ensure adequate microbial reduction when used in food handling environments.