Combined Effects of Peracetic Acid and Pulsed Light on Salmonella Typhimurium Inactivation

Abstract

Abstract Due to the potentially severe implications of pathogenic Salmonella in contaminated food products, especially in fresh and ready-to-eat products, there is a need for alternative microbial intervention methods. This study investigates the effectiveness of combining pulsed light (PL), a non-thermal treatment, and peracetic acid (PAA), an emerging disinfectant, to inactivate Salmonella Typhimurium and evaluate potential synergy. PAA concentrations of 25–800 ppm (pH 5–7) were examined both individually and in combination with PL. The effects of PAA concentration, timing of PL application, and light energy on treatment efficacy were assessed. As a reference, for isolating the pH effect, inorganic hydrochloric acid (HCl) treatment was also performed. An acidified agar model inoculated with S . Typhimurium was used to evaluate the efficacy of treatment on organic surfaces. The Weibull model fit the PAA inactivation kinetics data ( R 2 ≥ 0.99) across all concentrations. Combined PL + PAA treatments resulted in greater inactivation than individual treatments. Organic PAA consistently showed greater inactivation than inorganic HCl, both alone and in combination with PL ( p < 0.05). Synergy between PL and PAA was quantified using a synergy index ( S ), with synergistic effects observed for all combinations ( S > 1). These findings demonstrate enhanced inactivation of S. typhimurium with the combined treatment, offering an effective and energy-efficient antimicrobial strategy and laying the foundation for future validation and optimization studies in food-related matrices.