Synergistic control of foodborne pathogens and the Listeria virulence gene using UV-LED combined with phytic and peracetic acids

This study evaluated the efficacy of phytic acid (PA), peracetic acid (PAA), and ultraviolet light-emitting diode (UV-LED) treatments, individually and in combination, for controlling key foodborne pathogens (Listeria monocytogenes, E. coli DH5α, Salmonella Typhimurium, Staphylococcus aureus, and vegetative Bacillus cereus) in aqueous solutions. L. monocytogenes inactivation, measured via plate count, followed first-order kinetics, with rate constants of 1.3(±0.2)×10-1 L/(mg×min) for PAA, 1.7(±0.04) to 8.6(±0.09)×10-1 L/(mg×min) for PA/PAA, and 1.3(±0.03) to 8.1(±0.03) cm2/mJ for PA/PAA/UV-LED treatments. The optimized PA/PAA/UV-LED treatment significantly degraded the hly gene (1561 bp), as measured by quantitative PCR, with rate constants ranging from 1.3(±0.03)×10-1 to 2.4(±0.07)×10-1 cm2/mJ. While PAA and PA/PAA exhibited marginal reactivity with DNA, UV-LED played a pivotal role in genetic material abatement. Physiological and biochemical alterations in L. monocytogenes, including intracellular substance leakage, membrane vesiculation, and lipid peroxidation, were observed through flow cytometry, scanning electron microscopy, and biochemical assays quantifying extracellular proteins, intracellular reactive oxygen species, and malondialdehyde. The combined PA/PAA/UV-LED treatment achieved >3 log (99.9 %) reductions of foodborne pathogens, excluding B. cereus spores, under simulated food-washing conditions. These findings highlight the potential of PA, PAA, and UV-LED to optimize combinational water disinfection systems, enhance food safety in processing environments, and mitigate microbial contamination in natural ecosystems.