Pulsed light (PL) technology is based on pulsed discharge in inert gases such as xenon to generate non-equilibrium plasma, and the UV component in its emission spectrum exhibits significant microbial inactivation capability. In this work, the inactivation efficacy of PL against E. coli and the bactericidal contributions of different PL spectral bands were investigated. The results showed that PL (1.36 J/cm², 10⁷ CFU/mL) achieved a >6‑log reduction of E. coli, with the UVC band contributing most significantly to bacterial inactivation. Furthermore, this study investigated the antibacterial mechanism of PL against E. coli, focusing on changes in morphology, ultrastructure, biochemical composition, intracellular leakage, metabolic activity, and membrane integrity. SEM and AFM indicated that PL severely disrupted cell morphology and integrity, caused numerous surface micro-damages, and altered mechanical properties. FT-IR revealed significant changes in membrane fatty acids and chemical structure. CLSM showed severe morphological damage, compromised membrane integrity, and leakage of DNA and proteins. Additionally, PL significantly increased intracellular ROS levels, triggering structural disruption and metabolic collapse that ultimately accelerated cell death.
 

Pulsed light; Escherichia coli; Inactivation; Antimicrobial mechanism; non-equilibrium plasma