Inactivation of foodborne pathogenic and spoilage bacteria by single and dual wavelength UV-LEDs : Synergistic effect and pulsed operation

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Original languageEnglish
Article number107999
Journal / PublicationFood Control
Online published22 Feb 2021
Publication statusPublished - Jul 2021


As an emerging UV source, UV light-emitting diodes (UV-LEDs) are an attractive alternative to traditional mercury vapor lamps for food decontamination. In this work, we sought to find the strategies for the improvement of UV-LED inactivation efficiencies on common foodborne pathogenic and spoilage bacteria. Inactivation efficiencies of UV-LEDs with peak emissions at 369 nm (UVA), 288 nm (UVB), and 271 nm (UVC) and combined emissions at 369/288, 369/271, and 288/271 nm on three foodborne pathogenic bacteria (Escherichia coli, Staphylococcus epidermidis, Salmonella Typhimurium) and two spoilage bacteria (Serratia marcescens, Pseudomonas alcaligenes), were investigated. The solid agar surface was chosen as a model to mimic the food surface. The UV dose delivered to the samples ranged between 0.75 and 6.75 mJ/cm2. For the application of single-wavelength UV-LEDs, 271 nm UV-LED displayed the highest inactivation efficiency on the tested bacteria. A synergistic effect was observed when E. coli, S. epidermidis, and S. Typhimurium were exposed to irradiation from 288/271 nm UV-LEDs. The synergy ratios ranged from 0.20 to 0.87. No synergy was observed for S. marcescens and P. alcaligenes, or any bacteria tested with 369/288 or 369/271 nm combined modules. Besides, the inactivation efficiencies of continuous and pulsed irradiation against E. coli and S. epidermidis were compared using three modules: 288 nm, 271 nm, and 288/271 nm UV-LEDs. All of the tested UV-LED modules showed comparable inactivation by continuous and pulsed irradiation with various duty cycles under an equivalent UV dose of 6.46 mJ/cm2. Based on the operation-specific microbial inactivation data, this study demonstrated an effective and sustainable method for inactivating foodborne pathogens and offered strategies to enhance disinfection efficiency for system designers and industrial engineers.

Research Area(s)

  • Bacteria, Disinfection, Foodborne pathogens, Pulsed irradiation, Synergistic effect, Ultraviolet light-emitting diode (UV-LED)