Blue 405 nm LED light effectively inactivates bacterial pathogens on substrates and packaging materials used in food
Hanyu Chen1, Yifan Cheng2, Carmen I Moraru3
1Department of Food Science, Cornell University, Ithaca, NY, 14853, USA.
Scientific Reports
|September 19, 2023
Summary
405 nm light emitting diodes (LEDs) show significant antimicrobial effectiveness against common foodborne pathogens on various surfaces and in liquid films. Nanoscale topography enhanced inactivation, demonstrating promise for food safety and healthcare applications.
Area of Science:
- Photochemistry and Photobiology
- Microbiology
- Materials Science
Background:
- Pathogenic bacteria pose significant risks in food processing, service, and healthcare settings.
- Traditional disinfection methods can be limited by efficacy, material compatibility, or chemical residues.
- Visible light disinfection offers a potential alternative for microbial control.
Purpose of the Study:
- To evaluate the antimicrobial efficacy of 405 nm light emitting diodes (LEDs).
- To assess inactivation of key foodborne pathogens including Escherichia coli O157:H7, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Typhimurium, and Staphylococcus aureus.
- To investigate the influence of surface materials and nanoscale topography on inactivation efficiency.
Main Methods:
- Exposure of bacterial pathogens in thin liquid films (TLF) and on solid surfaces to 405 nm LEDs for 48 hours.
- Utilized various materials: stainless steel (SS), high-density polyethylene (HDPE), low-density polyethylene (LDPE), borosilicate glass, and anodic aluminum oxide (AAO) with nanoscale topography.
- Analyzed inactivation kinetics using Weibull models and assessed the impact of surface properties like roughness, hydrophobicity, and reflectivity.
Main Results:
- Significant log reductions (1.3–6.3 log CFU) were achieved across tested bacteria and surfaces.
- Inactivation rates varied by pathogen and surface type, with faster rates observed on specific AAO nanopore surfaces.
- Inactivation curves followed nonlinear Weibull kinetics, with better model fit on solid surfaces (R² ≥ 0.89) than in TLF (R² ≥ 0.76).
Conclusions:
- 405 nm LEDs demonstrate potent antimicrobial activity against a range of critical pathogens.
- Surface topography, particularly nanoscale features, can enhance bacterial inactivation.
- This technology holds significant promise for non-thermal microbial control in food processing, handling, and healthcare environments.
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