Antibacterial efficacy of 405, 460 and 520 nm light emitting diodes on Lactobacillus plantarum, Staphylococcus aureus and Vibrio parahaemolyticus

Aims: Little information is available on a direct comparison of the antibacterial efficacy of light emitting diode (LEDs) of different peak wavelengths. Thus, the objective of this study was to evaluate the effect of LEDs of three different wavelengths on bacterial inactivation. Methods and Results: Lactobacillus plantarum, Staphylococcus aureus and Vibrio parahaemolyticus were illuminated with 405, 460 and 520 nm LEDs at 4, 10 and 25 degrees C respectively. Inactivation curves were plotted and fitted using Gompertz Model. Illumination with 405 and 460 nm LED produced significant inactivation (P < 0.05) in the population of V. parahaemolyticus (>4 log) while Lact. plantarum and Staph. aureus showed relatively less susceptibility to the LED illumination. The 520 nm LED produced negligible inactivation. Conclusions: The 405 and 460 nm LEDs proved more effective in inactivating the selected foodborne bacteria in this study compared to 520 nm LED. The 405 nm LED showed the greatest antibacterial effect at the same level of energy dose. Significance and Impact of the Study: The results in this study demonstrated the antibacterial efficacy of 405 nm LED on Lact. plantarum and V. parahaemolyticus, suggesting its potential for use in food industry for the control of these micro-organisms.