Development and optimization of LED systems for surface fungal decontamination of fresh produce

Abstract

Uneven irradiation is the major challenge of light-emitting diode (LED) antimicrobial technology. This study developed different LED illumination systems with multi-directional light sources, spotlight reflector (SR), and parabolic reflector (PR) to ensure the high antifungal efficiency of LED on artificially inoculated litchi fruit. Results showed that multi-light LEDs enable multi-angle irradiation, therefore, could reach higher inactivation rates under the comparable energy output. Integrating LED with SR could gather the scattering light and improve the inactivation efficiency (LEDs < LEDs + SR). The addition of PR enhanced bottom irradiation, leading to a comparable effect with an extra light source (LED + SR + PR = dual-LEDs). Moreover, when comparing the energy consumption required for 90 % inactivation of fungi, the LED systems combined SR and/or PR required less power consumption than those of LEDs alone. The antifungal effects of developed systems were further validated by natural samples. These results suggest several feasible solutions to improve the antifungal efficiency of LED and also provide practical system designs to broaden the LED application in the food industry.