Antifungal Efficacy of LEDs for Spoilage Pathogens on Litchi Fruit Packaged with Different Types and Thicknesses of Films

Penetration ability is one of the biggest concerns of light-emitting diode (LED) technology in the food industry, as most food matrices are usually in packaged conditions. This study aimed to evaluate the antifungal effects of LEDs on both pure culture and litchi fruit, which are packaged by nine commonly used commercial packaging films. Results showed that LEDs could penetrate these films with more than 88% energy transmittance. Under the same illumination condition, the inhibition rate in film packaged samples decreased by 8–35%. The difference might be due to the partial shielding of light by the films selected. However, when the illumination time was further extended, 410–420 nm LED still achieved complete inhibition of Fusarium sp. and Geotrichum candidum conidia in all tested films, particularly polyethylene (PE) 0.003 mm, polyethylene terephthalate (PET), and polyvinyl chloride (PVC). In vivo trials showed that LED illumination reduced the fungal populations on packaged litchi by ~ 99% with better physicochemical properties than the non-packaged ones. Although the presence of packaging films did affect the inactivation efficacy of LED, this study demonstrated that LED technology has the potential to be used for the decontamination of packaged litchi fruit and other packaged foods.