UVC LED system for prolonging the postharvest shelf life of murcotts

This study presents a simple optical system using ultraviolet C light-emitting diodes (UVC LEDs) to extend the postharvest shelf life of murcotts. The system featured a \(4 \times 4\) array of UVC LEDs with dome lenses, targeting irradiation for a corresponding \(4 \times 4\) array of murcotts. It achieves an irradiance distribution of 3 to 5 W/m² over the 34 × 34 cm target section, with uniformity of 85.4% in simulation and 77.2% in experiment, respectively. This system has the potential to integrate into automated controls, selectively switching off LEDs where murcotts are absent to save energy, ensuring others receive sufficient irradiance. In vitro results indicated that UVC dose over 0.3 kJ/m² inhibited conidial growth of Penicillium digitatum, the fungus that causes green mold in murcotts, by over 90% after 72 hours. In vivo results demonstrated UVC treatment effecitivelly mitigated the green mold disease on murcotts, with exposure times ranging from 3.0 to 15.0 min, corresponding to a UVC dose range of 0.9 to 4.5 kJ/m². This study aims to improve UVC technology in postharvest fruit preservation, advancing agricultural and food practices.