Inactivation of Pectobacterium carotovorum subsp. Carotovorum and Dickeya chrysanthemi on the surface of fresh produce using a 222 nm krypton-chlorine excimer lamp and 280 nm UVC light-emitting diodes

Abstract

Pectobacterium carotovorum subsp. carotovorum and Dickeya chrysanthemi have been reported to cause soft-rot diseases to fresh produces. The aim of this research was to investigate the inactivation efficacy of a 222 nm KrCl excimer lamp and 280 nm UVC-LED against P. carotovorum subsp. carotovorum and D. chrysanthemi on fresh produces. When samples were subjected to UVC treatment by a excimer lamp or UVC-LED at 450 mJ/cm2, it was observed that soft-rot bacteria on the surface of iceberg lettuce, strawberry, and tomato were reduced by a maximum of 5, 3, and 5 log units, respectively. The surface properties of fresh products, such as hydrophobicity, roughness, and topographic image, were analyzed under the hypothesis that the characteristics of the sample surface affected the inactivation efficacy of the excimer lamp and UVC-LED. It was determined that there was an inverse correlation between the surface roughness and inactivation efficacy of UVC treatment. The texture properties of samples were not significantly different (P > 0.05) from those of untreated samples. The results of this research substantiate that the excimer lamp and UVC-LED can be applied to decontamination processes for inactivating soft-rot bacteria, thereby prolonging the shelf life of fresh produce and reducing economic losses.