Comparison between Ultraviolet-A and Ultraviolet-C Irradiation on the Microbial Safety and Quality of Cherry

摘要

In this study, the effects of ultraviolet (UV)-A or UV-C irradiation on the microbial safety and nutritional quality of cherries were compared. After UV irradiation at 9 W/m2 for 5, 10, 15, and 20 min, the changes in the Listeria monocytogenes population and the contents of bioactive compounds in cherries were analyzed. Compared to the untreated samples, the total phenolic and anthocyanin contents increased with increasing UV treatment time regardless of the wavelength. In particular, the UV-C treatment produced more significant increases in the content of bioactive compounds than the UV-A treatment. In addition, the cherries irradiated with UV-A showed a 0.12 — 0.95 log CFU/g decrease in the L. monocytogenes population, whereas UV-C irradiation produced 0.60 —1.31 log reductions. This suggests that a UV-C treatment is more effective in L. monocytogenes inactivation. UV-C irradiation also damaged the bacterial membranes more than UV-A based on the scanning electron microscopy images. Therefore, UV-C irradiation is more effective on the microbial safety and quality of cherries than a UV-A treatment.