Effects of electron beam and ultraviolet-C irradiation on quality and microbial populations of leafy vegetables during storage

Effects of ultraviolet-C (UV-C) and electron beam irradiation on the quality and microbial populations of leafy vegetables were compared as a microbial decontamination method. Tatsoi and red chard leaves were treated with UV-C at a dose of 5 kJ/m² or by electron beam irradiation at doses of 0.5, 1, and 3 kGy. After UV-C or electron beam irradiation treatment, the samples were stored at 4 ± 1°C for 11 days. Populations of total aerobic bacteria in leafy vegetables decreased by 0.8-1.1 log CFU/g after treatment with UV-C irradiation, and those of yeast and molds decreased by 1.0-1.8 log CFU/g. On the contrary, electron beam irradiation at 0.5 or 1 kGy reduced the microbial populations by 2.0-2.5 log CFU/g. Electron beam irradiation at 3 kGy eliminated the microorganisms in the samples. These results suggest that electron beam irradiation at low dose below 3 kGy can be more effective than UV-C treatment for the inactivation of microorganisms in Tatsoi and red chard leaves.