title: Vegetable surface sterilization system using UVA light-emitting diodes.
abstract: Surface sterilization of fresh produce has been needed in the food manufacturing/processing industry. Here we report a UVA-LED (Ultra Violet A-Light Emitting Diode) system for surface sterilization that is safe, efficacious, low cost, and apparently harmless to fresh produce. To test the system, Escherichia coli strain DH5α was spot-inoculated onto vegetable tissues, and treated under UVA-LED. Tissues were homogenized and bacteria quantified by colony-forming assay. Possible effects of UVA-LED on vegetable quality were evaluated by HPLC. Tissue weight changes were checked after treatment at 4℃, 15℃, and 30℃. Bacterial inactivation by UVA-LED radiation was observed after a 10 min treatment and increased with increasing time of irradiation. The log survival ratio reached -3.23 after a 90 min treatment. Bacterial cells surviving treatment grew slowly compared to non-irradiated control cells. Cabbage tissue lost weight over time after treatment, and weight loss increased with increasing incubation temperature, but there was no difference between losses by UVA-LED treated and control tissues at any temperature tested. In addition, no differences of Vitamin C content in cabbage tissue were detected by HPLC after UVA-LED treatment. These results suggest that UVA-LED treatment has great potential for vegetable surface sterilization in the food manufacturing/processing industry.
authors.affiliation: Department of Preventive Environment and Nutrition, Institute of Health Biosciences, the University of Tokushima Graduate School.
authors.forename: Mutsumi
authors.initials: M
authors.lastname: Aihara
authors.forename: Xin
authors.initials: X
authors.lastname: Lian
authors.forename: Takaaki
authors.initials: T
authors.lastname: Shimohata
authors.forename: Takashi
authors.initials: T
authors.lastname: Uebanso
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Mawatari
authors.forename: Yumi
authors.initials: Y
authors.lastname: Harada
authors.forename: Masatake
authors.initials: M
authors.lastname: Akutagawa
authors.forename: Yohsuke
authors.initials: Y
authors.lastname: Kinouchi
authors.forename: Akira
authors.initials: A
authors.lastname: Takahashi
mesh_terms: D001419:Bacteria / Q000254:growth & development / Q000528:radiation effects*; D019649:Food Industry; D013242:Sterilization / Q000379:methods*; D014466:Ultraviolet Rays