PDF(Pubmed)
Abstract：
The use of blue light-emitting diodes (LEDs) is emerging as a promising dry decontamination method. In the present study, LEDs emitting ultra-high irradiance (UHI) density at 405 nm (842 mW/cm2) and 460 nm (615 mW/cm2) were used to deliver high-intensity photoinactivation treatments ranging from 221 to 1107 J/cm2. The efficacy of these treatments to inactivate E. coli O157:H7 dry cells was evaluated on clean and soiled stainless steel and cast-iron surfaces. On clean metal surfaces, the 405 and 460 nm LED treatment with a 221 J/cm2 dose resulted in E. coli reductions ranging from 2.0 to 4.1 log CFU/cm2. Increasing the treatment energy dose to 665 J/cm2 caused further significant reductions (>8 log CFU/cm2) in the E. coli population. LED treatments triggered a significant production of intracellular reactive oxygen species (ROS) in E. coli cells, as well as a significant temperature increase on metal surfaces. In the presence of organic matter, intracellular ROS generation in E. coli cells dropped significantly, and treatments with higher energy doses (>700 J/cm2) were required to uphold antimicrobial effectiveness. The mechanism of the bactericidal effect of UHI blue LED treatments is likely to be a combination of photothermal and photochemical effects. This study showed that LEDs emitting monochromatic blue light at UHI levels may serve as a viable and time-effective method for surface decontamination in dry food processing environments.
摘要：
蓝色发光二极管（LED）的使用正在成为一种有前途的干式去污方法。在本研究中,在405nm(842mW/cm2)和460nm(615mW/cm2)下发射超高辐照度(UHI)密度的LED用于递送范围为221至1107J/cm2的高强度光灭活处理。在清洁和污染的不锈钢和铸铁表面上评估这些处理使大肠杆菌O157:H7干细胞失活的功效。在干净的金属表面上，使用221J/cm2剂量的405和460nmLED处理导致大肠杆菌减少2.0至4.1logCFU/cm2。将处理能量剂量增加至665J/cm2导致大肠杆菌群体的进一步显著减少(>8logCFU/cm2)。LED处理引发了大肠杆菌细胞内活性氧（ROS）的大量产生，以及金属表面上的显著温度升高。在有机物的存在下，大肠杆菌细胞内ROS生成显著下降,并且需要更高能量剂量(>700J/cm2)的治疗来维持抗菌效果。UHI蓝光LED处理的杀菌效果的机制可能是光热和光化学效应的组合。这项研究表明，以UHI水平发射单色蓝光的LED可以作为干燥食品加工环境中表面净化的可行且时间有效的方法。
