Radiation sterilization is an effective method to kill microorganisms on most substances by using electromagnetic waves generated by electromagnetic radiation. Electromagnetic waves used for sterilization include microwaves, ultraviolet rays (UV), X-rays, and gamma rays. They all control microbial growth or kill microorganisms in a specific way.
For example, microwaves can kill microorganisms by heat; ultraviolet rays cause adjacent pyrimidines in DNA molecules to form pyrimidine dimers, inhibit DNA replication and transcription, and kill microorganisms; X-rays and gamma rays can oxidize other substances or Free radicals (OH·H) act on biomolecules, or act directly on biomolecules, interrupt hydrogen bonds, oxidize double bonds, destroy ring structures, or polymerize certain molecules, destroying and altering biomacromolecules The structure, thereby inhibiting or killing microorganisms.
Even if visible light is irradiated for a long time, it can damage microorganisms or kill them, because all photosynthetic organisms contain light-sensitive pigments such as chlorophyll (or bacteriochlorophyll), cytochrome, and flavin, which absorb light energy into an excited state or Activates and transfers the absorbed energy to oxygen, which produces oxygen free radicals that act on the cells, causing the body to mutate or die. The effect of radiation sterilization is restricted by other factors. For example, light can disintegrate pyrimidine dimer, reduce the effect of ultraviolet rays, and oxygen can improve the effect of X-ray or γ-ray.
Devices for performing radiation sterilization include microwave ovens, ultraviolet lamps, cathode ray tubes, X-ray generators, radionuclides, and the like. Commercially available radioactive sources for the sterilization of large quantities of articles are cobalt-60 and cesium-137, which emit gamma rays and are relatively inexpensive. Radiation sterilization is very versatile, such as medical devices and appliances (such as syringe lamps), food, many plastics in laboratories, and a variety of media are sterilized by this method.
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