Ultraviolet light (u.v.) is a low-energy electromagnetic radiation with poor penetration.

Ultraviolet light can be divided into: long wave: 320.0-400.0nm, medium wave: 275.0-320.0nm, short wave: 180.0-275.0nm. The ultraviolet ray with wavelength of 240.0-280.0nm has strong bactericidal power, and 253.7nm is generally taken as the representative of bactericidal ultraviolet ray wavelength.

  1. The killing effect of ultraviolet light on microorganisms

1, ultraviolet irradiation energy is low, not enough to cause the ionization of irradiated object atoms, only excitation effect.

  1. Non-ionizing radiation.
  1. Destroy the base structure in DNA, so that the adjacent thymidines on one DNA strand combine to form dimers. DNA can’t replicate. It kills you.
  2. After UV irradiation, degraded cell components can reverse or repair the damaged DNA or RNA by light resurrection under visible light irradiation (propagules), and dark repair can also be performed under dark conditions (mainly buds).
  3. Act on proteins, especially enzyme proteins, to inactivate enzymes.

Two, ultraviolet sterilization mechanism:

4, act on nucleic acid, cause bacterial mutation or death.

5, cause DNA-DNA cross-linking or DNA-protein cross-linking, affecting replication.

Three, the tolerance of different microorganisms to ultraviolet light:

1, UV sterilization spectrum is wide, can kill all microorganisms.

  1. Fungal spores showed the strongest tolerance, followed by bacterial buds, viruses and propagules (G+ > G-).

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