2.2.3.1 Ultra – violet (UV) radiation

2.2.3.1 Ultra – violet (UV) radiation

It is called non-ionising radiation. UV rays can kill all kinds of microorganisms due to its short wave length and high energy UV has maximum bactericidal effect or is lethal at a wave length of 260 nm. The primary mechanism of UV damage is the formation of thymine dimers in DNA. Two adjacent thymines in a DNA strand are covalently joined to inhibit DNA replication and function.

The sterilizing effect of sun light is attributed to its UV light (300 - 400 nm). Its killing is appreciable at 330 nm and below.

Use: Low pressure mercury vapour lamps emitting radiation at 254 nm are used to reduce airborne infection.

Sterilization using radiation is called cold sterilization as it does not generate heat, but brings about sterilization.

Last modified: Monday, 19 December 2011, 9:02 AM