How effective is radiation in destroying microorganisms?
The most lethal type of radiation is ultraviolet radiation with a wavelength of 260 nm. This is the wavelength most actively absorbed by DNA. Unfortunately, this type of radiation does not penetrate dirt, glass, water, or other substances. If a surface is dusty, then complete inactivation of all microorganisms may not occur. This type of radiation is also harmful if someone is directly exposed to it, as it may damage the skin and eyes. Due to its poor penetration, UV radiation is only useful for disinfecting outer surfaces. Ionizing radiation (gamma radiation) can penetrate deeper into objects, and is used to sterilize food, drugs, and medical supplies. The source of these gamma rays is usually cobalt-60 which has a half-life of 5 years. Materials which are sterilized using this type of radiation do not become radioactive, and irradiation of food does not change its nutritional value. In some cases the taste of the food is changed, similar to how milk changes taste once it is pasteuriz
