Effects of radiation sterilization on packaging materials

Irradiation by gamma rays produces some physico-chemical changes in many polymers due to crosslinking, degradation and oxidation depending on the type of polymer and the environment in which irradiation is carried out. Irradiation in an inert atmosphere is not practicable for packaging materials and therefore a proper choice is to be made after taking into account the various changes due to irradiation. It must however, be noted that the extent of any change in a variety of packaging materials at a sterilization dose of 2.5 Mrad is low enough to permit their successful use. Change in colour or odour, which are often seen to occur in some packaging materials even by exposure to sunlight, should not be mistaken as a deleterious effect of gamma radiation. The colour change does not affect in any way the quality of the contents. (author)