For many years, nonboilable collagen sutures have been sterilized by cumolization. In this process, heat sterilization is obtained at a minimum temperature of 155 C for a minimum period of one hour by placing the suture in a high-boiling hydrocarbon mixture. Tubing fluid is then added aseptically and the container sealed. A safer and cheaper method would be one in which sterilization is carried out in the final sealed container. This can be done by electron irradiation.
Studies1 have been made with over 100 species of micro-organisms, including bacterial spores and fungi, to determine the minimum lethal dose of electron irradiation. Three million rep was selected as the irradiation dose, as this gave a safety factor of about 50%, which is in contrast to a safety factor of approximately 5% with heatsterilization methods. Narat, Cangelosi, and Belmonte2 have reported that irradiated sutures lose less initial tensile strength than