Abstract
Sterilization by gamma radiation has proved to be a suitable method for the treatment of a variety of laboratory animal diets intended for specified-pathogen-free (SPF) and germ-free colonies. Due to the high penetrating power of this radiation the diets can be packed before treatment in a manner which prevents recontamination during transport and storage. The main bulk of diets is used for SPF animals and a radiation dose of 2.5 Mrad has proved effective for the control of contaminating organisms. No adverse effects on animals receiving the diets have been noted, observations having been made on growth, reproduction and general health. Irradiated diets formulated according to current laboratory animal practice appear to be nutritionally satisfactory.