Radioactive Contamination of Foodstuffs from Fall-out as a Source of Error in some Animal Experiments

Abstract

THE gastro-intestinal absorption of many substances may be determined by fæcal measurements following oral ingestion of a test dose containing a radioisotope. During the course of experiments of this type to determine the absorption of vitamin B₁₂ in rats, it was noticed that residual radioactivity appeared in the excreta of control animals which had not been given the radioactive test dose. This radioactivity, which was first noticed in July 1956, has recently increased to an extent which makes it impossible to continue the experiments as originally designed.