Abstract
Summary: The effect of ultra-high-temperature (U.H.T.) sterilization and of subsequent in-bottle sterilization on the availability of milk calcium has been studied in experiments with rats. The heated milks and the raw milk from which they were prepared were freeze-dried and added to a diet low in Ca so that the resulting diets contained some 0·11% Ca and 0·42% P.Ca retention by groups of six litter-mate male weanling rats was 98·4, 98·4 and 98·5% respectively from diets containing raw milk, U.H.T.-treated milk and milk treated by U.H.T. followed by in-bottle sterilization. It is clear that these processes did not affect the availability of milk Ca.