Whole and skimmed milk spray dried powders have been gas packed by two methods, and the chemical and physical changes taking place during storage at 17 and 37 °C for two years have been measured. The conventional method of double gas packing with nitrogen, with an interval of several days for desorption, was used as a control for a new method employing a single gas packing with a mixture of nitrogen (90%) and hydrogen (10%) plus the inclusion within the can of a solid catalyst pellet containing palladium.

The new system was more effective in removing oxygen and in maintaining an almost oxygen free atmosphere within the cans. Used on a commercial scale it would have several important advantages over the conventional method, and both whole and skimmed milk powders packed in this way would probably be usable after storage for 10 years at normal temperatures.

Because of the low general level of oxygen in all the cans packed by both methods and because of the low moisture content there was little difference in the keeping quality of the powders. What little there was, however, was in favour of the new method.