Packaging related problems with sacks of dairy powder

This paper deals with two packaging related problems occasionally encountered in the handling and storage of 25 kg sacks of dairy powder. One is caused by the production of low bulk density powder and the other is caused by excessive air entrapment in the sack. To gain a better insight into the problem, dairy powder manufacturers were visited and consultations were made with bagging machine manufacturers. The production of low bulk density powder is predominantly due to a low particle density, and the major contributory factors are total solids content, composition, state of protein denaturation of the feedstock and drier characteristics. Factors that affect excessive air entrapment in a sack are transport and storage of powder prior to bagging, powder properties and entrapment of headspace air. Possibilities for side-stepping the problem include the use of perforated liners or the development of semipermeable liners that are more permeable to air than conventional liners.