Milk powder is packed into either plastic-lined multi-wall bags (25 kg) or bulk bins
( 600 kg). WMPs are often packed under nitrogen gas to protect the product from oxidation
and to maintain their flavour and extend their keeping quality. Packaging is chosen to
provide a barrier to moisture, oxygen and light. Bags generally consist of several layers to
provide strength and the necessary barrier properties. Shipments of milk powder should
never suffer prolonged exposure to direct sunshine especially in tropical countries. A few
hours at elevated temperatures (> 40C) during transshipment can negate many weeks of
careful storage.