The storage of human milk for use later by the mother's own infant or an unrelated recipient has an impact on its constituents. These effects involve the storage container, heating, cooling and freezing the milk. Overall, glass is the least destructive container. Milk can be safely refrigerated for 72 h with little change. Freezing destroys cellular activity and reduces vitamins B6 and C. Boiling, in addition, destroys lipase and reduces the effect of immunoglobulin A and secretory immunoglobulin A. The nutrient value of human milk is essentially unchanged, but the immunological properties are reduced by various storage techniques.