Human milk banking. Effect of refrigeration on cellular components.

The storage of human milk at 4 C for 48 hours after expression resulted in a significant (p < 0.02) loss of cellular viability. Further, the concentration of milk macrophages and neutrophils decreased significantly (p < 0.02), presumably via cell adhesion to the milk container or cytolysis. The milk lymphocyte concentration, however, was not significantly affected by storage. Milk passage through a nasogastric feeding catheter had no additional effect on cell viability or concentration. Thus, while current banking methodologies allow greater availability of breast milk's resistance factors to newborn infants, they do so with significant, but not serious, alterations in both the quantity and quality of these components.