Storage beyond three hours at ambient temperature alters the biochemical and nutritional qualities of breast milk.

The effect of storage on stability of human breast milk was investigated in 30 lactating mothers. Samples stored for 3, 6 and 24 hours at ambient temperature of 302K (29 degrees) were analysed for protein, lactose, pH, and microbial content. There were significant (p < 0.01) decreases in protein, lactose and pH upon storage for 6 and 24 hours, compared with storage for 3 hours as control. The mean +/- SEM values for protein for 6 and 24 hours were 15.56 +/- 0.48 and 13.27 +/- 0.50, compared with 17.26 +/- 0.41 for 3 hours. For lactose, corresponding values for 6 and 24 hours were 0.08 +/- 0.005 and 0.07 +/- 0.006, compared with 3 hours (0.09 +/- 0.005). The pH values were 6.1 +/- 0.09, 5.9 +/- 0.07 in 3, 6 and 24 hour samples rspectively. The skin floras investigated were Streptococcus viridians, Straphylococcus aureus and Staphylococcus albus. The microbial content increased with increase in storage time from 3 to 24 hours. The predominant bacterial specie was S. Albus, followed by S.viridians and S. aureus. A positive correlation (r = 0.453, p < 0.01) between lactose level and pH were obtained. These results suggest that breast milk is stable for 3 hours, beyond which significant changes occur in its biochemical composition and nutritional quality. The implications of these findings are discussed with respect to its consequences on their child's survival.