Objective: To compare the fat content and contamination of expressed breast milk (EBM) before and after storage (30 d) in hard polypropylene containers (HC) and soft polyethylene bags (SB) containers.
Methods: Ninety specimens of EBM were collected into HC and separated into two HC and two SB. The fat content of each specimen of EBM in HC and SB was measured and cultures were performed. The specimens in the second HC and SB containers were kept frozen for 30 d before thawing and then measuring the fat content and performing cultures.
Results: The means ± SD of the fat content of fresh and thawed EBM in HC were 2.98 ± 0.97 and 2.66 ± 0.88 g/100 ml, respectively, with a loss of 0.32 g/100 ml (p < 0.001). The means ± SD of the fat content of fresh and thawed EBM in SB were 3.06 ± 1.00 and 2.77 ± 0.91 g/100 ml, respectively, with a mean loss of 0.29 g/100 ml during storage (p < 0.001). The loss of fat content during frozen storage did not differ significantly between the two types of containers (p = 0.53). All bacterial cultures of fresh and thawed EBM in HC and SB showed only nonpathogenic organisms.
Conclusions: SB can replace HC for the long-term storage of frozen EBM of up to 30 d without deleterious effects on fat loss or contamination.