The impact of processing on the retention and distribution of macronutrients and bioactive compounds in donor human milk

Evidence suggests that nutrients in donor human milk (DHM) are profoundly variable, yet there has been little exploration into how processes within milk banking affect nutrient variability. We hypothesized that processing methods for thawing, decanting, pooling, and mixing during bottling contribute to nutrient retention and distribution in DHM. Our investigation — based on observations from an environmental scan of 9 milk banks in the Human Milk Banking Association of North America (HMBANA) network — was divided into three specific aims. Aim 1: Two pooling attributes — number of donors per pool and if macronutrient analysis was used to select donors for a pool (“target pooling”; yes/no) — were assessed for fat and protein variability using samples of raw, pooled DHM from 20 milk banks (n = 300). Target pooled samples had less fat variability (p = 0.04). In samples not target pooled, more donors per pool reduced fat and protein variability (p 0.05). In conclusion, fat content was affected by several steps in DHM processing, but the impact may be mitigated under certain conditions: When processing milk frozen in a plastic storage bag, fat retention may be improved by using bag manipulation during decanting when thawing to a liquid state. When milk is pooled on one day and bottled on a subsequent day, more mixing is needed to reduce fat variability. Additionally, for milk banks that do not target pool, using a greater number of donors per pool may reduce both fat and protein variability