Milk in Life Conditions (MiLC): Bacterial Composition of Human Milk Pumped and Stored in "Real-Life" Conditions

The MiLC trial is a randomized control trial of two different breast pump set-ups: mother\'s own and sterile. The objective of this trial is to investigate the bacterial composition of human milk pumped and stored in \"real-life\" conditions. To meet this objective, lactating mothers will fully express breast milk from one breast on two consecutive pumping sessions at home, once with the participant\'s own pumps and collection kits (own pump set-up) and once with a hospital-grade pump and disposable, sterile collection kits (sterile pump set-up). Randomization will be used to determine which pump participants use first. From the total volume of milk pumped during each pumping session, the researchers will collect 1 oz. Milk from both pumps will be stored at home and sampled on days 0, 2, 4, and 30 after expression for analysis of its bacterial composition.