Many new mothers make a choice to breastfeed because of the numerous benefits associated with breastfeeding for both mother and baby. However, increasing and maintaining your breast milk supply often requires you to pump in addition to nursing. Additionally, it may be necessary for your partner, family member, friend, or care provider to bottle feed your baby breast milk. So how should you store your milk and what are acceptable exposure times for different temperature environments before your milk may not be good anymore? Read further to learn more about breast milk storage guidelines and tips.

What do I Need?

In addition to the equipment required for pumping, you will need sealable, BPA-free glass or hard plastic bottles for breast milk storage of your pumped or expressed milk. It is necessary that your chosen containers be sealable not only to avoid spills but to protect your milk from foreign contaminants that might fall into your milk if left uncovered. It should be noted that it is recommended to use only lids designed to work with your storage containers to ensure an appropriate seal is made. While breast milk can be left out at room temperature for a time, it is better to keep short-term supplies of milk in a refrigerator. Similarly, if you need to transport your breast milk or need to take bottles with you on an outing, it is advisable to invest in an appropriately sized cooler that that meets your needs. Your supply may also be frozen for extended duration breast milk storage (more on that later) and, if you choose to freeze your milk, you will need storage bags designed for freezing breast milk.

Storage Durations

As with any natural substance, given the right amount of time at a given temperature, bacteria can grow and multiply in breast milk breaking down fats and proteins during their expansion. This process causes the milk to spoil so it is important to follow breast milk storage best practices. According to Medela, milk can be stored at room temperature (66℉ to 78℉ or 19℃ to 26℃) for 4-6 hours while refrigerated milk (39℉ or 4℃) may be stored for 3-8 days. If you are using a cooler with ice packs (59℉ or 15℃), your milk may be stored for up to 24 hours. Finally, breast milk storage in a freezer (0℉ to 4℉ or -18℃ to -20℃) allows you to use your pumped or expressed milk 6-12 months later. It is critical to remember that these are guidelines for storage of breast milk and you should always use your best judgment before feeding your baby stored milk.

Long-Term Breast Milk Storage

If you are producing enough milk that you need to freeze some of it to save for later, it may be necessary to invest in a deep freezer as you may quickly run out of room in your kitchen freezer. Using a deep freezer allows you to maximize your breast milk storage duration (12 months) and frees up your kitchen freezer for food. It is also wise to lay breast milk stored in bags on a flat surface in the freezer because this allows the possibility of “bricking” your bags to maximize space usage in your deep freezer. Bricking is essentially stacking your individual milk bags into larger ziplock bags to form “bricks” that may be stacked for convenient storage. Also, to maximizing space usage, it is necessary to keep your milk organized with dates and amount of milk in each bag so you can easily (and logically) work your way through your supply. Having things labeled and packed in an organized manner also helps ensure that nothing goes to waste.