Storing human milk for later use can be a lifesaver. It helps to preserve the milk, cut back on time, and decrease the pressure of producing enough when your baby gets hungry. While this method can help to make things easier, it’s important to store the milk properly. Have you ever wondered, “How to safely store human milk?” In this blog, we cover the different ways to store and prepare human milk. Keep reading to learn more.

Why is it Important to Properly Store Human Milk?

Proper human milk storage is needed to prevent nutrient loss and contamination. Human milk is rich in the essential vitamins and minerals needed for your baby’s growth. To learn more about how nutrition affects your milk supply, check out our blog! When you store the milk properly, you’re making sure that your baby is getting the full benefits of human milk. Also, proper preparation and handling is needed to keep any bacteria and/or germs from contaminating the milk.

How to Store Human Milk

Milk stored in different ways will have different “best before” dates. Here are three ways to store human milk:

• Room temperature (20-22°Celsius)
  • Human milk can last up to 4-6 hours at room temperature once expressed or pumped (1,2)
• Refrigerator (about 2-4° Celsius)
  • In the fridge, human milk can last up to 4 days (1)
• Freezer: Fridge Freezer and Deep Freezer
  • Frozen human milk is best to be consumed within 6 months of freezing (1,2). If the supply can’t be used up in time, using the milk within 12 months is acceptable (1).
  • Deep freezer (also called chest freezers) are standalone appliances that can reach lower temperatures. This allows for the milk supply to last for longer term storage. Fridge freezers are convenient and more compact than deep freezers. When choosing between freezers, consider your needs, space available for storage, and how long you intend to freeze milk for.

How to Heat Human Milk

Human milk does not need to be warmed before serving (1). It can be served at room temperature or cold. If you find that your baby prefers warm milk, there are a couple of options:

• Reheating from frozen:
• Quick method: place the sealed container of milk under warm running water
• Thaw overnight in the refrigerator (see below for next steps)
• Reheating from the refrigerator:
• Seal the bag or container holding milk
• Place into a warm bowl of water
• Swirl the bag or container to mix the fats that may have separated during the reheating process

Important Things to Note When Storing Human Milk

• Do not refreeze human milk once it has thawed. Bacteria is given more opportunity to multiply when the temperature changes (4)
• Use milk within 24 hours of thawing in the refrigerator (2)
• Once thawed and room temperature/heated, use within 2 hours (1). Discard any leftover milk. 
• Avoid reheating human milk using the stove or the microwave. This process may cause uneven heating or remove the beneficial nutrients in the milk (1)

Important Tips for Storing Human MIlk

• Label milk using the date it was produced (1). This helps you to keep track of when the milk should be used by. 
• Use the oldest first: “first in, first out” principle. This also helps to avoid having to toss out the supply because it is past its “best before” date.
• Freeze in smaller amounts to make thawing and portion control easier (3)
• Store in the back of the freezer to ensure minimal temperature shifts (3)

Final Notes from The Nest

Proper storage of human milk helps to make sure that your baby is getting the full nutritional benefits from the milk. There are various ways to store human milk. Each method has its own timelines for use. Different methods of storage serve different purposes. If you have any further questions about lactation and human milk, book a free call with a Registered Dietitian at The Nest.

References

1. Proper storage and preparation of breast milk [Internet]. (updated 2022 Jan 24; c. 2023 Dec 23). Centers for Disease Control and Prevention; [about 5 screens] Available from: https://www.cdc.gov/breastfeeding/recommendations/handling_breastmilk.htm
2. Storing expressed breast milk [Internet]. (2023; c. 2023 Dec 23). City of Toronto: Pregnancy and Parenting; [about 3 screens]. Available from: https://www.toronto.ca/community-people/children-parenting/pregnancy-and-parenting/breastfeeding/expressing-breast-milk/storing-expressed-breast-milk/
3. Pumping and storing breastmilk [Internet]. (2021 Feb 21; c. 2023 Dec 23). U.S. Department of Health & Human Services: Office on Women’s Health; [about 8 screens]. Available from: https://www.womenshealth.gov/breastfeeding/pumping-and-storing-breastmilk
4. Breastfeeding FAQ [Internet]. (updated 2021 Aug 10; c. 2023 Dec 23). Centers for Disease Control and Prevention; [about 6 screens] Available from: https://www.cdc.gov/breastfeeding/recommendations/faq.html