Breastmilk Storage: 6 Helpful Guidelines, Plus Tips & Tricks

Breastmilk is often referred to as “liquid gold” due to its numerous benefits for babies. Whether you’re a working mother who wants to build up a stash of breastmilk before returning to the office, or a mom who simply wants to have some expressed milk readily available for occasional outings, knowing how to store breastmilk safely is essential. By following a few of our tips, you can ensure that your baby receives the full nutritional benefits of your breastmilk, even when you’re not physically there to nurse. In this article, we will explore helpful guidelines for proper breastmilk storage, along with some useful tips and tricks to make the process easier for you. So, let’s dive in!

Daily Mom Parent Portal Breastmilk Storage

History of Breastmilk Storage

Separately from a wet nurse and the use of animal milk, which have been in practice for centuries, the practice of storing breastmilk for later use dates back to the late 1800s when it was first documented in the medical literature. In the early days, mothers often expressed and boiled or pasteurized the milk to prevent spoilage and contamination, and it was stored in bottles or other containers. Over the years, modern technology has provided mothers with more options for safely expressing and storing their expressed breastmilk for babies with the use of pumps and other expression tools.

Today, breastmilk can be safely expressed and stored in a variety of containers while preventing contamination. It’s also easy to find specialized storage bags, bottles, and even products that can be used in the freezer to help with breastmilk storage. While the actual temperature at which milk should be stored depends on the length of time for which it will be stored, in general, breastmilk should always be stored in the fridge or freezer as soon as possible after expressing.

Why Store Breastmilk?

It’s amazing how mothers can produce milk to feed their babies. For thousands of years many babies have been sustained and fed on milk from their Storing breastmilk is a really cool and important option that moms have. Breastmilk is the most natural and nutritional option for a baby, containing many essential vitamins and minerals, plus antibodies. By pumping and storing it safely, parents can ensure that their baby is getting the very best nutrition throughout their development.

Having breastmilk storage allows parents to control how much and at what time their baby is being fed. It gives parents the flexibility to feed their baby while they are away from home or while a mother taking a break from breastfeeding. Pumping and storing breastmilk can be very helpful if a baby is also having trouble latching to the mom or if a mom is having difficulty producing enough milk.

All of this also allows parents to share the joy of feeding with other family members such as dad, siblings, or grandparents, making it a very special experience for everyone involved.

Breastmilk Storage vs. Formula Storage

It’s important to understand that breastmilk storage guidelines are different from bottle-feeding guidelines. While bottle-feeding with formula generally advises using formula within two hours after it has been prepared, breastmilk can remain at room temperature for up to four hours, and in the refrigerator for up to eight days. In the freezer, breastmilk can last up to six months. When storing breastmilk, a wide variety of containers including special storage bags, bottles, and even ice cube trays can be used giving plenty of flexibility.

In contrast, formula should be used within 24 hours of being prepared and any remaining formula should be discarded. Formula must also be stored in an airtight and non-breakable container and must be prepared fresh each time a new bottle is given. Ultimately, both breastmilk and formula should be stored in a cool and dry place, but the rules and regulations for each vary.

Breastmilk Storage Made Simple!

Breastmilk is an incredibly important source of nutrition and protection for infants. Feeding a child is key to a baby’s growth and development. Therefore, it is critical to take great care in breastmilk storage. Improper breastmilk storage can cause the product to quickly lose its beneficial properties and can even become unsafe to drink. The temperature of the storage environment and the length of time that the breastmilk is stored can both have a huge impact on its quality. Taking proper care when storing breastmilk is essential for keeping babies healthy and safe.

Daily Mom Parent Portal Breastmilk Storage

Expressing & Breastmilk Storage

  • Always begin with clean hands and a pump cleaned in hot, soapy water.
  • For short-term breastmilk storage, such as in the refrigerator, you can keep the milk in the plastic bottle that comes with your pump or transfer it to bottles measured for individual feedings. Some controversy exists as to whether you should use glass or plastic bottles. Immunological cells in the milk are purported to stick to the sides of glass bottles, however, the difference is probably negligible if your baby is receiving only some of his milk from bottles. If your baby is exclusively fed pumped milk, you may wish to use both plastic and glass.
  • If you’re pumping at work, you can store your milk in a travel cooler with ice packs or in a common space refrigerator. Although a bodily fluid, breastmilk is not considered a biohazard, and the CDC does not require special handling, labeling, or separate refrigeration (1). Many workplaces also now offer mothering rooms with refrigerators to properly store pumped breastmilk. Check with your workplace to find out more.
  • Milk that you plan to use within 8 days should be kept refrigerated, as opposed to frozen, so that thawing is not necessary. However, it’s also just find to go straight to the freezer for long-term breastmilk storage.
  • For long-term breastmilk storage, you can use glass or plastic containers, or plastic freezer bags made specifically for storing breastmilk. Some plastic breastmilk storage bags attach directly to a pump for easy handling. Breastmilk storage bags are thicker and have a lining to prevent fatty components from sticking to the side. They usually also have a space for easy labeling as well as scales for measuring. Squeeze out extra air and be sure to leave room in the bag for expansion. Plastic bottle liners are not suitable and likely to leak.
  • If you need to combine freshly expressed milk with frozen milk, cool the expressed milk first. Don’t add more than there is of the frozen, since you want to avoid the frozen milk thawing.
  • Lastly, don’t forget to label the bag with the date! If you combine milk from several pumping sessions, label it with the date of the oldest milk.
READ MORE: Returning to Work and Pumping

Guidelines for Storage

Breastmilk Storage Guidelines
Room temperature (66-78°F): 4-6 hours
Cooler with frozen ice packs (59°F): up to 24 hours
Fresh milk in refrigerator (≤39°F): up to 8 days
Thawed milk in refrigerator (≤39°F): up to 24 hours
Freezer unit: up to 6 months
Deep freeze unit: up to 12 months

Use & Handling

  • When you’re ready to use frozen milk, thaw in the refrigerator (usually 12 hours or overnight) or run under lukewarm water if needed right away.
  • Swirl your bottle of milk gently before use if the creamier portion has separated, but do not shake! Shaking can cause important proteins in the milk to break apart (2).
Daily Mom Parent Portal Breastmilk Storage
  • If your baby does not finish a bottle, most sources say it is OK to re-refrigerate once (3). That is, to avoid waste you can put the milk back in the fridge and offer again within a few hours. After that, if your baby does not finish the milk, it should be discarded. As a precaution, it should not be kept longer since bacteria from the baby’s mouth has contaminated the nipple.
  • When you need milk from your supply, always use the oldest first. Don’t worry if the oldest is weeks or months old. It is true that the composition of your milk changes over time to suit your growing baby’s needs. However, even older milk, as long as it has been properly stored and handled, is beneficial to your little one.
READ MORE: Breastfeeding During the Holidays
Daily Mom Parent Portal Breastmilk Storage

Tips & Tricks

  • When freezing, store milk in smaller portions such as 1-3 ounces in order to avoid waste.
  • Store breastmilk storage bags, tightly sealed, flat, and stacked. This will speed the thawing time.
  • If you wish to freeze your milk in glass containers, freezer-safe Bernardin Mason jars in 125 ml (4.2 oz) are a great, convenient size.
  • You can get extra use out of your pump accessories between washings by giving them a quick rinse, throwing them in a large ziploc bag, and storing them in the refrigerator until the next pumping session.
  • What to do if your power goes out? Open the door as little as possible. Full freezers will hold their temperature for approximately 48 hours if the door is kept closed (4). You might also consider taking your supply to a nearby neighbor with power. If there are still ice crystals in the milk, you can consider it to still be frozen. Most experts do not recommend refreezing the milk, although there has been little research on how repeated re-freezing changes the properties of breastmilk. If you know ahead of time of a potential long power outage, you might also consider packing your supply in dry ice.
  • Does your milk smell soapy? Most breastmilk has a mild or slightly sweet scent, but mothers occasionally report that thawed milk smells soapy. This may be due to enzymes in the milk digesting some of the fat and is probably fine if your baby accepts the milk. If not, scalding (but not boiling) the milk and quickly cooling prior to freezing may solve this problem if the baby is rejecting the milk, although this may lower the nutritive content and is not ideal (5).
  • If you and your baby experience thrush, you can still give milk pumped during the infection to your baby while being treated. After the infection has cleared, however, discard the milk as neither cooling nor freezing kills yeast (6).
  • Left some pumped milk out longer than the recommended guidelines? Instead of tossing the milk, consider using it for diaper rash, baby eczema, cradle cap, or any of a number of alternative uses.
READ MORE: Breastmilk Pancake Recipe

This post is meant for educational purposes only. It is not intended to replace medical advice from your physician, doctor or health care professional. Please read our terms of use for more information.

With a newborn baby at home, there are so many things to worry about. Is she sleeping well? Is he eating enough? Breastmilk storage doesn’t have to be one of those worries. Hopefully these breastmilk storage guidelines, tips and tricks help take some of the guesswork out of this important and meaningful task.



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Daily Mom Parent Portal Breastmilk Storage

Photo credits: Pixabay, The Whimsical Photographer, The Quintessential Mommy


  1. Center for Disease Control and Prevention: “Human Immunodeficiency Virus (HIV), and Acquired Immunodeficiency Virus (AIDS)“.
  2. Smith, Linda J. (1998) “Don’t Shake the Milk“. Bright Future Lactation Resource Center Ltd.
  3. The Academy of Breastfeeding Medicine Protocol Committee (2010). “ABM Clinical Protocol #8: Human Milk Storage Information for Home Use for Full-Term Infants (Original Protocol March 2004; Revision #1 March 2010)“. Breastfeeding Medicine, 5(3). doi: 10.1089/bfm.2010.9988
  4. USDA Food Safety and Inspection Service, US Department of Agriculture. “Keep Your Food Safe During Emergencies: Power Outages, Floods & Fires“.
  5. Kelly Mom, “My expressed breastmilk doesn’t smell fresh. What can I do?“. July 28, 2011.
  6. Le Leche League International. “What are the LLLI guidelines for storing my pumped milk?“.



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Laura is a wife and a new mom living on the East Coast. She and her husband welcomed their first child in September 2013. She has a passion for photography and an incurable case of Wanderlust. In her spare time she enjoys blogging about photography, travel, married life, and motherhood at The Whimsical Photographer.