Breast milk is often referred to as “liquid gold” due to its numerous benefits for a baby’s health and development. It provides essential nutrients and antibodies that help to protect babies from infections and illnesses. It is, therefore, important for nursing moms to store breast milk properly to maintain its quality and safety. One common question nursing moms often ask is “can you refreeze breast milk?” The short answer is that it depends on several factors, including the length of time the milk has been thawed, the storage conditions, and the baby’s health status.
Is it safe to refreeze breast milk?
There are three factors to consider if you are dealing with thawed breast milk. We recommend considering these three circumstances when deciding if you can refreeze breast milk. The answers will depend on your milk and your baby.
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1. Temperature of thawed breast milk
The first factor to consider when refreezing breast milk is how long the milk has been thawed and its current temperature. According to the CDC, breast milk can be stored in the refrigerator for up to four days and in the freezer for up to one year. Once thawed, breast milk should be used within 24 hours if stored in the refrigerator or within two hours if stored at room temperature.
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If breast milk has been thawed for a short period, such as a few hours, and it still has ice crystals it can be refrozen. The below picture is an example of partially thawed breast milk that can be refrozen. This bag of breast milk was not completely thawed. It had sat in the fridge overnight and thawed slightly. The thawed breast milk was poured into a bottle. The remaining breast milk was still frozen, making it possible to place the bag of partially thawed breast milk back into the freezer for use on another day.
However, if breast milk has been thawed for an extended period and no longer contains any ice crystals, it is not recommended to refreeze it. When breast milk is thawed, its nutritional content may change. This causes it to lose some of its antibodies and enzymes that protect babies from infections. Refreezing breast milk that has already lost some of its protective properties can further compromise its quality and safety.
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Additionally, if breast milk has been left out at room temperature for more than two hours, it is not recommended to refreeze it as it may contain bacteria that can cause illness.
2. Storage Conditions of Frozen Breast Milk
The second factor to consider when refreezing breast milk is the storage conditions. Breast milk should be stored in a clean, airtight container in the back of the refrigerator or freezer to keep it at a consistent temperature. Do not place breast milk that you want to refreeze in the door of a freezer. The temperature of a freezer door can fluctuate greatly compared to the back of the freezer. You want to keep your breast milk as cold (and frozen) as possible.
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Placing breast milk in the back of a freezer will also protect it if the power goes out for a short period of time. Depending on the type of freezer you are using (refrigerator/freezer combo or a stand alone deep freezer), your breast milk should stay frozen or partially frozen for up to 24 hours if the door is left shut. So, if your power goes out you don’t necessarily have to throw out your frozen breast milk. Make sure to check for ice crystals first.
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3. Baby’s Health Status
The third factor to consider when determining if you can refreeze breast milk is your baby’s health status. If your baby is healthy and has a strong immune system, refreezing breast milk may not be a significant concern. However, if your baby is premature, has a weakened immune system, has a medical condition that increases their risk of infection, or is immunocomprised in any way, it is recommended to avoid refreezing breast milk as it may increase the risk of illness.
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How long is breast milk good for after thawing?
| Type of Breast Milk | Countertop | Refrigerator | Freezer |
| Freshly Pumped | up to 4 hours | up to 4 days | up to 12 months |
| Thawed, Partially Frozen | 1-2 hours | up to 24 hours | up to 12 months from original pump date |
| Thawed Completely | 1-2 hours | up to 24 hours | never refreeze completely thawed breast milk |
| Warmed Milk for a Feeding | use within 2 hours | – | never refreeze milk after warming |
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Can you mix frozen breast milk from different days?
Yes, it is generally safe to mix frozen breast milk from different days, provided that the milk has been stored properly and is still within its recommended storage time. However, it’s important to follow some guidelines to ensure the safety and quality of the milk:
- Thaw the milk in the refrigerator or under cool running water. Do not use hot water or microwave to thaw breast milk, as this can cause nutrient loss and increase the risk of bacterial contamination. Make sure that the breast milk from different days is around the same temperature prior to mixing. Do not ever mix warm milk with refrigerated or frozen milk as the difference in temperatures can lead to deterioration of the antibodies and nutrients in the breast milk.
- Gently swirl the milk to mix the different batches together. Do not shake the milk vigorously, as this can damage some of the beneficial components of the milk.
- Use the mixed milk within 24 hours. As mentioned above, once breast milk has been thawed it should be used within 24 hours to minimize the risk of bacterial growth.
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I hope this information helps you determine if you can refreeze breast milk. Most of the moms I have spoken to have refrozen their breast milk with success and have never encountered any issues as long as they consider the above factors. I personally have done it countless times with all three of my kiddos. I hope you are able to, too!
