Unfrozen breast milk refers to milk that was previously frozen and has been thawed. Proper handling of this thawed milk is important for maintaining its safety and nutritional components. Understanding correct thawing and storage procedures helps ensure the milk remains suitable for consumption.
Safe Thawing Practices
Frozen breast milk can be safely thawed using several methods. The most recommended approach is placing the frozen container in the refrigerator overnight. For quicker thawing, hold the sealed container under lukewarm running water, ensuring the water does not exceed 99°F (37°C). Another option is to place the frozen milk in a bowl of warm water, rotating gently for even thawing.
Avoid certain thawing methods to protect milk quality. Microwaving breast milk is not recommended because it can destroy heat-sensitive nutrients and create “hot spots” that could burn a baby’s mouth. Similarly, boiling water should not be used for thawing or heating, as high temperatures can degrade the milk’s beneficial properties. Always use the oldest milk first when thawing from a frozen supply.
Storage Guidelines for Thawed Milk
Once breast milk has completely thawed, specific guidelines govern its safe storage. Thawed breast milk kept in a refrigerator at 40°F (4°C) or colder should be used within 24 hours. This 24-hour period begins once the milk is fully thawed, not from the moment it is moved from the freezer. Storing milk in the back of the refrigerator, rather than the door, helps maintain a consistent cool temperature.
If thawed breast milk is brought to room temperature (typically 77°F/25°C or colder), it should be used within 1 to 2 hours. Any milk left at room temperature for longer than two hours should be discarded. If a baby has started feeding from a bottle of thawed milk, any remaining milk should be used within two hours or discarded, as bacteria from the baby’s mouth can contaminate the milk.
Identifying Spoiled Breast Milk
Recognizing signs of spoilage in breast milk is important, even if stored within recommended timeframes. A primary indicator is a change in scent; fresh breast milk usually has a mild, slightly sweet, or sometimes soapy smell. If it develops a distinctly sour, rancid, or fishy odor, it has likely gone bad. Some mothers’ milk may have a naturally soapy or metallic smell due to high lipase activity, which does not necessarily mean it is spoiled.
The appearance of breast milk can also signal spoilage. While it is normal for breast milk to separate into layers (creamy on top, watery below), these layers should easily mix back together with a gentle swirl. If the milk remains chunky, curdled, or contains visible clumps that do not blend back in, it may be spoiled. Unusual colors, such as green, orange, or brown, can also indicate that the milk is no longer safe.
Understanding Refreezing
Refreezing breast milk after it has fully thawed is generally not recommended. This practice can compromise the milk’s nutritional quality and immunological properties. Each freezing and thawing cycle can degrade its components. Additionally, bacterial growth can occur during the initial thawing process, and refreezing milk with active bacteria could pose a health risk to an infant once thawed again.
The texture and taste of the milk can also be negatively affected by refreezing. An exception to this guideline is if the breast milk is only partially thawed and still contains ice crystals. In such cases, it can be safely refrozen. However, any milk from which a baby has already fed should never be refrozen, regardless of its state.