Breast milk provides essential nutrition for infants. Protecting its nutritional value and safety requires careful attention to storage and handling practices. Understanding how to manage breast milk after expression, especially once thawed, ensures infants receive its benefits safely.
Defrosted Breast Milk at Room Temperature
Thawed breast milk can remain at room temperature for up to one to two hours. Leaving milk out longer allows bacteria to multiply, potentially compromising its safety. The Centers for Disease Control and Prevention (CDC) recommends using thawed breast milk within two hours if it has reached room temperature or been warmed.
If breast milk is thawed in the refrigerator, it can be safely stored there for up to 24 hours from the time it is completely thawed. The 24-hour countdown begins once all ice crystals have melted, not when it was initially moved from the freezer. This helps prevent bacterial growth, as colder temperatures slow proliferation. Rapid thawing methods, such as placing milk under warm running water, mean the milk reaches warmer temperatures faster, requiring quicker use.
Best Practices for Handling Defrosted Milk
The most recommended thawing method involves transferring frozen milk to the refrigerator overnight, which can take approximately 12 hours. For quicker thawing, milk can be placed under cool or lukewarm running water or in a bowl of warm water. Avoid using very hot water or a microwave for thawing. High heat can destroy beneficial antibodies and nutrients, and microwaves can create dangerous hot spots that might burn an infant.
After thawing, breast milk does not necessarily require warming, as many babies accept it at room temperature or even cold. If warming is desired, placing the sealed container in a bowl of warm water or holding it under warm, not hot, running water for a few minutes is recommended. The milk’s temperature should be tested on the wrist to ensure it is comfortably warm, around body temperature, before feeding. Reheating breast milk more than once is not advised, as this can degrade its nutritional quality and increase the risk of bacterial contamination.
Defrosted breast milk should never be re-frozen, as this can lead to nutrient loss and increased bacterial growth, especially if fully thawed. However, if breast milk is still partially frozen with ice crystals, it can be refrozen. Discard any defrosted milk left at room temperature beyond the recommended time. Also, if a baby does not finish a bottle, discard any leftover milk within two hours of the feeding starting, due to potential bacterial contamination from saliva.
Identifying Spoiled Breast Milk
Recognizing signs of spoilage in breast milk is important for infant safety. Fresh breast milk has a mild, pleasant scent and an ivory-white color. If thawed milk develops a distinctly sour, rancid, or fishy odor, it has likely spoiled and should not be used. A soapy or metallic smell can indicate high lipase activity; while not harmful, some babies might refuse milk with this altered taste.
Visual cues can also indicate spoilage. Breast milk naturally separates into layers, with a cream layer on top and a more watery layer beneath, which is normal and can be recombined by gentle swirling. However, if the milk appears chunky, curdled, or if the separated layers do not mix back together after swirling, it suggests spoilage. Unusual colors, such as green, orange, or brown, also point to spoilage.
Taste can be another indicator, though it should be used cautiously. Fresh breast milk has a slightly sweet or mild flavor. If the milk tastes distinctly sour, bitter, or rancid, it has likely gone bad. When in doubt about the quality of thawed breast milk, it is always safest to discard it to prevent any potential health issues for the infant.