how long is breast milk good for after heating

Guide: How Long Is Breast Milk Good For After Heating?

Every mom is different. Some moms produce an abundance of breast milk, while others struggle to produce enough. If you have enough that you have to store for later use, or you want to store some because you are going on a trip, it is important to know the guidelines for storage and reheating milk.

This article helps you to understand how to keep your breast milk safe for your baby while it is being frozen, heated, and stored, and answers questions like how long is breast milk good for after heating.

How Long Does Breast Milk Last After Heating?

Breast Milk

According to the Centers for Disease Control (CDC), once breast milk has been warmed up to room temperature or above, you have about two hours to use it.

This is if you have heated it up for your baby to drink and they didn’t finish the bottle. If you leave it at room temperature such as on the counter, you have about two hours to use it or it should be tossed for health reasons.

If you have simply moved it from the freezer to the fridge, you have about 24 hours.

Can You Put It Back in the Fridge After Heating it Up?

If the baby has already drank from it, you will not want to refrigerate it again because of the potential bacteria that could get into the milk. If your baby has been fed from the milk, it is best to use it within two hours or toss it.

But raising a baby is hard, and you might make two batches of milk because you didn’t remember you made the first. If you heat up baby milk but never use it, you can put it back in the fridge for the next 24 hours.

Can You Reheat Breast Milk?


The general guideline is that you don’t want to reheat it more than once. To put it simply, after the second time heating up milk, it should be tossed. While it isn’t necessarily bad or dangerous, every reheating kills some of the good bacteria and nutrients that your baby will need. Without nutrition, milk serves no purpose for your baby.

What Do Professionals Say About How Long Breast Milk Lasts?

There are four main ways breast milk can be stored. Each one has drastically different storage times according to professionals.

The first is just room temperature. If the breast milk is fresh, it can easily be left at room temperature for about six hours. However, if the room is warm, or just to be safe, you want to use it or look at long-term storage options around the four-hour mark.

Then there is portable storage. This usually works via an insulated bag or cooler with some ice packs in it. If freshly expressed, breast milk can stay in a cooler with ice packs for typically a day or so.

For refrigerated milk that is fresh and not frozen before, you can usually keep it there for three to four days before it goes bad. Most professionals say three days to be on the safe side, but four is often still okay.

If you freeze breast milk, it will easily last a year. Technically, frozen products never go bad, but they will start to lose their nutrients over time as well as their flavor. If you want to get the most nutrients from your breast milk, using it within around six months is optimal.

Since life is already hectic with a new baby, there is a simple guideline to follow to be extra safe. It is called the rule of fours. Fresh breast milk can stay on the counter for four hours, in the fridge for four days, and in the freezer for four months. This isn’t perfect, but it is a good way to make sure you remember some safe numbers.

How to Store Breast Milk: 11 Tips


1. Always wash your hands and all containers before handling.
2. You can also sterilize all containers by putting them in very hot to boiling water.
3. Use new bags and bottles for each pumping session.
4. Storing batches of milk in small amounts allows you to not have much waste. Usually, 2 to 4 ounces is ideal.
5. Don’t microwave breast milk, as you can lose important nutrients by overheating your milk. This means you have to thaw in advance.
6. Label all milk containers with the date so you know what to use first.
7. If you send your baby to a care provider that handles multiple children, put your baby’s name on the container.
8. Leave space in the containers when storing, since milk expands as it freezes
9. Put milk in the back or bottom of a freezer to keep it at a consistent temperature. The same goes for the fridge.
10. Don’t fully tighten bottles or containers of milk until it is frozen solid to allow air to move with expansion.
11. Make sure your storage containers don’t use BPA plastics. It is best to use containers designed specifically for breast milk.

How to Tell If Breast Milk Is Bad

There are three main ways to tell if breast milk is bad. The first is from the smell. This is the most obvious method as it is easily noticeable. Like regular milk, breast milk will start to go sour and have a strong, foul smell.

If you give your milk a quick sniff, it should be almost instantly noticeable if the milk is bad due to the smell.

The second is taste. Though it may sound weird to some, giving your breast milk a regular test before giving it to your baby can be a good idea. This lets you know what it should normally taste like and you can quickly identify if something is wrong with it or different than normal.

If milk has gone bad, it will usually have a sour aftertaste. Again, this is reminiscent of regular milk and it should be unpleasant to the palate.

The final way is the swirl of the milk. Breast milk tends to separate rather easily with the fats and non-fatty parts moving to different areas. However, they should mix back up rather easily. If they aren’t mixing as they should, or the milk doesn’t get a swirl when you shake it, it is a sign it may be bad.

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