How Long Can Breast Milk Really Sit Out Before It Goes Bad?

We’ve all been there, right?

Peering into the bottle, sniffing it… Is it still good?

In our frantic, worried state of mind, we desperately try to remember what time it was when we pumped or got the bottle out of the fridge.

Please don’t tell me I’ve wasted my valuable breast milk because I fell asleep before putting it away! What a nightmare.

What To Do?

This has happened to me a number of times, so the best recommendation I can offer you is to make a note of what time it is whenever you pump or heat up a bottle.

I get frustrated when I’m not finished pumping and my daughter wakes up, so I usually just let the milk sit out, and I finish pumping next time she falls asleep.

It can be frightening if we fail to put our breast milk in the refrigerator or on ice within a few hours, or if we mistakenly leave it out for longer than intended.

The Good News

Don’t panic! The good news is: breast milk can sit out for a while without going bad. Whew! But how long is too long?

Well, the amazing thing about breast milk is it is loaded with antibodies which fight off bad bacteria.

That’s why it’s able to sit out at room temperature longer than most foods. Of course, it has its limits. But rest assured, even if it’s gone bad, it won’t be a danger to your baby. It will merely taste bad and lose its potency of nutrients.

According to Baby Center:

Freshly pumped milk can safely be left at room temperature (60℉-85℉) for 6-8 hours. If the room is warmer than 85℉, 3-4 hours.

Reheated breast milk should be consumed within one hour, if possible. If your baby doesn’t finish the bottle, refrigerate it again within 30 minutes of your child finishing, and it can be reheated one more time.

Refrigerated breast milk will stay fresh for 3-5 days. But if it was previously frozen, only 24 hours. It is recommended that you always store your milk in the back of the fridge and freezer so it isn’t influenced by the blast of warm air every time the door opens.

If you pump away from home, you can put it in a cooler with ice packs for up to 24 hours.

For frozen milk, it depends on the type of freezer you have. If you have a refrigerator with the freezer within the same door as the refrigerator, it will only last 2 weeks. But if your freezer has a separate door from your fridge, 3-6 months. If you have a “deep freeze”, such as a freezer in the garage, it will keep for 6-12 months.

These guidelines do not necessarily apply for pre-term, sick, or hospitalized infants. It is recommended that you ask your doctor in these cases.

A Few Details…

According to the CDC, the longer the milk has been in the fridge, the sooner it will go bad if left out. So if it’s already been in the fridge for 5 days, don’t assume you can let it sit out for 8 hours.

The Mayo Clinic website recommends refrigerating your milk as soon as possible after expressing it because the Vitamin C in the milk will diminish the longer it sits out.

If the milk has more bacteria in it (for example, if the bottle or pumping equipment wasn’t properly cleaned or your hands weren’t washed), it won’t last as long.

Or if the milk has already sat out at room temperature for a while, the amount of time it will last in the refrigerator shortens. If you’re unsure, it’s best to err on the side of caution. But milk is milk, so if it smells bad, it’s bad.

The Science Behind It

We’ve all heard “breast is best”, but fresh is also best, like with any food. Obviously it’s ideal to feed your baby directly from the breast because your milk changes with your baby’s needs.

I find it so remarkable that my body gets information from her saliva and will begin producing whatever she needs. It’s like magic!

But there are many reasons we need to pump, whether we work away from home, our baby has trouble latching, or we just want someone else to be able to feed them so we can have a break. Expressing our milk can be so helpful, and it’s a relief to know that if we leave a bottle out for a few hours, it’s still good to go!

*Please note that these guidelines are for breast milk only–not formula! Formula must be used or tossed–it cannot be refrigerated and used again.