- Freshly expressed breast milk can be kept outside at room temperature for four hours.
- Store breast milk in the bottom of the refrigerator for up to 4 days and in the freezer for 6 to 12 months.
- To avoid losing milk, freeze 2 to 4 ounces in a food grade container with a tight lid.
- Visit the Insider Health Reference Library for more tips.
To be connected to a chest pump it’s a reality for many new moms.
But like any other milk in the refrigerator, your breast milk can, and will, go bad.
To maximize safety and freshness, here’s what you need to know about the use and preservation of pumped breast milk.
Breast milk can stay at room temperature for up to 4 hours
Doctors agree that it is best if you keep breast milk in 4 hours of expression. Especially if the room is warmer than 77 degrees Fahrenheit because the batteries in the milk will hurt faster at warmer temperatures.
If your baby has not finished a bottle of breast milk, you can leave it on the bed at room temperature and reuse it in two hours.
The time you can let go of used breast milk is shorter than for fresh milk expressed because the baby’s mouth introduces new bacteria into the milk, which can cause it to go bad sooner.
Use refrigerated breast milk within a week of storage
The CDC recommends storing fresh breast milk expressed in the refrigerator for up to four days.
When stored in the refrigerator, Syeda Amna Husain, MD, a Pure Direct Pediatrician, tells the Insider that you should put breast milk in the bottom of the refrigerator, not the door. That’s because, compared to the door, which is always exposed to room temperature, the back of the refrigerator stays cooler. Check twice and make sure the temperature in your refrigerator is 39 to 40 degrees Fahrenheit.
When you are ready to use, put the bag or container in a pot of hot water or run it under hot water for a few minutes.
For extended use, store breast milk in the freezer
Whether you create a stash for later or you have a surplus of breast milk, you can store it safely in the freezer for six to 12 months. Even if the shorter time passes, the better.
A little 2012 study, published in the Academy of Livestock Medicine, said that after three months of storage, breast milk samples had fewer calories and less fat compared to fresh milk.
As with the refrigerator, you should keep your milk in the bottom of the freezer at 0 degrees Fahrenheit or colder. And the colder, the better. The same 2012 study reported that the fat and calorie content in milk decreased if milk was stored at temperatures above -4 degrees Fahrenheit.
When you are ready to thaw the milk, take the older milk out of the freezer and put it in the bottom of the refrigerator. Do not place it on the counter to thaw at room temperature, as this may give the bacteria a chance to grow and ruin the milk before it is completely thawed.
Once thawed in the refrigerator, use the milk in 24 hours. After taking the thawed milk out of the refrigerator and leaving it at room temperature, use it in 2 hours.
Never refresh your chest milk after it has been thawed.
The rule of four
If you are worried that you will forget about these dates and these time intervals, consider using the rule of four. “Four hours at room temperature, four days in the fridge,” Husain says.
Husain also suggests that if you intend to store milk, you should label it with the date and time of pumping before putting it in the refrigerator or freezer.
How to know if breast milk is bad
No matter how careful you are, sometimes your breast milk can always go bad before you use it. It can be said to be bad if it tastes or has an acidic taste – similar to cow’s milk when spoiled.
But don’t confuse thawed milk with bad milk. Sometimes, thawed breast milk will have a different odor, often a soapy odor, or consistency than fresh milk. As long as you follow the conservation and thawing guidelines, the the milk must be safe to use.
The best way to preserve breast milk
After pumping, put breast milk in storage bags made specifically for breast milk or in clean food-grade containers with tight lids.
For the milk you plan to use in 4 days, drain it, and put it in the bottom of the refrigerator. Needless to say, freeze immediately. To avoid losing milk, freeze 2 to 4 ounces in each bag or container.
Take away the Insider
How to store breast milk depends on how soon you plan to use it. If you do not want to use freshly pumped breast milk immediately, you can store it in the refrigerator for up to four days. Or, you can freeze it for up to a year.
However, despite your best efforts, breast milk can still go bad sometimes. Spoiled breast milk will have a bad odor or a sour taste. To minimize spoilage, store breast milk in clean, food-grade containers with tight lids.