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Guest Post: Breast Milk Storage 101

We are delighted to host a guest post from Helen Anderson, RN, CLE of Milkies LLC about storage guidelines for breast milk.  Milkies has graciously provided a Milk-Saver for review (read Becky’s review here!) and one to give away to one of our readers!  That giveaway ends tonight (10/3/11) at midnight, so hurry and enter now!

Breastfeeding is the best way to nourish your sweet baby, the American Academy of Pediatrics recommends breastfeeding for a minimum of one year. If you are returning to work or need some flexibility in your day, you should start storing your breast milk as soon as possible.

Breast milk is a dynamic fluid that is easy to collect and store safely. It can be kept at room temperature for several hours and has anti-bacterial properties that keep your milk safe for your baby to consume. If you follow a few basic guidelines you will be an expert at milk storage in no time!

In the beginning…

If you plan on returning to work start collecting and storing early. Only use a Milk-Saver when your milk comes in, it is not recommended to begin pumping before your baby is 3 weeks of age. In the early weeks your body is trying to establish a supply that is perfect for your baby’s needs, pumping can disrupt this process.

Getting started freezing…

Wash your hands before pumping or transferring milk. Make sure any containers are cleaned in hot soapy water and thoroughly rinsed. There are several options available for storing your milk- zip top storage bags, plastic or glass jars or special trays made just to freeze breast milk (my favorite!). If you are storing more than a few feedings, it’s a good idea to write the date on the bag or container. You can combine milk from different pumping sessions, just date the container with the earliest date.

To reduce waste when freezing and thawing breast milk, consider filling bags or jars to the 2 ounce mark.  Once your milk is thawed, it cannot be re-frozen and must be used in 24 hours. So only thaw what will be used very soon.

Thawing and warming…

Slowly thawing in the fridge is the easiest but can take about 12 hours, you can pull it out of the freezer the night before it is needed. For faster thawing, hold the container under cool water and gradually warm the water. Bottle warmers are another great option, be sure they are safe for breast milk (some brands of bottle warmers heat to a temperature that can damage the proteins in breast milk). Never microwave breast milk or warm it on the stove, it can heat the milk unevenly leaving dangerous hot spots. High heat will damage the valuable living nutrients in your milk.

When your milk is thawed you may notice a white or yellow cream on top of a lighter colored or even greyish fluid. This is normal separation of the fatty cream from the less dense portion of your milk. Do not shake the container to combine it, your milk contains groups of cells that can be broken apart. Treat your milk gently and swirl to mix. Always check the temperature of the milk before offering it to your baby.

You can do it…

With some advance planning you can continue to provide your baby the best nutrition, even when you can’t be there to breastfeed. If you are returning to work, stay committed to pumping every 4 hours to keep your milk supply strong. It can be challenging at first, but soon you will get used to the new routine.  Your employer is required under the law to provide you a time and place to pump or nurse your baby. See the chart below for easy reference. Print it out and tape it to the fridge, all caregivers should be familiar with the guidelines.

Happy Nursing (and pumping!)


TemperatureStorage Time
Freshly Expressed Milk
Warm Room79°F / 25°C4-6 Hours
Room Temperature66-72°F / 19-22°C10 Hours
Insulated Cooler / Ice Packs60°F / 15°C24 Hours
Refrigerated Milk (Store at back, away from door)
Refrigerator (Fresh milk)32-39°F / 0-4°C8 Days
Refrigerator (Thawed milk)32-39°F / 0-4°C24 Hours
Frozen Milk (Do not refreeze! Store at back, away from door/sides)
Freezer compartment inside refrigerator (older-style)Varies2 Weeks
Self-contained freezer unit
of a refrigerator/freezer
Varies3-6 Months
Separate deep freeze0°F / 19°C6-12 Months
These guidelines are for milk expressed for a full-term healthy baby.
If baby is seriously ill and/or hospitalized, discuss storage guidelines with baby’s doctor.

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  1. Rachel Carl says:

    Thank you so much for sharing this! As I’m 5 months pregnant with our first, I need all of the help I can get and really appreciated this!