Last updated on January 28th, 2020
Posted on 8 Comments

How To Pasteurize Breast Milk

This home method mimics the same process that milk banks use to pasteurize milk from donors. You’ll need glass bottles for pasteurizing the breast milk such as the 8 ounce Evenflo Classic Glass bottle 6 Pack. These are available online and at baby stores for $15 or less. Six bottles may be a good starting point, but don’t hesitate to get a second set to make your Be sure to get enough bottles so you’re not having to constantly wash and reuse the same bottles. Four to eight bottles is a good starting point.

Once you have the bottles wash them. Using the dishwasher is fine. Next, thaw the donated breast milk if it’s frozen, then pour 5 ounces into each bottle and screw on the cap. If you bought 8 glass bottles, you can pasteurize 40 ounces of breast milk at a time.

Next get a pot large enough to easily hold the bottles to be pasteurized while leaving a one inch space between each bottle and its neighbor. Fill the pot 4 to 5 inches with water – the water should be at the same level as the milk in the bottles or a little higher. Remember the water level will rise each time you put a bottle in the pot.

After you have test fitted the bottles and the water level, take all the bottles out of the pot and heat the water to boiling. Remove the pot from the heat, wait 1 minute and then put the bottles in the pot spacing them at least an inch from the nearest neighbor.

Wait 30 minutes and remove the bottles from the pot. Leave the caps on until you are ready to use the milk. Once the milk cools it can be consumed immediately, stored in the refrigerator for 12 hours or frozen.

Please Note: Don’t actively boil the bottles – that is not how to pasteurize breast milk! Be sure to remove the pot from the burner and let it sit for one minute before putting in the milk bottles – otherwise you could cook the milk!

8 thoughts on “How To Pasteurize Breast Milk

  1. Hi! Thanks for the info. I am seeing many different methods of pasteurizing online and am confused! Some say to cool the milk immediately after in running water, but yours does not. Do you know if I need to cool the bottles after exposing to the heat? Or just put right into the fridge for use through the day? Also, are you confident that it’s ok to use defrosted milk, pasteurize, then re-freeze? I’m finding conflicting info online, and this conflicts with my understanding of standard frozen milk handling, which says never to re-freeze. Thanks so much!

    1. Not sure about blanching the milk as I’ve seen that too. All the blanching does is stop the cooking/heating process abruptly, I am unsure if that is necessary or not. You can refreeze milk if you pasteurize it from raw. That’s how a lot of milk banks do it. They get frozen raw milk thaw and pasteurize it then refreeze it.

    2. Hello,

      I would like to share so that people who read this blog are aware: breast milk should not be pasteurized before feeding your baby. Actually, pasteurizing milk degrades many of its protective properties that makes it so wonderful for growing babies, including water-soluble vitamins, immunoglobulins, lactoferrin, and cytokines. This is one challenge that donor banks and neonatal intensive care units who give donor milk (when needed) are researching on. Milk straight from the breast or bottle-stored is always best!

      A neonatal nurse and lactation researcher

      1. I definitely understand unpasteurized breast milk has the most benefit, but my concern are viruses or bacteria which could potentially be growing in the donor milk due to improper storage or contamination in the expression process… I just started informally milk sharing but now I’m paranoid the lack of screening (for drugs, alcohol, diseases) and absence of pasteurization is going to be putting my baby at more risk than just giving her formula.

      2. Thank you this is very helpful . I’m trying to donate milk and because I take nifedipine ( bp medication)I was told I can not donate and my milk would need to be tested and pasteurized. This I dont understand being that I am as i write this breastfeeding my son who is only a month old. If my milk were contaminated or harmful wouldn’t it be harming him? I find it very confusing and sad bc I don’t want to waste this milk i over produce so I’m trying to help a mama in need who also takes bp meds and would like to breastfeed her baby but can’t or that doesnt produce enough milk.

  2. While I know that it is relatively rare (according to research), does the process of pasteurization kill group b strep in breast milk?

  3. Unfortunately this method did inactive the lipase in my frozen breastmilk

    1. I actually have high lipase so am looking for a method to inactive it. This is good to know.

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