Why do we need to Pasteurize?

The often asked question, “Why do you Pasteurize your milk donations?” has a simple answer to it: because pasteurization kills the bad while retaining the good. But that answer most of the time fails to satisfy those who believe that breast milk is best used in its raw form.

While generally, we agree with the belief that breast milk is best untouched, our mission is to provide donor milk to the population of infants who are highly prone to infection. It’s our job to provide the best nutrition while ensuring we do no harm. But most of the Pediatrics Centers recommend the use of donor milk in its pasteurized form, if mother’s milk is unavailable. Therefore we have a responsibility to ensure proper procedures so to deliver the safest possible end-product for the newborns.

Before we pasteurize milk donations, we first make sure that our donors are free of communicable diseases and are generally healthy with limited medication use. We require a blood test for all our milk donors to check for HIV, HTLV, Syphilis, Hepatitis B &C. We make sure our donor maintain a lifestyle that is compatible for donation- they are a non-smoker, aren’t taking a medication that will affect a premature baby and pump and store their milk in a safe way.

But what about the milk itself? What in the milk is killed during pasteurization and what is maintained?

What is retained when pasteurized?

  • The enzyme that destroys bacteria by disrupting their cell walls retains 75% of its activity. Lysozyme, with many other bioactive components, allow a baby to create their own immunity in their urinary tract. Meaning, babies fed breast milk are less likely to develop a urinary tract infection.
  • Oligosaccharides, a complex chain of sugars unique to human milk are unchanged by pasteurization. You might be wondering, why are these sugars important? They exist to feed the tiny organisms that make up a baby’s digestive system. In fact, some researchers believe that human milk was evolved to be more protective than to provide nutrition.
  • 70% of the concentrated IgA antibodies are also retained through pasteurization. These are the antibodies to things like E. coli, group B streptococci and Brucella abortus, all bacteria that can be harmful if not deadly to a preterm infant.


Does the pasteurized milk changes, how?

  • The good news is, NOT MUCH CHANGES! Well, aside from the things we want to change like the elimination of pathogens and viruses.
  • Some of you might have heard about Lipase or have experienced high amounts of it in your own frozen milk, Pasteurization inactivates the enzyme.


Our final step to ensure sure the milk we are sending to the most fragile infants is completely safe involves testing for potential bacteria. Each batch has a random sample checked by an independent lab that performs a 48 hour culture to check that all potential pathogens and viruses are destroyed.