Home pasteurization

When full screening is not available, donor health status is unknown, or to reduce the potential risks of exposure to HIV and/or other pathogens, there are two methods that can easily be used for home pasteurization.

Holder pasteurization
(Low-Temperature Long Time – 62.5°C/145°F for 30 minutes)

Holder pasteurization is considered the standard1 for human and cow’s milk pasteurization. It has been shown to inactivate pathogens while maintaining adequate nutritious properties. However, given its longer time-temperature curves, this method damages more of the antimicrobial factors2 of breastmilk than would flash pasteurization.3

This method of pasteurization can be done by parents or caregivers on the stovetop, or with a home pasteurizer kit for human milk. Some may decide they want to buy commercial-grade pasteurizers which are also available.

Explanation of how to perform Holder pasteurization at home.

Flash-heating
(High-Temperature Short Time – (72ºC/161.6ºF for 15 seconds)

Flash-heating is a low-tech method of pasteurizing breastmilk that was developed for those who are HIV positive in developing countries that had no safe or affordable alternatives for feeding their infants.4 Studies5 by a research team led by Israel-Ballard,6 7 8 have shown that FH breastmilk inactivates HIV and 4 common bacteria.9

Explanation of how to perform the Flash-heat method of pasteurization at home.


Cooling down heat-treated milk

Cooked foods have a danger zone,10 a temperature range from 60ºC (41˚F) to 21.1ºC (140˚F) where bacteria like to grow. It is therefore important to cool the milk down quickly after it has been heated. Cooling the container in ice water11 is the quickest way to cool milk. Depending on the amount of milk, cooling it in the refrigerator is generally not recommended as the milk may cool down unevenly,12 leaving some milk too warm for too long. Please know that not all glass is suited for heating and rapid cooling.

Reusing heat-treated milk

In the study on bacterial safety, K. Israel-Ballard, et al. discuss that after cooling, flash-heat was successful in eliminating bacteria in the majority of samples, and prevented substantial growth for up to 8 h when stored at room temperature.

A study from 2013 concludes that “HIV-positive mothers living without access to refrigeration can be reassured that heat-treated breastmilk is safe for their infant to drink for up to 24 h after flash heating.“13

Milk banks recommend that donor human milk be used within the next 48 hours.14

It should be noted that most literature speaks in terms of heating expressed milk for feeding but that parents generally warm the (thawed) milk under running warm water or set it in a container in warm water for a short while to get the chill out of it. Gently warming should not be considered heat-treating. For optimal properties of breastmilk, reheating (warming) milk should not be done directly in a pan on the stovetop nor in a container set in boiling water on the stovetop (which would be heat-treating it unnecessarily).

Heat-treated (pasteurized) milk can be refrigerated or frozen following common food safety protocols. We suggest, however, that after a first feeding, milk that was heat-treated not be refrigerated and reheated again as anti-bacteriological properties can decline with increased handling.

Next: Holder pasteurization explained

_______________

  1. Kim Updegrove, MSN, MPH, APRN, CNM, et al. 2020. HMBANA Standards for Donor Human Milk Banking: An Overview ↩︎
  2. Douglas B. Tully, et al. 2001. Donor Milk: What’s in It and What’s Not ↩︎
  3. Dr. John May, et al. 2005. La Trobe Tables ↩︎
  4. Please see Human Immunodeficiency Virus (HIV) and HIV and the global context of infant feeding for more information. ↩︎
  5. HIV in breastmilk killed by flash-heating ↩︎
  6. Mduduzi N. N. Mbuya, et al. 2010. Heat Treatment of Expressed Breast Milk Is a Feasible Option for Feeding HIV-Exposed, Uninfected Children after 6 Months of Age in Rural Zimbabwe ↩︎
  7. Kiersten Israel-Ballard, MPH, et al. 2007. Flash-Heat Inactivation of HIV-1 in Human Milk ↩︎
  8. Letter to the Editor. Mylene L. Volk, MS, Carl V. Hanson, PhD, Kiersten Israel-Ballard, PhD, Caroline J. Chantry, MD. J Acquir Immune Defic Syndr. Volume 53, Number 5, April 15, 2010. Inactivation of Cell-Associated and Cell-Free HIV-1 by Flash-Heat Treatment of Breast Milk ↩︎
  9. K. Israel-Ballard, et al. 2006. Bacterial Safety of Flash-heated and Unheated Expressed Breastmilk during Storage ↩︎
  10. King County – Food safety in your home kitchen ↩︎
  11. New York City Department of Health and Mental Hygiene. Food Matters, Spring 2017, Issue No 19. Food Keeping Your Customers Safe by Cooling Food Properly ↩︎
  12. Ovesen L, et al. Int J Food Sci Nutr 1996. The effect of microwave heating on vitamins B1 and E, and linoleic and linolenic acids, and immunoglobulins in human milk. ↩︎
  13. Maxwell Bressler, et al. 2013. How Long Does Flashe-Heated Breastmilk Remain Safe for a Baby to Drink at Room Temperature? ↩︎
  14. Mothers’ Milk Bank Northeast – Storing, Defrosting, and Warming Pasteurized Donor Human Milk ↩︎