Flash-heating vs Flash-pasteurizing

Flash-heating (FH) is a low-tech method of pasteurizing human milk that was developed for HIV-positive mothers in developing countries who had no safe nor affordable alternatives for feeding their infants.1 Studies2 3 by a research team led by Israel-Ballard,4 5 6 have shown that FH грудне молоко inactivates HIV and 4 common bacteria.7 The World Health Organization supports expressing and heat-treating milk of those who are HIV positive for temporary feeding during an emergency and when no other safe options are available.8

Flash-heating is however not to be confused with flash-pasteurizing (FP), which is a commercial process. Both are forms of High-Temperature Short Time (HTST) Pasteurization, but flash-pasteurizing requires special equipment whereas flash heating does not.9 FP involves heating to exactly 72ºC/161.5ºF for 15 seconds. This process is followed by the dairy industry and is an officially accepted method of pasteurization. 10 11 Flash-pasteurization of human milk has been demonstrated to inactivate bacteria as well as certain important pathogenic viruses, specifically HIV, HTLV, HBV and HCV, and CMV.12

While the temperature of milk when FH typically reaches 72ºC/161.5ºF,13 this is not as accurate as with the FP process. In a home setting, the time and temperature are not easily controlled, nor are milk and water volumes.

For instance, the temperature of human milk when using FH will greatly vary depending on altitude and atmospheric pressure. Water boils at 100ºC/212ºF at sea level, but the higher the altitude, the lower the boiling point of water.14 Using FH at home and removing the milk from the heat when the water boils will thus not always result in the milk attaining exactly 72ºC/161.5ºF, the safe temperature needed for flash pasteurization. We do not know how heat-treating milk at 71ºC for instance affects the viral load, except for HIV (see below).

Another aspect is that, contrary to FP where the temperature is held for 15 seconds, the whole process of FH takes about 5 хвилин. Holding the milk at a precise temperature for a specific amount of time is not feasible in a home setting. Both temperature and time are important however when flash-pasteurizing.

While FH has been researched and is proven to deactivate HIV, its effectiveness on other viruses is theoretical. We, as a milksharing network, cannot make assumptions and tell our community that both processes do the same thing. HIV is destroyed at low temperatures (57ºC/134.5ºF) and so boiling water anywhere for any time will result in milk that is hot enough to deactivate the virus. While the positive results of FH might be comparable to those of FP, when it comes to the other viruses, more research is needed to address this directly.

Currently, there is no clear evidence on whether heat-treating breastmilk should be used as a permanent solution.15

For more information on infant feeding and HIV, please see Human Immunodeficiency Virus (HIV) і ВІЛ і глобальний контекст вигодовування немовлят

Next: Pretoria pasteurization.

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  1. The terms flash-heating and flash-pasteurizing are often used interchangeably. Flash-heating refers to the at-home method of pasteurizing as demonstrated in the Kiersten Ballard-Israel studies. Please see Flash heating explanation for information on how this is done. ↩︎
  2. UCBerkelyNews – HIV in breastmilk killed by flash-heating ↩︎
  3. Flash-Heating Breast Milk Kills HIV – YouTube ↩︎
  4. Mduduzi N. N. Mbuya, та ін. 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 ↩︎
  5. Kiersten Israel-Ballard, MPH, та ін. 2007. Flash-Heat Inactivation of HIV-1 in Human Milk ↩︎
  6. Letter to the Editor. Mylene L. Volk, РС, 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 ↩︎
  7. K. Israel-Ballard, та ін. 2006. Bacterial Safety of Flash-heated and Unheated Expressed Breastmilk during Storage ↩︎
  8. Всесвітня організація охорони здоров’я. 2016. Guideline. Updates on HIV and Infant Feeding ↩︎
  9. доктор. Джон Мей, та ін. 2005. Столи La Trobe ↩︎
  10. FDA – GUIDE TO INSPECTIONS OF DAIRY PRODUCT MANUFACTURERS ↩︎
  11. Legal pasteurization is a combination of time and temperature as per the 2017 FDA – Grade A Pasteurized Milk Ordinance item 16p Administrative procedures section 1. ↩︎
  12. Fokke G. Terpstra, та ін. 2007. Antimicrobial and Antiviral Effect of High-Temperature Short-Time (HTST) Pasteurization Applied to Human Milk ↩︎
  13. Kiersten Israel-Ballard. 2007. Flash-Heat Inactivation of HIV-1 in Human Milk Flash heating typically reached temperatures greater than 56Cº for 6 хвилин 15 seconds and peaked at 72.9C.º ↩︎
  14. Manitoba Food Safety Program. Thermometer Calibration Guide Thermometers need to be calibrated when used at higher altitudes if one needed to precisely measure the temperature of the milk. ↩︎
  15. Всесвітня організація охорони здоров’я. 2016. Guideline. Updates on HIV and Infant Feeding Those who are HIV positive may consider expressing and heat-treating breastmilk as a temporary feeding strategy under the following circumstances: In special circumstances such as when the infant is born with low birth weight or is otherwise ill in the neonatal period and unable to breastfeed; When the lactating parent or caretaker is unwell and temporarily unable to breastfeed or has a temporary breast health problem such as mastitis; To assist lactating parents and caretakers to stop breastfeeding; If antiretroviral drugs are temporarily not available. ↩︎