Pasteurizing Breast Milk Inactivates SARS-CoV-2, U of T Study Shows

Jul 10, 2020
Author: 
By Kim Barnhardt and Jim Oldfield

Photo by Golfxx, DreamstimePhoto by Golfxx, Dreamstime Researchers at the University of Toronto and Sinai Health have found that a common technique to pasteurize breast milk inactivates the virus that causes COVID-19, making it safe for use. 

The findings provide further assurance for parents and families who use human milk banks to feed their infants. 

Current advice is for women with COVID-19 to continue to breastfeed their own infants, and it is standard care in Canada to provide pasteurized breast milk to very-low-birth-weight babies in hospital until their own mother's milk supply is adequate. 

"In the event that a woman who is COVID-19-positive donates human milk that contains SARS-CoV-2, whether by transmission through the mammary gland or by contamination through respiratory droplets, skin, breast pumps and milk containers, this method of pasteurization renders milk safe for consumption," the authors write in their study, published this week in the Canadian Medical Association Journal

The lead author on the paper was Sharon Unger, a professor of paediatrics and nutritional sciences at U of T and neonatologist at Sinai Health, who is medical director of the Rogers Hixon Ontario Human Milk Bank

Unger said the current pandemic is a time for extra efforts to protect the supply of donated human milk, in part because formula was scarce and previous pandemics — notably HIV/AIDS — created major challenges for human milk bank supply. 

The Holder method, a technique used to pasteurize milk in all Canadian milk banks (62.5°C for 30 minutes), is effective at neutralizing viruses such as HIV, hepatitis and others that are known to be transmitted through human milk. 

Professors Deborah O'Connor and Sharon UngerProfessors Deborah O'Connor and Sharon Unger In this study, researchers spiked human breast milk with a viral load of SARS-CoV-2 in U of T’s combined containment level 3 unit, and tested samples that either sat at room temperature for 30 minutes or were warmed to 62.5°C for 30 minutes. The virus in the pasteurized milk was inactivated after heating. 

Interestingly, the virus in the unheated milk was also weakened, said Deborah O’Connor, the senior author on the paper who is chair of nutritional sciences at U of T and a researcher in the Joannah & Brian Lawson Centre for Child Nutrition.  

O’Connor said this finding suggests some properties of breast milk may counteract the virus, and she recently received funding to pursue research on that topic. 

The impact of pasteurization on coronaviruses in human milk has not been previously reported in the scientific literature. 

More than 650 human breast milk banks around the world use the Holder method to ensure a safe supply of milk for vulnerable infants. 

The research was supported by the Canadian Institutes of Health Research, and through the University of Toronto and the Temerty Foundation, which provided funding for enhanced capacity and operations of the university’s combined containment level 3 facility during the COVID-19 pandemic. 

Tweets

Temerty Medicine
@uoftmedicine
RT : Middle-aged people who sleep six hours or less a night may be more likely to develop dementia in their late 70s, a… https://t.co/9yg0I66jSH
Temerty Medicine
@uoftmedicine
Can you still spread COVID-19 if you’re fully vaccinated? What if you’re only hanging out with other vaccinated peo… https://t.co/DMqt6qZwcz
Temerty Medicine
@uoftmedicine
RT : Do you know a grade 9 or 10 Indigenous student interested in the health professions? If so, please share this inf… https://t.co/njsZvUZ2Rq

Researchers are mobilizing against the novel SARS-CoV-2 coronavirus and COVID-19.

Make a gift and support their important work.
Oct 5 – May 6
Academic Health Leadership Training – Now Accepting Applications 2020-2021 Cohort
Course | 8:00am–5:00pm
Oct 13 – Jun 8
Certificate Program in CPD Foundations
Course | 12:00pm–1:30pm
Oct 27 – Jun 23
Leading and Influencing Change in CPD
Course | 9:00am–12:00pm
Jan 15 – Nov 19
Virtual Hereditary Cancer Series
Workshop/Seminar | 12:00pm–1:00pm
Feb 9 – Jun 8
Teaching with Technology - Digital Program
Other | 11:00am–1:30pm
Feb 24 – Jun 23
ECHO Concussion at UHN
Other | 4:30pm–6:00pm
Apr
15 – 30
The 100th Anniversary of University of Toronto’s Discovery of Insulin: A Scientific Symposium Celebration
Symposium | All day