Pasteurization inactivates COVID-19 virus in human milk: new research


Date:
August 11, 2020
Source:
University of New South Wales
Summary:
A new study has confirmed what researchers already suspected to
be the case: heat inactivates SARS-CoV-2 in human milk.



FULL STORY ==========================================================================
A team of medical researchers has found that in human milk, pasteurisation inactivates the virus that causes COVID-19, confirming milk bank
processes have been safe throughout the pandemic, and will remain safe
going forward, too.


==========================================================================
The study -- published this month in the Journal of Paediatrics and
Child Health -- was a partnership between UNSW and a multidisciplinary
team from Australian Red Cross Lifeblood Milk.

There are five human milk banks in Australia. As the COVID-19 pandemic
evolves, these milk banks continue to provide donated breast milk to
preterm babies who lack access to their mother's own milk. Donors are
screened for diseases, and milk is tested and pasteurised to ensure that
it is safe for medically fragile babies.

"While there is no evidence that the virus can be transmitted through
breast milk, there is always a theoretical risk," says Greg Walker,
lead author and PhD candidate in Professor Bill Rawlinson's group at
UNSW Medicine.

"We've seen in previous pandemics that pasteurised donor human milk
(PDHM) supplies may be interrupted because of safety considerations, so
that's why we wanted to show that PDHM remains safe." For this study,
the team worked in the Kirby Institute's PC3 lab to experimentally infect
small amounts of frozen and freshly expressed breast milk from healthy Lifeblood Milk donors.



==========================================================================
"We then heated the milk samples -- now infected with SARS-CoV-2 -- to
63?C for 30 minutes to simulate the pasteurisation process that occurs
in milk banks, and found that after this process, they did not contain
any infectious, live virus," Mr Walker says.

"Our findings demonstrate that the SARS-CoV-2 virus can be effectively inactivated by pasteurisation." The researchers say their experiments simulated a theoretical worst-case scenario.

"The amount of virus we use in the lab is a lot higher than what would
be found in breast milk from women who have COVID-19 -- so we can be
really confident in these findings," Mr Walker says.

Dr Laura Klein, Research Fellow and Lifeblood Milk senior study author, explains that the purpose of the research was to provide evidence behind
what people already expected.



========================================================================== "Pasteurisation is well known to inactivate many viruses, including the coronaviruses that cause SARS and MERS," she says.

"These findings are also consistent with a recent study that reported
SARS-CoV- 2 is inactivated by heat treatment in some contexts."
Kirby Institute researcher and study co-author, Associate Professor
Stuart Turville, says this work was a first.

"We've been working in real time to grow and make tools against this
new pathogen, which has been an exponential learning curve for everyone involved.

This work and many others that are continuing in the PC3 lab tell us
how we can be safe at the front line working with this virus in the
real world." Cold storage doesn't inactivate the virus The researchers
also tested if storing SARS-CoV-2 in human milk at 4DEGC or - 30DEGC
would inactivate the virus -- the first time a study has assessed the
stability of experimentally infected SARS-CoV-2 in human milk under
common storage conditions.

"We found that cold storage did not significantly impact infectious
viral load over a 48-hour period," Mr Walker says.

"While freezing the milk resulted in a slight reduction in the virus
present, we still recovered viable virus after 48 hours of storage."
The researchers say the fact that SARS-CoV-2 was stable in refrigerated
or frozen human milk could help inform guidelines around safe expressing
and storing of milk from COVID-19 infected mothers.

"For example, we now know that it is particularly important for mothers
with COVID-19 to ensure their expressed breast milk does not become contaminated with SARS-CoV-2," Dr Klein says.

"But it's also important to note that breastfeeding is still safe
for mothers with COVID-19 -- there is no evidence to suggest that
SARS-CoV-2 can be transmitted through breastmilk." Donated breast
milk is recommended by the World Health Organisation when mother's own
milk is not available to reduce the risks of some health challenges
premature babies can face. Lifeblood Milk has provided donor milk to
over 1500 babies born premature in 11 NICUs across New South Wales,
South Australia, and Queensland since launching in 2018.


========================================================================== Story Source: Materials provided by
University_of_New_South_Wales. Original written by Isabelle Dubach. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Gregory J Walker, Vanessa Clifford, Nidhi Bansal, Alberto O Stella,
Stuart Turville, Sacha Stelzer‐Braid, Laura D Klein, William
Rawlinson. SARS‐CoV‐2 in human milk is inactivated by
Holder pasteurisation but not cold storage. Journal of Paediatrics
and Child Health, 2020; DOI: 10.1111/jpc.15065 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200811120217.htm

--- up 3 weeks, 6 days, 1 hour, 55 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1337:3/111)