The safety of donor human milk is the paramount concern of every milk bank

At the Hearts Milk Bank, we have adopted the highest standards of safety from the outset.
The National Institute for Health and Care Excellence (NICE) aims to improve health and social care through evidence-based guidance. The NICE Guideline for the Operation of a Human Milk Bank was developed over a 2-year period by a working group that included  Gillian Weaver, HMB cofounder, and Dr Jim Gray, Expert Advisor on Microbiology to the HMB. It was published in 2010. Guideline #93 has been fully adopted by the HMB and is referred to daily as a minimum standard of safety. We aim to exceed the safety parameters in the Guideline, as well as inform its future iterations by conducting carefully designed research studies alongside our routine work that aim to enhance safety, efficiency and cost-effectiveness of the milk banking services.

At the Hearts Milk Bank, we strive to go even further for safety

We have invested in state-of-the-art equipment, such as our Class 2 Biosafety Cabinet, which uses an ultra-microfilter to remove particles as small as viruses from the air within the cabinet. Additional disinfection of jugs and stirrers, as well as containers, is provided by ultraviolet light before the milk is poured. During processing, milk containers are only ever opened within this cabinet, minimising the risk of any contamination.  

One area that needs close attention regardless of the scale of a milk bank’s operation is the tracking and traceability of donor milk. Without barcode tracking, larger milk banks are challenged by the administrative burden of ensuring full traceability of every container of milk donated and issued from the bank. It is this complete traceability that ensures milk is only ever issued once all the safety checks have been carried out and that uptodate as well as historical records are fully maintained. When thousands of litres are passing through a milk bank, it can be an enormous task. We are proud to be the first milk bank to have adopted the Savant LiLac Donor Milk Tracking System. Savant are the leading UK company that develop tracking systems for human tissues, and have worked closely with the NHS Blood and Transplant Service.  

The importance of safety and training

As the clinical and scientific evidence increases for the importance of supporting mothers to breastfeed and protect vulnerable babies, more hospitals are using screened donor milk from non-profit human milk banks to bridge the gap between the baby needing feeding and the mother’s full milk supply coming in.


All milk banks follow very strict guidelines that bring safety to the core of every step of the process. Donors are rigorously screened, milk is heat-treated (pasteurised) and then checked before and after treatment for any bacterial contamination.


At the Hearts Milk Bank, we must currently discard around 10% of all milk because there are too many bacteria in the milk when it is donated. We work with donors to understand why this is happening, and usually some simple changes to basic cleaning processes make all the difference. We also test every batch of milk after pasteurisation to know that it meets the strict safety requirements for being dispatched to neonatal units.


Milk banks follow similar procedures, which is why, globally, they have such an excellent safety record. At the  Hearts Milk Bank, we also offer training to hospital staff in the safe handling of donor milk before units start to use it. This is also to ensure staff feel confident to answer questions  about milk donation and the milk banking process.


Importantly, guidance around using donor milk is given to each family in the community who receives milk for their babies, and we have a 24-hour helpline for any questions.

We will continue to raise the profile of training in this area of healthcare provision, and share our expertise to support other milk banks to ensure that safety continues to be at the heart of the service that we all provide.


As a milk bank that supplies into the NHS to feed some of the most vulnerable babies, it is critically important that our services are as safe as possible. In fact, everything we do places safety at the heart of the Hearts Milk Bank. Every year we conduct an audit against all the recommendations included in the National Institute of Health and Care Excellence Clinical Guideline 93 – the Operation of a Human Milk Bank.


Our audit for 2020 has shown we are 100% compliant with the key recommendations of this guideline – you can read the full details of the audit here. We have also been awarded a 5-Star Food Standards Agency rating.

COVID-19 Information

WHO states no evidence of live coronavirus in human milk


The  World Health Organization (WHO) has stated there is no evidence of live coronavirus (SARS-CoV-2) in human milk. Although a handful of reports have shown RNA to be present in some mothers, these are thought to be fragments of the virus that could help the infant immune system recognise and fight the virus in future. There is no evidence of the virus being transmitted from mother to baby through breastfeeding.


The Director General of the WHO made these comments on the safety of human milk on the 12th June 2020: “WHO has also carefully investigated the risks of women transmitting COVID-19 to their babies during breastfeeding. We know that children are at relatively low-risk of COVID-19, but are at high risk of numerous other diseases and conditions that breastfeeding prevents. Based on the available evidence, WHO’s advice is that the benefits of breastfeeding outweigh any potential risks of transmission of COVID-19. Mothers with suspected or confirmed COVID-19 should be encouraged to initiate and continue  breastfeeding and not be separated from their infants, unless the mother is too unwell. WHO has detailed information in our clinical guidance about how to breastfeed safely.”


Since January 2020 and then through our work with the Global Alliance of Milk Banks and Associations, created in March 2020 in response to the Covid-19 pandemic, we have worked round the clock to stay ahead of the evidence through developing and implementing safety guidance in consensus with milk bank leaders around the world. Safety is always the main concern of non-profit milk banks – the safety of donors, transportation teams, our own teams working with the milk and of course the recipient babies and healthcare professionals working with families in hospitals and at home. This statement from the WHO confirms our reading of the available evidence, and we will continue to work together with our expert advisory board and colleagues around the world to monitor new findings as they appear. This will help us to make sure The Hearts Milk Bank and other milk banks can offer the safest standards every day.

You can read more in the  New York Times  and the transcript of the  Director General’s statement.

Milk donation and COVID-19 vaccination


Women in the UK are now able to receive vaccinations against SARS-CoV-2, the virus that causes COVID-19 after a  change in guidance  by the Medicines and Healthcare products Regulatory Agency (MHRA). We ask women who receive a COVID-19 vaccination while donating their

breastmilk to the Hearts Milk Bank, to please let the team know on the screening questionnaire, but there is no need to stop expressing for donation after receiving the vaccine.


Vaccinations are typically safe for breastfeeding women and women who donate milk don’t need to stop or delay donating after most vaccines. This is because most are made from fragments of viruses designed to trick the body into preparing an immune response that will kick into action if they encounter the actual virus again in the future. Some vaccines are made using small doses of live virus, not enough to cause illness, but enough to help train the immune response to respond to an infectious dose. For live vaccines such as yellow fever, mothers are asked to stop donating milk for 28 days after their vaccination as a precaution.

Messenger RNA

Several COVID-19 vaccines are now in use in the UK. The Oxford vaccine produced by AstraZeneca uses a standard technology for producing vaccines, wrapping up a fragment of SARS-CoV-2 in another virus, which itself cannot reproduce and is therefore harmless to the recipient. The Pfizer and the Moderna vaccines use a short fragment of messenger RNA, the recipe that tells cells how to make a small fragment of the SARS-CoV-2 virus, wrapped up in a liposome – a tiny package made of nano-scale fatty acids.

This allows the body to mount a small immune response that will then be ready to act if exposed to the full virus.

Donating Milk

There is no evidence that either vaccine would reach the breast and enter the milk, and even if small quantities of the vaccine did, there is  no plausible mechanism  by which this could cause harm. Neither vaccine is live, and therefore there is no evidence to support asking milk donors not to stop donating milk after vaccination.

Therefore, after consulting with our expert advisors, scientists, doctors and other milk bank leaders from around the world, we conclude women will be able to donate milk to the Hearts Milk Bank as normal after vaccination for COVID-19.

There may also be benefits to receiving milk donated after vaccination, with antibodies produced that could get into milk and therefore help protect vulnerable infants. Our team is actively carrying out research to understand more about this, and we will keep you posted.

COVID-19 vaccination and fertility, pregnancy and breastfeeding

If you are trying to conceive, pregnant or breastfeeding, or just have questions about any of these issues, then please watch this webinar from the 19th April 2021, hosted by Rt Hon Stella Creasy MP. HMF Cofounder and Imperial College Fellow Dr Natalie Shenker talks through the latest evidence to help breastfeeding women make the decision about vaccination.

It is the responsibility of the HMF Expert Advisory and leadership teams to stay fully up to date with regards to all of the latest scientific and medical developments related to milk donation, including vaccinations. They can then make sure that all of the safety considerations are thought through to ensure milk donations can continue in the best way possible, always considering the safety of donor and their baby, recipients, milk bank team and volunteers.