Using Expressed Breast Milk or Infant Formula Safely
Expressed breast milk
Breastfeeding supports optimum growth, development and health, and also ensures a better future health for infants and their mothers. Mothers often express their breast milk so that their babies and toddlers can continue to drink it even if they are away from their mother – for example, when mums go back to work.
When expressing breast milk, and feeding breast milk from a bottle, it’s important to use clean, sterilised equipment and to store the expressed milk safely. Our guide Best Practice for Infant Feeding in Ireland gives advice on expressing breast milk and storing it safely.
Sharing expressed breast milk
Some mothers who have surplus breast milk may wish to share it. The FSAI strongly urges that breast milk is not shared through unregulated sources such as websites or social media. Instead, mothers with surplus milk could donate it to a registered milk bank.
See also the European Milk Bank Association’s statement on sharing breast milk
Milk banks supply maternity and children’s hospitals with donated breast milk. Infants that have a very low birth weight, who are premature, or sick have a much better chance of survival if they are fed breast milk. When babies are born prematurely, their mothers may not be able to provide enough breast milk, especially in the early days after birth. Therefore, milk banks provide a critical service for these infants.
Milk banks follow strict protocols to ensure that the donated breast milk fed to these infants is safe:
- Donors’ blood is screened for infectious diseases
- Donors follow strict guidelines on how to hygienically express their milk and how to store and transport it at the correct temperature
- Donated milk is tested for microorganisms – contaminated milk is rejected
- Donated milk is pasteurised
- Pasteurised milk is stored and transported to the hospitals hygienically and at the correct temperature.
Mothers who donate their milk to milk banks do so out of good will. They do not receive payment. Access information on becoming a donor
Sharing expressed breast milk outside milk banks
Some mothers choose to share or sell their expressed breast milk on websites or social media. The FSAI strongly advises that you do not obtain breast milk from these sources. Unlike breast milk from milk banks, there are no controls in place for informal breast milk sharing. This means there is no guarantee that the milk is safe to drink. The milk may:
- come from a mother who has an infection
- be contaminated with harmful microorganisms, medications, alcohol, nicotine, drugs or other contaminants
- not have been expressed hygienically
- have been shipped at the wrong temperature, allowing bacteria to multiply
- have been diluted to increase profit for the seller
- not be human breast milk
One study (1), found that 74% (74/101) of breast milk samples purchased online failed the Human Milk Banking Association of North America (HMBANA) criteria for feeding without pasteurisation as they contained a pathogen or large numbers of bacteria (>104 cfu/ml total aerobic count). Salmonella was found in three of the samples purchased online.
(1) Sarah Keim and colleagues (2013). Microbiological contamination of human milk purchased via the internet. Pediatrics Volume 132, Number 5, November 2013
In another study (2), 10% (10/102) of breast milk samples purchased online were found to be diluted with at least 10% cow’s milk. This is harmful as an infant fed with diluted milk will not get the correct balance of nutrients they require. The infant may also have a cow’s milk protein allergy or intolerance.
(2) Sarah Keim and colleagues (2015). Cow’s milk contamination of human milk purchased via the internet. Pediatrics Volume 135, number 5, May 2015
See our update on Changes to Infant Formula Composition (October 2019)
Breast milk is the best and most natural food for babies, it’s ready to feed and it’s free. However, if you have made an informed decision to feed your baby infant formula, you need to know how to prepare and store it safely – just follow the steps in safefood’s booklet: How to Prepare your Baby’s Bottle
Using bottled water to prepare infant formula
We recommend that cold tap water, boiled only once and cooled for no longer than 30 minutes, is best for preparing infant formula. However, in certain circumstances you may need to use bottled water.
If using bottled water:
- use still water only, never fizzy or sparkling water
- always boil the bottled water before using it to make up feeds. Bottled water is not sterile
- it is best not to use bottled water labelled as ‘natural mineral water’ as it can have higher levels of sodium and other minerals. It can be used if no other water is available, for as short a time as possible, as it is important to keep babies hydrated.
FSAI statement on the use of automatic machines to prepare powdered infant formula
The FSAI does not recommend the use of automatic machines to prepare bottles of powdered infant formula because there is insufficient data available to verify the safety and efficacy of these machines. The FSAI continues to recommend the use of cold tap water that has been boiled once and then cooled for no longer than 30 minutes to >70°C to prepare feeds from powdered infant formula, described in a step-by-step way in safefood’s booklet: How to Prepare your Baby’s Bottle
Last reviewed: 16/6/2021