Bottle feeding

How to bottle feed

Meticulous hygiene

A young baby’s immune system is not as strong or as well developed as an adult’s, which means that they are much more susceptible to illness and infection.

If you decide to bottle feed your baby, it is vital you keep meticulous hygiene standards when preparing feeds, and that all equipment is cleaned and sterilised thoroughly before use.

Infant formula milk must be prepared in the safest way possible. Even though tins or packets of milk powder are sealed, powdered infant formula is not a sterile product. It can contain bacteria, such as Enterobacter sakazakii or, in rare cases, salmonella.

If not prepared correctly, these bacteria can cause infections which, although rare, can be life-threatening if they occur. In order to kill the bacteria, formula milk should be made up using water that has been boiled and left to cool for no more than 30 minutes.

The water must still be hot when it is added to the formula to ensure that any bacteria are killed. Be careful when pouring the water from the kettle because even at 70C, it is still hot enough to scald.

For premature or low birth weight babies, commercially sterile, ready-to-feed liquid products are recommended.

Bottle feeding using formula milk

If you decide to bottle feed your baby using infant formula milk, before preparing a feed, you should wash your hands and ensure that the preparation area is clean. Bottles and teats need to be cleaned and sterilised after each feed to reduce the chances of your baby getting sickness and diarrhoea.

When making up feeds, follow the manufacturer’s instructions carefully. The ratio of powder to liquid has been precisely calculated to give your baby the right amount of food and water in order to prevent them becoming constipated or dehydrated.

Cleaning and rinsing equipment

Sterilising bottle feeding equipment is essential for at least the first 12 months of a baby’s life. This is because a baby's immune system becomes more resistant to germs after the age of 12 months.

Cups and mugs need to only be sterilised for six months. After this time, they just require careful cleaning. However, bottles must be sterilised for longer because they have areas that are hard to clean properly, such as the teats. Even if a tiny amount of milk gets trapped inside the bottle, bacteria can start to grow.

As soon as possible after a feed, you should clean the bottle and teat using hot soapy water and a clean brush that reaches to the bottom of the bottle to remove all traces of milk. All equipment should be rinsed thoroughly in clean running water before it is sterilised.

Steam sterilising

Steam sterilising can either be done using a microwave steriliser or a purpose-made steam steriliser. Follow the manufacturer’s instructions carefully:

  • Pour the specified amount of water into the steriliser.
  • Place the bottles and teats face down in the steriliser to ensure that they are fully sterilised.
  • Put the lid on the steam steriliser and switch it on for the recommended length of time.
  • Only put in equipment that is safe to heat, and be careful of the steam when removing the lid.
  • Always use sterilised equipment immediately. Any equipment that is not used straight away will need to be re-sterilised before it is used. However, microwave sterilisers can keep feeding equipment sterile for up to three hours if the lid is kept on.

Cold water sterilising

Cold water sterilising is an effective method of sterilisation, and provides a good standby method in situations when a microwave or steam steriliser, is unavailable. When cold water sterilising, you should follow the manufacturer’s instructions carefully:

  • Change the sterilising solution every 24 hours.
  • Put the feeding equipment into a container with cold water and a sterilising tablet for the prescribed length of time (at least 30 minutes).
  • Check that there are no air bubbles trapped in the bottles or teats when you put them into the sterilising solution.
  • Use a floating cover or a plate to ensure that the feeding equipment is totally submerged in the sterilising solution.
  • Wash your hands before removing the equipment from the container.


You can also sterilise equipment by boiling it in water for at least 10 minutes. Like cold water sterilisation, boiling is another useful alternative method of sterilisation. However, teats tend to rot faster, and you must ensure that whatever you sterilise in this way is safe to boil.

Making up formula feeds

To make up formula feeds, you should follow the steps that are listed below.

Preparing the equipment

  • Clean and disinfect the kitchen surface you are going to use.
  • Wash your hands before making up a feed.
  • If you are using a cold water steriliser, shake off any excess solution from the bottle and teat, or rinse the bottle using cooled boiled water from the kettle (not the tap).
  • Stand the bottle on a clean work surface, but make sure that you keep the teat and cap on the upturned lid of the steriliser (not the work surface).

Preparing the feed

  • Fill the kettle using fresh tap water (not bottled water) and after it has boiled, let it cool for no more than 30 minutes.
  • Avoid using artificially sweetened water, or repeatedly boiled water. If you have to use bottled water, you will still need to boil it first.
  • It is important that the cooled water is still hot (at least 70°C) otherwise any bacteria in the milk powder may not be destroyed. Always put the cooled water in the bottle first.
  • Taking care not to scald yourself, fill the bottle to the correct level (as specified by the formula manufacturer on the packet or container).
  • Using the scoop provided, loosely fill it with milk powder and level it off using a clean, dry knife. Add the number of scoops of milk powder as specified by the manufacturer on the container. It important that you only use the scoop that is enclosed with the milk powder.
  • Do not add sugar or cereals to the feed in the bottle.
  • Holding the edge of the teat, put it on to the bottle, screw the retaining ring into place, and cover the teat with the cap.
  • Shake the bottle until all the powder has dissolved.

It is always best to feed your baby using freshly made formula milk because using formula milk that has been stored increases the likelihood of your baby becoming ill.

Feeding your baby

Before feeding your baby, you should always cool the milk down to the required temperature, as at 70°C it is still hot enough to scald.

To cool the milk, hold the bottle, with the cap covering the teat, under cold running water. You can test the temperature of the milk by squeezing a little bit onto the inside of your wrist. It should feel warm to the touch, but not hot.

When feeding your baby, make sure that you keep the teat full of milk otherwise your baby will take in air. Never leave your baby alone with a bottle.

Always throw away milk that has not been used within two hours.

Feeding away from home

If you need to feed your baby while you are away from home, you can take a measured amount of milk powder in a small, dry container, plus a flask (or bottle) of hot water that has been boiled, and an empty, sterilised feeding bottle. This will enable you to make up a fresh feed as and when you need it.

However, the water must still be hot when you use it so that any bacteria in the milk powder are destroyed. Remember to cool the bottle under cold running water before you start to feed your baby. Alternatively, you could use ready-to-drink infant formula milk.

If you are unable to follow the above advice, or if you need to take a feed to another location, such as to a nursery, or a child minder's house, you should prepare the feed at home, and cool it at the back of the fridge. Take it out of the fridge just before you leave and transport it in a cool bag with an ice pack.

You should use the feed within four hours, or if you reach your destination within four hours, take it out of the cool bag and store it at the back of the fridge. Do not store the feed for more than 24 hours. However, this length of time is no longer considered to be ideal, particularly for young babies. Wherever possible, it is always safer to make up a fresh feed.

Bottle feeding using expressed breast milk

Breast milk can be expressed (squeezed) into a bottle, either by hand, or using a manual or electric breast pump.

This allows you to give your baby all the health benefits of breast milk, while also being able to share the feeding with your partner or another carer. It can be a particularly useful feeding method if you are returning to work, or if you are going out for the evening.

When using this feeding method, you must sterilise the bottles, teats, and pump in the same way as if you were using formula milk. The recommendations for storing expressed breast milk are as follows:

  • up to five days in the main part of a fridge (at a temperature of 4°C, or lower),
  • up to two weeks in the freezer compartment of a fridge, and
  • up to six months in a domestic freezer (at a temperature of minus 18°C, or lower).

Frozen breast milk should be defrosted in the fridge, and it should not be refrozen after it has thawed. Do not defrost or warm frozen breast milk in a microwave oven.

Combining breastfeeding with bottle feeding

Some women find that combining breastfeeding with bottle feeding is a convenient option for them. However, if you decide to breastfeed your baby, you should avoid introducing bottle feeding during the first six weeks of life because it can confuse the baby. This can cause feeding problems and interfere with the establishment of breastfeeding.

Any amount of breastfeeding is good for both the mother and baby, and you should continue to breastfeed for as long as possible. Also, if you decide to breastfeed, it is important to maintain it for a sustained period because if you stop it can be very difficult to start again.

If you decide to bottle feed your baby from birth, you can switch to breastfeeding if you decide to do so within the first few days. However, if you are considering breastfeeding, it is best to try it as soon as possible after birth.

This will ensure that your baby receives the benefits of colostrum (a thick, yellow coloured milk that is produced during the first few days following birth) which contains disease fighting antibodies. Starting to breastfeed soon after birth will also help your body to adjust to the process of breastfeeding, and will help you to establish a routine.


Vomiting is when you bring up the contents of your stomach through your mouth.
Immune system
The immune system is the body's defence system, which helps protect it from disease, bacteria and viruses.
Constipation is when you pass stools less often than usual, or when you are having difficulty going to the toilet because your stools are hard and small.
Antibodies and immunoglobins are proteins in the blood. They are produced by the immune system to fight against bacteria, viruses and disease.
Diarrhoea is the passing of frequent watery stools when you go to the toilet.
Bacteria are tiny, single-celled organisms that live in the body. Some can cause illness and disease and some others are good for you.
Dehydration is an excessive loss of fluids and minerals from the body.
Last updated: 04 October 2011

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