Parents need to be aware that powdered infant formula milk is not a sterile product. Infections are rare, but they do occur, they can be very serious.
Low birth weight and premature babies, and babies under six weeks old are most at risk from these infections. It’s important to try to destroy any infective material when making up formula milk for a baby.
Bacteria can be destroyed by making up the milk with water at a temperature of around 70°C. In practice, this means boiling the kettle and leaving it to cool for no longer than 30 minutes.
If you are likely to need a bottle in a hurry, pour freshly boiled water into a flask, seal it and use this to make a fresh formula milk when necessary. This is safer than storing made-up formula milk in the fridge. Alternatively, you could use ready-to-feed liquid formula.