If it isn't possible to make your feeds up on the go, or if you need to transport a feed (for example, to a nursery), NHS Choices advises that you:
Prepare the feed at home and cool it for at least one hour in the back of the fridge.
Take it out of the fridge just before you leave and carry it in a cool bag with an ice pack, and use it within four hours. If you don't have an ice pack, or access to a fridge, the made-up infant formula must be used within two hours.
If made-up formula is stored:
- in a fridge – use within 24 hours
- in a cool bag with an ice pack – use within four hours
- at room temperature – use within two hours