Hi Kenneth, expressed milk should be kept in the fridge or freezer for future use. In room temp, you can keep up to 4 hours, in the fridge up to 4 days and in the freezer up to 6 months. Warm it in the bottle warmer only when you need it.
Hi Kenneth, it could be true since the warmer it is, the more conducive the environment for bacteria growth. Best to only warm milk up when baby need it.
Lena Tan