Remember, when you give your baby expressed breast milk or formula in a bottle, there’s an important rule:
Once your baby starts drinking, the milk is only safe to use for up to 1 hour.
If your little one doesn’t finish it within that time, it’s best to discard it.
Why? Because once saliva mixes with the milk, bacteria can grow and it’s no longer safe.
To avoid wasting your hard-pumped milk, try offering small portions (1–2 oz) at a time, and refill if your baby wants more. I know how hard it is to throw away that liquid gold 
