one hour formula rule

I was under the impression that once the baby starts to eat you can only feed him up until 1 hour after and then discard.

Then someone told me the hour rule starts once the formula is prepared or warmed up.

I am not sure what rule to use?

Re: one hour formula rule

It's when the baby eats though the differential is probably like 5 min so you can apply either one.

The reason it's when the baby eats is that the bacteria may grow when their saliva comes in contact with the formula.