Storing bottles of formula in the fridge

I have a 4mo and exclusively formula feed. NHS guidance states that formula bottles should be used within 2 hours if baby has started eating, then discarded, or if baby hasn’t taken anything from the bottle, it can sit for 4 hours in the fridge before being used or discarded. I believe this is due to the build up of bacteria, from babies mouth or just from sitting made up for too long.

My husband believes we can keep the bottles, eaten from or not, for longer than 4 hours if put in the fridge, as bacteria will not bloom to dangerous levels while stored at such cool temperatures. I don’t mean we would keep it for any extended length or time or overnight in the fridge, more like an extra few hours before taking it out to reheat and use.

I can understand his logic, but don’t like to disregard what the NHS guidance is. Can anyone share any evidence or experience with this?

• EDIT -

My husband wants me to be a bit more specific. He wants to know where the evidence behind the NHS / health organisations guidance comes from. I.E what studies or research have been done to support the time limits stated in guidance for made up bottles.

His argument is that a bottle made and eaten from should be safe for a few hours in a fridge to then be reheated and finished off after a few hours, as the cool temperature will stop additional bacteria growth.