What is the correct internal temperature for a fridge?

Enterprise_1701C

I've got into the habit of having mine on just above zero at the bottom, mainly because of the amount of times it has been left open for a short while whilst DD dashes upstairs to do something while the milk is out waiting for the kettle to boil! When she is not around it does not seem to be running too long, but think I will turn the temperature up slightly soon, see what difference it makes.

OP, does your milk go off quickly? That is how I normally know if a fridge is going wrong.