You should clean your fridge every week; this is something that many people fail to do. First, you should take out all the shelves and drawers and wash them in warm soapy water, then dry thoroughly. Clean out the inside as well - a little washing up liquid is ok, then rinse well, or you can use a solution of warm water and bicarbonate of soda (about a teaspoon of bicarbonate per pint/1/2 litre of water; but for stubborn stains use more bic and less water.) The outer surface and handle should be cleaned in the same day. Finally, use an old toothbrush to clean the rubber seals. Then you can put everything back (this is also a good opportunity to throw out any food that is no longer fresh or safe to eat.)

If there is a freezer compartment you may need to defrost and clean out that as well - you should look at the instructions for your fridge first.

This video also has helpful tips.