In order to get rid of that bad fridge smell first make sure you get rid of whatever is creating that foul smell.
After getting rid of the reason behind the smell, get a spray cleaner and spray the fridge clean. USe baking soda and water to scrub the plastic parts. Then Wipe shelves with lemon juice, then put a bowl of one of these odor-killers on a shelf. Get vanilla extract; white vinegar; coffee grounds, baking soda; or activated charcoal from a pet store or aquarium.
If all else fails, you could fill the whole thing with balled-up newspapers. Last and not least, go get yourself a Berry-Breeze , an ionic air filter that eats fridge odors and keeps produce fresh for weeks—a boon for both nose and wallet.