I’m not suggesting not to clean your fridge of course! However, this actually works when some kind of smell, like a rotten orange, persists even if you clean the fridge thoroughly.
Put 2 tsp of ground coffee (I use Greek ground coffee which has a unique scent but I suppose it works with other ground coffees too) in a small plate and just place it in the fridge. Leave it at least for one day. It will absorb all the bad smelling.
You can also use it in a cabinet or a box or even the car. Try it and get rid of persistent smells.