Vanilla will work wonders. I have used this for years on marine fridges, ice chest, etc. First wet a rag and wring it out, then wet it with vanilla, wipe the sides down with the rag. Leave the rag in the fridge and close the door. Check and repeat every day, re-wetting the rag, till smell is gone.
This has removed the smell of rotted fish from a new ice chest someone lost and a fridge that had rotten meat in it for a week in the middle of a TX summer. Need I say more?
KLO hit it right! The professionals use vanilla (the real stuff) full strength. Wipe down and let it dry....repeat if necessary. The smell of a locked freezer returned to a store and left till repairs are done can even be taken care of with it. I always had to leave the building but the refrigeration tech always did the repair and cleaned it up with vanilla. They were always resold too, so now you know what you might get with (reconditioned, returned but new) freezers.
2005 Ford F250SD
V-10 torqshift, tow command
2004 Komfort
"April" the attack cat!