Tip #1: I clean fridge or freezer that has rotten smells
with either bleach or baking soda or vinegar, but also I
remove the drip pan at the bottom of fridge/freezer either in
the back or front at bottom as if the blood from the meat
dripped down into it the smell will stay and only get worse. I cleaned out a fridge that had raw meat that got rotten
in it and still it smelled bad till I pulled the drip pan
out and cleaned it out really good. I keep an open box of
baking soda in both the fridge and freezer at all times.
Tip #2: Try placing a container of vinegar in the freezer. Leave the container open.
Tip #3: Put a large bowl or pan of kitty litter in the freezer and close it for a week. Be sure to use the kind that contains chlorophyll...the green stuff...not the clay type! This worked wonders for us!
Tip #4: Try a freshly opened can of coffee. This is what they use in the trucks that they haul animal hides in.