A box of baking soda in the fridge or freezer absorbs odors.
kitchen myth cooking urban legend

This is a very clever and successful marketing ploy by the baking soda people, but the fact is that baking soda is very poor at absorbing odors. It seems to make sense, however, so lots of people have spent untold billions of dollars to put boxes of baking soda in their fridge or freezer to no effect.