Place bowls filled with about 1 cup each of baking soda into your cupboards. Replace the baking soda each month. The soda naturally absorbs odor and also absorbs any moisture that may build up inside of the cupboards.
Fill a spray bottle with 2 cups water and 1/2 cup white vinegar. If you notice any stinky smell caused by food residue, add a squirt of dish soap to the bottle to cut through the food buildup.
Spray the solution over the wood surface of the cupboards and wipe off with a damp cleaning rag. The vinegar will disinfect and deodorize without harming the wood.
Leave the cupboards open and allow them to air dry. Also keep the cupboards open overnight every week or so to allow air to circulate through the cupboards.