If food has been allowed to spoil in a refrigerator or freezer, the strong odors associated with food spoilage may be extremely difficult to remove.
The first step is to clean the appliance with a gentle household cleaning solution and water. Use a bleach solution (one tablespoon chlorine bleach per gallon of water) to rinse inside surfaces. While the unit is unplugged, leave the door open for a day or two to air it out. Spray disinfectant around hinges and locks and into any openings. If the odor remains, try one of the following methods:
•Place trays of activated charcoal, clean kitty litter or baking soda on the shelves of the refrigerator or freezer. Run the appliance empty for 2 or 3 days. Activated charcoal can be purchased from stores that sell aquarium and terrarium supplies.
•Place freshly ground coffee on cookie sheets in the refrigerator or freezer and close the door. Again, run the appliance empty for 2 or 3 days. A slight coffee odor may remain, but will disappear after washing and rinsing.
•Pack each refrigerator or freezer shelf with crumpled newspaper. Set a cup of water on the top shelf or sprinkle the newspaper with water. Allow the refrigerator or freezer to run for approximately 5 or 6 days. This method is time consuming, but effectively removes strong odors.
•Several commercial products are available for removal of refrigerator and freezer odors. These products may be purchased at hardware, grocery, discount and variety stores.
If the unit has been off several days, it is possible the odor has gone into the insulation. If the odor has penetrated the insulation, much work is needed to get it out. An air compressor might be needed to blow air into this section of the unit. If the above methods do not satisfactorily take care of odor problems, it may be that drippings from meat or fish leaked into the insulation. This problem would require service by a refrigerator technician, who may have to remove the liner and replace the insulation.
Source: Nebraska Extension