A freezer should be set to 0 degrees Fahrenheit. The best way for a homeowner to check this is to use an appliance thermometer, which is an inexpensive accessory found at most department stores.
If a homeowner suspects that the freezer is not keeping food cold enough, the food may begin to spoil. Spoiled food may smell bad, take on an unusual color or have mold on it. Though mold is not necessarily dangerous, it can change the taste of the food. Spoiled food may also contain dangerous bacteria, so it is recommended that any food suspected of being spoiled be thrown away. Individuals should keep in mind that not all spoiled food looks or smells bad, so if food is stored for more than two hours in less than ideal conditions, it should be thrown out.