The Food and Drug Administration recommends that home refrigerators be kept at or below 40 degrees. The FDA also recommends using an appliance thermometer to verify that the refrigerator is maintaining the proper temperature.
The University of Nebraska advises that refrigerated foods may be kept in the range of 34 to 40 degrees and that areas of the refrigerator closest to the freezer compartment are usually the coldest. Lower temperatures risk freezing foods, while higher temperatures allow harmful bacteria to grow.
During power outages or other times when refrigerated or frozen foods are allowed to reach room temperature, such foods are safe for up to two hours before they should be discarded, according to the FDA.