Keep a refrigerator set between 34 and 40 degrees Fahrenheit to prevent the growth of bacteria in food. Even when refrigerators are set at the proper temperature, a refrigerator thermometer is required to determine if the appliance is staying cold enough.
Some refrigerators have cold spots that maintain a lower temperature than the rest of the appliance, and milk and meats should be stored in the coldest location possible. To keep food at the correct temperature, refrigerator shelves must be uncovered, and foods must be stored with enough room in between them to allow for proper air circulation. The U.S. Department of Agriculture recommends discarding meat and milk if a refrigerator operates higher than 40 degrees F for more than two hours.