A refrigerator's temperature should be maintained between 34 degrees Fahrenheit and 40 degrees Fahrenheit. If the temperature dips to 32 degrees Fahrenheit or lower, food can freeze and start to deteriorate quickly. Frost-free refrigerators offer the most even distribution of cold air.
Although a refrigerator's temperature will not kill foodborne pathogens, such as salmonella or E. coli, it can slow the growth of bacteria already present in the food. The colder the temperature, the slower these dangerous microorganisms grow. The FDA recommends placing perishable groceries in the refrigerator or freezer within two hours of purchase. Refrigerator thermometers help monitor and maintain the proper temperature.