The refrigerator is one of the key appliances in every home and most people take it for granted. We use it to keep all kinds of food fresh for longer periods and to prevent it from developing dangerous bacteria that can cause foodborne illness (food poisoning), which can be fatal. However, some bacteria can grow even at low temperatures. That’s why it’s essential to make sure your fridge is set to the right temperature to significantly reduce microbial growth. This temperature is 40 degrees Fahrenheit (4.44 degrees Celsius) or lower, according to the US Food and Drug Administration (FDA) for refrigerated foods. The freezer temperature should not exceed 0 degrees Fahrenheit (-17.77 degrees Celsius). Consumer Reports (CR) recommends even lower temperatures for refrigerated foods than the FDA: 37 degrees Fahrenheit (2.77 degrees Celsius).
FoodSafety.gov provides the same guidance as the FDA, stating that food should be kept at 40 degrees Fahrenheit (4.44 degrees Celsius) in the refrigerator and 0 degrees Fahrenheit (-17.77 degrees Celsius) in the freezer. The French national food safety agency ANSES lists a similar maximum temperature of 39.2 degrees Fahrenheit (4 degrees Celsius) for the refrigerator, noting that a recent EU study showed that the average temperature of refrigerators in Europe is slightly higher than the recommendations of 43.52 degrees Fahrenheit (6.4 degrees Celsius).
Consumer Reports warns that some refrigerators may not always provide accurate temperature controls. Some have dials with numbers (1 to 5) instead of temperature values, while others have digital controls; in this case, a more basic unit might be better than an expensive smart fridge. CR recommends users put a refrigerator thermometer in their refrigerators to ensure correct temperature settings. The FDA and FoodSafety.gov also advise users to rely on a thermometer to check temperature readings.
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Why is 40°F (4.44°C) the recommended maximum?
A person who adjusts the temperature in the refrigerator. – Vladdeep/Getty Images
The limit of 40 degrees Fahrenheit (4.44 degrees Celsius) is not arbitrary. It is the recommended temperature to slow down the growth of dangerous bacteria that are present on food and can multiply significantly at higher temperatures. The FDA notes that “at room temperature, the number of bacteria that cause foodborne illness can double every 20 minutes.” FoodSafety.gov calls the range of 40 degrees Fahrenheit (4.44 degrees Celsius) to 140 degrees Fahrenheit (60 degrees Celsius) the “temperature danger zone,” where microorganisms grow rapidly. Similarly, ANSES explains that a bacterium such as Listeria monocytogenes can multiply at temperatures as low as 35.6 degrees Fahrenheit (2 degrees Celsius), or below the recommended maximum for refrigerated foods, with the bacterium growing even faster at higher temperatures. ANSES points out that a temperature below 39.2 degrees Fahrenheit (4 degrees Celsius) stops “the growth of most microorganisms, including Salmonella, which is a major source of foodborne illness in Europe.”
Salmonella is also a major cause of concern for the US, leading to food recalls in the past. FDA statistics indicate that Salmonella causes “millions of cases of foodborne illness annually and is the leading cause of foodborne deaths.” According to estimates as of March 2024, approximately 48 million cases of foodborne illness occur each year in the U.S. caused by various bacteria. Of these, about 128,000 cases require hospitalization, and about 3,000 people die each year from an infection. The agency also points out a key detail about pathogenic bacteria that can lead to foodborne illness. It also does not spoil the food in any detectable way – the food may not look, taste or smell bad, which would warn a person to avoid eating it.
Refrigerate food as soon as possible
Bags of groceries on a kitchen counter. – Brizmaker/Getty Images
Pathogenic bacteria are already present on various foods, including raw meat, poultry, seafood, milk, eggs, water, fruits and vegetables. Undercooked food can also allow dangerous bacteria to multiply. That is why it is important to keep both raw and cooked foods at the correct temperature in the refrigerator and freezer properly. The FDA advises people to refrigerate or freeze food within two hours of purchase or cooking. If the ambient temperature is above 90 degrees Fahrenheit (32.22 degrees Celsius), you should refrigerate the food within one hour. It is not recommended to leave food in the car for longer periods, as the vehicle may be even warmer than normal room temperature.
The same two-hour rule applies to home-cooked meals, doggie bags and takeaways. The FDA says putting hot food in the refrigerator will not harm the refrigerator. Leftovers should be refrigerated or frozen within the same two-hour period. FoodSafety.gov echoes that guidance, noting that foods that will not be served immediately after cooking should be kept out of that dangerous temperature zone, using a heat source to keep them above 140 degrees Fahrenheit (60 degrees Celsius) until served. Even an inexpensive cooking thermometer can help monitor food temperature.
Refrigerator and freezer thermometers can also help you determine if food is still safe after power outages. The FDA says that if the readings are higher than the recommendation of 40 degrees Fahrenheit (4.44 degrees Celsius), you may want to throw the food away. Setting your refrigerator temperature to the slightly lower level that Consumer Reports recommends, 37 degrees Fahrenheit (2.77 degrees Celsius), can be one way to ensure that the appliance cools food to lower temperatures than the FDA recommends.
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