The two numbers that everything depends on
- Refrigerator: at or below 40 °F (4 °C). Between 40 °F and 140 °F (4–60 °C) — the “danger zone” — bacteria multiply rapidly. The FDA recommends keeping the refrigerator at or below 40 °F. The UK FSA works to a target of 5 °C or below.
- Freezer: 0 °F (−18 °C). At this temperature microbial growth stops entirely, which is why continuously frozen food stays safe indefinitely — only its quality declines.
Use an appliance thermometer
Built-in dials show a setting, not a temperature. An inexpensive appliance thermometer is the only way to know what your food actually experiences. Place it in the warmest part of the refrigerator (often the door shelves or top shelf) and check it periodically — the Temperature Log tool keeps a private record on this device.
Where the cold spots are
The door is the warmest zone — poor for milk and eggs, fine for condiments. The back of the bottom shelf is coldest — right for raw meat (which also belongs at the bottom so it cannot drip on anything). Crisper drawers manage humidity, not temperature.
Common mistakes
- Packing the freezer vents shut, creating warm pockets.
- Cooling large pots of hot food in the refrigerator — divide into shallow containers first.
- Trusting the “5” on the dial instead of a thermometer.