Danger zone
The danger zone is the temperature range where bacteria grow fastest, 4 to 60°C (40 to 140°F) in USDA guidance. Keep food out of it as much as you can.
Also called Temperature danger zone.
The danger zone is the range of temperatures in which bacteria that cause food poisoning grow fastest. The USDA puts it at 4 to 60°C (40 to 140°F), and says bacteria in this range can double in number in as little as 20 minutes. Cold slows bacteria down and heat kills most of them, so the aim is to keep perishable food either cold or hot and to move it through the middle quickly.
UK guidance uses slightly different numbers. The Food Standards Agency advises keeping your fridge at 5°C (41°F) or below, and food businesses in England must keep chilled food at 8°C (46°F) or below and hot food at 63°C (145°F) or above.
How to use it
- Keep cold food cold: fridge at 5°C (41°F) or below, and 4°C (40°F) or below in USDA guidance. Check it with a fridge thermometer.
- Keep hot food hot: 60°C (140°F) or above in USDA guidance, 63°C (145°F) in UK rules for businesses.
- Follow the USDA 2-hour rule: do not leave perishable food out for more than 2 hours, or 1 hour when it is above 32°C (90°F).
- Cook food to a safe internal temperature, and reheat leftovers until steaming hot all the way through.
- Thaw food in the fridge, in cold water or in the microwave, not on the counter.
- Marinate in the fridge.
Common mistakes
- Leaving cooked food out overnight to cool. See cooling food safely for faster methods.
- Thinking reheating makes food safe again. Some bacteria make toxins that heat does not destroy.
- Partly cooking meat to finish later. The center sits in the danger zone, so cook it fully at once.
- Keeping a buffet out for hours. Set hot dishes on a warmer and cold dishes over ice, and replace them rather than topping them up.
- Leaving groceries in a warm car.
In recipes
When a recipe says to bring meat, eggs or butter to room temperature, it means a short time on the counter, usually 30 to 60 minutes, not hours. Steps such as "refrigerate until needed" or "keep warm in a low oven" are there to keep food out of the danger zone.
Related terms
- Cooling food safelyCooling food safely means getting hot leftovers cold fast so bacteria cannot grow. Split big batches, use shallow containers and chill within 2 hours.
- ReheatReheating leftovers safely means heating them until steaming hot all the way through, 74°C (165°F) in the center. Here is how to do it on each appliance.
- ThawThawing brings frozen food back above freezing safely, in the fridge, in cold water or in the microwave, and never on the kitchen counter.
- Internal temperatureInternal temperature is the heat at the center of food, read with a probe thermometer. It is the surest way to know meat, fish and bread are done and safe.
- ThermometerA kitchen thermometer checks the heat of meat, oil, sugar and your oven, so food is safe and cooked how you want. Here is which type to use and how.
- Room temperatureRoom temperature in recipes means about 20 to 22°C (68 to 72°F). Eggs, butter and dairy at that heat mix more smoothly and help cakes rise evenly.