How long can food be left out?

Bacteria multiply fastest between roughly 8°C and 63°C — the range food passes through on its way from the oven to the fridge. The clock is cumulative across the day, which is the part most often missed: an hour on the counter before dinner and another after counts as two.

Safety

Step by step

1. Know the two-hour limit.Perishable food should not spend more than two hours in total between about 8°C and 63°C. Above roughly 32°C — a hot day or a warm kitchen — that halves to one hour.
2. Count the time cumulatively.Time on the counter before serving, time on the table, and time waiting to be put away all add up. It does not reset when you move the dish.
3. Cool leftovers quickly rather than slowly.Divide into shallow containers, and get them into the fridge within two hours. A large pot left to cool on the hob can sit in the danger zone for hours.
4. Be strictest with the highest-risk foods.Cooked rice, cooked meat and poultry, fish, dairy, egg dishes, cooked pasta, gravies and anything with a sauce. Cooked rice in particular.
5. Keep hot food hot if it is waiting.Above 63°C. A low oven or a slow cooker on warm. Lukewarm is the worst of all options.
6. Do not rely on your senses.The bacteria that cause food poisoning generally do not produce off smells or tastes. Food that smells fine can still make you ill.
7. Throw it out if it has been out too long.Refrigerating it afterwards does not undo the growth, and reheating does not destroy every toxin. The cost of the food is not the thing to weigh here.

Tips

• Cooked rice is the strictest case. The spores survive cooking and produce toxin at room temperature, so cool it fast and refrigerate within an hour where you can.
• At a buffet or a party, put out small amounts and replenish rather than leaving everything out for the duration.
• Shallow containers cool food far faster than deep ones. Depth matters more than the fridge setting.

Common mistakes

• Leaving a pot to cool fully on the hob — A large volume takes hours to pass through the danger zone. Divide it up and refrigerate within two hours.
• Smelling food to decide whether it is safe — The organisms that cause food poisoning generally leave no smell. Spoilage and safety are different things.

Questions people ask