How to Store Leftovers Safely and Know How Long They Keep

This guide is for anyone who has stood at the open fridge wondering whether last Tuesday's curry is still safe. You will learn how to cool food quickly, store it at the right temperature, judge cautious keeping times for common leftovers, freeze and thaw safely, and reheat properly. Food-safety rules differ between countries and are updated over time, so treat the times here as cautious general guides and check your national food-safety agency for the official advice. General information, not professional advice.

Why leftovers go wrong

Most food poisoning from leftovers is not caused by food that looks or smells bad. It is caused by bacteria that grow quietly while food sits at the wrong temperature, or that produce toxins which reheating does not destroy. That is why the nose test is not a safety test.

Bacteria multiply fastest in the range food-safety agencies often call the danger zone, roughly between 5 C and 60 C (about 40 F to 140 F). Exact figures vary slightly by country. Cold slows bacteria down, freezing stops them growing, and thorough cooking kills most of them. Leftover safety is mostly about keeping food out of the danger zone as much as possible.

• Time: the longer food spends warm, the more bacteria can grow.
• Temperature: a fridge that is not cold enough lets bacteria keep multiplying.
• Cross-contamination: raw meat juices dripping onto cooked food can spread bacteria.
• Repeated reheating: each warm-up and cool-down gives bacteria another chance to grow.

People at higher risk from food poisoning, including pregnant people, young children, older adults and anyone with a weakened immune system, should be especially cautious and follow the stricter advice from their health service.

To find the official rules where you live, search for the name of your country plus "food safety leftovers" and look for a government food-safety agency or national health service website. Note its recommended fridge temperature and keeping times on the worksheet at the back of this guide.

Cool food quickly

Cooling is the step most people get wrong. A big pot of stew left on the hob overnight to cool spends hours in the danger zone. Many food-safety agencies advise getting cooked food into the fridge within about two hours, and within one hour in hot weather. Some advise even faster for certain foods, such as rice. Check your local guidance.

1. Divide it up Split large quantities into smaller portions. A big, deep pot holds its heat for a long time.
2. Use shallow containers Spread food into shallow containers, a few centimetres deep, so heat can escape quickly.
3. Let steam escape briefly Leave lids slightly open or off for a few minutes so steam can escape, then cover once the food has stopped steaming heavily.
4. Speed it up if needed For soups and stews, stand the pot in a sink of cold water or ice and stir. Cut large joints of meat into smaller pieces.
5. Into the fridge promptly Do not wait for food to reach room temperature. Modern fridges can cope with warm, not piping hot, food in small containers; leave some space around them for air to circulate.