Primrose Fristoun, a leading microbiologist at the University of Leicester (UK), warns that even refrigerated leftovers can still make you sick.
“Food poisoning happens when you eat food contaminated with pathogenic bacteria, fungi, or viruses,” the expert wrote for The Conversation.
Most people know food poisoning can come from undercooked meals or spoiled ingredients. But few talk about the fact that storing food too long in the fridge can also cause illness.
How long is leftover pizza safe in the fridge
“Dried herbs and spices often sprinkled on pizza — like basil, pepper, and oregano — are prone to microbial contamination. That contamination can happen during harvest and production,” Fristoun says.
Pathogens that can survive on dried herbs include bacteria that cause food poisoning, such as Salmonella, Bacillus cereus, and Clostridium perfringens, Fristoun says.
She says if you leave pizza uneaten, put it in the refrigerator within two hours of delivery.
“If you leave pizza at room temperature for more than a couple of hours, microbes will multiply quickly. The pizza will be unsafe to eat the next day — no matter how it looks or smells,” Fristoun warns.
Also, to prevent airborne germs from spreading, cover the pizza before putting it in the fridge. Eat it within two days. Common storage mistakes often cause food to spoil faster.
How long does cooked chicken last in the fridge
Cooked chicken spoils quickly after cooling because it has a high water content, plenty of nutrients, and low acidity.
“After you take cooked chicken out of the oven or grill packaging, cover any portion you won’t eat right away and refrigerate it as soon as it cools,” the microbiologist says. Ideally, cooked chicken should sit at room temperature no more than two hours and can be stored in the fridge for up to three days.
But if you notice blood on the poultry, do not eat it — not cold and not reheated. Fristoun says that indicates the dish was undercooked and may be contaminated.
How long do rice dishes last in the fridge
Rice dishes can also be dangerous if left too long in the fridge. Raw rice can contain spores of Bacillus cereus, a common bacterium that lives in starchy foods and causes food poisoning.
While cooking kills the bacterial cells, their spores are heat-resistant and can survive. If cooked rice sits at room temperature for more than two hours, those spores can turn into active bacteria and start multiplying. The spores can also produce toxins in cooked rice, and that can cause severe poisoning.
Cover leftover rice dishes and put them in the fridge. Eat them within 24 hours.
How long to keep opened canned goods in the fridge
You can store opened canned goods in their original can, but cover them with a lid and keep them in the fridge to avoid airborne contamination.
How long opened canned foods are safe to eat depends on their contents. Canned tomatoes and other high-acid products keep for five to seven days because the acid suppresses bacterial growth.
Low-acid canned foods — such as meat, fish, fruit, vegetables, and pasta — should be kept no more than three days.
“You can safely eat leftovers cold. Just refrigerate them as quickly as possible and eat them within one to two days,” Fristoun emphasized.
So, to sum up: how long can you keep leftovers?
| Food | Storage time in the fridge |
| Pizza | 2 days |
| Chicken | 3 days |
| Rice dishes | 1 day |
| High‑acid canned goods | 5–7 days |
| Low‑acid canned goods | 3 days |
Tips for storing leftovers safely
Cover leftovers before placing them in the fridge.
Don’t leave food at room temperature for more than 2 hours.
Reheat leftovers only once.
Follow these storage times:
- Pizza – 2 days
- Chicken – 3 days
- Rice dishes – 1 day
- High‑acid canned goods – 5–7 days
- Low‑acid canned goods – 3 days
Check leftovers before eating — follow the time limits rather than relying on smell or appearance.
Use separate containers for different foods to avoid cross-contamination.
Frequently asked questions about fridge storage times and conditions
How should you cool food before putting it in the fridge?
Divide food into portions and move it to the fridge within two hours of cooking to prevent bacterial growth.
What should the fridge temperature be for safe storage? Keep the fridge at about +4°C (39°F) or lower to slow microbial growth.
How quickly should food cool so it’s safe to refrigerate?
Break a large dish, like soup or stew, into smaller portions and cool it faster so it reaches a safe temperature sooner.
Can you put hot food straight into the fridge?
Yes. Placing hot food in the fridge speeds cooling and reduces the time it spends in the temperature “danger zone” where bacteria multiply faster.
How long can most leftovers be kept in the fridge?
As a general guideline, most leftovers are safe for 3–4 days, after which you should eat them or throw them out.
What signs show that leftovers are no longer safe to eat?
Food that has changed color, developed an off smell, or has an altered texture is usually unsafe regardless of how long it was stored.
Should you freeze food if you don’t plan to eat it within a few days?
Yes. Freezing stops the growth of most bacteria and lets dishes keep much longer, but after thawing eat them within a few days.
What can you do so food lasts longer and stays safer in the fridge?
Use airtight containers, divide large portions into smaller ones, label items with dates, and clean the fridge regularly.
