Pizza Left Out Overnight: Is It Safe?
Written by Jordan Morley · Reviewed against FSA chilling & danger-zone guidance · Last updated 28 October 2026
No — pizza left out overnight should be thrown away. The cheese and meat toppings make it a perishable food, whatever late-night tradition says.
Why overnight is too long
In the fridge, pizza keeps up to 2 days (FSA and NHS advice) — on the counter, the limit is 2 hours. Food kept between about 8°C and 63°C is in the range where bacteria can multiply; overnight is 6–8+ hours in it. Cooling quickly and keeping food cold is what the UK agencies stress, not reheating food that sat out, so reheating pizza in the morning is not a reliable fix. It may look and smell completely normal; bin it anyway.
You can also check the calorie content of pizza alongside its safety information.
The official advice says bin it. One expert says it's fine. Here is how we decide
This is one of the few food-safety questions where credible people disagree, so rather than repeat '2 hours' we will lay it out:
| Who | What they say | Basis |
|---|---|---|
| USDA / FoodSafety.gov chart | 'Pizza with any topping': discard if held above 40°F for more than 2 hours | Rule-based, applied to all pizza |
| Cleveland Clinic | Don't leave pizza out overnight; 2 hours, or 1 hour in hot weather | USDA guidance; toppings don't change the rule, and vegan cheese counts as perishable too |
| Don Schaffner, food microbiologist at Rutgers University (interviewed on New Hampshire Public Radio's Outside/In, 17 July 2026) | 'I'm going to say it's not risky to leave it on the counter overnight' | Component-by-component reasoning plus about two decades of Rutgers dining-hall data; he also says a 'perfect storm' could still cause food poisoning. The study was not identified by title on the page, and dining halls are not home kitchens |
Why the expert's view isn't crazy, and why we still say bin it
Schaffner's argument, as reported by NHPR, is that pizza's parts are each fairly hostile to bacteria:
| Part of the pizza | Reasoning reported | Catch |
|---|---|---|
| Crust | Essentially bread | Fine on its own |
| Tomato sauce | Acidic, which slows bacterial growth | Slows growth; it does not make the pizza safe on its own |
| Cheese | Slightly acidic with low water activity | Soft, melted cheese sits on the USDA's discard list |
| Baking | Kills most bacteria | Some spore-forming bacteria survive cooking |
| Cured pepperoni | Typically shelf-stable | Other meats are not |
| Beef or other meat toppings | A concern: spore-formers can survive baking | The most likely source of trouble |
| Vegetables | Higher moisture but few spore-formers | Depends on the vegetable |
We still say bin it, for three reasons. The published rule is 2 hours and nobody has a regulator figure for overnight. The study NHPR describes is reported to have found about 8 hours safe, and a night out is commonly 8 to 12 hours, so it sits at or beyond that edge, in a home kitchen rather than a dining hall. And the people most harmed by a bad night, such as pregnant people, young children, older people and anyone with a weakened immune system, are exactly those a rule is written for. If you are a healthy adult and the pizza was plain, you are taking a small risk that official advice tells you not to take; if it had meat or you are in a higher-risk group, don't.
Next time: how to keep leftover pizza
| Step | UK guidance | US guidance |
|---|---|---|
| Get it in the fridge | Cool, then refrigerate within 1 to 2 hours (Food Standards Agency) | Within 2 hours; 1 hour above 90°F (USDA) |
| How long it keeps | Eat within 48 hours or freeze (Food Standards Agency) | 3 to 4 days (USDA FSIS; Cleveland Clinic) |
| Reheat | Steaming hot throughout, once only | To 165°F (74°C) |
We use the stricter UK 48 hours on this site. For takeaway pizza, the 2 hours starts when it arrives or comes out of the oven, not when you open the box.
Sources checked
Everything in the sections above was checked against these pages on 28 October 2026.
- USDA FSIS: Keeping Food Safe During an Emergency (refrigerated foods chart) — 'Pizza with any topping' discard after more than 2 hours above 40°F
- Cleveland Clinic: Is it safe to leave pizza out overnight? — 2 hours, 1 hour in heat; toppings and vegan cheese don't change the rule; 3 to 4 days in the fridge
- NHPR / Outside/In (17 July 2026): Is leaving pizza out overnight risky? — Don Schaffner (Rutgers): not risky overnight; component reasoning; caveats
- Food Standards Agency: How to chill, freeze and defrost food safely — cool then refrigerate within 1 to 2 hours; eat within 48 hours or freeze
- USDA FSIS: Leftovers and Food Safety — 2 hours, 1 hour above 90°F; 3 to 4 days; reheat to 165°F
Pizza left out: how long is too long?
| Time out | Verdict | What to do |
|---|---|---|
| Under 2 hours | Fine | Chill promptly; eat within 2 days (FSA/NHS; USDA allows 3–4) |
| 2–4 hours | Risky; most guidance says bin it | Cooler rooms don't change the 2-hour rule |
| Overnight (6+ hours) | Throw away | Bacterial toxins aren't destroyed by reheating |
| In a hot car or room over 32°C | 1 hour | The rule halves in heat |
Cheese-only pizza counts. A slice with meat, egg or seafood topping is riskier still.
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Pizza: the other answers on this site
| Question | Short answer (links to the full page) |
|---|---|
| In pregnancy | Safe |
| In the fridge | Up to 2 days in the fridge |
| In the freezer | Yes — freezes well (best quality for 1–2 months) |
| Reheating | Yes — if stored properly |
Common questions
Can I reheat pizza that was left out overnight to make it safe?
No. Reheating cannot be relied on to make food that sat out overnight safe, because bacteria that multiplied overnight may have left toxins behind that heat does not reliably remove (Healthline makes this point for Bacillus cereus in rice). Our advice is to bin it.
It looks and smells fine — is it really unsafe?
Unfortunately the bacteria that cause food poisoning don't usually change how food looks, smells or tastes. 'It seems fine' is not a safety test.
What if it was only out for a few hours?
The widely used cautious rule is a maximum of 2 hours at room temperature (1 hour above about 32°C), and NHS and FSA advice is to cool and chill leftovers within 1–2 hours. Past that, bacteria may have multiplied to risky numbers and some make toxins that cooking will not destroy, so 'only 3 hours' is not a safe bet.
Does cheese-only pizza count?
Yes. The melted cheese makes it a perishable dairy food, and the tomato sauce does not make it acidic enough to stop bacterial growth. Meat toppings make it riskier still.
How long does pizza last if it IS stored properly?
In the fridge at 0–5°C, pizza lasts Up to 2 days (FSA and NHS advice) — as long as it goes in within 2 hours of cooking or serving. NHS and FSA advice for cooked leftovers is to eat them within 2 days. On the counter the limit is 2 hours; that gap is the whole point of the rule.
Why do some sites say it's fine to eat pizza left out overnight?
Because a food microbiologist at Rutgers University, Don Schaffner, told NHPR in July 2026 that it is not risky, reasoning from pizza's ingredients and decades of dining-hall data. Official guidance (the USDA's chart) still says to discard pizza with any topping after 2 hours. We follow the official advice and especially for anyone in a higher-risk group.
Is cheese pizza safer than meat pizza overnight?
Slightly, in theory: Schaffner singled out beef and other meat toppings as the concern, because some spore-forming bacteria survive baking. But the USDA does not distinguish toppings, and Cleveland Clinic says plain cheese, veggie and meat pizzas all need refrigerating.
How long does leftover pizza last in the fridge?
Eat it within 2 days (UK Food Standards Agency: within 48 hours or freeze it); the US figure is 3 to 4 days. The clock starts when the pizza was cooked, not when you open the box.
Related answers
Primary source: FSA chilling & danger-zone guidance.
General information only, not medical advice: see the medical disclaimer. Feeling unwell after eating something? Contact NHS 111 or your GP.