How to reheat leftovers to a safe temperature
USDA FSIS guidance says to heat leftovers to 165°F (73.9°C) all the way through, checked with a food thermometer rather than guessed by sight or time. UK guidance (Food Standards Agency / GOV.UK) puts it as "steaming hot throughout" rather than a specific number, and adds a rule worth keeping regardless of which country's guidance you follow: only reheat a dish once. If you're reheating a large batch, stir partway through and check the coldest-looking spot, usually the centre, since that's what's most likely to fall short of 165°F.
165°F (73.9°C) all the way through, checked with a thermometer, and only reheat once.
Why 165°F specifically
165°F (73.9°C) is the same target USDA FSIS uses for cooking poultry from raw — it's the point at which the bacteria that could have grown during storage (see how long leftovers last in the fridge) are reliably killed. Reheating to "warm" or "hot to the touch" doesn't guarantee the same result, because surface heat and centre heat aren't the same thing, especially in a microwave or a thick casserole.
How to check it, by method
| Method | How to reheat | How to check |
|---|---|---|
| Stovetop | Bring to a simmer, stirring occasionally | Thermometer in the thickest part |
| Oven | 325°F (163°C) or higher, covered to retain moisture | Thermometer in the centre |
| Microwave | Cover, stir halfway, let stand 1 minute | Thermometer after standing time |
| Rice specifically | Reheat until steaming hot; don't reheat more than once | See our rice storage guide |
Edge cases
- Sauces and gravies. These reach temperature fast but can scorch on high heat — a gentle simmer with regular stirring gets there without burning the bottom.
- Reheating from frozen. Fully thaw first where possible; if reheating straight from frozen, it will take noticeably longer to reach 165°F throughout and the outside can overcook before the centre catches up.
- Buffet or party reheating. If you're reheating to serve immediately and keep it out for a while afterward, the danger zone rule still applies once it's back below 140°F — 2 hours out, 1 hour if it's a hot room.
- A casserole with a crust or topping. The top can look done well before the centre reaches 165°F, especially if it went in cold from the fridge. Check the middle specifically, not just the browned surface, and cover loosely with foil if the top is colouring faster than the inside is heating.
How GetLadle handles this
Cook Mode's step timers work for any step in a recipe, including a reheating step you've added to a saved dish — set the time, get a countdown, and move to the next step without losing your place. It doesn't measure temperature for you; the thermometer check above is still the part that confirms food safety, not the timer.
Sources
Numbers on this page come from USDA FSIS's Kitchen Companion handbook and the UK Government's chilling and freezing guidance, both fetched and checked in September 2026 (see the sources list above).
Frequently asked questions
Can I reheat leftovers in the microwave and hit 165°F?
Yes, but microwaves heat unevenly, so stir the dish partway through and let it stand a minute before checking the centre with a thermometer. USDA FSIS guidance treats microwave reheating the same as any other method: the food needs to reach 165°F (73.9°C), not just feel hot on the surface.
Do I need a thermometer every time?
USDA FSIS's own guidance is to use one — sight and smell don't reliably tell you the internal temperature. If you genuinely don't own a food thermometer, the UK's "steaming hot all the way through, with visible steam" is a reasonable fallback, though it's less precise.
Can I reheat a dish twice if I only eat half of it?
GOV.UK guidance says no — once a dish has been reheated, don't reheat what's left a second time. Split it into individual portions before the first reheat so you're only heating what you'll actually eat.
Related
- How Long Do Leftovers Last in the Fridge?
- How Long Can You Freeze Cooked Meals For?
- How Long Does Cooked Rice Keep in the Fridge?
- Why Step-by-Step Guided Cooking Beats Scrolling a Recipe on Your Phone
- GetLadle Answer Hub
Sources
- USDA FSIS: Kitchen Companion — Your Safe Food Handbook
- GOV.UK / Food Standards Agency: How to chill, freeze and defrost food safely
Last reviewed 2026-09-15 · GetLadle