FAQ
Four rules that sit underneath most pages on this site. The numbers live on each food page; these answers explain when to discard — not when something is “probably fine.”
What is the two-hour rule?
Perishable food must not sit in the danger zone (40°F–140°F) for more than 2 hours total — 1 hour if the air is above 90°F (hot car, summer picnic). The clock is cumulative across the life of the food, not reset each time you put it away. Miss the clock and discard it. Reheating does not reverse a missed clock; some toxins survive cooking.
Full explanation: the danger zone and the picnic and buffet clock. Examples: leftovers, cooked rice, raw chicken.
Does reheating leftovers reset the clock?
No. Reheat leftovers to 165°F (sauces, soups, and gravies to a rolling boil) so they are safe to eat now. That does not restart the refrigerated storage window. The 3–4 day fridge rule for leftovers runs from when the food was cooked and chilled on time — regardless of how many times you warm a portion. Food left out too long before it ever reached the fridge cannot be rescued by cooking it harder.
Guide: leftovers and the 165°F reheat rule. Food pages: leftovers, soup, pizza.
Fridge = safety, freezer = quality?
Yes — that is how the charts on this site are meant to be read. Refrigerator windows are safety windows from FoodSafety.gov and USDA FSIS. Past them, discard it, even if it still looks fine. Freezer times are quality windows: food held at 0°F stays safe for food- safety purposes longer, but texture and flavor fade after the months we list. Freezing does not fix food that already sat out too long or spent too many days in the fridge.
Related: fridge temperature, storage mistakes, and the full food catalog.
Can I taste it to check?
No. Discard it — do not taste food to check whether it is still good. Spoilage organisms that make food smell sour are largely not the same ones that make you ill. Pathogens can leave food looking and smelling normal. Smell and taste are not a safety test. When a food is past its window, when the two-hour rule was missed, or when you are unsure how it was handled: discard it.
USDA’s line is the same one we end on: when in doubt, throw it out. See the danger zone and how we source guidance.
Where else to look
Browse by food in the catalog, or by category from the home page. For the rules behind the numbers, start with the guides.
Sources
These answers summarize pages already on this site. Primary federal citations used there:
- USDA FSIS: "Danger Zone" (40°F–140°F) (USDA FSIS)
- USDA FSIS: Leftovers and Food Safety (USDA FSIS)
- FoodSafety.gov Cold Food Storage Chart (FoodSafety.gov)
- USDA FSIS: Keep Food Safe! Food Safety Basics (USDA FSIS)
- CDC: Four Steps to Food Safety (CDC)
- FDA: Refrigerator Thermometers — Cold Facts about Food Safety (FDA)