How to Tell If Food Has Gone Bad
- 2 cited USDA/FDA/FSIS sources
- Reviewed 2026-06-26 by FoodLasts Editorial Team
Spoilage is not always obvious, but most foods give sensory clues before they become dangerous. Use look, smell, and touch together — and know which pathogens give no warning at all.
Smell
Sour, putrid, ammonia-like, or “off” odors on meat, dairy, and seafood are strong discard signals. However, Salmonella and other pathogens do not always change how chicken smells — never use smell alone for raw poultry.
Texture and appearance
- Slime on meat or fish — discard.
- Mold on soft foods (berries, bread, soft cheese) — discard the item; do not trim and eat.
- Discoloration — gray-green patches on meat, pink slime on lunch meat, or dull, mushy produce.
- Curdled or lumpy milk and separated, watery yogurt.
When sensory checks fail
Cooked food left in the danger zone (40°F–140°F) for more than 2 hours should be discarded even if it looks fine. Bacteria such as Staphylococcus aureus can produce toxins that reheating does not destroy.
Use our food pages
Every FoodLasts food page lists spoilage signs specific to that food, plus fridge, freezer, and pantry times tied to the cited sources shown on that page.
Related on FoodLasts
Guides: Mold on produce · Date labels explained
Was this helpful?
Thanks — your feedback helps us improve.
Sources: FoodSafety.gov — Keep Food Safe , USDA FSIS — Danger Zone (40°F – 140°F) . Last reviewed 2026-06-26 by the FoodLasts Editorial Team.