How to Tell If Mushrooms Are Bad
Quick answer
Bad mushrooms are slimy, sticky, and dark, with a sour, fishy, or ammonia-like smell. Dry, wrinkled mushrooms with firm flesh are okay, but slime means toss them.
Signs Mushrooms have gone bad
- Slimy, sticky film. Run a finger over the cap. A slick film that doesn’t wipe away means bacteria have taken over. Toss them.
- Dark, wet spots. Dark brown or black wet patches on caps or gills are decay. A few dry dark spots can be wiped, but wet and spreading means discard.
- Sour, fishy, or ammonia smell. Fresh mushrooms smell earthy and mild. A strong sour, fishy, or chemical odor means they’ve turned.
- Mushy, collapsing caps. Firm mushrooms bounce back. If they feel spongy, squishy, or are caving in, they’re past use.
- Fuzzy mold. White fuzz that looks like cotton, as opposed to the mushroom’s natural texture, means mold. Discard the whole package.
- Pooled liquid in the package. Wet, soggy mushrooms in a sealed tray tend to spoil fast. If they’re also slimy or smell off, toss them.
Looks weird, but it's fine
- Dry, wrinkled caps. Mushrooms lose moisture. If they’re firm and smell fine, they’re okay to cook.
- Dark gills under the cap. Gills darken with age and sometimes drop spores. If the mushroom is still firm and not slimy, it’s usable, though a bit stronger in flavor.
- Light brown, dry spots. Small dry bruises that wipe or cut off are harmless.
How long do Mushrooms last?
| Where | How long | Note |
|---|---|---|
| Fridge | 5–7 days | whole, in a paper bag |
| Fridge | 3–4 days | sliced or cooked |
| Freezer | 10–12 months | cooked or sautéed |
How to store them
- Store mushrooms in a paper bag, not plastic, so moisture can escape and slime doesn’t form.
- Wipe them clean with a damp cloth right before cooking instead of washing ahead.
- Sauté extras and freeze them in portions, since raw mushrooms freeze poorly.
Use it up before it turns
Frequently asked questions
Can you eat slimy mushrooms?
No. Slime means bacterial growth. Discard them, since cooking won’t make them safe.
Can you eat mushrooms that are dark or wrinkled?
If they’re firm, dry, and smell normal, yes. Darkening gills and wrinkling are age signs. If they’re wet or smell off, toss them.
Is it safe to cut mold off mushrooms?
No. Mushrooms are soft and porous, so mold can spread beyond what you see. Throw out the batch if there’s fuzzy mold.
More food freshness guides
General guidance based on USDA FoodKeeper. Storage times are estimates and conditions vary. When in doubt, throw it out.