How to Tell If Tuna Is Bad
Quick answer
Opened canned tuna that smells sour or sharply fishy, looks slimy, or has an off color should be tossed. Transfer leftovers to a sealed container and use within 3 to 4 days.
When in doubt, throw it out. Bacteria that cause food poisoning often don't change the smell or look. Go by the time limits below too.
Signs Tuna has gone bad
- Sour or sharp fishy smell. Canned tuna smells fishy by nature, but a sour, rancid, or ammonia-like odor beyond the usual means it has spoiled.
- Slimy or sticky texture. Fresh-opened tuna is moist and flaky. A slick, tacky film on the flesh signals bacterial growth.
- Off color. Pink to light tan is normal. Green, gray-green, or very dark patches in opened tuna point to spoilage.
- Fuzzy or colorful mold. Any fuzzy spots, even small ones, mean the whole container should go. Tuna is too moist and soft to cut around.
- Bulging, leaking, or deeply dented can. Before you even open it, toss any can that is bulging, leaking, rusted through, or has a sharp dent along a seam. A swollen can can signal dangerous bacterial growth.
Looks weird, but it's fine
- Dark patches in the meat. Darker brownish tuna is just the bloodline or dark muscle. It tastes stronger but isn't spoiled.
- Small, hard crystals. Tiny glass-like crystals can form in canned tuna; they're struvite, a harmless mineral compound that dissolves in stomach acid.
- Cloudy packing liquid. Cooking juices from the fish can make the liquid look cloudy. That's normal in a fresh can, but check smell and color too.
How long does Tuna last?
| Where | How long | Note |
|---|---|---|
| Pantry (unopened can) | 3 to 5 years | Best quality; check can for damage |
| Fridge (opened) | 3 to 4 days | Move to a sealed glass or plastic container |
| Fridge (tuna salad) | 3 to 5 days | Keep at 40°F or below |
| Counter | Max 2 hours | 1 hour at 90°F or above |
How to store it
- Never store opened tuna in the can. Move it to an airtight container so it doesn't pick up metallic taste.
- Write the date you opened it on the lid so you remember the 3 to 4 day window.
- Keep tuna salad cold, especially at picnics or lunches, and toss it after 2 hours out of the fridge.
Use it up before it turns
Frequently asked questions
How long does opened canned tuna last?
Up to 3 to 4 days in the fridge in a sealed container. After that, toss it even if it still smells fine.
Is it safe to eat tuna past the best-by date?
Unopened, undamaged canned tuna is often fine past its date, since the date is about quality. Check the can for dents, bulges, or leaks, and trust your nose when you open it.
Why does my canned tuna taste metallic?
Storing it in the opened can can give a metallic taste. It's usually a quality problem, but if there's also a sour smell or odd texture, throw it out.
More food freshness guides
General guidance based on USDA FoodKeeper. Storage times are estimates and conditions vary. When in doubt, throw it out.