3 Things to Know About Discolored Tuna

Grayish-brown tuna is safe to eat That discoloration is just oxidation or bruising, not spoilage. Fresh tuna gets its red color from myoglobin, which turns brown when exposed to air, like a cut apple.

Use your nose, not your eyes, to check freshness If the tuna doesn’t smell sour, ammonia-like, or off, and the texture is firm and moist, it’s fine. If it smells like low tide or feels slimy, toss it.

Color alone is an unreliable freshness test for tuna The tuna was likely cut hours earlier or resting against something in the package. Trust your sense of smell over appearance.