How To Tell If Raw Tuna Has Gone Bad

Proper cooking begins with the selection of ingredients: You want food that is clean, as fresh as possible, and definitely not rotten. Tuna and most fish are very healthy components of a complete diet. Full of vitamin B-12, omega-3 fatty acids, and vitamin D, via WebMD, tuna should be a part of every health bound diet. But before you go running to your nearest sushi restaurant, there are some things you should know.

Fortunately, discerning whether or not a piece of tuna is spoiled is not overly difficult. Usually, all it takes is a thorough visual check. The first and simplest step is to inspect the sell by date or the expiration date. If you've gone through these, perhaps it's time to order takeout. According to Lacademie, raw tuna that has spoiled will appear off-colored, usually with a milky look or with shades of brown. Meanwhile, healthy raw tuna is a deep red or a light pink color.

If your fish has started to change color or you see some sort of growth (like mold) toss that fish in the trash.

Other signs your raw tuna has expired

In addition to the less-than-appetizing rainbow of colors, raw tuna that has gone bad will develop a slimy film that is as unsavory as it is dangerous to eat (via Lacademie). If you see this slime on your raw tuna, discard the fish immediately. Perhaps the most egregiously noticeable trait of raw tuna gone bad though — even more offensive to the senses than green shades or slimy textures — is the smell. Fishy smells are not typically overly welcome, but when the fish has expired, the smell is singularly horrendous and notoriously difficult to get rid of, per Still Tasty. The smell of bad tuna has been described as sour, and can ruin any kitchen with its stench.

Food poisoning from rotten fish is particularly nasty, with symptoms including fever and vomiting, so whenever preparing and eating raw tuna, remember to look closely for the signs of spoilage. Tuna is incredibly nutritious and definitely should be included in your diet, but tread carefully when choosing which fish to eat and which to wrap and throw away.