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How to Tell if Tuna Steak is Bad [Definitive Guide]

Tuna, whether it’s Bluefin, Yellowfin, Bigeye or Albacore, is delicious in a range of dishes and cuisines from around the world.

But, unless you’re catching it fresh from the deep-blue, do you know how to tell if your tuna steak is bad? Read on to find out, and avoid spoiled tuna.

How to Tell if Tuna Steak is Bad

When purchasing your whole tuna, tuna steak, or prepared fillets, there are a few key signs you can use to judge the freshness of the fish. Ideally, you want the fish to meet all of these standards:

Appearance

Ideally, no matter which type of tuna steak you’re buying, it should all be a deep red through to pinky colour, and clear eyes if the fish is whole.

Whether you’re choosing a cut from the whole fish or a prepared steak, look for that sign of freshness: as close to ruby-red colour.

Smell

‘Fresh from the sea’ is a nice selling term, but in reality that actually ‘smells’ like saltwater. The fish should not smell ‘fishy’ at all; a faint aroma is fine, but nothing more.

Fish that smells overly fishy is old, and the proteins within the muscles etc have begun to break down or go bad.

Texture

As with any fresh fish, there should be firmness across the whole fish, you can test this by pressing your finger into the side of the fish. If the indent disappears, the fish is fresh. If the indent remains, the fish is older, and should not be bought.

Taste

Whilst raw fish is not to everyone’s tastes, tuna makes an ideal option for sashimi, ceviche or carpaccio, as its texture is quite meaty, and holds its moisture well, without being smelly or tasting overly fishy.

Bad tuna steak on the other hand will be the opposite; it will smell and taste extremely fishy, and the flakes will be verging on mushy. It is unwise to eat tuna in this condition, as it can lead to illness.

Mould

At no time should you see anything resembling mould on your tuna. Do not purchase or consume fresh tuna that has milky-white fluid pooling around it, or unidentified blemishes on the skin. The fish is old, or damaged, and has become spoiled.

How to Tell if Tuna Steak is Bad when Cooked

So you’ve bought your tuna steaks, brought them home, cooked them but can’t manage to eat it all. Leftovers are a great treat, but how do you know if that cooked tuna steak has gone bad?

Appearance

Once cooked, tuna should look more like cooked chicken on the outside, with a tender pink inside – tuna is often cooked right through, and served overcooked.

Unfortunately, whilst this may allay some people’s fears, this overcooking also ruins the flavour and texture of the tuna.

The tuna should have a warm internal temperature but primarily seared on the outside to a quarter of the steak’s depth (much like you would a beefsteak).

Smell

This is the quickest identifier that the tuna has gone bad; the smell is usually a nose-turning sour, like rotten lemon juice. If the tuna is hot, this smell should be noticeable immediately.

However, if the tuna is served cooked, but cold, this aroma may be dulled, but still discernable when carefully sniffed.

Texture

Whilst fresh tuna should have a firm texture, holding its shape, cooked tuna can vary depending on the cooking process; seared steaks versus canning.

A tuna steak should be firm to the touch, like a regular beefsteak, and have a meaty consistency when chewed. If your tuna steak disintegrates when cut into, this is a sign that the steak is spoiled.

Canned tuna, however, will easily flake apart, and is better suited to sandwich fillings and the like.

Taste

Your tuna steak should taste clean, fresh, and faintly fishy, like tuna. There should be a hint of salty seawater, and the overall mouth-feel should be clean.

However, if the tuna steak tastes sour, mushy, or oily, it has most likely spoiled, and should be discarded immediately – do not swallow, as consuming spoiled tuna can lead to illness.

Mould

This should be apparent, if ANY mould is visible, the tuna steak has spoiled and should be discarded immediately. Equally, any milky-white or other liquids seeping from the cooked fish are signs that the tuna has spoiled.

Note: during cooking, juices do escape, the above refers to tuna that has been cooked, cooled, and stored and the liquids appearing afterwards.

How Long Does Tuna Steak Last

How long your tuna steak will last depends on if it is raw or cooked, the time limits vary from 1-2 days, 3-4 days, or even longer all depending on how you store your tuna steak.

How Long Does Tuna Steak Last in the Fridge

Where possible, tuna should be kept at the back of the fridge, and as low as possible, where the temperature is more stable, and less likely to be affected by temperature fluctuations due to the door being opened/closed.

How Long Does Tuna Steak Last Raw

As a raw tuna steak, it should keep for 1-2 days, beyond that you can expect it to begin to spoil, if not outright go bad. Do carefully check ‘Use By’ or ‘Best Before’ dates, and ideally, you should purchase and consume tuna steak within 24hours.

How Long Does Tuna Steak Last When Cooked

Once cooked, your tuna steak should last for 3-4 days if placed in an airtight container and kept in a similar place to where you’d store it raw. If approaching the 4-day mark, do carefully check the steak before consuming.

How Long Does Tuna Steak Last in the Freezer

Tuna steaks will normally keep for 2-3 months at -0˚C/-32˚F, provided that the tuna is fresh when frozen, and is packed carefully. Fish placed directly on ice is likely to be affected by ‘freezer burn’, and this will cause the tuna to spoil. See below for how to store your tuna steak.

How Long Does Tuna Steak Last on the Countertop

This is the worst place to store your tuna steaks, and tuna that’s left out for over 2 hours should be discarded immediately. You can safely leave your tuna steak out to come to room temperature before cooking, as this generally only takes 10-20 minutes depending on thickness.

How to Store Tuna Steak

As mentioned, ideally you’ll be able to purchase and eat your tuna steak on the same day. But, that’s not always possible, so how should you store your tuna steak to keep it in the best condition.

How to Store Tuna Steak in the Fridge

This is where most people will keep their tuna steak. After purchasing it from either a supermarket or fishmonger, freshly cut or in prepared fillets and steaks with a ‘Use By’ date stamped on a label.

To get the maximum amount of time before consuming your tuna steak, keep your steak in an airtight container, or tight wrappings, at the back and bottom of your fridge.

Kept here, the temperature is more stable, and less likely to be affected by the door opening/closing. It’s also important to keep as much air as possible away/off the steak, as this will promote oxidisation and cause the steak to spoil.

How to Store Tuna Steak in the Freezer

If purchasing to freeze, it’s worth taking a little extra time to fully prepare and package the tuna steaks, fillets or whole fish, to protect it from the freezing temperatures.

Fish that is not correctly prepared can be affected by freezer burn, and this will cause the fish to spoil whilst still being kept in the freezer.

To prevent this, wrap the tuna steaks in layers of greaseproof paper, 2 or 3 times, and place in either vacuum-sealed bags, or thick plastic bags, and remove as much air as possible.

Place the prepared fish deep into your freezer, where the steaks won’t be affected by invading warm air when the freezer is opened.

How to Store Tuna Steak on the Countertop

In an ideal world, you won’t be keeping your tuna steaks on the countertop for any longer than absolutely necessary. Any fish that has been left out for 2 hours, or longer, should be considered unsafe to eat and discarded.

However, to marinate your steaks, or to serve it raw in sashimi, ceviche, or carpaccio, the tuna steaks should be just below room temperature, approximately 15˚C/59˚F.

This warmer than fridge temperature will showcase the flavour better, as well as make the tuna more able to accept marinades or infusions of flavour.

To Sum Up

There’s little better than a fresh tuna steak, but knowing how to tell if it’s fresh is key.

If you can’t eat it right away, then storing your tuna steak safely for 1-2 days, to maximise its shelf life, is an important factor. For long-term storage, keeping your tuna in the freezer is the best idea, but not for more than 3 months. 

Most of all, it’s important to remember not to leave your tuna steaks out on the countertop for a long time before cooking them, and definitely not over 2 hours!

Enjoy your tuna steak fresh for the best experience.