How to Tell If Canned Tuna is Bad

Bad Canned Tuna

Most people have canned tuna stacked in their pantries. This is because canned foods are easy to work with. However, canned tuna can quickly poison you if you eat it when it is spoilt. It is important to check and see if your canned tuna is not decayed before you can serve it, otherwise you might get ill from sea food poisoning.


Canned tuna

Tuna is a sleek fish popular in the United States of America. Canned tuna is the steak of that sleek and streamlined fish, frozen, stored in cans with water, vegetable broth or oil. Canned tuna is sterilized to prevent spoilage and to also lengthen its shelf life.

How to tell if canned tuna is bad

        i.            Check expiry date

Canned foods usually have a use-by date. The use by date does not necessary point out that beyond it the canned tuna will have been spoilt, but the quality of your canned tuna after that date will not be guaranteed. It is best to mark the date when you purchase your canned tuna so that you know how long you would have stored it on your pantry shelves. Checking the dates is the first step to discovering if your canned tuna is safe or not. While tuna can certainly be safe to eat past the best before date, it’s safer to throw the tuna cans away, if the expiration date passed a long time back.

       ii.            Abnormal tuna can

Check your tuna can before opening it; see if there is a sign of something being wrong. Check for any sign of the can being damaged or if your tuna can is bloated. If your tuna can is bloated or bulging at the top DO NOT ATTEMPT TO OPEN. That could be a sign of botulism, just getting botulism in the air is dangerous. If you do try to open up a tuna can with a bulging top or one that is bloated, it can burp open in your face, splattering you with its poisonous content. Toss the tuna can away.

     iii.            Corrosion

If you discover some sort of corrosion on your tuna can, there is a high possibility that the tuna was exposed to air. Chances of your tuna having been poisoned are high. Checking if the tuna is not corroded, doesn’t necessarily mean you will be looking to find big dents or holes. Pinprick sized holes which are nearly unnoticeable are enough to cause a spoilage. Do not take chances, throw such tuna cans out.

     iv.            Rust

Rust is sometimes a cause of corrosion. If your tuna can has a rusted spot, it is best to discard it. Rust creates holes on the surface of your tuna can causing air to circulate inside the can, and that leads to spoilage.

       v.            Dents on a tuna can lid

If the lid of your tuna can is dented, then that is a very bad sign. The pressurization of the can will have been released, allowing the spread of bacteria over your tuna. Get rid of that tuna can. Be careful to check for such signs even on purchasing the tuna. You might find the dented tuna tins at a lower cost, do not sacrifice a few dollars for your health. Dented tuna cans are not to be trusted at all.

     vi.            Leakage

A tuna can should by no means leak. The can is meant to preserve the tuna, sealing it, to keep pressure inside, allowing no air inside. Leaking means the tuna is no longer safe. Forget the expiring date and toss the can away immediately, you don’t even have to try and taste it. Even if the leakage is not very noticeable and you are the only one who seems to see it; it’s better to pick the next tuna can than to pick the one you are doubting.

   vii.            Emission of a psss! Sound

If by any chance while you open the tuna can, you hear a hissing sound coming out of the can, that is warning enough. Stop and throw it away. That hissing sound is proof that a certain toxic gas has formed inside the tuna can and it is no longer safe for consumption.

 viii.            An exploding tuna can

This is one sign which cannot be missed. If your tuna flies out of its can after you open it, discard it. Sometimes the tuna does not explode as such, it may pour out quickly upon opening the can, that too is a sign that something is wrong.

     ix.            Bad odour

If you are used to eating tuna, you probably know how it is supposed to smell. If not, tuna is a fish so it smells like sea food. If it smells off or if it smells acidic, discard that tuna can. An acrid smell is not what you should smell upon opening a tuna can, expect a strong pungent appetizing aroma. If you have no experience with canned tuna and you don’t like the smell that meets your nose when you open the tuna can, throw it out. There is no need for you to risk your health over a can of might be spoiled tuna.

       x.            Weird colours on your tuna

Canned tuna has a beige to brown colour. You have to watch for dark brown, black or green colours on your tuna. Also check if your tuna has not turned pink or bright red. All these discolorations are a sign that your can of tuna is no longer safe for consumption.

     xi.            Slime on the tuna

When your canned tuna has some form of sliminess as you empty it from the can, throw it away. Slime is an obvious indication that your tuna has gone bad.

   xii.            Bubbles at the bottom

After emptying your tuna, if you discover bubbles having formed on the surface of the can that could be a sign of the content being spoiled. Get rid of the can and its contents.

  xiii.            Mushy texture

If your canned tuna turns out to have a mushy texture that you do not trust, that could be a sign of it starting to decompose; feel free to discard the canned tuna.

  xiv.            Awful taste

If nothing seems out of the ordinary and after the first bite of your tuna, you discover it doesn’t taste right. Take no risk at all, toss it away immediately.

It is very important to avoid tasting the canned tuna if you are suspecting it of being spoilt, as that could have serious consequences. When in doubt, better throw that can of tuna out and away.

Always remember to store your canned tuna in cool dark areas, preferably the pantry, where light does not penetrate.

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