Can You Heat Canned Tuna: Is Canned Tuna Cooked?

Tuna is one of the most versatile foods - it can be the star of the show or a helping hand for flavor.

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You can even put it in salads to give them more oomph! While fresh tuna has a pretty poor shelf life, canned tuna is a different story altogether. 

Thanks to the processing and preservation, canned tuna will last in your pantry for months. You might be wondering if canned tuna is safe to heat up before consuming due to the scary can that surrounds the meat. 

However, there is nothing to worry about here. You can safely heat up canned tuna as well as other canned fish, such as cod, mackerel, and swordfish.

Having said that, there are always necessary precautions to take when heating up meat.

Today we’ll be looking at how you can prepare your canned tuna and other fish so that it is safely heated and ready for human consumption. We know you’re itching to get your meal cooking, so what are we waiting for?

How are tuna and other fish canned in the first place?

The first rule in cooking properly is to always know what you’re dealing with. If you don’t know how your tuna was canned in the first place, how are you to know how to heat it?

Is canned tuna cooked? Most canned fish is cooked before being preserved in metal, so they’re safe to eat straight out of the can. 

However, make sure that you haven’t accidentally purchased a fish that requires cooking beforehand. Going back to the norm, though, have you ever wondered why canned fish is so often cooked already? 

The fish will have been boiled for longer than it needed in a bid to remove as much bacteria and the potential for bacteria as possible. If your tuna is harboring bacteria and you consume it cold, you might find yourself getting ill from it. 

Now let’s look at the process that the fish goes through before it ends up in your pantry, shall we? 

Step One

The fish is caught by a fisherman and delivered to the canneries.

While the fish is fresh when it’s recently been caught, the fishermen will often freeze the fish to preserve it until it reaches the correct cannery.

Step Two

The cannery will assess the quality of the fish when it comes in. They might also check the fishing boat that the fish came in on to ensure that it was kept correctly.

Once they’re happy with the quality they will accept the fish.

Step Three

Once the fish arrives at its desired destination, the cannery will keep the fish frozen until they’re ready to use it.

Chances are that the fish came in large quantities, so the fish will need to be sorted into different weight and size categories.

Step Four

When the tuna is ready to be used, it is thawed completely and sent to be cleaned. Before any cleaning happens; however, the fish is steam baked to remove any oil that might be difficult to clean off.

The steam will also loosen the debris and make cleaning an easier process. 

Step Five

The fish will be cooled after the cleaning and the bones will be removed.

The skin and heads will also be taken off as you don’t find these in canned tuna. 

Step Six

The fish is now boiled to remove bacteria. However, if the cannery steam baked the fish beforehand they might skip this stem as it is deemed unnecessary.

The latter option leaves the fish tasting fresher as an end result. 

Step Seven

The tuna is added to its cans, along with the preserving method. This might be saltwater, brine, oil, or broth. The can is vacuum-sealed and sterilized before being shipped off to the shops.

Some companies do a quality assurance test the day before to ensure that the product is fit for consumption. 

How do you heat canned tuna and other fish? 

There is no one way to freeze tuna and, unfortunately, a lot of manufacturers don’t put heating instructions on the packaging. So, we’ve been left to our own devices and hope that we do it correctly!

While heating canned fish sounds simple and there are many different ways to do it, you should be cautious that heating it carelessly might result in an altered texture and taste. Luckily, we have all the answers on how to heat your tuna and other fish properly. 

As we mentioned already, there are different ways that you can heat your tuna up. Let’s look at the most common methods now. 

Microwaving canned fish

Microwaving canned tuna is one of the easiest and quickest ways to heat it. If you want to add a can of hot tuna to a readymade dish you can microwave it and within minutes be ready to eat. 

The one main thing to remember when heating up tuna in the microwave is to always remove it from the can! Unless this is your first time using a microwave, chances are that you know not to put metal in the microwave. 

So, remove the fish from the can and put it into a microwave-safe bowl or plate. Cover the dish with a paper towel and blast it for 30 seconds at a time.

After every 30 seconds is up you should test the warmth of the tuna. If it’s not hot enough yet, give it a stir and resume the microwave. 

Heating canned fish on the stove

If you don’t have a microwave, don’t worry. Heating the fish on the stove is still simple and easy to do, it’s just not as quick as the microwave.

Empty the contents of the can into your pan and introduce it to low to medium heat. Continue to heat up the fish until it reaches your desired heat. 

It’s worth noting that tuna in oil is the best for heating on the stovetop. This is because the oil prevents the fish from sticking to the pan once it begins to heat up.

If your tuna isn’t in oil, add a few drops to the pan to mimic the same effect. 

Cooking as part of a dish

Alternatively, you can simply add the tuna to whatever dish you’re planning to cook it with. Many recipes call for the canned tuna to be added to the dish before being cooked in the oven, so just follow the instructions. 

The other ingredients will help the canned fish to heat up and take care of it throughout the process. A great example of this is if you were making a tuna casserole.

Put all of the ingredients in the casserole dish (including the cold tuna) and let the oven do the work. 

What are the risks of heating canned tuna and other fish?

There is nothing to worry about before opening the can of tuna, as the fish has been sterilized and preserved to ensure that no bacteria is left within the fish. The only potential risks come from how the tuna is treated after the can is opened. 

For example, if you leave it open for too long the chances of bacteria being able to grow are much higher.

So you should never leave the can open for too long and you should use the meat as quickly as possible. This is the same for almost every food, whether it be raw or cooked. 

But that’s a risk of leaving the tuna unattended for too long. What are the risks of actually heating your canned tuna? Luckily, there aren’t many to choose from and they’re mostly to do with the quality of the fish. 

For example, if you don’t heat the tuna properly you might end up burning the tuna and having to endure overcooked fish. This could also ruin the flavor and texture of your fish, so be careful that you don’t take your eyes off the tuna for too long.

Another risk is that everyone is sure to experience different cooking times for their tuna. So, if your friend swears that their tuna takes two minutes 36 seconds in the microwave, don’t blindly follow this instruction as well. You might end up with burned tuna, so heat it in 30-second intervals. 

Remember that you’re only reheating the meat as it has already been cooked. It is going to take much less time than it would cook the fish, so don’t leave it for longer than it needs. You should never boil or sear canned tuna as this could easily overdo your meat. 

The most important thing to remember is that canned fish is almost always cooked already, so you’re only reheating it. If you’ve ever reheated something before you’ll know that it only takes a fraction of the original cooking time. 

So, keep an eye on your canned tuna while it’s being heated. Every can will heat differently and there are a number of factors that can affect the cooking time, so be careful not to overcook the fish. 

Why is canned tuna so great? 

Canned tuna can be used for so many reasons, which is why it’s so popular for people to keep in case of an emergency.

Whenever you walk into the pantry and find that you really need to visit a grocery store, your trusted canned tuna can help tide you over. 

Many people think that fresh fish is best, and in many cases they’re right, but can a fresh tuna last at room temperature for months on end? We didn’t think so, either!

There are lots of dishes that you can use canned tuna in, so we find it hard to believe that we’d ever get bored of canned tuna. 

Are you struggling to think of dishes that you can use your canned tuna in? We’ve listed some of our favorites below in case you’re experiencing a mental block. 

Tuna Casserole

Throw some mushroom soup, vegetables, cheese, and tuna together and stir it all together in a large casserole dish.

Bake for 20 minutes or so and tuck into a quickly prepared meal. You’ll be eating leftovers for days! 

Tuna Cheesy Pasta

Boil your pasta, drain it, and mix in as much cheese as you can possibly fit. Add in a can of drained tuna and keep mixing until the cheese is melted into stringy deliciousness.

The heat of the pasta will heat your tuna too, so no need to prepare it beforehand. 

Tuna Patties

Prepare all of the other ingredients that you’d usually use for your patties, but use tuna rather than beef.

Fry, grill, or oven cook them however you’d like and serve on a bed of salad. Remember that tuna won’t need as long to cook as beef would, so cooking time will be greatly reduced. 

How great do those dishes sound? You can also use tuna for tuna sandwiches, tuna salad, and homemade sushi rolls. Salad and pasta go excellently well with tuna, so cook these ingredients up to however you like them best and enjoy! 

But what about other canned fish that we haven’t talked about? While we know that the main focus of our article is to look at canned tuna, we also have to give other fish some love don’t we?

Below are some of our favorite ideas on what you can make with canned fish. 

  • Any canned fish would go well in a chowder
  • Canned mackerel fish cakes 
  • Salmon patties with canned salmon
  • Any canned fish with most pasta dishes
  • Canned fish on a pizza base with cheese
  • Salmon dip with canned salmon
  • Sardine sandwiches
  • Smoked fish on top of avocado toast
  • Any canned fish in a salad

These are just a few of the possibilities that you can achieve with the canned fish in your pantry.

It is so easy to turn your nose up at something canned over the fresh alternative, but canned fish actually makes for amazing dishes. 

Why choose canned fish over fresh? 

Fresh food is great if you want to eat it all right away, but a lot of fresh fish comes in their natural form.

This can make preparation very difficult and long-winded as you have to skin and debone the fish before you can even begin cooking it. 

You might also waste a lot of meat if you don’t know how to debone a fish correctly. Also, there might just be too much meat for you to consume before it goes bad. These are just some of the reasons why we like canned fish so much. 

It is cooked and ready to eat straight out of the can, and it comes in serving portions already so that you’re not wasting any. Not to mention that canned fish is often cheaper than buying fresh fish unless you’re going to catch it yourself. 

Canned fish can be pulled right off of the shelf whenever you fancy it, without having to go out and purchase a fresh fish.

Canned fish has all of the nutrients that fresh fish does, so you’re not getting any fewer benefits. Finally, canned fish tastes exactly the same as fresh fish to many people. 

Canned foods often get a bad reputation because they are considered second best to fresh food, but we think differently.

If your lifestyle fits better with canned fish rather than fresh, go for it! We always have a can or two of tuna in our pantry in case we ever have a hankering for it. 

Frequently Asked Questions

Is canned fish good for you?

Yes, canned fish is very good for you. Many of them are full of omega fatty acids and protein.

Canned tuna is also rich in vitamin D, a nutrient that a lot of people are unknowingly lacking. There are minimal fat and salt within canned fish, so there are no bad ingredients within the can. 

The preserving process chosen for the tuna affects the healthiness of the fish slightly. Water is the healthiest as there are no calories added, while brine adds some salt to your fish.

Oil is higher in calories, but a small amount is not considered bad for your health. 

Does canned tuna contain mercury?

Canned tuna does contain mercury, as does fresh tuna. However, it is not enough to put you off this nutritious fish. There have been cases in which people have got mercury poisoning from their tuna, but don’t let this put you off. 

To get mercury poisoning from tuna, you’d have to consume a lot of tuna for many days in a row. Eating canned tuna several times a week will not fill your body with enough mercury to get poisoning from it. 

Which canned fish is the best? 

The answer to this question all comes down to personal preference.

Some people consider tuna to be the best fish while others will only go near mackerel. The most common types of canned fish are salmon, sardines, tuna, trout, and sardines. 

However, the best canned fish is relative to your taste buds, so listen to what your body enjoys the most when it comes to canned fish. 

Can You Heat Up Tuna with Mayo?

Tuna and mayo are very commonly paired together and are a great way to add flavor and texture to your tuna, particularly if it’s out of a can of brine. 

Tuna often arrives canned and already cooked and is often paired with mayonnaise to make a simple and tasty dish that goes well with pasta and bread. 

If you want to try heating your tuna mayonnaise there isn’t a precise method to abide by, but there are a few tips you should be aware of to make sure you don’t ruin the taste or texture of your lunch!

The first thing to note is that canned tuna often doesn’t pose a safety concern due to the fact it is treated and can even be cooked before it is canned to reduce the risk of bacteria. Tuna being canned with brine also reduces this risk and also adds a delicious salty flavor to the tuna.

There aren’t any major concerns about heating canned tuna to any temperature, however, a lot of heat may dry out your tuna and make it flaky. If you like the sound of flaky tuna then you can cook it as much as you please (it actually makes an excellent pizza topping in this format!)

The only risk caused by heating up tuna fish comes with opening the tin and leaving the tuna exposed to the air and any other bacteria that may be able to find their way into the meat.

The longer any foodstuff remains exposed, the greater the risk of some sort of contamination taking place. This can occur with any food, be it raw, canned cooked, or fresh.

Ultimately you want to reduce this risk as much as possible, so make sure to always keep your food sealed in its can or whatever other container it has arrived in to reduce the risk of contamination.

As long as you observe this rule you should be able to enjoy tuna with mayo warm or cold, whatever your preference!

Should I boil canned tuna?

If you really want to boil your canned tuna for some reason you certainly can, but it absolutely isn’t necessary.

This is because most canned foods are cooked before they are canned. This is usually done by boiling the food, which of course kills off bacteria and microbes as part of the process, making the food safe to eat once opened. 

The canning process is completed by sealing the food completely, preventing any new bacteria from entering your can of tuna. So canned tuna is automatically sterile and safe to eat once it's opened. 

The only time this isn’t the case is if the can your tuna is in has been damaged or tampered with, which will usually be noticeable and should be checked before you use canned tuna.

If you think your canned food has ever been improperly canned or damaged don’t eat it at all, even boiled, as this can have really bad consequences.

Can you eat canned tuna raw?

Yes. You can eat canned tuna raw, as during the canning process tuna is cooked enough so as to be edible straight out of the tin. This is highly convenient for consumers and also makes canned tuna long-lasting.

Can you get botulism from canned tuna?

While rare, it is possible to get botulism from canned tuna. This usually only happens due to a malfunction in the canning process or damage/tampering that occurs after the canning process has finished. 

Some telltale signs that botulism could be present in your canned tuna is if the can is damaged in any way or compromised.

If the can seems to be bulging or have an abnormally high pressure built up inside which could indicate some sort of decay or fermentation. And finally, the smell of the canned tuna once opened, which will have a pretty bad smell.

If you’re ever in doubt about this, definitely play it safe, because botulism can be really nasty and it simply isn’t worth the risk.


Canned tuna and other fish are very beneficial in a plethora of ways, such as they’re easier to prepare, quicker to cook, and less expensive than fresh fish.

Canned tuna has been prepared and preserved carefully to ensure that it is fit for human consumption. 

Canned fish can be used in many different dishes, and there are three ways for you to heat it up. While using a microwave is quickest, you can sometimes let the cooking process heat the fish for you.

Remember if you’re heating it on the stove, add a few drops of oil to avoid the meat sticking to the pan. 

The main risk factor of heating tuna and other fish is that you will overcook the meat. As the fish is already cooked in the can, there is no risk of undercooking the meat.

However, leaving it too long in the heat will cause it to burn and become rubbery. 

We hope that you’ve learned something valuable about canned fish and how to heat them. What are you waiting for? Get making that mouthwatering fishy dish! 

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Cassie brings decades of experience to the Kitchen Community. She is a noted chef and avid gardener. Her new book "Healthy Eating Through the Garden" will be released shortly. When not writing or speaking about food and gardens Cassie can be found puttering around farmer's markets and greenhouses looking for the next great idea.
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