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9 Ways to Tell if Your Canned Tuna Is Bad

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Canned goods fill our pantries for simple meals and backup. You never know when you may be stuck at home for an extended period and need to be able to whip up meals. Or maybe you’re simply a planner and like to keep your canned goods stocked well for meals and everyday use. 

Whatever the thought process behind your pantry stocking, you most likely have several types of canned goods. Tuna is a popular canned good because it’s inexpensive and can be used for a lot of different things. It’s simple to work with and lasts in the can for quite some time. 

Canned goods usually have “expiration dates” but how can you really tell if your canned tuna has actually gone bad or not? Interestingly enough, there are several tips and tricks you can hone in on to help you know if your canned tuna has gone bad. 

The top ways to tell if your canned tuna has gone bad is to check the expiration date, see if the can is leaking, smell it to check for bad odors, see if it’s changed color, check the can for damages, and finally, taste it, which should be your last option if you’re suspicious.

In this guide, we will cover 9 very basic tips for you so that you can understand when it’s time to toss that tuna out. These tips have simple guidelines that will help you determine whether your canned tuna is safe for consumption. 

Keep reading to learn all of the best ways to know if your canned tuna is good or bad. 

Canned Tuna – Understanding if It is Good or Bad

Canned tuna is incredibly versatile. We buy it because we like the flavor of tuna and because it costs very little to stock our pantries and cabinets with it. You can do a lot of different things with tuna and as a canned good, it will stay fresh for quite some time. 

The nice thing about canned goods is they often last much longer than the fresh version of the food. With proper storage methods, your canned tuna will most likely stay good on the shelf for anywhere from 3-5 years, which is an incredible length of time. 

canned tuna

Canned tuna typically has an expiration date. All canned goods are required to have a date stamp. What you should understand is that these dates are really “best-by” dates meaning they can’t guarantee the quality after that date. 

Proper storage is key but it won’t necessarily go bad if you have it stored beyond that date. Let’s talk about 9 ways you can try to determine if your canned tuna is bad. 

1. Check the Dates

Typically, canned goods can still be eaten past the best-by stamped date. This date is there to ensure quality over time. Obviously, the longer your tuna is stored the more you risk losing the essential quality of the tuna. 

We mentioned before that you can usually still eat your tuna after the date but we still want you to be aware of the date. We recommend marking the date you purchased the tuna as a good measurement of how long you’ve stored it on your pantry shelves. 

This is the starting point. If you’re at all worried about your tuna going bad, you can check the date and use this tip in coordination with some of our other tips to truly know whether or not you should toss it out. 

2. Leaking Can

If the can is leaking in any way, don’t eat the tuna. Leaking cans doesn’t happen all that often but it is possible. 

If your canned tuna is leaking, it means something has gone wrong with the preservation process and it’s no longer preserved by the can that it is in. If it is leaking, do not eat it, regardless of the date stamp and other factors. 

The purpose of canned goods for preservation is that everything is pressure sealed into the can. If something is leaking, then the internal items of the can are not guaranteed to be properly preserved. 

A leaking can means that you shouldn’t even consider the meat, just throw it out. 

3. Odors Talk

Canned goods don’t always smell the best when you pop open that can. That’s because whatever is in that can has been locked in there with some oil or water to preserve it for some extended length of time. 

However, tuna is a form of fish and therefore has a fishy smell. If you’ve eaten very much canned tuna, you’re probably somewhat familiar with how it typically smells when you open the can. 

A good way to determine whether your tuna is bad is to take a good whiff of it. You will most likely catch an off odor as soon as you open the can. It won’t smell as fishy but will rather smell acrid or even slightly acidic, rather than smelling like canned fish. 

If you notice an acrid or spoiled smell, we recommend tossing it out and washing your hands to ensure you didn’t get any of that spoiled mess on you. 

4. Green, Black, Brown = Bad

This one will be an obvious way to tell if your food has gone bad. 

Tuna that has gone bad will typically have dark brown streaks, streaks that might even appear black. These streaks will be obvious discoloration running through the meat and you should definitely not try to eat it. 

At times, the tuna might also turn green, which is another sign that the tuna has gone bad. If your tuna has any of this discoloration, it is not safe to eat. 

5. Look for Pink

This tip goes hand in hand with tip #4. The coloring of tuna meat ranges anywhere from light pink to bright red. The bright red might even have a slightly brown tint. 

tuna can open

So, how do you tell if it’s a good brown or bad brown? Bad tuna will be very dark obvious brown-streaked through, potentially close to black. Good tuna, when dark in color will still have more of a reddish hue. You’ll know the difference. 

6. Exploding Cans

The can probably won’t explode sitting in the cabinet (although it is possible). However, if you open the can and things explode or project out of the can, this is a sign that something was wrong. Sometimes, the can might even be bulging. 

You may hear an explosive noise or your food might just come pouring out quickly when you pop the can, either way, it’s not a good sign for the tuna. 

Just clean up the mess and toss it all out. The tuna is bad, something in the canning process was not effective. 

7. Canned Corrosion

If you notice corrosion or rust on the can, it’s probably better to be safe than sorry. Corrosion can cause pinprick sized holes to appear on the surface of your can. These holes are relatively tiny and you may not even really be able to see them. 

It’s better not to take the chance. If you notice your canned tuna showing signs of corrosion, it means that air and possible even moisture are able to get to the food in the can and you should throw it out. 

8. Dented & Damaged Cans

We’re not saying that you can’t eat food that is in a dented can. Many grocery stores will reduce the cost of damaged canned goods because the expiration date could be negatively affected by the damage. 

A dent, specifically a dent to the lid of the can, could mean that the pressurization of the can was released and you don’t even know it. In this case, bacteria can gather on the food item, leading to salmonella and other nasty things you don’t want to consume. 

If you notice a dent on the top lid of the can, we recommend tossing it out. 

9. Sample It 

If all else fails and nothing seems out of ordinary for your tuna, take a small bite. If the tuna doesn’t taste right or has an off flavor, we wouldn’t risk it. 

When it comes to foods, particularly canned foods, it’s better to toss it out than risk making yourself very sick. Tuna is inexpensive and it’s not worth the risk to your health just to save a can of tuna. 

Related Questions

We hope that you find this guide to the 9 best ways to tell if your canned tuna is bad to be a helpful resource for understanding whether or not you should eat that tuna. 

We invite you to take a look at the following question and answer section for some additional information that may be valuable to you. 

How Do You Properly Store Canned Tuna?

The best way to store any canned good is out of direct sunlight and heat. Store canned tuna in cool, dry areas. Pantries or cabinets with closing doors are the best storage locations to preserve canned tuna and other canned goods. 

Does Canned Tuna Need to Be Refrigerated?

You do not need to store your canned tuna in the refrigerator until after the can has been opened. Canned goods typically do not require refrigeration when they are unopened. 

However, after you have opened your canned tuna any leftover tuna should be stored in the fridge or tossed out. 

Up Next: Can You Reheat Tuna Pasta Bake?


  1. I just read this article after mixing up some tuna for a tuna melt, and I realized that it had an off smell and I couldn’t tell what it was. Thank god I read this article it was def an acrid smell… BARF.

  2. How to clean canned would be a better question to answer? treat in ozonated for water, then re-cook it again?

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