How to Tell if Canned Tuna is Bad?

We will go over a few of the signs you should look for. In this article, you will get all the information about how to tell if canned tuna is bad. We will also talk about the expiration date and other essential tips. A can that is leaking means it is no longer safe for consumption.

In general, canned tuna has three to five years of shelf life. As long as you don’t open the can before it’s expired, canned tuna can last for years. Once it’s opened, it will be safe to eat for three to five days. However, if you open the can, you’ll probably find that the flavor has changed. When that happens, it’s time to toss it.

How to Tell If Canned Tuna is Bad

A leaking can is another sign that your canned tuna is terrible. You can tell if it has gone wrong if the can be bulging or bursting. When the cans burst open, bacteria and air can get in them. If the can is damaged, it should be discarded immediately.

It should not be opened if dented or leaking because it allows the pressure inside to release. Tuna is a sleek fish that is popular in the United States. The steak of that slim and streamlined fish is canned tuna, frozen and preserved in cans with water, vegetable broth, or oil. To avoid spoiling and extend the shelf life of canned tuna, it is sterilized.

How to Tell if Canned Tuna is Bad?

The majority of folks have canned tuna in their pantry. This is because canned foods are simple to prepare. However, if you eat spoiled canned tuna, you will immediately become ill. Before serving canned tuna, make sure it hasn’t gone bad; you could get seafood illness.

When opening a can of fish or any other canned product, it should smell fishy. This is a sign that the can is spoiled. It should have a fishy smell, but it should be thrown away if it has an acrid smell. Also, canned tuna is not recommended for people who have not eaten it before. It is not worth risking your health over a can of tuna.

A discolored can is another symptom that your tuna is terrible. A discolored can contain dark brown streaks or discoloration throughout the meat. These are also signs of spoiled tuna. However, if you are unfamiliar with canned tuna, it is best to avoid it and buy a new can. And be sure to check for other signs of lousy tuna before you eat it.

1. Check the Expiry Date

A use-by date is commonly printed on canned foods. The use-by date does not necessarily mean that the canned tuna will be spoiled after that date, but it does mean that the quality of your canned tuna after that date cannot be guaranteed.

It’s good to write down the date you bought your canned tuna so you know how long it’s been sitting on your cupboard shelves. The first step in determining whether or not your canned tuna is safe is to look at the dates. While it is possible to eat tuna past its best-before date, it is safer to discard tuna cans if the expiration date passed a long time ago.

The best way to check for the safety of your canned tuna is to examine the use-by date. A more than five-year-old can may not be safe to eat, even though it may look stale and have gone wrong. In addition, if you have leftovers of canned tuna, make sure you refrigerate them. Otherwise, it may become spoiled and not worth buying.

2. Abnormal Tuna Can

Before you open it, your tuna can look for signs of something wrong. Check for any signs of damage to the tuna can and if it is swollen. Do not attempt to open a bloated tuna can or bulge at the top.

That could indicate botulism, and even just inhaling botulinum is deadly. If you try to open a tuna can with a bulging or swollen lid, it will burp openly in your face, splattering you with its toxic contents. Toss the tuna can in the trash.

3. Corrosion

If you notice corrosion on your tuna can, the tuna was likely exposed to air, and there’s a good chance your tuna was tainted.

Whether you’re checking to see if the tuna isn’t corrupted, it doesn’t mean you’ll be looking for large dents or holes. Pinprick-sized holes that are almost undetectable are enough to damage the product. Don’t take any chances; throw these tuna cans away.

4. Rust

Corrosion is occasionally caused by rust. Tossing your tuna can is recommended if it has a corroded spot. Rust causes holes in the surface of your tuna can, allowing air to move inside and causing deterioration.

5. Dents On a Tuna Can Lid

If your tuna can’s lid has been dented, that’s a bad indicator. The can’s pressure will loosen, allowing bacteria to spread across your tuna. Get rid of that tuna can as soon as possible.

Even while buying tuna, keep an eye out for such indicators. You might be able to find the dented tuna tins for a lower price, but don’t risk your health for a few bucks. Tuna cans with dents should be avoided at all costs.

6. Leakage

A tuna can should not, under any circumstances, spill. The can is designed to keep the tuna fresh by closing it and maintaining constant pressure. Leaking indicates that the tuna is no longer safe to eat.

Ignore the expiration date and throw the can away right away; you don’t even have to sample it. Even if the leaking isn’t apparent and you’re the only one who notices it, it’s preferable to pick the next tuna can than the one you’re unsure about.

7. Bad Odor

If you’ve ever eaten tuna, you’re undoubtedly familiar with how it should smell. If not, tuna smells like seafood because it is a fish. Throw the tuna aside if it has a rancid or sour smell.

Don’t expect an unpleasant odor when you open a tuna can; instead, expect a powerful pungent delectable aroma. If you’ve never had canned tuna before and don’t enjoy the smell greets you when you open the can, toss it aside. No reason to jeopardize your health over a can of potentially rotten tuna.

8. Weird Colors on Your Tuna

The color of canned tuna ranges from beige to brown.

Dark brown, black, or green colors on your tuna should be avoided. Check to see if your tuna isn’t becoming pink or bright red. These discolorations indicate that your tuna can is no longer safe to eat.

9. Awful Taste

If nothing seems unusual, but after taking your first bite of tuna, you realize it doesn’t taste right. Take no chances and throw it out right away. It’s critical not to taste the canned tuna if you suspect it’s spoiled, as this could result in terrible consequences.

When in doubt, toss that can of tuna out the window. Always keep your canned tuna in a cool, dark place, preferably the pantry, where light cannot get to it.

How to Tell If Canned Tuna is Bad

Why Is Tuna Not Required to Be Kept Refrigerated?

First and foremost: Keep your tuna cans away from direct heat (i.e., don’t keep them in the cabinet over the stove or in direct sunlight). Heat will hasten the deterioration of your tuna and may make it unhealthy to eat. Tuna cans that have not been opened do not need to be refrigerated.

The tuna is either salted or placed in the can on its own at Wild Planet. The cans are then placed in a cooker that swiftly heats them to a high temperature under pressure. The tuna is vacuum-sealed and sterilized in the cans during this procedure, making it shelf-stable and safe to eat.

Is Canned Tuna Good for You?

There are many benefits of eating canned tuna.

  • In particular, it is an inexpensive source of protein.
  • It also keeps for a long time, and some brands can last for 2–5 years in your pantry.
  • If you want to lose weight, canned tuna is a good option because it is low in calories yet high in protein.
  • Protein-rich diets have been linked to weight loss advantages, including enhanced feelings of fullness and decreased cravings.
  • Despite its low-fat content, Tuna is a good source of omega-3 fatty acids.
  • Omega-3 fatty acids are necessary dietary fats for your heart, eyes, and brain. Fish is a good source of omega-3 fatty acids, but you can also acquire them from plant foods.
  • As a result, the American Dietary Guidelines recommend that people take 8 ounces (227 grams) of seafood every week.
  • Consuming canned tuna is a simple method to boost your omega-3 intake.
  • The types and amounts of fats in canned tuna might vary depending on the brand, so study the labels if you wish to compare brands.
  • Canned tuna is a beautiful source of various vitamins and minerals, particularly vitamin D, selenium, and healthful fats.
  • Finally, many canned tuna products are lightly processed, having only tuna, water or oil, and salt, although they are canned. Some brands may add seasonings or broth.

What Happens if You Eat Old Tuna?

The most popular fish are tuna, mackerel, mahi-mahi, sardine, anchovy, herring, bluefish, amberjack, and marlin. Food poisoning caused by scombroid, often known as scombroid, is a foodborne sickness caused by eating contaminated fish.

Possible symptoms include flushed skin, headaches, itching, blurred vision, gastrointestinal cramps, and diarrhea. We’re not talking about mercury poisoning here, but bad canned tuna can make you sick.

Raw fish should be handled with caution. There are a few things to keep in mind regarding canned fish. If canned tuna is mishandled, it might cause food poisoning.

What Are the Side Effects of Eating Canned Tuna?

Mercury Poisoning

Mercury poisoning, also known as hydrargyria, is usually caused by consuming heavy metal food, a known neurotoxin. “All fish include some mercury, but the amount varies greatly; canned tuna contains relatively high levels of mercury, so eating more than three or so portions per week could be detrimental,” explains Andrea Paul, MD, Illuminate Labs’ medical adviser.

Itching or a pins-and-needles sensation in the toes and fingertips, muscle weakness, coordination, speech, hearing impairment, and impaired peripheral vision are all symptoms of mercury poisoning. High mercury levels in pregnant women may cause central nervous system abnormalities in their children.

Scombroid Poisoning

You could be allergic to a bacterium in spoiled marine seafood if you experience facial flushing, sweating, dizziness, and a peppery taste in your mouth and throat after eating canned tuna. “Scombrotoxin is a unique food illness found most commonly in tuna and mackerel fish,” says Janilyn Hutchings, CP-FS (certified professional in food safety) of

“The toxin is produced by spoilage bacteria due to incorrect handling and is not removed throughout the canning process,” says the author. The culprit isn’t only canned fish. Anglers who keep their catch out of the cooler for an extended period might encourage bacterial development in the fish, which raises levels of the histamine that causes symptoms.

The toxin is also linked to non-scombroid gamefish such as bluefish, mahi-mahi, and amberjack. Hives, diarrhea, and blurred vision are among the most advanced symptoms. If your symptoms worsen or linger longer than 4 to 6 hours, you should see a doctor.

BPA Toxicity

Animal research and some human studies reveal that Bisphenol A (BPA), a known endocrine-disrupting pollutant, may influence your health, raising blood pressure, causing infertility, birth deformities, and increasing the risk of obesity, diabetes, heart disease, and cancer.

“BPA is a contentious ingredient in several food containers, including some cans,” Hutchings explains. Following a 2008 National Toxicology Program analysis stating that the levels of BPA consumed by the US population at the time could be harmful to health, the FDA tightened food container standards.

High Blood Pressure

Fresh fish is abundant in protein and heart-healthy omega-3 fatty acids, but canned tuna, while convenient, may not be the healthiest option for people who have high blood pressure. “Anyone with heart disease or diabetes can’t risk eating canned tuna since it has an average of 200-300 mg of salt per serving,” explains Cassidy Gunderson, Ph.D., nutritionist, and owner of Spiro Health & Wellness in Salt Lake City, who helps her clients manage chronic disease via food.

Consuming canned tuna and other high-sodium foods such as canned soups, baked goods, processed foods, and restaurant meals increase your risk of high blood pressure, renal disease, diabetes, and sleep apnea.

The American Heart Association recommends that consumers consume less than 1,500 mg of sodium per day. Fortunately, there are a variety of no-salt-added tuna brands available, as detailed in our guide: Six of the best-canned tunas on the market, plus four to avoid.


Some people are worried about botulism, a rare but dangerous food-borne disease. It’s caused by Clostridium botulinum, which generally lives harmlessly in water and soil. But sometimes, the bacteria become active and release spores of neurotoxin.

Canned tuna can be contaminated with botulism. One outbreak in Spain led to the recall of albacore tuna, and four people died in the outbreak. Even home-canned tuna is more susceptible to botulism. Rusty cans and bulging cans are not safe to eat. Generally, canned tuna has a longer shelf life than tuna outside the can.

It is essential to store it in a cool, dark, airtight container to extend its shelf life. If the tuna is damaged or rusted, you should throw it away. You should also ensure that the can is airtight. If you find it has signs of spoilage, it is probably time to throw it out.

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