Canned food is a lifesaver when it comes to long-term storage.
Regardless of whether you’re prepping for an emergency, stocking your pantry, or just want to stretch out your groceries a bit, canned foods can last for a long time and are incredibly convenient to prepare and eat.
But here’s the thing: just because food is sealed in a can doesn’t mean it’s safe forever. In fact, canned food can go bad.
The key to staying safe is knowing what to look for. There are some clear red flags that tell you when it’s time to toss that can instead of opening it.
If you notice any of these signs we’re about to cover, you’ll want to throw your canned food out.
Bulging or Popped Lids – The Biggest Red Flag of All
One of the most obvious and dangerous signs that your canned food has gone bad is a bulging or popped lid. This is the biggest red flag you can spot, and if you see it, it’s time to toss that can immediately (as in don’t even think about opening it).
A bulging lid specifically means there’s likely gas buildup inside the can, which is often caused by bacteria growing in the food. When bacteria like Clostridium botulinum multiply, they produce gasses that create pressure inside the can.
This can cause the lid to swell or even pop open. It’s also important to pay attention when you open the can. If you hear a loud “hiss” or notice air being released (almost like opening a soda), that’s another bad sign.
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Leaking or Rusty Can – A Clear Sign of Contamination
A leaking or rusty can is another clear sign that your canned food is no longer safe to eat. Leaks or rust might seem like minor cosmetic issues, but they can mean that the can has been compromised.
Even a small leak means that the seal has been broken, and when air gets inside, it allows bacteria to grow.
Rust is just as concerning. While a little surface rust might not seem like a big deal, heavy rust can weaken the can and create tiny holes or cracks that aren’t always visible. Rust is more common in cans stored in damp or humid areas.
Foul Smells – Avoid At All Costs
Foul smells are never a good thing when it comes to food. As in literally never. The beauty of this warning sign is that your sense of smell is pretty good at detecting when food has gone bad.
Spoiled canned food can give off a variety of odors, from sour and musty to metallic or just a plain rotten stench. These smells usually indicate that bacteria or mold has been growing inside the can, which will lead to serious foodborne illnesses if you consume the fod inside. Even if the food looks okay at first glance, a bad odor is enough reason to throw it out. Remember, you can always trust your nose!
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Unusual Colors – It’s Spoiled
If the food inside the can looks discolored, has dark spots, or simply doesn’t look the way it should, it’s a major indicator that it has spoiled and should not be eaten.
Fresh canned food typically maintains its original color, or something close to it, even after being stored for very long periods of time.
But when spoilage occurs, the food can take on strange, unnatural hues. For example, vegetables may appear faded, meats can look gray or brown, and fruits might develop dark or black spots.
Another telltale sign of spoilage is the presence of mold, which may appear as white, green, or black patches on the surface of the food. Color changes like this often result from exposure to air or bacterial contamination, both of which can happen when the can’s seal is compromised.
Dented Cans – Proceed with Caution
Dented cans are a tricky subject. While not every dented can is dangerous, some dents can seriously compromise the safety of the food inside, so it’s important to proceed with caution.
When inspecting a dented can, pay close attention to where the dent is located. If the dent occurs near the seams or the lid of the can, there’s a risk that the seal has been broken, which can let in air and bacteria. Small, shallow dents on the body of the can are usually less of a concern, however, and you’ll want to look for other signs of spoilage or contamination like we’ve covered above.
Another thing to look out for is whether the can feels soft or has any movement in the dented area. If the dent is deep enough that you can press on it and it moves or flexes, that’s a bad sign. Cans are designed to be rigid, and any structural weakness could mean the can is no longer sealed the way it should be.
When it comes to canned food, safety should always come first. While cans are designed to preserve food for long periods, they aren’t invincible, and knowing the signs of spoilage like we’ve covered above is crucial to avoid serious health risks.
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Bachelism poisening is indeed the main culpret here
Dented cans or broken seals or backteria into the food created by air or forign debres
I had saved a fairly large batch of canned food , survival food for about 25 years , then when i moved to my final destination and all seemed fairly stable , I started opening up the foods, cases of FD , # 10 cans Beans, Rice, Flour , other goods , shook well , preserved well
but after opening , product was stale , tasted like foul smells or NO taste .
So being cautious , My family chose to Throw out the Food
about 15 cases
never gave it a second thought , being of military backgrounds we always prepared and thought the elites would eventually destroy all for thier pleasure and control .
we never rotated the product , never looked at the product , never even sampled the product
then when time came we found Rusted seals, broken seals, NO dents , lables rotted off cans but still in cases and some cans had expanded , which represented bacterial invasion .
The sum of the story is : Pay attention to details , times, lapse in time , and product rotation . everything has a time stamp on it , and rots , decays , fades away .
Time happens , and you wake up and your 30,40,50 years older . Life changes , so prepare for that eventual change .
pray, believe , Trust in the word of God s provision : Jesus Christ Savior to the fallen world
Great information from someone who ACTUALLY knows what he’s talking about. Unfortunately, you lost the 4 atheist who just could’nt accept your last sentence. They always show their colors on this board. I will pray for their souls.
Home canned foods will hiss on opening and it is caused from the vacuum releasing I have found this to be true in store canned foods. Watch for other signs!
Good information to know!
It is good to put this information out there but don’t let it scare the daylights out of you.
I posted on here once about my concern regarding botulism and another reader ask that I keep it in perspective that cases in the USA are very rare, and I now do. So I will offer this information from Wikipedia,
Between 1990 and 2000 the CDC reported 263 individual foodborne cases from 160 botulism events in the United States with a case-fatality rate of 4%. Thirty-nine percent (103 cases and 58 events) occurred in Alaska. The highest incidence rates occurred in Alaska, Idaho, Washington, and Oregon. All other states had an incidence rate of 1 case per ten million people or less.
At a risk level of one in ten million, I think I will find other things to try and wrap my mind around.
Most of this is really common sense. Most of us by now know about bulging can lids. Dents are a tricky subject. If it’s a sharp dent then more than likely it has compromised the coating on the inside of the can. If it’s a round dent and not too deep there should be no problem. Most canned foods will be safe long past their best by date. The exceptions are things like canned tomatoes that are very acidic and should not be stored for too long and checked more often than the other stored cans. Otherwise check and rotate periodically. I know peanut butter usually doesn’t come in cans but another thing that doesn’t last forever. The oil in the peanut butter is that which becomes rancid. Not the peanut butter itself. You can save rancid peanut butter by scraping off the first half inch or so out of the jar and then you’re good to go.
Every thing i open up hisses….go figure that one out ….still alive . or well preserved. I could be dead and in hell .
My mom would just scrap or cut the mold off of food and make me swallow a teaspoon of ransid cod liver oil ever mourning before i walk 2 miles to grade school …..every day….maybe thats what’s wrong with me. i think i can eat any thing now with no worries. She was definitely a prepper by current standards….Covid never happened to me as far as i know….i do trust God .
Light surface rust on the bottom rim of stored cans is not necessarily a red flag.
Some of that is normal.
I don’t think my tax dollars should go to democrate scientists like Dr…..Anthony Fauci…..Did that brilliant man and members of the DNC create the aids virus ? I would not put it pass them….truly evil if so….Why would i even think of such a thing ? I also agree there’s valuable info. in this article.I need to watch my thoughts….Dems still in power….plus people are still voting for dems in my state and county. So I’ll continue to read the articles on this site….and prepare for the worst….both spiritually and what ever. A.K.A. Outer Spice.
Be aware of those cans that use ring pulls and not a can opener to open, it’s like a glue seal and will degrade faster than standard cans.
If it comes down to a survival/prepper situation then make sure these are always rotated to the front as these are the ones that will more than likely be compromised first.
Maybe that’s why companies changed to these types of cans, we see them as convenient to open, they see the seal degrade so you need to buy more (if you don’t can everything).
The most important takeaway is to make do with what you have. Few people live far enough away from a food shop to understand how this works. It takes me two hours to travel to one, so I’ve been doing this for several years.