# How to tell when canned goods go bad?



## webley445 (Jun 12, 2006)

How can you tell if canned goods are bad, not good for consumption?
Ones I have don't have expiration dates.
I recall long ago reading about the cans "bulging" being a bad sign, but that isn't good enough in my opinion.
There's gotta be some effective way to determine its freshness. I'm thinking write the date of purchase with a sharpie on the label, but then how long can you wait to use it?


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## ABTOMAT (Jun 12, 2006)

Bulging and rusting are the only sure signs I know of. Better to mark them when bought.


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## CLHC (Jun 12, 2006)

I'd have to agree with the "bulging and rusting" of the cans also. But if the canned goods do have dates on them, here's some general guidelines.

"*Best before*" is advisory (the food is best before that date, it's up to you if you want to eat it after that). "*Use by*" isn't advisory, it's "throw it out after that date, you shouldn't eat it".

For those without dates and whereupon I don't know how long it's been sitting, well, I don't take that much of a chance, maybe even opening it up and have a look and smell and taste "test" if you will.


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## James S (Jun 12, 2006)

rusted or bulging cans are bad news, or even fatal. Obviously anything thats leaking. examine anything that is dented very carefully as the point of what hit it can cause a small perforation that even if it's not leaking can still spoil the insides. Dont rely on the smell, botulism has no smell and it will still kill you, and you can't cook it out as it's not the bacteria that will kill you, but the toxin that it leaves behind even after you kill all the little buggers.

webley is right about best before and use by dates

Generally, they say that high acid foods, like fruit or anything with tomatoes in it can be kept for a year or 18 months, low acid things like veggies are good for 2 to 5 years.

but thats the official, worst case scenario. Things MAY be good for much longer than that, but you takes your chances.


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## smokinbasser (Jun 12, 2006)

I guess that means those eggs in my fridge with an expiration date of 12/05 should be just about ready to cook.


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## eluminator (Jun 13, 2006)

The cans that bother me are those ones with the aluminum tops you yank off with your finger. 

I bought a can of deviled ham a few years ago. It had a plastic lid that is used to cover the can after it's opened. I noticed the inside of the plastic lid was covered with a film of condensed moisture. When I opened the can it looked and smelled okay, but the contents had apparently shrunk from moisture loss and had shrunk away from the sides of the can. I don't know if the contents were bad. I gotta believe others have gotten such cans, and most people probably wouldn't have noticed the moisture under the plastic lid, and even if they had, they probably wouldn't have known what that meant.

Now Bumble Bee has a snack pack with tuna salad in such a can, along with a small package of crackers. Unfortunately it doesn't have the telltale plastic lid. Twice I've noticed the contents of the can didn't contact the sides. I don't know if it was from shrinkage or just the way the can was filled. I don't buy those things anymore either.


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## raggie33 (Jun 13, 2006)

i as most know i buy lots a stuff at time cause a sales like a few weeks ago they had name brand vedgies in cans 3 for 1 buck .but i notice there is no dates on can .so whats the guide line there?they all looks like they was made recently to me lol


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## eluminator (Jun 13, 2006)

I suppose the "best" thing to do is what most people do, and don't worry about it. Of course the above advice about looking and smelling is good.

But if canned food is high up on your list of things to worry about, you can Google. Searching for "shelf life of canned vegetables" turned up this one, among others. It sez if you call the company on the label, they may tell you how to decode the numbers on the cans. It also sez the US Army found the food in cans to be well preserved after 46 years. Just how many truckloads of canned vegetables did you buy 
http://whatcom.wsu.edu/family/facts/shelflif.htm


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## chmsam (Jun 13, 2006)

Bulges, dents near the ends of cans, and rust are reasons to toss out cans automatically. These can let air in and start bacteria to grow.

Ask if your grocery store has a booklet on how to store food and how long certain types of food can be stored. 

"Gee, but I save so much money by buying the really big cases of stuf." Not if it tastes like crap by the time you are ready to use it. Everyday food ain't like survival rations. Use up everyday foods as soon as practical. Fresh is always better.

Check the USDA and consumer protection websites for more info. Call your co-operative extension.

Smokinbasser, those eggs might be able to cook themselves. Not to mention all the flavors and odors they have picked up. Eggshells are air permeable.


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## Diesel_Bomber (Jun 13, 2006)

I toss out cans that don't "hiss" with air being sucked in when I open them. It's only happened a few times and the stuff was probably ok, but better safe than sorry.


Cheers. :buddies:


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## FrogsInWinter (Jun 13, 2006)

chmsam said:


> Bulges, dents near the ends of cans, and rust are reasons to toss out cans automatically. These can let air in and start bacteria to grow.


 
Good adivce Chmsam, one thing I would add to that is if that can has any sharp dents in its sidewalls. Minor dents in the sidewalls are usually ok. But sometimes even if a can shows none of those signs the food inside can still be bad. Certain bacteria can cause what's called "flat-sour" spoilage, basically the bacteria cause the food to become spoiled without creating any gas. So on the outside the can looks perfectly fine but inside, the food is spoiled.
The thing I always remember (and this goes for any food):

When in doubt, throw it out.


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## Lee1959 (Jun 13, 2006)

Useless trivia time . Did you know that one of the leading theories about why the Franklin Artic Expedition expedition failed, with the insanity and resultant deaths that came about from the poor health and descion making ocured because of poor food canning? 

Older cans were sealed with lead, which if not done correctly, and kept too long, leached lead into the food. Some of the mummies dug up from that expedition had extremely high toxic lead amounts in them. Scurvy and starvation were other factors most likely, along with poor planning and execution. 

Ok, sorry for the off topic. I thought it was interesting . 

Bulged and rusty cans like everyone has said are two of the best signs.


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## JohnK (Jun 13, 2006)

Odd that this thread came up now.

My daughter was visiting, and looking fot fruit for her 2 Y.O. daughter.

She showed me a large can of pinapple from the pantry, that was so swollen, it approached the shape of a sphere. No leaks, or bursting. 

I couldn't figure out the date "code", but I sure wasn't going to eat this stuff.

I thought about just putting the thing in the trash, but decided it would make an interesting target for a 125 gr. .357 Mag. round (we live way out).

Blew up with a huge spray, that didn't smell like good pinapple.


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## bruddamoke (Jun 13, 2006)

JohnK said:


> Blew up with a huge spray, that didn't smell like good pinapple.


That would have made a really neat video.


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## greenlight (Jun 14, 2006)

I'm going camping and starting to question everything in my pantry. Do I just go buy new cans for the trip and leave the old stuff for the earthquake?

What is the risk of eating canned food that has spoiled? Botulism? Minor food poisining? Does overcooking the food help?

Can you find out anything by shaking the can?


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## webley445 (Jun 14, 2006)

greenlight said:


> I'm going camping and starting to question everything in my pantry. Do I just go buy new cans for the trip and leave the old stuff for the earthquake?
> 
> What is the risk of eating canned food that has spoiled? Botulism? Minor food poisining? Does overcooking the food help?
> 
> Can you find out anything by shaking the can?


 
If you read the whole thread you'd have the answers


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## chmsam (Jun 14, 2006)

Once food is contaminated cooking will not help. It isn't just the bacteria but the toxins they produce that cause problems. Washing won't help after the toxins are present.

In other words, if you have a seriously dented can, swollen can of food, or a jar of food that the seal has been comprimised, etc., just toss it out. Don't bother washing it. Don't bother cooking it. Don't bother to put it in the microwave. None of those will help.

Shaking tells you nothing.

There are reasons they put dates for use on food. So, use the food by the date on it or toss it. Simple concept. But this is a separate issue from dented cans.

If you have cans or packages of food that are close to but not past the expiration dates simply use those for camping or just use 'em at home. As was stated above, survivalist rations are made for long term storage but even these have use by dates.

Packages, cans, and bottles that intact should be OK, obviously, but they still have a limited shelf life. Again, these are two separate issues.

Survival rations are a bet that something severe is going to happen. However, I'll bet that the vast majority of rations get tossed. Very little food is available with an extremely long shelf life. Here's a tip -- simply rotate what's in your pantry as grocery stores rotate what's on their shelves. You'll save money and cut waste, too, and still have rations for "just in case." 

So, generally speaking, if anyone buys what they need and not a whole lot more, you won't end up throwing away what you couldn't use. You'll waste less and save more. It's even more environmentally sensible. 

As always, fresh food is better every time, plain and simple.


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## Lee1959 (Jun 14, 2006)

If you are going to have a "stockpile" of food, the best bet is to buy only what you eat on a normal basis. When you eat something remove it from your stores, and then replace it that week with new and put it to the back stores, moving older items to the front. This way,unless you start out with a huge number of the same item and do not use before expiration dates, what you have is always good. 

It is a simple FIFO inventory system used by every store.


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## Illum (Jun 14, 2006)

JohnK said:


> Odd that this thread came up now.
> 
> My daughter was visiting, and looking fot fruit for her 2 Y.O. daughter.
> 
> ...




It is best to wear CBN suits and indoors and call in the ordinance disposal and let them "disable" the power unit :lolsign:


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## James S (Jun 15, 2006)

All this talk about it prompted me to go through my own canned food shelf last night. I only found 6 cans that were expired (some cans do not have a date on them, only the enigmatic manufacturer code thing which is unreadable unless you call them and ask them) and 1, a can of artichoke hearts from way back when, was noticeably bloated. Not as spectacular as the aforementioned can of pineapple  but still obviously wrong. I threw it away.

Then I took stock of the pantry and everything else and used a sharpie to draw in thick black ink the expiration date of everying on the front of the can, or the top of the bottle or wherever it would be most obvious and arranged things so that the oldest would get used first. I've always tried to buy stuff before I need it, keep one in the pantry rather than run out so I'm a little bit ahead of starting from scratch here.

I am going to order some further dehydrated canned food today, spend a couple of hundred on something to pack into the back of the pantry just in case, just as a way to make sure there is some protein available. Carbs I've got plenty of in the regular pantry.

Keep in mind as you store other things. If you were to do something like buy a dozen bags of flour, if your AC goes out that paper bag it comes in and the flour will mold and go bad just as fast as your wallpaper and everything else. And even faster if there is any flooding or leaking. My rule is that anything that goes into the pantry must be in a can or sealed in plastic. Anything that is not I vacuum seal myself.


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