I'm helping an elderly lady clean out her HUGE pantry.  She has canned
salmon in there that her husband caught and had canned way back in the
'70s. She regularly eats canned food that is 10-15 years old, and
doesn't understand what all the fuss is about . . . what's the scoop
on the safety of canned goods?  the cans are not rusted; they're
well-sealed, (not with rings and lids, but professionally canned like
you get in the grocer) Actually I would like to know the shelf life
for both home canned items and professionally canned items.

Hi there!

Perhaps unsurprisingly, the shelf life for various canned goods
depends on what is in the can.  There are a number of resources
available to help you determine when something was canned, and whether
or not it is still safe to eat.  Some items, like Welches Grape Jelly,
are good for just 12 months, while others, like StarKist Tuna, are
good for a remarkable 96 months!

Quality Foods Centers, however, suggest keeping canned goods no longer
than 24 months:

"What is the shelf life of canned goods?
Because of growing and harvesting limitations, canned fruits and
vegetables can be packed only a few weeks of every year. That product
packed during those few weeks must be adequate to fill the needs of
consumers throughout the entire year. The shelf life of high acid
items (like tomato products) is generally no more than 18-24 months
from the pack date. By the time the product is stored and shipped
throughout the year, it generally has a shelf life of no more than
12-18 months when purchased at the store. Low acid canned fruits and
vegetables may be good for two years or more, depending on storage
conditions and the condition of the can itself. We do not recommend
using dented, bulging, or rusted canned goods."

Grocery FAQs
http://www.qfconline.com/faqs_grocery.htm

You can use these pages to help you determine what is still safe:

Canned Good Shelf Life and Stamped Code Decoder
http://www.y2kkitchen.com/html/can_code_decoder.html

Food Storage Guidelines for Consumers
http://www.ext.vt.edu/pubs/foods/348-960/348-960.html

Dateline:  Shelf Life
http://www.msnbc.com/OnAir/nbc/Dateline/Food/shelf.asp

Expiration, Use By and Sell By Dates
http://homecooking.about.com/library/weekly/aa102102c.htm

As for home canned foods, the USDA recommends that such items be kept
no more than a year, and only if you can verify that they were
properly canned:

Home Canning Safety
http://homecooking.about.com/library/weekly/aa082498.htm  

As a home canner myself, I cannot stress enough that it is easy for
things to go awry during the canning process.  If the jars don't have
dates on them, toss 'em.  If they do and they're more than a year old,
toss 'em.  It might annoy your friend to have to get rid of what she
perceives to be perfectly good food, but it's better than a trip to
the ER to treat botulism!

Best of luck to you,

--Missy

Search terms:  [ shelf life of canned goods ]

hi missy,
nice to meet you . . .
I figured this would be the 'official' answer (official from the USDA
point of view, anyway)
personally, two years is my own limit and I am often at odds over this
with my husband

but the big challenge is going to be breaking the news to my elderly friend
perhaps we could donate all that salmon (there are CASES and CASES of
it!) to the local animal shelter?  What do you think?  Is that a
really bad idea?  (I'm a cat lover, and wouldn't want the kitties to
get sick either)  Dunno.

thanks!

Small world department:  there was an article on this very topic in yesterday's
New York Times (Jan.4).  You can read it for free on nytimes.com for
up to a week.  After that you have to pay for it.  It's called "When
Your Prunes Are
Passed Their Prime" by Jane Brody and it's about how long you can keep all kinds
of food.
Here's her section on cans:

"Foods without an obvious expiration date, especially if they are high
in acid, can go bad if kept too long. I recently had a long-forgotten
can of anchovies leak all over my pantry shelf.

Years ago, we had a mess with canned crushed tomatoes that exploded
all over the room, as soon as the can opener made a hole in the top.

High-acid canned foods like tomatoes and some fruits should be used
within 18 months of purchase. Low-acid canned foods, like fish, meats
and most vegetables and fruits, will keep in the pantry for two to
five years.

Consider dating these cans when you buy them. Whatever the contents,
never use food from a bulging can, and if you don't want a kitchenwide
mess, don't try to open it before you discard it.

Foods stored in the freezer have other considerations, mainly related
to quality and flavor.

If they have remained consistently frozen, they are safe to eat at any
time. I recently made jam from wild plum juice I had kept frozen since
1986.

But meats, fish and poultry are highly vulnerable to freezer burn and
loss of flavor if stored too long.

Fatty fish like salmon is best used within three months of the date it was frozen.

And, if you repackage foods before freezing them, be sure to put a
date on the contents label."

There's a lot more -- really interesting...

This is such a great question! My husband and I dicker over whether
stuff is still good - when we moved in together, he had a lot of
canned goods...most of them so old, that the packaging has changed a
couple times since the original purchase! His argument is that canned
food never goes bad, now I can refute that :-)

I had the same concern a while back regarding some canned products
from prominent companies - they had been pushed back on an upper shelf
and hidden from view for a long while.  I phoned customer service for
the respective companies and they asked for the control number stamped
on the can.  From those, they could tell me when they were canned and
what the probable expiration date was for each item.

Best regards,
journalist-ga

Hi Timespacette!

Salmon and tuna are actually very bad for cats. They are too rich and
oily for a cat's sensitive digestive organs. Cats should be fed only
cat food.

I know it seems like a waste to throw out all that food, but lets face
it, like Missy says, its better than a trip to the hospital or even
worse.

Steph53

Around 1966 I and some others were fossicking in the cellars of a
friend's house and we found cans (we say tins) of self heating WWII
soup.

Needless to say we fired them up and ate them - they were not bad for
21 (est min) years old.

However, nowadays I would never buy a tin if it had the faintest dent,
and have even been known to bin suspicious things that are a mere 10
years old.

Chances are that your 70 year old is pretty canny (forgive the pun)
and examines her stock carefully (check for dust and leaking cans -
lack of dust is a good sign that someone has been monitoring their
stocks)

I suggest that you approach your friend with the line that:
   'it is 99% probably Ok, but for purely selfish reasons you do not
want her to take that 1% risk'

I suspect that your friend's guts are tougher than those of the cats ...