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What Is The True Shelf Life Of Store-Bought Canned Foods?

What Is The True Shelf Life Of Store-Bought Canned Foods?

Image source: Flickr / Creative Commons

Have you ever wondered how long store-bought canned good will last in your stockpile? Professional food processors and manufacturers have both the equipment and knowledge to properly preserve food — plus the tests and inspections from the federal government.

However, most canned foods are packed in water. That makes a big difference. Water or any other liquid can potentially become a petri dish for future bacterial growth. This is especially true for home canning, but we’ll get to that later.

pH 101

pH is a measure of the acidity or alkalinity of any food. Foods with a higher acidity (measured on the pH scale as between 0 and 4.6) form a natural barrier to bacteria and require simple processing and less processing time, but the acids can quickly compromise the integrity of a can or jar lid and the food itself. These foods include:

Juices (tomato, orange, lemon, lime and grapefruit); tomatoes, grapefruit, apples and apple products like apple sauce, mixed fruit, peaches, pears, plums, all berries, pickles, sauerkraut; foods treated with vinegar-based sauces or dressing like German potato salad and sauerbraten.

Quite often, these kinds of canned goods will have a white plastic coating on the inside of the can to prevent corrosion.

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Foods with a high level of alkalinity require more complex processing under pressure and longer processing time, but those robust processing steps actually add to the shelf life with no danger of internal acidity compromising the can or lid on a glass jar. These foods include:

Canned meats, poultry, stews, soups except tomato, pastas in sauce, potatoes, corn, carrots, spinach, beans, beets, peas and pumpkin.

What becomes clear is that you can’t lump all store-bought canned goods together in your storage area with long-term food products and assume all be well. You’ll have to separate them and write on the label or can the purchase date and the shelf-life. In fact, you should do this with all food stores, including long-term foods and most definitely with any home canning.

What About Expiration Dates?

Are expiration dates for real? Yes and no, Even the USDA says that expiration dates are suggestions or recommendations rather than a hard-and-fast rule or deadline. The reason is that so many factors can affect the shelf life of food. In fact, the dates on packaged goods aren’t referred to as expiration dates but “sell by” or “best by” dates.

Even then, some products don’t have any of these dates but instead a cryptic combination of letters and numbers. These are usually codes to indicate the point of origin for a particular product in the event of a recall.

The other truth is that a product does not suddenly go bad when it reaches its “best by” date. In fact, many canned goods are edible and safe for years after a “best by” date if stored properly. But be careful out there.

Several factors affect the storage of foods:

The temperature that any food is stored at is the most critical factor impacting shelf life. The standard recommendation is a temperature between 50 and 70 degrees Fahrenheit for canned goods. The lower the better, but don’t go below freezing; also, any canned food stored at or above 85 degrees Fahrenheit will quickly degrade and potentially become unsafe to eat

Temperature Extremes

What Is The True Shelf Life Of Store-Bought Canned Foods?

Image source: Wikipedia

Variations in temperature in an environment where you are storing any food is perhaps the greatest threat to shelf life. This is particularly true if any food goes through a pattern of freezing and thawing over a period of months or even years, and the freezing can complicate things, given that most canned food is preserved in water. The end result is often a tasteless mass of grey mush in a can bursting at the seams. Bulging cans are also a sign of bacterial contamination.

That’s why storing any food in an attic space, an unheated or unventilated garage or any other area subject to winter/summer temperature extremes is a bad idea. A root cellar is fairly stable, and a home basement, as long as water or moisture are properly managed, is fine, too. A dedicated pantry also works, and it may encourage you to engage in a recommended practice for food storage.

Eat What You Store!

“Eat what you store and store what you eat.” This is a very good idea, but I must admit I have a hard time doing it with long-term food storage. Long-term foods are usually dried foods in big, No. 10 cans, and my kitchen pantry only has so much room. I do have a No. 10 can of macaroni and a No. 10 can of cheese powder on the bottom shelf in the pantry, but that’s because my kids eat mac and cheese like wolverines.

On the other hand, I’m not real anxious to use taco flavored TVP (textured vegetable protein) as an everyday food on my tacos when I can still get a pound of ground beef and taco seasoning at the grocery store. And that starts to point to the desire to supplement long-term food stories with grocery-store canned foods.

Here’s six things to watch for when purchasing canned goods from the grocery store:

  1. Don’t buy or store a dented can. It’s more likely to be exposed to air, and bacteria will soon follow.
  2. Check any can or jar lid for corrosion. If you can wipe it off you may be okay, but you should probably toss it.
  3. If a can is bulging or the contents spurt out when you open it, stand back and put it into a double plastic bag and get rid of it. That could be sign of botulism and it could kill you if you consume it.
  4. Smell the contents after opening. If you detect any kind of off-odor, throw it away.
  5. Observe the color. Are the orange peaches a pale yellow? Are the dark, red kidney beans a shade of grey? It may be okay to eat, but boil it first.
  6. Boil all canned goods if they have been stored for a long time, and then smell and taste afterward. Acid foods should be boiled for 10 minutes and alkaline foods for 20. This will kill most residual bacteria, but will probably not kill any botulism microbes or spores.

Here’s a chart you can print and put up in your long-term food storage area if you are storing store-bought canned goods. These recommendations were made by the USDA:

FOOD STORAGE ON SHELF NOTES
Canned Ham 2 to 5 years
Low-acid canned foods:  Canned meats, poultry, stews, soups except tomato, pastas in sauce, potatoes, corn, carrots, spinach, beans, beets, peas, pumpkin. 2 to 5 years. Low-acid foods have a pH level of greater than 4.6. They require high-pressure processing and longer processing times but have a better shelf-life
High-acid canned goods: Juices (tomato, orange, lemon, lime and grapefruit); tomatoes, grapefruit, apples and apple products like apple sauce, mixed fruit, peaches, pears, plums, all berries, pickles, sauerkraut; foods treated with vinegar-based sauces or dressing like German potato salad and sauerbraten. 12 months. To 18 months High-acid foods have a pH of 0-4.6 and only require water-bath processing but have a lower shelf-life due to the effect of acids deteriorating both product and can, or jar/lid integrity over time.
All home-canned foods 12 months. Before using, boil for 10 minutes for high-acid foods; 20 minutes for low-acid foods. Add one minute for every 1,000 feet above sea-level. Home canned foods are potentially the most dangerous from a food contamination standpoint if not processed properly. The shelf life is limited to one year.


Do you agree or disagree? Share your thoughts on storing cans long-term in the section below:

 

 

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8 comments

  1. Disagree with canned shelf life. Many years ago as a teen-eager canoeing in upper Maine for two months, we often found abandoned logging camps. Many had canned food of all sorts older than probably 20-30 years. Since we were living ion a mostly fish diet we readily ate them with no ill effects. Not sure I’d do it now, but none of us had any problems and they were certainly welcomed.

    • Probably a good working rule after the “Dates” pass by is “It is good until it isn’t”. I was living in the mountains in my early 20’s and was eating only deer meat and berries until I cam across an old hunting camp where off to the side someone had stashed a large black garbage bag full of canned goods…probably about 5 years before…and the bag had rotted with the cans rolling down the mountain side a good 7 feet. I ate most of them if I remember…it has been 27 years…Dinty Moore Stew and more. Even the Country Time lemonade powder had a crusty shell when once broken the contents were as dry and good as if opened fresh. Nice treat for a mountain man.

  2. My wife was able to find some shelves designed for retail stores that have chutes for cans that allow the automatic presentation of the oldest cans first. It is adjustable for different size cans. This has saved us a lot of money in avoiding spoiled canned food over the years.

  3. When I was in Army boot camp each one of us had to take a turn to do Kitchen duty (KP) for a couple of days in the kitchen . This was in 1963. The sergeant in charge of the mess hall had me opening military cans of beef for the cook to prepare for lunch. I was 18 years old at the time and noticed that the dates on the cans of beef indicated that the beef was canned several years before I was born way back in ww2. I asked the cook if it was safe to eat cans of beef that was at least 18 years old and more. The cook told me that as long as the cans had vacuum it was safe.
    The cook used the old canned beef and made the meal with it and all the troops in my company ate it with no bad results. (I later found out that the sergeant had been selling the new canned goods to a Army surplus store and using the old food from the Army surplus store to feed the troops.)
    My wife and I have eaten cans of food we stored 6 years ago with no bad results. They had full vacuum. A few of the cans had the lids pushed up so we knew they had no vacuum and were not fit to eat so we threw those away saving only the cans with good vacuum and no rust on the cans at all. (rusted spots on cans will sometimes have pin hole size holes under the rust that let in air to the can and spoil the contents)
    I am not recommending to anyone to do as we do but just relating to you our experience. Our experience may not be the same as your experience.
    It is my personal believe and experience that as long as the lid of the can is hard and pushed in, which indicates good vacuum in the can, and the can has no rust spots, the food will be ok to eat. But if you can push in the top of the can because the top of the can is pushed up a little, then the can has no vacuum and the food within the can has been exposed to air and airborne germs and is rotten and poison. Never eat food from a can that has a lid you can push down with your fingers. The lid must be concave (sunk in) to have vacuum.

  4. marshall reagan

    i would trust what food we canned in glass jars with the 2 piece lids before I would a lot of the commercially canned foods as long as the lids are not rusty and are sealed the way they are supposed to be . we used to can all of our food except what meat we cured in salt. most of the old-timers ate that because they had no choice.

  5. An association of canned foods manufacturers states parenthetically that there’s no health issue with properly canned food. It remains sterile for decades, but does lose some nutritional value.

    USDA? “I’m from the government and I’m here to help you.”

  6. Personally I am of the opinion the the expiration dates, especially on canned goods are the result of heavy pressure($$?) by the respective lobbyists and have no scientific data to support the dates. Surely the feds have done such studies but have not released them, most likely.

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