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When does canned food really expire?

When in doubt, throw it out? Not so fast.
/ Source: TODAY

When in doubt, throw it out? Not so fast. When it comes to canned goods, it can be hard to tell when the goods are no longer good. Because they last so long — think decades — the Food and Drug Administration doesn’t even require canned foods to come labeled with expiration dates. That said, many manufacturers voluntarily label their products with “best by” or “sell by” dates.

These dates, however, are far from a hard stop. In fact, it’s not illegal for stores to sell canned foods months or even years past these dates. According to the United States Department of Agriculture, canned contents are safe to eat as long as the can is in “good shape.” The Canned Food Alliance agrees, citing 100-year-old canned food recovered from sunken ships that tested microbiologically safe.

Does that mean you can eat food out of a can found on the Titanic? Yes. Does it mean you’ll you want to? Probably not.

Taste, texture and nutritional value are all negatively affected over time. Still, it can take years to notice anything is suspect. According to the Canned Food Alliance, canned food stored in moderate temperatures (75 F or below), has a shelf life of about two years from the date it was processed. After that, you can expect the quality, first the color and texture, to change. Nutritional value can last “well beyond two years.” In terms of edibility, canned food is playing the long game. In fact, most experts don't believe in expiration dates.

“Canned foods do not expire on a certain date,” Ron Giles, quality assurance director of Goya Foods told TODAY Food. “One cannot say that the canned food is good on one day and not good the next day.” Dana Gunders, a former food scientist at the Natural Resources Defence Council, has a similar opinion. “The idea that there's a magic date when foods all of a sudden ‘expire’ is a myth,” said the executive director of ReFED, a nonprofit committed to ending food waste. “I personally would eat anything within 10 years or so of the date it's 'best by' as long as it looked, smelled and tasted fine.”

Which products have a longer shelf life? In general, foods that are more acidic, like fruits and vegetables, will go "bad" sooner. Foods with a more basic pH level will last longer. (Yes, this means good old Spam will likely outlive canned peaches.) For example, Goya’s tomato sauce and fruit have a “best by” date three years from the day of production. Its beans, meanwhile, boast a “best by” date five years from the day of production.

Goya — one of the world's largest food-processing companies — determines a product’s shelf life by looking at industry standards and doing internal evaluations. “As products age we look at taste, texture and appearance,” explained Giles. “Then we compare and contrast those results with recently produced samples.” The company also conducts vacuum tests because the absence of oxygen extends a product’s shelf life.

“Often, we associate canned foods with the can itself, but canning is also a process,” explained Mark Haas, CEO of the Helmsman Group, a company specializing in food and beverage product development. “There are many foods that go through aseptic or retort processing to stabilize the food for long-term storage.” Still, it's OK to try to judge a can’s contents by its cover.

The problem with cans that are in less-than-perfect condition (think dents, dings and swollen areas) is that the hermetic seal and protective lining inside might be broken. Cans are coated with an interior lining that prevents the can's metal from coming in direct contact with its contents. If the outside of the can is dented, there’s a good chance the interior lining is compromised as well.

Usually, this results in the can rusting or swelling up as the food reacts with the steel, tin or aluminum. Bacteria can also grow and release gases that make the can bulge. (Botulism is a concern for goods improperly canned at home, but it's not a concern for commercially canned food.)

If the can looks fine but you’re still uncomfortable with it being past the "best by" date, donate it to a food pantry. Many food pantries accept — or will properly dispose of — expired goods. To avoid getting into a tricky situation in the first place, implement the first in, first out rule. Store newer items in the back and keep older items in front so you use them in order of their "best by" dates.

If the can looks fine and you want to go for it, no problem! Just get a good whiff of what's inside before digging in. And if something doesn't smell right (or look right), don't eat it. And don't serve it to others.