Expiration dates are stamped on food packages as a way to keep consumers safe. You can become ill if you consume some foods, such as meat or dairy products, past their expiration dates, so it's important to pay close attention to the dates stamped on the foods. Canned goods are a little different, however, because the date on the can is technically a "best by" date rather than a hard-and-fast expiration date.
Expiration Date Rules and Regulations
With the exception of infant formula, it's not a federal law that manufacturers put an expiration date on their food packaging, though 20 states have their own regulations, according to the United States Department of Agriculture. If, however, a manufacturer does put a date on its packaging, it must include a month and year, as well as words to describe if that's the expiration date, sell-by date, or the date after which the product will begin to lose freshness. Food manufacturers must follow federal laws requiring food to be wholesome and fit for human consumption. The U.S. Food and Drug Administration can investigate any food manufacturer that isn't following this guideline.
As They Pertain to Canned Goods
Expiration dates aren't found on canned goods except in rare cases, according to the Colorado State University Cooperative Extension website. Instead, most canned goods have a date suggesting that consumers consume it before a date for the best quality. This date is generally within two years of the food being canned. Many canned foods are still safe and edible after two years, but they might have a degraded appearance and taste. One exception is acidic foods, such as canned tomato products and canned citrus fruits, which only keep for about a year and a half, according to the USDA. Another exception is infant formula, which you should never use after the "use by" date.
When to Toss Those Cans
While canned goods have a long shelf life, there are times when you should toss the cans even if the date stamped on the bottom hasn't occurred yet. You should toss cans that have bulging ends or return them, unopened, to the store where you purchased them, according to the Colorado State University Cooperative Extension website. Though rare, bulging cans can be contaminated with the botulism bacteria. Toss cans that are leaking or that spurt liquid when you open them. These are additional signs that the food inside has spoiled. If you open a can of food and find that the food has an odd odor or appearance, err on the side of caution and throw it away, too.
To keep cans as safe as possible, store them in a dark, dry place such as a kitchen cabinet or pantry. If you tend to keep cans for long periods of time, you might note the date you purchased the cans by writing it on the can with a permanent marker, especially if there is no date stamped on the can. It's up the consumer to check dates on canned goods, or any other food, however. Stores might sell foods past the date stamped on the outside of the package, warns the FDA. Whether it's due to negligence or simple human error, it's possible that expired food is sitting on store shelves, so always check the dates before purchasing items.