How to Read Food Expiration Date Codes

If you have diarrhea after eating eggs, you may be wondering if your eggs are bad. Although the expiration date code on your carton of eggs and other packaged foods may provide some clues, these dates are more about food quality than food safety.

When you're looking through your kitchen cupboard for a can of unsweetened cocoa so you can make chocolate zucchini muffins or some other treat, you may come across a few items you forgot about. When you look at the expiration date codes on the back, you may be surprised and possibly embarrassed to learn that the items in your cupboard expired over a year ago. Or did they?

According to the USDA Food Safety and Inspection Service (USDA FSIS), only infant formula requires expiration dating. All other foods labeled with "best-by" or "use-by" dates are determined by the manufacturer and not required by law. The dating of food is voluntary and not indicative of whether the food is safe to eat or not.

Manufacturers use labeling terms when referencing dates for you and the store, including:

• Best if used by: date of optimal flavor and quality for consumer
• Sell by: date store needs to pull product from the shelf
• Use by: date that indicates last day of peak quality

The expiration dates on food are more about quality. According to the USDA FSIS, the dates on your bread bag, milk jug and cereal box determine how long these items will taste like you expect them to taste, not whether they're responsible for your tummy troubles.

Read more: 9 Things You May Not Know About Eggs

You're not the only one with an expired can of peas in the cupboard who wondered whether to cook it or toss it. According to the American Heart Association (AHA), foods that expire during home storage should be safe as long as you stored them properly.

Milk, for example, has a sell-by date, and as long you put your carton in the refrigerator as soon as you get home from the store, your milk should be safe to drink seven days past the sell-by date. Fresh meats, such as chicken or ground beef, also have sell-by dates but have a shorter shelf life than milk and should be cooked or placed in your freezer within three to five days of purchase. Fish should be prepared within one to two days.

The AHA says you need to pay attention to the dates on your eggs and always buy them before their sell-by or expiration date. At home, if you store your eggs in the coldest part of your refrigerator (not the door) in their original container, they should be safe to eat for three to five weeks after you purchase them, even after the sell-by date or expiration date on the label.

If you develop a stomachache after eating eggs in the morning, but followed the food safety rules for your eggs — even if you whipped them up after they expired — your tummy troubles may be from some other cause. That being said, any food with an off odor or texture or with mold growth should be tossed in the trash no matter what the date says.

Read more: What Happens if You Cook Meat After It Has Gone Bad?

According to the Canned Food Alliance, canned foods don't have expiration dates. The codes on the back of your cans, which usually include a series of letters and numbers, refer to the date and place of canning. The USDA refers to these dates as closed dating and manufacturers use the dates to track products, assist with food rotation and locate recalled items.

Though list of letters and numbers on your canned goods aren't expiration date codes, many canned food manufacturers now place best-by dates on their items to indicate quality. However, as noted by the Canned Food Alliance, canned goods have a shelf life of two years after the date of purchase, which may be after the expiration date noted on the can.

Like your more perishable items, if your canned goods look or smell funny, you should toss them. The University of Minnesota Extension also recommends you throw away any cans that are bulging or badly dented, which may be signs of yeast or bacterial growth.