Understanding product expiration dates can be like trying to read a foreign language to those who don’t understand how they work, but knowing how to decipher them is key to avoiding food related illnesses.

Food packaging is typically labeled with an “expiration date,” a “sell by date” or a “best if used by date” — labels that are supposed to provide a clear guideline of a product’s freshness.

A survey released this week by NSF International, a global health and safety organization, found food labels are actually the cause of a lot of headaches for Americans. The survey found that 27 percent of Americans don’t throw away food by the expiration date, which indicates the date food should be thrown away.

However, Callie Nelson, Dallas County extension coordinator, said a lot of the confusion comes from the “sell by” label.

“Most people think that if it says “sale by” that it is no longer good and that you shouldn’t buy it,” Nelson said. “It doesn’t mean it’s not good. It just means the store can no longer sell it and guarantee its freshness.”

Nelson said most food bought on the sell by date needs to be used within two to three days, especially if it is a meat.

The “best if used by” label has nothing to do with food safety. Instead, it refers to when the food will be at its peak quality and freshness, although Nelson said it would not typically spoil.

“Those things don’t really expire,” Nelson said. “They will never get will they will poison you, like cereal or macaroni and rice. That stuff will last forever. It may not taste the best, because the flavor won’t get off but it will not spoil.”

The survey by NSF International said that 51 percent of those polled throw out food based on the “best if used by” date, which results in a lot of food being wasted each year.

Dave Oliver, owner of Dave’s Market in Valley Grande, said he stresses every day to the store’s employees how important keeping track of expiration dates is. He has been in the grocery store business for over 40 years, so he has witnessed first hand how expiration labels have been implemented through the years.

“They are getting tougher on dates,” Oliver said. “Everything is dated now, except for the non-food stuff. Baby food and WIC items, they check you. You’ve got the county health inspector and state inspector checking you. You have to stress dates.”