Open dating is found primarily on perishable foods such as meat, poultry, eggs and dairy products. "Closed" or "coded" dating might appear on shelf-stable products such as cans and boxes of food.
A "Sell-By" date tells the store how long to display the product for sale. You should buy the product before the date expires.
A "Best if Used By (or Before)" date is recommended for best flavor or quality. It is not a purchase or safety date.
A "Use-By" date is the last date recommended for the use of the product while at peak quality. The date has been determined by the manufacturer of the product.
"Closed or coded dates" are packing numbers for use by the manufacturer.
Except for "use-by" dates, product dates don't always refer to home storage and use after purchase. But even if the date expires during home storage, a product should be safe, wholesome and of good quality -- if handled properly and kept at 40° F or below.
Foods can develop an off odor, flavor or appearance due to spoilage bacteria. If a food has developed such characteristics, you should not use it for quality reasons.
If foods are mishandled, however, foodborne bacteria can grow and cause foodborne illness -- before or after the date on the package. For example, if hot dogs are taken to a picnic and left out several hours, they wouldn't be safe if used thereafter, even if the date hasn't expired.
Other examples of potential mishandling are products that have been: defrosted at room temperature more than two hours; cross contaminated; or handled by people who don't use proper sanitary practices. Make sure to follow the handling and preparation instructions on the label to ensure top quality and safety.
Last updated July 15, 2015