What is the significance of the "Sell-By" date on the package?

"Sell-By" dates are a guide for retailers. Although many products bear "Sell-By" dates, product dating is not a Federal requirement. While these dates are helpful to the retailer, they are reliable only if the food has been kept at proper temperature during storage and handling. USDA suggests that consumers cook or freeze ground beef within 2 days after purchase for maximum quality.