Expiration Dates Are Not Regulated
As more and more consumers began to crack the codes, food manufacturers, suppliers, and supermarkets started to voluntarily label their food products with labels featuring information like date of production and date of expiration. Eventually, Congress attempted to pass a few bills which would have regulated such labels but were never successful in doing so. A couple of examples include the Fair Packaging and Labeling Act and the Open Dating Perishable Food Act of 1973—both of which were killed in the Senate by politicians influenced by corporate lobbyists (of course).
With that said, best before dates have become a method in which grocers and other businesses in the resale food industry fool consumers into purchasing products confidently. And since there are no regulations preventing companies from manipulating best before dates, supermarkets can simply re-sticker items with new best before dates until they sell the items. This explains how supermarkets and grocery stores can make so much profit—they’re selling us expired food, essentially.