Not exactly true
Peter Cassel, spokesperson for the FDA, says that “Drinking milk a day or two after the milk’s expiration date (otherwise known as the sell-by date) may not be a safety issue but may be more of a taste issue.”
While drinking milk a few days past the expiration date isn’t exactly a bad thing, it does up your chances of developing a food-borne illness if you are someone with a weakened immune system.