Dr Oz: Food Safety Tips + What Does a Sell By Date Really Mean? NEXT PAGE ADVERTISEMENT Dr Oz: What Does the “Sell By” Date Really Mean on Food Labels? Have you ever wondered what the dates on food labels really mean? Registered dietitian Frances Largeman-Roth breaks it down and what she reveals might just surprise you! Dr Oz says the “sell by” date on a product is strictly for the retailer so they know how long they can keep the item on the shelf.