What do label expiration dates mean?                        

                The term expiration date is a misnomer. For many products it’s only a calendar date but you will usually see sell by or best if used by or something similar on food items. None of these dates have anything to do with safety or imminent spoilage. Sell by is posted for the benefit of the retailer. It would be bad PR to leave a product on the shelf after the sell by date.

            Food doesn’t spoil immediately after the use by date but quality might suffer. You’re not likely to notice the difference but it’s the best guess by the manufacturer of the time when flavor and possibly nutrient value are likely to decline. The degree and the rate of spoilage vary greatly. Did the late Twinkies even have an expiration date?

            Canned and frozen foods sometimes have expiration dates but they don’t really need them. The former can last unchanged for decades and the use by dates of frozen foods are usually about two years out. There is little reason to keep food that long.

            Eggs don’t change much for about 4 or 5 weeks after they are placed on the grocery store rack and the sell by date is usually twice that long. It’s a good idea to keep them refrigerated anyway.

            Most prescription drugs have expiration dates but determining them is an art as well as a science. In dry, cool conditions they are likely to retain potency beyond their stated shelf life but the calendar date gives an estimate of the time until which they retain their full effectiveness. Specifically, prescription drugs do not become toxic if they are taken after the date stamped on the box or bottle. There is one exception but it was an antibiotic that is no longer being manufactured. Still, because the effectiveness of medications does decline with time it’s a good idea not to take a prescription drug longer than a month or so beyond the posted date.

Our modern agribusiness has selected and manipulated varieties of fruits and vegetables that “keep” much better than those that our grandparents knew. These plant products must survive days if not weeks of storage and travel, sometimes across an ocean, and still look good in the produce bin. We’ve all experienced flavorless tomatoes, mealy peaches and tasteless bananas. Perhaps if they were labeled with “best if eaten by” dates we would have more enlightened choices.