That ‘Sell By’ Date Doesn’t Tell You When Your Food Will Go Bad

Trying to decide whether that quarter-gallon of milk left in the back of the fridge is any good? You’ll probably want to check the date. Unfortunately, it probably says “sell by,” not exactly informative.

“Sell by” date hasn’t passed? You might pour a glass and still have it come out all chunky. “Sell by” date went by a few weeks ago? You still might toss some perfectly-good milk in the trash.

“The Dating Game,” a study by Emily Broad Leib, Director of the Harvard Food Law and Policy Clinic, found that the inconsistent and confusing food dating system leads to food waste and decreased food safety, and that change is needed.

That’s because consumers are trying to base decisions on dates that are meant for manufacture and retail use. Before the 1970s, “sell by” dates were largely “closed,” meaning they were written in symbols and codes that were unreadable by consumers.


That changed throughout the 70s as consumers demanded more information about the freshness of what they were eating. Retailers often responded by simply “opening” the “sell by” dates.

But these dates have little meaning for consumers. And at the same time, different retailers adopted different labels meaning different things, including “best by,” “use before,” and “enjoy by,” and different states introduced a patchwork of labeling requirements across the country.

So consumers tend to fixate on misleading dates, assuming that anything past the date has gone bad, which is not the case. They also tend to discount reasons that pre-date food could be bad, like poor refrigeration, leading to potential food poisoning.

The Harvard report recommended making “sell by” dates invisible to consumers again, replacing them with a “reliable, coherent, and uniform consumer-facing dating system” that would give consumers the information they need, and nothing more.

Misleading expiration dates compound the serious problem of food waste in the U.S. Americans throw out about 40% of their food, and decomposing food releases methane, a greenhouse gas 20 times more effective at trapping heat than carbon. Seventeen percent of U.S. methane emissions come from landfills, according to the EPA. And 2 percent of all U.S. energy goes to produce food that will be wasted.


Food waste globally emits so much in the way of greenhouse gases that if it was a country, it would be the third-largest emitter in the world. Fixing food date labeling could go a long way towards reducing the U.S. contribution to those emissions.