Expiration dates mean very little.

What to eat. What not to eat.
Feb. 17 2010 10:18 AM

Ignore Expiration Dates

"Best by," "Sell by," and all those other labels mean very little.

Illustration by Rob Donnelly. Click image to expand.

There's a filet mignon in my fridge that expired four days ago, but it seems OK to me. I take a hesitant whiff and detect no putrid odor of rotting flesh, no oozing, fetid cow juice—just the full-bodied aroma of well-aged meat. A feast for one; I retrieve my frying pan. This is not an isolated experiment or a sad symptom of my radical frugality. With a spirit of teenage rebellion, I disavow any regard for expiration dates.

The fact is that expiration dates mean very little. Food starts to deteriorate from the moment it's harvested, butchered, or processed, but the rate at which it spoils depends less on time than on the conditions under which it's stored. Moisture and warmth are especially detrimental. A package of ground meat, say, will stay fresher longer if placed near the coldest part of a refrigerator (below 40 degrees Fahrenheit), than next to the heat-emitting light bulb. Besides, as University of Minnesota food scientist Ted Labuza explained to me, expiration dates address quality—optimum freshness—rather than safety and are extremely conservative. To account for all manner of consumer, manufacturers imagine how the laziest people with the most undesirable kitchens might store and handle their food, then test their products based on these criteria.

With perishables like milk and meat, most responsible consumers (those who refrigerate their groceries as soon as they get home, for instance) have a three–to-seven-day grace period after the "Sell by" date has elapsed. As for pre-packaged greens, studies show that nutrient loss in vegetables is linked to a decline in appearance. When your broccoli florets yellow or your green beans shrivel, this signals a depletion of vitamins. But if they haven't lost their looks, ignore the printed date. Pasta and rice will taste fine for a year. Unopened packs of cookies are edible for months before the fat oxidizes and they turn rancid. Pancake and cake mixes have at least six months. Canned items are potentially the safest foods around and will keep five years or more if stored in a cold pantry. Labuza recalls a seven-year-old can of chicken chunks he ate recently. "It tasted just like chicken," he said.

Not only are expiration dates misleading, but there's no uniformity in their inaccuracy. Some manufacturers prefer the elusive "Best if used by," others opt for the imperative "Use by," and then there are those who litter their goods with the most unhelpful "Sell by" stamps. (I'm happy my bodega owner is clear on when to dump, but what about me?) Such disparities are a consequence of the fact that, with the exception of infant formula and some baby foods, package dates are unregulated by the federal government. And while some states do exercise oversight, there's no standardization. A handful of states, including Massachusetts and West Virginia, and Washington, D.C., require dating of some form for perishable foods. Twenty states insist on dating for milk products, but each has distinct regulations. Milk heading for consumers in Connecticut must bear a "Sell by" date not more than 12 days from the day of pasteurization. Dairies serving Pennsylvania must conform to 14 days.

That dates feature so prolifically is almost entirely due to industry practices voluntarily adopted by manufacturers and grocery stores. As America urbanized in the early 20th century, town and city dwellers resorted more and more to processed food. In the 1930s, the magazine Consumer Reports argued that Americans increasingly looked to expiration dates as an indication of freshness and quality. Supermarkets responded and in the 1970s some chains implemented their own dating systems. Despite the fact that in the '70s and '80s consumer groups and processors held hearings to establish a federally regulated system, nothing came of them.

These dates have no real legal meaning, either. Only last year, 7th Circuit Judge Richard Posner reversed the conviction of a wily entrepreneur who'd relabeled 1.6 million bottles of Henri's salad dressing with a new "Best when purchased by" date. Posner decided that the prosecutor had unjustly condemned the dressing as rancid, rotten, and harmful, when in fact there was no evidence to suggest that the mature product posed a safety threat.

Expiration dates are intended to inspire confidence, but they only invest us with a false sense of security. The reality is that the onus lies with consumers to judge and maintain the freshness and edibility of their food—by checking for offensive slime, rank smells, and off colors. Perhaps, then, we should do away with dates altogether and have packages equipped with more instructive guidance on properly storing foods, and on detecting spoilage. Better yet, we should focus our efforts on what really matters to our health—not spoilage bacteria, which are fairly docile, but their malevolent counterparts: disease-causing pathogens like salmonella and Listeria, which infect the food we eat not because it's old but as a result of unsanitary conditions at factories or elsewhere along the supply chain. A new system that could somehow prevent the next E. coli outbreak would be far more useful to consumers than a fairly arbitrary set of labels that merely (try to) guarantee taste.

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Nadia Arumugam is a New York City-based food writer and contributer to Forbes.com. Follow her on her blog Chew on This and on Twitter.