Do expiration dates really matter? Some judge the quality of perishable food using the sniff test, keeping it refrigerated until smells rotten or rancid, while others toss the food out the minute it hits 12:00 a.m. on the sell-by date.

In a recent opinion piece for Slate, well-known food author Nadia Arumugam answers the question with an emphatic “no.” She spoke with a variety of food scientists and food safety consultants while researching her piece, and came to the conclusion that expiration dates mean very little.

“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,” she said. Expiration dates, according to Arumugam, only provide a false sense of security.

The recent prevalence and diversity of foodborne illness outbreaks has caused people to nervously peer more closely at expiration dates. Until a few years ago, common knowledge had foodborne illness associated with meat and few other food sources.  Outbreaks from foods like spinach, peanut butter, and cookie dough, however, have changed that.

But Arumugam insists that expiration dates address quality–optimum freshness–not safety. So while your broccoli may appear yellow and shriveled, it’s not actually unsafe to eat, just nutrient-depleted.

And according to Arumugam, the rate at which food spoils depends less on time than on the conditions under which it’s stored.

“A package of ground meat will stay fresher longer if placed near the coldest part of the refrigerator (below 40 degrees), than next to the heat-emitting light bulb,” she says.

Instead, Arumugam suggests focusing not on spoilage bacteria, but on disease-causing pathogens like Salmonella and Listeria.

“A new system that somehow prevents the next E. coli outbreak would be far more useful than a fairly arbitrary set of labels that merely (try to) guarantee taste.”

For more on product dating and what it means, see “A Lesson in Food Product Dating, Oct. 14, 2009.”