Do Food Expiration Dates Really Matter?

New York Times

4 hours ago

When you open your fridge, how often do you check the dates on your food? The yogurt container says it's still good for a few more days, but the label on the half-used barbecue sauce says it was best before last Sunday. Should you still eat it?
The answer is complicated. Dates on food packaging usually indicate when food tastes best, not when it's unsafe to eat. In the United States, there are roughly 50 variations of date labels, including 'use by,' 'sell by' and 'packaged on,' nearly all of which indicate when quality or freshness begins declining.
While it's important to mind the printed dates for some foods, an estimated three billion pounds of food get thrown away each year because of confusion over the date label, according to the food waste nonprofit ReFED. Infant formula is the only product that has standardized, federally regulated date labels, leaving lots of questions about when to toss other aging perishables.
Here's what you should know.
A confusing array of tests
In the early to mid-1900s, American households began transitioning from locally grown food toward processed and packaged goods, and some producers began putting dates on their products to ease concerns about freshness. But these labels didn't become widespread until the 1960s and '70s, alongside broader efforts to improve nutrition labeling and transparency.
Today, individual food companies still determine what date goes on their products. But each uses its own methodology, said Londa Nwadike, a food science professor at South Dakota State University.
For instance, she said, some companies might use mathematical models to forecast when freshness declines, while others might conduct special tests wherein food is stored in hotter temperatures, high humidity or increased oxygen levels. Still others might expose a product to mold, yeast or pathogens like E. coli or salmonella. Some companies can't afford to run extensive tests and may simply base their dates on those of competitors.
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