This is MYTH.
As industrialization and urbanization spread, people moved away from their farms and into cities. They began purchasing foods from grocery stores, but had no way to monitor freshness and food quality…and so the demand for expiration dates spread, and “sell by,” “use by,” and “best by/before” popped up on foodstuffs across America. These dates, however, don’t really measure food safety at all, and lead to perfectly good foods being tossed into the trash before their time. According to a 2013 report from the Natural Resources Defense Council (NRDC) and Harvard, more than 90% of Americans throw away food that’s still fresh because dates are leading them astray!
What “Sell By” Really Means
That “sell by” date on your egg carton isn’t meant for you, the consumer, but for food retailers to keep track of stock and proper turnover. Unfortunately, many consumers use the “sell by” date as an indicator of food safety, leading to an inordinate amount of wasted food. The authors of the NRDC report suggest making these “sell by” dates invisible to consumers so that they aren’t led astray, although the United States Department of Agriculture recommends not buying after the “sell by” date has passed.
What “Best By” or “Best Before” Really Means
These labels are also not indicators of expiration, but of freshness. It simply means, “this is when the product is at its freshest and best quality.” When consumed after the date, the effect on freshness, texture, and taste is often very little.
“What “Use By” Really Means
The “use by” date marks the last day the product is at peak freshness…not the last date when it’s safe to eat. And these dates vary widely even among similar products. According to the NRDC report, “In most cases, consumers have no way of knowing how a “sell by” or “use by” date has been defined or calculated, and the method of calculation may vary widely by product type, manufacturer and geography.”
The USDA advises against eating foods beyond their “use by” date, but also explains: “Use by” dates usually refer to best quality and are not safety dates. Even if the date expires during home storage, a product should be safe, wholesome and of good quality if handled properly.”
In the United States, there is no regulated or uniform system for food dating. Perishables such as eggs, dairy and meats are typically labeled with “open dating,” which refers to a calendar day, while processed boxed and canned goods are marked with “closed” or coded” dates for manufacturer use only.
Throw Out Those Moldy Foods!
On the flipside, all moldy foods should go. Don’t be tempted to cut around the moldy portions of bread. Chances are the roots of the mold have spread and infected the whole loaf. When you spy mold, throw away perishables such as soft cheeses, breads, fruits, and vegetables.