How long is food safe to eat after the best if used by date? Longer than you think.

In a Facebook group focused on Trader Joe’s meal ideas, a woman created a post in February with a photo of the store’s branded Green Goddess Salad Dressing.

She’d bought the bottle months earlier, she wrote, and it had a use by date of Dec. 16, 2021. But she hadn’t opened it and it had been refrigerated. The photo of the bottle showed it appeared the typical green color.

“Do you think it’s still good or should I toss it?” she asked group members.

And the great debate began.

“Heck, it’s unopened and refrigerated, I’m sure it’s fine!” one woman replied.

“I wouldn't chance getting sick,” said another.

“Toss it,” many people chimed in.

“I would eat it,” said others.

Out of 80 comments the post garnered, exactly 50% were of the “toss it” variety and the other half said either it’s OK to eat, or taste it and if it tastes good it’s fine.

Erin Kuhn, the original poster, thanked the group for their input. She said via messenger that she threw out the salad dressing because most of the responses that came in early said to toss it.

It’s possible the dressing wouldn’t have tasted fresh, but very unlikely that it would have made anyone sick, food safety experts said. That’s because the date labels we see on products such as “best by” or “sell by” are tied to food quality, not safety.

There is no federal regulation that requires these dates. Manufacturers apply them to help consumers and retailers decide when food is of the best quality.

“It is the manufacturer wanting to present the same quality product to their consumer every single time,” said Trevor Craig, corporate director of technical training and consulting for food testing company Microbac Laboratories.

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Except for infant formula, dates are not an indicator of the product’s safety.

But many consumers don’t know the origin of these dates or their true meaning.

People adhering too strictly to a best by date leads to wholesome food being discarded – to the tune of 30 million tons of food waste from homes every year, according to the nonprofit ReFED.

That uneaten food costs the average family of four between $1,500 and $1,800 a year, according to Richard Chesley, manager of the South Carolina Department of Health and Environmental Control’s recycling office.

“Food labels are a significant cause of wasted food,” Chesley said. His office runs the state’s “Don’t Waste Food SC” campaign with a goal of cutting food waste in half by 2030.

The food industry has taken steps to standardize the wording of food labels, asking manufacturers to voluntarily switch to just two descriptions: “best if used by” to indicate quality, and “use by” to indicate potential safety hazards for some foods.

A Consumer Brands Association survey of its members in late 2018 showed 87% compliance with that wording.

But many consumers still see other phrases on their food including “sell by” and “use by" or "freeze by.”

Matching bills in the House and Senate aim to make it federal policy that if a food date label is applied, it must use only the labels “best if used by” and “use by.” The bills also require education campaigns to make sure consumers understand what those two labels mean going forward.

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What does a best-by date mean?

There are two types of dates that may appear on food containers you purchase, according to the U.S. Department of Agriculture.

“Open dating” is a calendar date applied by the manufacturer or retailer and accompanied by a phrase like “best if used by.” The intention is to inform consumers of the date up to which they can expect the food to retain its desired quality and flavor.

“Closed dating” is a series of letters and numbers applied by manufacturers to identify the date and time of production. These codes are more typical on canned goods and shelf-stable products and are used by the manufacturer to track their products across the country and in the case of a recall, according to the USDA.

Open dating started to be added to food in the mid-1980s, according to Andy Harig, vice president of tax, trade, sustainability and policy development for FMI, The Food Industry Association. It was intended to help customers but was never intended to serve as a hard and fast expiration date, he said.

An open dating phrase that instructs consumers to use a product by a certain date is not saying the food is inedible, dangerous or expired on that date. It simply means the manufacturer determined that after that date the food may not be at its optimal taste.

Food manufacturers want you to eat their products when they are at their peak freshness because the food will taste good, Craig said.

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If a product has changed color, smell, texture or taste – even though it may still be perfectly safe to eat – your experience as a consumer is going to be diminished and you might not buy that product again.

Even though they are all focused on quality, different companies have different meanings when they say "best by" or "sell by," Craig said.

"Sell by" is often used to indicate to the retailer when to pull the product from the shelves because neither the manufacturer nor the grocery store wants something that looks bad on display.

Best by dates are usually driven by quality standards within the manufacturer, Craig said.

Companies hire a lab like Microbac to run shelf-life studies and determine how long their products retain the best look, smell, texture, and taste.

“You want a good reputation,” Craig said. “You want the people who eat your product to say it just tastes amazing. … I can't wait to buy more of it.”

Use by dates, meanwhile, are more typically seen in dairy, meat and eggs.

Craig said you can still use it a little bit afterward and it’s still safe until signs of spoilage are detected.

Spoiled foods will develop an off odor, flavor or texture due to naturally occurring spoilage bacteria. If a food has developed such spoilage characteristics, it should not be eaten, according to the USDA.

“Everyone probably has taken a sip of some milk that's not quite as fresh as you wish it was and had a regretful moment there,” Craig said.

“But the important thing to realize is that all three of these are quality driven, not safety,” he said. “So even though something may not look the best, or maybe there's a little bit of wrinkling or color change; that doesn't necessarily mean that it's not safe to eat.”

Food banks have varying policies when it comes to date labels, but there's no law preventing them from taking donations and distributing food that is past the best by date.

"Though some items distributed by food banks may be past a food label date, that product is still safe for consumption," said Wayne Melichar, senior director of food safety at Feeding America.

Their network of 200 food banks and 60,000 food pantries uses the USDA's Food Keeper App to help determine which foods are still good to distribute.

Manufacturers are prohibited from placing false or misleading information on a label, according to the U.S. Food and Drug Administration. But they are not required to obtain FDA approval of their date labels or specify how they arrived at the date they’ve applied.

If a label’s accuracy was called into question, Craig said, the FDA might ask for data to support their claims of quality past a certain date.

Drugs and formula do have expiration dates

Over-the-counter and prescription drugs do have expiration dates because over time the effectiveness of the drug at the recommended dosage may fade.

If taking one pill per day would normally treat an illness, the same pill might be only half as effective past its expiration date.

FDA regulations require drug makers to provide data with a proposed expiration date and storage conditions when they submit an application for FDA approval of their drug.

“If a drug has degraded, it might not provide the patient with the intended benefit because it has a lower strength than intended,” the FDA’s drug expiration date page says. “In addition, when a drug degrades it may yield toxic compounds that could cause consumers to experience unintended side effects.”

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Infant formula also has different rules.

Federal regulations require a use by date on the product label of infant formula that gets inspected by the FDA.

The date ensures the formula contains the quantity of nutrients its label promises.

The FDA said consumers should not buy or use baby formula after its use by date.

Initiative, legislation, say 'best if used by' should be standard food label

In February 2017, FMI and the Consumer Brands Association launched an initiative to standardize the language of food date labels.

Based on research, it was determined that 70% of consumers understood the term “best if used by” to mean that their food will taste best before that date but is not unsafe to eat afterward, according to Emily Broad Leib, director of the Harvard Law School Food Law and Policy Clinic.

The industry partners decided to push for that term to indicate the quality of products while “use by” was reserved for more perishable items.

"'Use by’ applies to the few products that are highly perishable and/or have a food safety concern over time; these products should be consumed by the date listed on the package – and disposed of after that date,” the announcement of the initiative said.

There has been wide adoption of these terms, Broad Leib said, but not universal.

There’s also been an issue in some states where state law requires different labels on foods like eggs.

In 44 states there are regulations concerning food date labeling and 23 states prohibit the sale of certain foods past their printed date label. This means consumers in different states get different messaging about how long food is edible past the date on the packaging.

The Food Date Labeling Act of 2021, introduced in both the Senate and the House last year, would require nationwide compliance with the two standardized terms already voluntarily adopted by much of the food industry.

Education is still key whether the uniform wording is adopted or not. Experts said there are still many consumers who don’t understand when food is okay to eat or not.

“My mom considered expiration dates as a suggestion,” Craig said. “While my father was the opposite way. After something was opened, he thought it started to taste funny within just a few days.”

The shelf-life of food also depends greatly on how it is stored and prepared, Harig said. Something that is supposed to be good for six weeks could go bad much faster if it’s stored in too hot an environment, he said.

The Food Keeper app, developed by the USDA's Food Safety and Inspection Service with Cornell University and FMI, allows consumers to see shelf-life, storage and preparation recommendations for many common types of food.

Consumers also need to trust their instincts, Chesley said. “Use your eyes, use your nose.”

How can you save money when inflation is high?

With inflation at record levels, consumers can save hundreds by not throwing away food just because it’s past its best by date.

“Most of us aren’t aware of how much we waste,” Chesley said.

In South Carolina, one in nine people are food insecure including 1 in 7 children, Chesley said. But for many Americans, “food is just too darn convenient,” making it easy for them to toss food that’s past its best by date and replace it, though it's still safe to eat.

Consumers can also get creative by finding an alternative use for foods that may be slightly stale or past their best by dates, Harig said.

Don’t Waste Food SC has tips for reducing food waste on its website.

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This article originally appeared on USA TODAY: Expiration dates: Is 'best if used by date' accurate? Not entirely.