When Should You Toss Those Leftovers?

You’re rummaging through your fridge, looking for something to eat for dinner. You come across leftover takeout—but you can’t remember when you ordered it. Was it a few days ago or a couple weeks ago? Is eating this a bad idea?

The same goes for packaged products you bought from the grocery store. They have “sell by” or “best if used by” dates. But if the date on the container has recently come and gone, you might be left wondering if you’ll get sick from eating it or if throwing it out would be wasteful.Leftovers pbs rewire

And when you’re on a tight budget, being wasteful is the last thing you want to do.

It turns out, we aren’t very good at gauging when food is beyond edible. In fact, “90 percent of us throw away food too soon,” according to the National Resources Defense Council.

Waste not, want not

The food waste problem feels lose-lose. If we calculate wrong and eat food that’s really unsafe, we risk discomfort, medical costs or even a health emergency.

Yet we also lose big when we throw our money in the trash. In the U.S. alone, an estimated $162 billion in food is pitched each year, a lot of it unspoiled, according to an article by Londa Nwadike, a consumer food safety specialist for Kansas and Missouri.

“Part of these losses are due to consumers being confused about the “use-by” and “best before” dates on food packaging,” she wrote. “Contrary to popular impression, the current system of food product dating isn’t really designed to help us figure out when something from the fridge has passed the line from edible to inedible.”

Making labels smart

Fortunately, researchers are working to bring us a better way of reducing food waste.

At a recent meeting of the American Chemical Society, researchers reported that they are developing “smart labels” that could alert consumers to the spoilage status of their foods, cosmetics and other products.

These paper sensors test products for a toxin that’s present in spoiling products ranging from cereal to coffee. Their use could be extended to testing for other things, including salmonella and E. coli.

Don’t look for these smart labels on grocery store shelves near you just yet, however. The labels are still a work in progress.

So, how can you tell when something’s unsafe to eat?

As National Food Safety Education Month comes to a close, Nwadike shared these tips for minimizing food waste without risking your health:

1. Avoid the “temperature danger zone”
When it comes to foods that need to be refrigerated, temperatures between 40 degrees and 140 degrees can be hazardous. When a food sits in those temperatures for an extended period of time, it can become unsafe to eat.

Even if it’s in a cold or air-conditioned environment, make sure you don’t leave food out of the refrigerator for more than two hours. Food should only be exposed to warm temperatures (like an outdoor picnic on a 90-degree day) for an hour, maximum.

Be mindful of when you schedule your grocery shopping. Make food shopping the last errand before you return home.

2. Don’t let food become garbage

Become a self-aware grocery shopper. Don’t buy more food than you can reasonably eat before it starts to go bad.

Label takeout containers with the date you ordered the food. Label containers of leftovers from homemade meals with the date you cooked the meal.

And “don’t buy way more food than you need, just because it’s on sale,” Nwadike said.

If foods are getting a little past their prime but still seem safe to eat, consider alternative uses for them. For example, you could include slightly mushy vegetables in a soup, or sauté limp spinach.

3. Understand the purpose of dates on food packaging

Despite how much credence we give them, the dates stamped on food aren’t federally regulated in the U.S., with the exception of those included on infant formula and baby food packaging.

Leftovers pbs rewireHowever, some states regulate the dates that manufacturers put on their packaging.

Keep in mind that “sell by,” “best if used by” and “use by” dates all have different meanings:

– “Sell by” dates are meant to be used by stores that are selling food, not by consumers.

– “Best if used by” dates indicate when food is at its peak quality in terms of flavor.

– “Use by” is the last date a manufacturer recommends you consume the food.

Manufacturers can determine these dates by conducting their own testing on the food or by adopting dating systems that resemble those used by other companies that make similar types of food.

Manufacturers want to create a “nice eating experience for the customer,” Nwadike said, so these dates tend to reflect that.

There is usually a window of time between a “use by” date and when a food is actually unsafe to eat. But, it can be difficult to gauge just how much wiggle room that date includes. Whether this is days, weeks or more depends on the amount of time each individual manufacturer has decided to build in. It’s always a good policy to do a sniff test on expired food before using it or throwing it out.

4. Use storage guidelines instead.

You can access storage guidelines from a variety of sources, including universities and the federal government. The FoodKeeper app can help, too.

For example, eggs can live in your fridge for four to five weeks. You can keep prepackaged meals in your freezer for three to four months. But only keep raw hamburger in your fridge for one to two days, according to the FDA’s helpful fact sheet.

You might even consider printing off a copy of the storage guidelines and hanging it on your refrigerator as a quick reference when you’re unsure about whether a food is still safe to eat.

If a food is approaching the end of its useful life, consider freezing it. You can keep it frozen for long periods of time and foods will be “just as safe when you take them out as when you put them in,” Nwadike said.

However, if the food was unsafe to eat when you froze it, freezing it won’t rid it of harmful bacteria and other contaminants.

5. “When in doubt, throw it out.”

Sure, you might feel guilty when you find leftovers you forgot about in the back of the fridge. But don’t let your guilt trick you into eating food that’s sketchy. If you can’t remember how old it is, get rid of it. The same goes for if the food has a strange smell or “looks funny.”

If the food’s texture has changed, it’s a judgment call. If it’s just watery, it might still be safe to eat. However, there are other texture changes that are more worrisome. For example, when milk curdles, “that’s a warning sign,” Nwadike said.

Rachel Crowell

Rachel Crowell is a Midwest-based writer exploring science and math. Rachel lives in Iowa with Delilah, a golden retriever a stranger once called “the cutest thing in America.” Outside of STEM topics, Rachel welcomes writing opportunities on everything from art to finance. Follow Rachel on Twitter at @writesRCrowell. Reach Rachel at [email protected]