We've all been there – you're digging through your pantry or fridge when you come across a forgotten yogurt or an opened bag of chips. You check the label, and sure enough, the best-by date has passed. Do you take a chance and eat it, or toss it in the trash?

For many of us, this decision is a familiar one, and it’s tough to know what to do. But with a little bit of knowledge about what these labels really mean, you can make informed decisions about your food.

“Knowing the difference can impact your grocery buying, your wallet, and protect you from food borne illnesses,” said Kelly Elliot, a Registered Dietitian Nutritionist at Saint Joseph’s Weight Loss Surgery Center.

A while ago, we detailed the recent U.S. Food and Drug Administration’s changes in food labeling. Now we’re breaking it down further with some of the most common shelf life labels:

Sell-By

This label is usually printed on perishable items like meat, dairy products, and bakery items. It indicates the date by which the store should sell the product to ensure it remains fresh and safe to eat for a reasonable period of time afterward. If you see a product with a sell-by date that has already passed, it doesn't necessarily mean it’s no longer safe to eat. But inspect the product carefully to make sure it hasn't spoiled.

Use-By or Best-By

These labels indicate the date by which the manufacturer recommends using the product for optimal quality and freshness. Unlike expiration dates, use-by or best-by dates are not safety dates, and products can often be consumed safely after these dates have passed, as long as they've been stored properly.

“If a product is at the sell-by date or use-by date but not yet at the expiration date, you could save some money if you know you will be eating it in the next few days,” said Kelly.

Expiration Date

This label indicates the last date on which the manufacturer guarantees the product's safety and quality. After this date has passed, the product may be unsafe to eat and should be thrown out.

“It is important to notice these dates and pay close attention,” said Kelly. “Food poison won’t kill you, but you may almost wish it had! It is a horrible experience and can happen to anyone.”

These labels are only estimates and actual shelf life of a product can vary. For example, if you store a product at a temperature that's too warm, it may spoil quicker than the label suggests. Or if you open a package and expose the contents to air, moisture, or light, they may degrade faster.

You should always inspect products before consuming them, paying attention to things like appearance, texture, and smell. If it looks or smells off, or has an unusual texture or flavor, it's best to err on the side of caution and discard.

Make sure to store your products in optimal conditions recommended on the packaging. This may mean keeping items in the fridge or freezer, or storing them in a cool, dry, dark place.

If you have regular trouble using up certain products before they spoil, consider buying smaller quantities, or freezing leftover ingredients.

“Buying bigger bags of fruits, vegetables, and meat can save money, but not if you are letting much of it go to waste,” said Kelly. “Sometimes smaller packages are cheaper in the long run.”

If buying food in bulk, Kelly suggested dividing contents between the fridge for more immediate needs, and the freezer for later on. Doing inventory checks and properly storing perishables will maximize their use.

With a little bit of planning and attention, you’ll get to enjoy your food safely, and not have to toss forgotten yogurts.