Every year, people throw away 1.3 billion tons of food—that’s one-third of all food produced going straight into the trash. Imagine coming home from the store and chucking one-third of your groceries—sounds crazy, right?

The average American family of four tosses away about $1,500 dollars per year when they scrape their plates and clean out the refrigerator. According to the UK organization Love Food, Hate Waste, 45 percent of people misunderstand food labeling and toss away food that is still safe to eat. Think you know fetid from just fine? Take this mini-quiz to see if you are wasting food too:

Q: Making some scrambled eggs, but they are a few days passed the “best by” date. Chuck em or fry em?

A:Most likely, fry away. Best by dates are just suggestions. Food producers stamp best by dates on products to ensure the food is perfectly fresh when it is consumed, but food is often safe to eat for days to months after the date.

Q: Salad for lunch: some avocado, shredded carrots, edamame—but the kale is a week past the “sell by” date. It looks fresh and frilly, chop it or drop it?

A: Kale yeah! Chop it up. Ignore the sell by date—that’s for grocers. You are eating the food, not selling it.

Q: Whipping up a pineapple-upside-down cake for dessert. The milk says “use by” yesterday’s date. Toss it in or toss it out?

A: Take a whiff first. “Use by” dates pertain to safety. Products that may be harmful if eaten after spoilage are labeled with these guidelines. The dates are only suggestions, but use caution if you decide to eat after the date.

How did you do? If you didn’t pick up on it, expiration dates are unofficial. With the exception of baby food and formula, they are not federally regulated and are irrelevant to food safety.

It comes down to common sense. If the milk smells sour, don’t drink it. Pass on a fuzzy tomato. Don’t eat the stuff that tastes bad. For more food conservation tips, check out 7 foods that are still delicious (and safe) to eat after expiration.

Follow Sierra on Facebook, Twitter, Pinterest, Instagram and YouTube.