Did you know that as much as 40 percent of the food in America gets sent to the landfill or dumped down the drain each year?

That's 133 billion pounds.

Part of the reason why is we throw away a lot of food that's actually still good to eat.

So it begs the question... can you still eat that?

Why do we throw so much food away?

It might have to do with expiration dates.

First off, the term "expiration date" is misleading.

For many foods, they're just suggestions made by the manufacturer for when the food is at its peak quality, not when it's unsafe to eat.

Except for infant formula, deli meats and a few others, expiration dates have nothing to do with food poisoning.

And these dates usually aren't based on current science.

Stuff sealed in cans or other shelf-stable foods can stay safe for years.

For the stuff that is perishable, it's easy to tell if something's gone bad.

If it smells or tastes weird, don't eat it.

For other stuff, here's what's going on and how to handle it.

Let's start with the easy stuff.

These fruits might look a little gross, but they're probably still good to eat.

Okay maybe this one is best for some banana bread.

Why are they soft?

Because enzymes.

Enzymes are biochemical workhorses that make reactions possible by reducing the amount of energy needed to, well, react.

In this case, they speed up the reaction that breaks down the cell walls in this mushy pear.

As fruit ripens, enzymes turn parts of the rigid plant cell walls into simple sugars like glucose.

Meanwhile, other enzymes break down starch inside those cells to make even more of those simple sugars.

What I'm trying to say is, the riper the fruit, the sweeter it is.

So unless you see mold on it or it's slimy, soft, ripe fruit is probably OK to eat!

Okay, but why does it get brown?

When the compounds in plants are exposed to the air, like if you slice an apple or save half an avocado for later, oxidation reactions happen.

An enzyme called polyphenol oxidase starts oxidizing polyphenols iin the fruit, which turns those colorless molecules into brown-colored ones.

Other oxidation reactions are happening as well, breaking down flavor molecules.

So some overripe fruits and vegetables might not taste as good, but that doesn't mean they're bad for you.

What about this guy though?

This guy you don't want to eat.

That fuzzy stuff is mold, a type of fungus.

Not all molds are bad.

The molds in these cheeses are there on purpose.

But generally, if your fruit or vegetables or bread are growing mold, get rid of them!

And we're talking about that entire loaf here, not that one slice with mold.

The same thing goes for any cooked leftovers with mold.

In hard cheeses, it's okay to cut the mold out, along with at least 1 inch chunk of the food around it.

The reason you want to throw away moldy foods is because the thread-like molds can penetrate deep into your food, like tree roots.

Especially in moist foods such as bread or fruits, these strands can extend deep within.

The problem with molds is some make chemicals called mycotoxins (MY-coh-tox-inns), compounds made by fungi that can harm us.

Mycotoxins are behind the irritation from athlete's foot.

More serious ones can attack the nervous system and other organs, or even cause cancer years down the road.

While mycotoxins only come from certain molds under certain conditions, it's better to be safe than sorry.

Now when milk goes bad, that's because of bacteria.

Some feed on the sugar lactose in milk, producing lactic acid as a byproduct.

Acids have a sour taste, which is why your milk tastes sour now.

Other bacterias break down fats and proteins into gross tasting waste products.

These bacteria are mostly harmless, and with pasteurization there's little chance that anything bad is going to grow in store-bought milk.

So follow safe cooking and storage guidelines, especially for meats.

And if something looks or smells really weird, don't eat it!

Just don't worry too much if your banana's getting brown or the milk is a little funky.

What about other food?

We can't cover everything in this video, so we left some helpful links in the doobley-do below, including a neat app from scientists at Cornell and the USDA called FoodKeeper.

It can tell you important stuff like whether that slice of pizza is still edible...

Which, by the way, it is not.

It's been in your fridge for two weeks.

Get your life together.

Who doesn't eat leftover pizza.

Anyway like share and subscribe and hey, thanks for watching!