Don't Toss That Sour Milk! And Other Tips To Cut Kitchen Food Waste

One man's trash is another man's treasure.

As we show in the video above, this is what chef Dan Barber demonstrated earlier this year, when he temporarily turned Blue Hill, his Michelin-starred restaurant in New York City, into an incubator for garbage-to-plate dining.

Barber's intent was to raise awareness about the vast issue of food waste. As we've reported, an estimated 133 billion pounds of food is wasted in the U.S. each year. The typical American family tosses out about $1,500 of food yearly.

All this wasted food is the largest component of solid waste in our landfills, and when it rots, it emits methane — a potent greenhouse gas linked to climate change.

So, you may be wondering, what can I do in my own kitchen?

I talked to Dana Gunders of the Natural Resources Defense Council. Her new book, Waste-Free Kitchen Handbook, which is out this month, is full of tips for tackling food waste at home. An edited transcript of our conversation follows.

I've got to start with my favorite tip in the book: eggs. There's actually a simple test to tell whether they're still good to eat?

Yes. I was really surprised to learn that eggs are good for three to five weeks after their expiration date. And a trick to know if they're still good is to put them in a bowl of water, and if the eggs sink, they're still good to eat. But if they float, they're not good to eat.

The science is that the eggshells are somewhat air permeable, and so over time, they lose moisture and it gets replaced with air.

Decoding expiration dates: A lot of Americans toss food away once the date stamped on a food package passes. But, as we've reported, lots of food is still perfectly good to eat. Is this correct?

Yes. A lot of people misunderstand the dates on food packages. Those dates are actually a manufacturer's best guess as to when a product is at its freshest. Often products can be eaten days, weeks and months after those dates, depending on the product.

To extend shelf life, there are a range of tips. For instance, cheese is best stored in wax paper, because it lets it breathe and it's less likely to mold.

[Editor's note: The book has a directory listing over 85 types of food and information on how long the products stay fresh and how to store, freeze and use them up.]

I know I'm guilty of letting farmers market produce sit in the back of a crisper drawer too long, and once I finally find, say, a head of greens, it's all wilted. I see that in the book, you say there may still be hope for these sorry-looking vegetables?

Yes, most vegetables that wilt in the fridge can be soaked in a bowl of ice water, and that will crisp them up. [For instance, this works well with carrots, greens and broccoli.]

I've been amazed at how a droopy carrot can perk up in a bowl of ice water.

Even lettuce? It seems once lettuce goes a little brown and watery, it's too far gone to eat.

We saute all our other greens. Why not lettuce? When it gets a little brown or wilted, sauteing it is a way to use it up. It's especially good for those bags of mixed greens [that often sit in the fridge too long].

You talk about the importance of using your freezer to its full potential. Can you give some examples?

If I have a bit of a leftover ingredient — say, an onion — I'll chop it up and toss it in the freezer. Or, if I have a half-can of tomatoes, it's easy to pop it in the freezer. They'll last longer.

Bread is a great thing to stick in the freezer. If it's unsliced, it's best to slice it before freezing. That way, you don't have to defrost the whole thing. You can just pop it in the toaster.

And milk. It's easy to put your milk in the freezer when you go on vacation. Defrost it when you come back. Then you don't need to go to the store to get milk for your coffee on the first day back!

I'm imagining that milk is one of the more common items that Americans toss out. I know we don't often finish an entire gallon in a week. But your tip here is that you don't have to throw away sour milk. You can actually cook with it?

Actually, cooking with sour milk is delicious. It's a substitute for buttermilk. You can [use it] in pancake or biscuit batter. And you can't taste the sour! I've pushed it, and let the milk get really old. The pancakes turned out fluffy, and really good.

[Scroll down for Gunders' pancake recipe. Note: As long as it's pasteurized, sour milk is unlikely to make you sick, Gunders writes, because as milk ages, it becomes more acidic, creating an environment "unfriendly to microbes that might cause illness." Raw milk is a different story.]

In the book, you talk about the proper ways to store food in the refrigerator. What are the most useful tips to remember?

Most fruits and vegetables — particularly after being cut — store better in an airtight container. [There are exceptions to this rule.] And it's best to store them in see-through containers so we don't forget about them.

Also, your refrigerator is coldest on bottom and warmest on top. So storing things that need to be colder, like meats, on the bottom is helpful. And [store] things that don't need to be quite as cold, like yogurt, higher up.

Where should eggs be stored? My fridge has a built-in egg crate space on the door.

Never put eggs on the door of the fridge! This is the warmest place, because it gets a blast of room temperature air every time you open the door. So it's better to keep eggs in the main part of the refrigerator.

There must be things that we should toss, right? For instance, meats that have gone off in smell or color? Or what are some other examples?

Potatoes are actually something you want to be careful with. If there's any kind of green tint to the potato, that's something you do not want to eat. It has a natural toxin once it turns green.

Speaking of what not to eat, I was surprised to read that the leafy tops of strawberries are edible. Or maybe I'm just used to slicing them off.

The green tops to strawberries are edible, but they don't taste very good. If you want to use [the whole] strawberry in a smoothie, it saves time.

How can we be smarter in the grocery store?

Industry research shows that about 55 percent of purchases we make in the grocery store are unplanned.

So if we plan better, we may waste less?

Yes, have a few meals in mind. And when you get to the checkout, look in your cart and make sure you're going to have time to eat everything that's in there.

Planning your meals does not need to take two hours. It's just thinking ahead about what you're going to cook that week.

There are lots more planning tips, recipes and storage guidance in the book.

How do you prevent food waste at home? Join the conversation with @NPRFood on Twitter and share your kitchen tips at #foodwaste.

Dana Gunders' Sour Milk Pancakes

Makes about 8 pancakes

Uses up: milk that is beginning to sour

Ingredients:

1 cup/120 grams all-purpose flour or whole-wheat flour (or use 1/2 cup/60 grams of each)

1 tablespoon neutral-flavored oil, such as light olive, grapeseed or canola

2 teaspoons sugar

3/4 teaspoon salt

1/2 teaspoon baking powder

1/4 teaspoon baking soda

1 cup/240 millileters sour milk

2 eggs

Butter or oil for the pan

Optional toppings:

Maple syrup

Raspberries, blueberries, sliced strawberries

Sliced banana

Peanut butter or almond butter

Most of us have had the experience of sniffing a carton of milk, making a gruesome face and going straight to the drain with it. But it turns out there's something better you can do with that milk! Next time you give the sniff test and you're on the fence about it, use it as you would buttermilk in pancakes, waffles and other baked goods. It's amazing how you won't taste even the slightest bit of bitterness.

Of course, you can only eat so many pancakes, so if you know you're not going to get to use milk before it turns sour, put it in the freezer. It may separate a bit when it thaws, but it will be perfectly fine. And if you completely forget about your milk and it's a clotted mess surrounded by a thin, bitter liquid . . . well, it might be time to throw it out.

In a large bowl, whisk together the flour, sugar, salt, baking powder and baking soda until well-combined. In a medium bowl, beat together the milk, eggs and oil. Make a well in the center of the dry ingredients and blend in the milk mixture until the batter is smooth.

Heat a large skillet or griddle over medium heat and coat with a little butter.

Ladle 1/4 cup/60 millileters batter onto the pan to make 4- to 5-inch/10- to 12-centimeter pancakes. Cook for 1 to 2 minutes, until bubbles appear and "dry out," then flip and cook for another 1 to 2 minutes on the second side. Repeat with the remaining batter, using more butter for the pan as needed.

Serve warm with the toppings of your choice.

Planning ahead: Baked goods freeze very well, so you can bake them up to rescue your sour milk, then freeze them for later. You can even do this with pancakes and waffles: Once they're cooled, freeze them solid and store in an airtight container or zip-top bag. Then reheat straight from frozen in a toaster oven or microwave for a real grab-and-go breakfast.