In the U.S., diners throw away about 40 percent of the country's food supply every year. Food waste is a huge issue, but it’s hard not to occasionally let fruits, vegetables, deli meats, and other fresh foods wither in your fridge. What if you could avoid the frustration of taking out a slice of bread only to realize it’s covered in mold?

Andy George of the video series "How to Make Everything" wanted to put together a sandwich that wouldn’t go bad—one that he could come back to in a year and still safely eat. To do so, he talked to Daniel O’Sullivan, a professor of microbiology at the University of Minnesota, about the causes of spoilage. Essentially, keeping foods from spoiling means creating an environment where mold, yeast, and bacteria can’t grow.

The main ways to stop food from going bad include lowering temperatures, dehydrating, or lowering the pH (through pickling or fermentation), all of which make it difficult for those microbes to grow. George pickled, dried, smoked, and salted everything he needed to make a sandwich (even the bread), trying each technique on each ingredient to compare how they aged.

Delicious? Absolutely not. But safe? Yes—at least some of them. (Note: Don’t smoke your eggs.)

[h/t likeCOOL]