Today’s Wonder of the Day was inspired by Katelyn from Cleveland, OH. Katelyn Wonders, “Why does milk spoil?” Thanks for WONDERing with us, Katelyn!

On busy school mornings, it can seem nearly impossible to get up, get showered, and get out the door on time. Often, the thing we sacrifice when time is short is the most important meal of the day: breakfast.

While it would be nice to sit down each morning to a plate of bacon and eggs or maybe biscuits and gravy, there's no reason to leave the house without eating something. In fact, there's one go-to breakfast favorite that doesn't require any cooking: cereal.

Just pour your favorite cereal into a bowl, add milk, and you'll be ready to start your day off with a burst of energy. Whatever kind of milk your family prefers, always make sure it's fresh and safe to drink. There's nothing worse than pouring spoiled milk on your cereal!

How can you tell if milk is spoiled? Your nose usually knows. The "sniff" test will usually reveal a tell-tale sour odor if your milk is spoiled. You can also check the date on the carton to make sure the expiration date hasn't passed.

With today's modern technology, it's fairly easy to keep milk refrigerated and fresh for many days. In the past, though, that wasn't always the case. To keep milk from spoiling, people had to use a variety of strategies and tricks.

If you happened to live in Russia long ago, an old folk belief would have you add one thing to your milk to keep it from spoiling: a frog. How in the world did a folk belief that Russian brown frogs could keep milk fresh ever get started?

No one knows for sure. Some historians point to old folk tales that featured both frogs and milk. Others believe the association may have developed from the fact that frogs often found their way into milk cans that were submerged in natural springs to keep them cold.

Regardless of the source of the belief, no one ever gave it much scientific credence until recently. In 2012, organic chemists from Moscow State University announced that their studies of frog skin secretions revealed that frogs secrete antibacterial compounds called peptides through their skin.

In fact, they found that some of the peptides they identified were as effective against dangerous bacteria, such as Salmonella and Staphylococcus, as popular prescription antibiotics.

Researchers believe the peptides secreted by frogs act as a first line of defense against potentially-harmful bacteria and other microorganisms that thrive in the damp places frogs and other amphibians call home.

So if your milk is nearing its expiration date, should you throw a frog into it? Scientists don't recommend letting frogs swim in your milk to keep it fresh. Just keep it in the refrigerator and don't let it go past its expiration date.

As for frogs and their skin secretions, scientists hope that the peptides they've identified will help them create new antibiotic drugs. With more and more strains of bacteria becoming resistant to traditional antibiotics, the potential for new drugs synthesized from peptides found in frog's skin is a promising development.

Wonder What's Next?

You’re sure to enjoy tomorrow’s Wonder of the Day if you’re a wizard with flippers!