The myth of the immortal Twinkie is dead, thanks to a new analysis of moldy snack cakes

• When Colin Purrington tweeted photos of his eight-year-old Twinkies, he caught the attention of fungi researchers.
• The researchers analyzed Purrington's Twinkies and found that mold had colonized them.
• Their findings kill the myth that Twinkies last forever.

Matthew Kasson usually studies fungi that sicken trees and wipe out crops. But lately, he's gotten into moldy desserts. A plant pathologist and mycologist at West Virginia University, Kasson tested how various types of fungi grow on marshmallow Peeps last year.

So when he saw photos of strange-looking Twinkies on the Twitter account of former biology professor Colin Purrington, he reached out.

Purrington, a self-described "science fan," turned out to have unearthed some Twinkies he'd kept in his basement since 2012. Thinking the preservative-packed treats might have survived those eight years unscathed, Purrington unwrapped one and took a bite. It turned out to be a bad idea.

"The one I bit into was chewy, unsweet, and smelled like rotting ginkgo fruit," Purrington tweeted on October 4. "I gagged."

One of Purrington's Twinkie photos in particular intrigued Kasson and his colleague Brian Lovett.

"It look[ed] like a mummy finger," Kasson told Business Insider.

Once in contact with the scientists, Purrington mailed them a few Twinkies. Kasson's team analyzed the desserts by drilling into their cores using a bone-marrow biopsy tool, then extracting long cross-sections. They put the samples in lab dishes with fungi nutrients to find out what the Twinkies had living in them.

So far, they've discovered that one of the Twinkies contained cladosporium, a common kitchen mold. They couldn't coax any mold from the wrinkly old Twinkie seen above on the left, likely because it had long since eaten through the cake and died.

The researchers' findings have killed a common myth held about Twinkies: that they stay fresh and edible for decades, or even forever.

"We just thought that some foods were invincible," Kasson said.

Debunking the myth of Twinkie immortality

Contrary to popular belief, the shelf life of a Twinkie is really only about 25 days (and no, they would not survive nuclear war). So after eight years, Purrington's Twinkies had gotten pretty gross.

However, some other old Twinkies have not gotten as moldy as Purrington's did. For instance, one Twinkie has survived relatively intact for 44 years at the George Stevens Academy in Blue Hill, Maine, though it's now a bit dry and dusty.

"Maybe the basement where Colin had these stored had the right conditions for fungal colonization," Kasson said.

Still, the new research suggests that even when fungi colonize Twinkies' outsides, they don't necessarily eat through their insides. For example, the Twinkie with the brown spot in the image above turned out to have a relatively untouched, fluffy white core. Kasson said that's likely because the fluff part is so sugary that it wasn't hospitable to the type of fungi that ate the Twinkie's slightly less sweet golden shell.

'We are advocating for more inclusion of mycology'

Fungi are neither plants nor animals. The organisms exist all over the planet, and they break materials down in processes like fermentation and decomposition. Countless spores float through the air, where they enter humans' airways and settle on food.

But fungi are underappreciated, Kasson said. Bread, beer, and cheese would not exist without them, and nature walks wouldn't be possible, either.

"If you walked through a forest without fungi, you couldn't, because you'd be wading through a mile-high pile of wood," he said.

With their Twinkie and Peeps experiments, Kasson and Lovett hope to raise the profile of mycology, the study of fungi, in the worlds of science education and communication.

"Fungi are grossly underrepresented in biology curriculum. We are advocating for more inclusion of mycology," Kasson said.

His wish is being granted, at least in one sense: Since he began publicizing the Twinkie experiment, Kasson said, he's gotten "five or six" emails from people trying to mail him boxes of Twinkies they've kept stockpiled in their homes. His team has also been offered some 40-year-old Peeps.

"It's funny to receive these emails," he said, adding that instead of being disappointed that their Twinkies won't live forever, the writers seem to have recast their reasons for stockpiling them as aiding in a scientific quest.

"'I understand these are so important now,'" he said, paraphrasing the emails. "'I kept them for a reason, and here is the reason.'"