Twinkies reportedly have a shelf life of 45 days—but given that they’re chock-full of preservatives, how long can they really last? Apparently, 40 years and counting, judging from the survival of a long-lived Twinkie in a high school in Blue Hill, Maine, where in 1976 a chemistry instructor began a science experiment that's still going on.

ABC News recently interviewed Roger Bennatti, a now-retired teacher who launched his now-famous snack cake experiment while working at Blue Hill’s George Stevens Academy. Bennatti was teaching a lesson on food additives and shelf life, and a student asked him how long a Twinkie could last.

Bennatti didn’t know the answer, but he was willing to find out. He gave his students a few dollars, and they ran off to the store and returned with a package of two Twinkies. Bennatti opened the package, ate one of them, and placed the second one on top of the blackboard.

Bennatti’s chemistry students eventually graduated, but the Twinkie remained at George Stevens Academy for decades. Bennatti retired in 2005 and passed the still-intact Twinkie on to dean of students Libby Rosemeier, who was herself in Bennatti's class in 1976. Today, the cake sits on display in a glass case in Rosemeier's office and is known as George Stevens Academy’s claim to fame.

Bennatti doesn’t advise taste testing the Twinkie to see if its flavor aged as well as its appearance. He spoke to NPR about the Twinkie in 2005, and even then, the cake was “rather dusty,” Bennatti told Michele Norris, the show’s host at the time. “It's—I must admit, in the past year, because of its fame, it's been sort of taken out and shown more in the past year than in the previous 30 years. So it's begun to sort of exfoliate a little bit. It's starting to flake off just a tad. But it's sort of an off-yellow, dusty—the bottom, you know, appears to be a little, you know, perhaps moldy, but just a little bit of the bottom of it.”

Even though he taught science, Bennatti couldn’t explain to NPR’s Norris why the Twinkie wasn’t covered in green fuzz. He hypothesized that the cake stayed mold-free because it dried out, and also because of its added preservatives. “I'm not sure I'd try to eat it right now,” Bennatti told Norris. “I don't think I'd want to risk it.”

Rosemeier, the Twinkie’s current owner, is thinking about retiring in the next five years. She joked to ABC about finding a new home for the Twinkie at the Smithsonian. (Hopefully, its display case would be far, far away from Julia Child’s kitchen.) To see a picture of the middle-aged dessert, read ABC News's story in full.

[h/t ABC News