Can fruitcake last forever? A food-safety expert answers.

The legend of the fruitcake is that there is only one, which gets passed from person to person, year after year, at least according to a joke attributed to Johnny Carson.

But how long can fruitcake really last? In an entertaining post over at North Carolina State University’s news blog, press officer Matt Shipman decided to get down to the bottom of this and interviewed one of the university’s food scientists to find out:

“All of these dried and candied ingredients have what we call ‘low water activity,’ meaning they have very little moisture available,” says Ben Chapman, a food safety researcher at NC State. “Low water activity is important because many microorganisms, including foodborne illness-causing bacteria, need moisture in order to reproduce.

“In practical terms, this makes most fruitcakes extremely shelf stable, so they would be safe to eat for a long time – a really long time,” Chapman says. “But it might taste pretty bad.”

The USDA cites two to three months, refrigerated, according to Shipman. Chapman comes up with something somewhat vague, but a lot longer. Head over to the post to read the whole thing.