Sticks poked into caramel apples release enough juice to make a nice, nourishing place for Listeria bacteria to grow, researchers reported Tuesday.
The finding could explain a caramel apple-linked Listeria outbreak linked that killed seven people and sickened at least 35 last month, NBC News reported.
"Caramel-coated apples are not a food on which Listeria monocytogenes should grow," said Kathleen Glass, of the University of Wisconsin-Madison, and colleagues.
But in their experiment, the researchers found that apples with sticks inserted did grow Listeria, even inside refrigerators, albeit more slowly, they wrote.
U.S. & World
Listeria can kill the very young, very old and people with weakened immune systems, and can cause miscarriages and stillbirths.