A public bathroom hand dryer isn’t blowing hot air from an aromatic garden of tulips. The dryer is sucking in air from every nook and cranny of the restroom. And these machines pick up a few tiny passengers along the way, including bacteria, and deposit these microbes on your newly washed hands.

This is what researchers at the University of Connecticut’s medical school found when they tested the hand dryers in their school’s public restrooms. The bacteria come from a variety of sources, including the skin of people walking into the restroom. But there are other obvious sources: the toilets.

In fact, scientists have a specific term for the eruption of microscopic bacteria from a flushing toilet. It’s called “toilet plume.” Bacteria can be launched into the air, riding the gentle currents until a hand dryer draws them in and deposits them onto your fingers, hands and face.

The researchers examined glucose-coated plates exposed to 30 seconds of air flow from a dryer and found discovered up to 60 bacterial colonies. When they took samples with the hand dryers off, exposing the plates to undisturbed restroom air, the colony count was no higher than six.

Bacteria included those found in the human gut as well as bacteria suspected of causing infections.

The researchers noted they could reduce the number of bacteria four-fold by installing high-efficiency particulate air, or HEPA, filters. But in this case, medical school officials decided it was best to move in a different direction. They switched out the hand dryers in their bathrooms for paper towels.

The lesson in all of this: If given a choice in a public “tulip garden,” consider picking paper, not hot air.