(CNN) — There’s no better way to test your body’s immune system than by subjecting it to air travel.
With all those enclosed spaces, recirculated air and non-stop streams of people, airports and planes are prime breeding grounds for bacteria.
But which surfaces are the dirtiest of all?
Website Travelmath.com sent a microbiologist to take 26 samples from five U.S. airports and four flights by two major carriers — although it didn’t specify which ones.
According to the lab results, the airplane tray table was the dirtiest of all the locations and surfaces they tested.
Tested tray tables were found to have an average of 2,155 colony-forming units (CFUs) per square inch.
“Since this could provide bacteria direct transmission to your mouth, a clear takeaway from this is to eliminate any direct contact your food has with the tray table,” said Travelmath’s report on the findings.
Coming second on the dirty list were airport drinking fountain buttons, followed by airplane overhead air vents.