These airport surfaces are covered in the most bacteria

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Be careful what you touch the next time you're at the airport.

According to recent tests conducted at a handful of the United States' top airports, self-check-in screens are covered in germs.

The same goes for the armrests on the chairs near airline gates, and water fountain buttons throughout the airport.

Over the recent holiday travel season, tested surfaces at three of the country's busiest airports. Swabs from those tests were then sent off to a lab to determine the average number of viable bacteria and fungal cells per square inch, or colony-forming units (CFU) as they are otherwise known.

While not entirely surprising, the resulting report shows some alarming levels of bacteria. One particular self-check-in screen had more than 1 million CFU. The average self-check-in screen had about 253,857 CFU.

To put that in perspective, the average bathroom doorknob has about 203 CFU.

"The kiosks may offer more convenience, but at what cost?" states the report.

Handrests on chairs near boarding gates were found to have about 21,630 CFU. How bad is that exactly? Kitchen sinks, typically the most contaminated places in a home, hosting more bacteria than a toilet seat, have fewer bacteria than an armrest at the airport.

Airport surfaces weren't the only places tested for the report. Researchers also took to the skies and inspected airplane surfaces.

Coming as no surprise, the lavatory flush button was found to be the dirtiest place travelers touch on a plane. They have an average of 95,145 CFU. Kitchen countertops, by comparison, have an average of 361 CFU.

"It's often thought airplanes are cleaned between each flight, but the FAA actually doesn't regulate or inspect aircraft cleaning," states the report. "Each airline can decide how often and how well an airplane is cleaned, so if the turnaround time between flights is low, the plane may not be cleaned at all."

The report additionally states, however, even when planes are cleaned, only basic, general cleaners are being used not strong disinfectants. In other words, the dangerous germs remain.

Tray tables should also be approached with caution. The report found them to have 11,595 CFU. Even seat belt buckles didn't escape the list. They have 1,116 CFU.

Though not all bacteria are harmful, there's definitely reason to take caution. A type of bacteria known as gram-positive cocci, for instance, are often the cause of pneumonia; skin, ear and sinus infections; food poisoning, meningitis and toxic shock syndrome.

This particular strain of bacteria was found on all of the surfaces that were tested as part of the report. The greatest percentages turned up on lavatory flush buttons (82 percent) and tray tables (65 percent).

The moral of the story? Germs are everywhere and unavoidable. So pack hand sanitizer and sanitizing wipes on your next trip.