Expert sounds alarm after study finds popular travel item carries far more bacteria than expected

Researchers swabbed several common travel items, then incubated the samples to measure bacterial growth in colony-forming units (CFUs).

The results showed that passports - far exceeding every other item tested - contained 436 CFUs. 

Checked baggage ranked second in the study with 97 CFUs, followed by shoes at 65, hand-held luggage at 56, phones at 45 - and coats at 15, according to the test.

Airports and public transportation hubs are high-contact environments. 

Travelers frequently touch shared surfaces such as check-in kiosks, security bins, handrails and luggage handles.

She also advised wiping down high-touch personal items, including passports, phones and luggage handles, before and after trips.

While bacteria are a normal part of everyday life, being aware of how easily they transfer from item to item during travel can help reduce unnecessary exposure, she also indicated. 

Other items called out by experts for attracting an undue amount of dirt and germs include the seatback pockets on airplanes, plus seat belts. 

Freestone also recently commented on another common item that attracts far more dirt and germs than people think. 

She said people should change their kitchen sponges on a daily basis. 

"How often you clean your kitchen sponge depends on what you have been using the sponge for," the expert told The Daily Mail.