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Germs on Your Phone: Counting Bacteria on Cell Phones and headphones

We live in a world connected by smartphones – some of which are becoming more and more like full-service computers that fit perfectly in the palm of our hand. With the average American checking their phone 80 times per day and people actually developing separation anxiety from their devices, knowing the risks that come along with consistent use is important.

We've all heard the scary stories of phones causing beds to ignite and the warnings that too much screen time can cause cancer, but these scenarios are not the norm. Fire-causing phones are usually caused by manufacturer defects and no direct link to cancer has been found.

So, what risks are there? Turns out the risk to our health may be on the surface of our devices – and the headphones we use with them. We swabbed personal headphones and cell phones, as well as in-store display phones, to see how dirty our devices really are. Keep reading to find out how many germs you may come into contact with every time you check your phone.

Aural Organisms

Germs on In-Ear headphones

Mobile phones are already pretty convenient to use compared to the corded phones we used to be tethered to, but headphones have added another layer of convenience by allowing users to take phone calls without the use of hands. However, not touching your phone doesn't mean you're not coming into contact with germs. The average pair of personal in-ear headphones is home to 119,186 CFU, or colony-forming units. That's more than 2,700 times the bacteria on an average cutting board and 330 times more bacteria than a kitchen countertop.

Not all headphones are crawling with bacteria, though. Of the five headphones we performed gram and stain swabs on, one pair had a CFU count of 20, while another had a whopping 830,000 CFU. Even with such a large range and the possibility of your headphones falling toward the lower end, it can't hurt to take a few minutes and disinfect them every so often.

Germs on the Go

Germs on Display Versus Personal Cell Phones

Going hands-free may be more convenient for on-the-go talkers, but plugging in headphones is definitely less sanitary. Surprisingly, mobile phones don't have that much bacteria – the average personal phone has only 22 CFU. Compared to headphones, this seems very minimal, but it is still more CFU than are typically found on paper money.

Phones on display in a store, however, are a minefield for bacteria. Compared to personal phones, display phones have over 500 times more bacteria, with an average of 11,210 CFU. The three phones with the highest number of CFU happened to be iPhones, but this may be due to the massive amount of traffic Apple stores get each day. Regardless of whether you're using an Android or Apple device, washing your hands after testing out display phones can help keep germs at bay.

Sanitize Your Cellphone

Since we can't see the pesky germs on the devices we use every day, it would be best to sanitize our phone and headphones every once in a while. And when you decide to play with the latest device in the store, be sure to wash your hands afterward to help ensure no germs are following you home.

Methodology

We conducted 15 individual gram and stain culture swab tests. Five swabs were conducted for in-store display cell phones, personal cell phones, and personal in-ear headphone buds. Display phones were swabbed at two individual retail locations located within a shopping mall. Display phones were limited to the latest available models at the time of swab. Personal phones and personal in-ear headphone buds were swabbed from five individual users. Swabs of phones covered a 1 square inch surface area of the home button or bottom-center of the screen. Phones were limited to devices that did not have a protective screen cover. In-ear headphone buds were swabbed across the entirety of the headphone bud and within the center of the bud. Colony-forming units per square inch were averaged for each surface type.

Fair Use Statement

After you've disinfected your device, feel free to share this study. We grant you permission to use this project's content and images for non-commercial purposes. Just make sure to link back to this page so the authors get proper credit.