Students at the University of Surrey had some interesting results when studying the bacteria on their mobile phones.
Molecular Biology senior lecturer Dr Simon Park said as part of the Practical and Biomedical Bacteriology undergraduate course this year, he asked students to imprint their mobile phones onto bacteriological growth Petri dishes.
In other words, the phones are pressed, keyboard-side, into agar, a firm jelly containing bacterial food such as vitamins and sugars. The bacteria sticks to the jelly and feeds on it for two to three days, growing to colonies that are visible to the naked eye, Dr Park said.
Dr Park said the voluntary project aimed to engage students with their microbiological world that they may overlook everyday.
“For me, it’s a way to engage people with microbiology, not to scare people but to make people more aware of the everyday.”
Most of the students participated and were quite happy to do it, being curious to find out, he said.
“Particularly when we swab the noses and stuff they’re always sort of excited to see what they grow.”
On older phones, the bacteria was more often found on the keyboards of older phones with separate screens, where people were touched the keys continously. The newer touchscreen smartphones generally had bacteria all over, Dr Park said.
While the results look pretty disgusting, most of the bacteria found were harmless, he said. However occasionally some disease carrying bacteria were found such as staphylococcus aureus.
This bacterium generally lived in the nostrils, Dr Park said.
“So a furtive pick of the nose, and quick text after, and you end up with this pathogen on your smartphone.”
The weirdest bacteria found was one called bacillus mycoides, Dr Park said, which was a soil bacterium and very noticeable as it swarms all over the plate with a delicate lace-like pattern.
“It shows that the person who used the phone, either the phone itself or the person has been in contact with soil.”
Every mobile phone tested had something on it and this didn’t surprise Dr Park, he said.
“It’s sort of a microbiological world, whatever we touch and interact with has bacteria and we exchange bacteria with those things.”
Phones varied in how much bacteria were present on phones – some had very few, Dr Park said – so Douglas Adams may have been right after all and telephone sanitizers exist (and run a booming business).
“Each phone tells a story. From these results, it seems that the mobile phone doesn’t just remember telephone numbers, but also harbours a history of our personal and physical contacts such as other people, soil and other matter.”
Thanks to Dr Simon Park for the use of both photos.