Agroup of students from University of Surrey in Britain has revealed that the home button on your smartphone may be harbouring millions of bacteria – some even harmful.

They found that it is not just your own germs that can be found on your phone. The devices also carry bacteria you have picked up from other people, news.com.au reported.

For the study, the team dipped phones into Petri dishes and watched the growths of bacteria flourish. According to Simon Park, the lecturer behind the university’s annual study, phones store a record of our personal touch as well, especially on the home button.

“It is unusual but very effective way of engaging our students with the often overlooked microbiology of everyday life,” Park was quoted as saying.

Most of the bacteria is harmless but some disease-carrying bacteria such as the Staphylococcus aureus were also seen during the experiment.