The plastic wrist straps on a Fitbit and an Apple Watch could harbour high levels of potentially harmful bacteria, according to a study.
Researchers at Florida Atlantic University swabbed 20 watches belonging to various men and women working as firefighters, vets and office workers among other professions.
Levels of E.coli and Staphylococcus were found on 60 and 85 per cent of all watch wristbands.
E.Coli can cause severe gastrointestinal infections, while staphylococcus can cause skin infections such as sores and boils.
Pseudomonas, which can lead to serious infections including urinary tract infections, was found on 30 per cent of bands.
Analysis of the samples found that cloth bands were the dirtiest, followed by plastic, rubber, leather and then metal. Gold bands had no detectable bacteria.
Dr Nwadiuto Esiobu, senior author of the study, said: “Porous and static surfaces tend to attract and be colonised by bacteria.
“The quantity and taxonomy of bacteria we found on the wristbands show that there is a need for regular sanitation of these surfaces.
“Even at relatively low numbers these pathogens are of public health significance. Importantly, the ability of many of these bacteria to significantly affect the health of immunocompromised hosts indicates a special need for health care workers and others in hospital environments to regularly sanitise these surfaces.”
The scientists also experimented with different cleaning solutions to see which were most efficient at killing the bacteria.
Lysol disinfectant spray and 70 per cent ethanol was found to kill nearly 100 per cent of the bacteria within 30 seconds, while apple cider vinegar took around 2 minutes to reduce bacteria.
The study was published in the journal Advances in Infectious Diseases.
