Scientific testing of mobiles shows that they can have dangerous levels of bacterial activity, which should make you think twice about keeping your mobile phone clean.

Constantly glued to our ears, out mobile phones are just like another limb. But chances are, you've never cleaned yours.

Put your mobile phone under the microscope though, and what it looks like is pretty frightening - crawling with germs, some so bad they could make you very sick.

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Bacteria like e. coli, salmonella and golden staph can all cause food poisoning, and in some cases even kill.

According to Australia's leading professor of microbiology Peter Collington, "golden staph is one of the more serious germs if it gets into our blood stream. Many thousands of Australians per year have that, and about twenty to 30 per cent of people die who have that."

Professor Collington says if we practiced better hand hygiene, our phones wouldn't get contaminated in the first place.

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"After we've been to the toilet, we're expected to wash our hands. If our mobile phone is an extension of our hand, that means you should wash that as well," he said.

Professor Collingwood recommends cleaning your phone with alcohol wipes regularly.

"If everybody was really terrific with hygiene, hardly any of us would be sick, so we've all got a lot of scope to improve."

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This reporter is on Twitter at @PGardnerNews