Office workers are exposed to more germs from their phones and keyboards than toilet seats, scientists reveal.
Flu germs can be transferred
Work stations contain nearly 400 times as many microbes than lavatories, it is claimed.
Office equipment should be regularly disinfected to prevent the spread of viruses and bacteria responsible for disease.
The reality of our grubby working environments is exposed in a study by the University of Arizona.
A desk is capable of supporting 10 million bacteria and the average office contains 20,961 germs per square inch, according to research.
The key offenders are telephones, which harbour up to 25,127 germs per square inch, keyboards 3,295 and computer mice 1,676.
By contrast, the average toilet seat contains 49 germs per square inch, the survey showed.
Microbiologist Dr Charles Gerba, of the University of Arizona, who carried out the research, said: "When someone is infected with a cold or flu bug the surfaces they touch during the day become germ transfer points because some cold and flu viruses can survive on surfaces for up to 72 hours.
"An office can become an incubator."
Dr Gerba's study found bacteria levels increased drastically during the day, peaking after lunch.
Food spills, such as tea and biscuits, can support mini eco-systems, but cleaning of keyboards and phones is not always given high priority.
Dr Gerba said: "Without cleaning, a small area on your desk of phone can sustain millions of bacteria that could potentially cause illness."
The study found that where office workers who were told to clean their desks with disinfecting wipes, bacterial levels were reduced by 99%.
British microbiologist Professor Sally Bloomfield said the study reinforced the need for good hygiene practice both at work and in the home.
She said: "The superhighways for bacteria are hands and the surfaces we touch.
"Viruses are transferred by our hands, especially cold viruses."
She said it was impossible to turn our surroundings into sterile zones, but we can minimise the risk by washing our hands regularly and using alcoholic wipes on office furniture like phones and keyboards.