When did you last clean your keyboard?

Which? Computing magazine asked a microbiologist to swab 33 keyboards, a toilet seat, and a toilet door handle at its London office to look for bugs that could cause food poisoning such as e.coli and staphylococcus aureas.

Subsequent tests revealed that four keyboards were "potential health hazards" and that one had far higher levels of germs than a toilet seat - five times worse, and 150 times the acceptable limit for bacteria.

The main cause of the bacteria was people eating their lunch at their desks, according to Which? Poor personal hygiene, such as dodging the hand washing basin after going to the toilet, could also be to blame, it said.

Which? Computing claimed there was nothing particularly unique about its office that could have produced the results. Microbiologist James Francis, of Kingmoor Technical Services, added: "These results are generally typical of offices up and down the country."

Clean IT!

A survey by the magazine showed that the frequency with which people cleaned their computers varied widely.

One in ten (11%) said they never cleaned their keyboard with a further 20% admitting to never cleaning their mouse. Almost half (46%) cleaned their keyboard less than once a month.

Sarah Kidner, editor of Which? Computing, said: "Most people don’t give much thought to the grime that builds up on their PC, but if you don’t clean your computer, you might as well eat your lunch off the toilet.

"Why not give your PC a spring clean? It’s quite simple to do and could prevent your computer from becoming a health hazard."

The magazine offered the following advice:

• Before you start cleaning, shut down the computer and unplug it.

• Gently wipe surfaces with a soft, lint-free cloth. Lightly dampen (not wet) the cloth with a small amount of water or an approved computer cleaning fluid.

• Unplug your keyboard, turn it upside down and shake out any loose dust and food crumbs inside. Disinfect the surface with alcohol wipes.

• There’s an internet myth that you can wash your keyboard in a dishwasher. Don’t!

• Use a vacuum cleaner with a rubber or brush nozzle on exterior surfaces and vents.

• Use compressed air in short bursts to blow dust and debris off computer components. Don’t use a cloth to wipe down internal computer components.

• Headphones can be used by multiple people and can spread germs or even head lice. Wipe them with a damp cloth.