Don't eat at your desk!

Experts believe the tendency for workers to eat lunch at their desk is the reason for the massive rise in office germs.

The dirtiest spot on the desktop is the phone, the researchers found, where about 25,127 microbes live per square inch. Experts believe this is because handsets are often passed between people.

The next filthiest area is the desk surface, where 20,961 invisible microbes can be found living and breathing on every square inch.

By comparison, the average lavatory seat contains just 49 germs per square inch.

Other unclean areas are water fountain handles and microwave door handles, the study noted.

The report, by University of Arizona microbiologist Dr Charles Gerba, says desktops have become breeding grounds for germs largely because they have turned into tables where workers eat lunches and breakfasts.

This, combined with the fact that desks are not frequently cleaned , makes them the perfect environment for microorganisms.

"We don't think twice about eating at our desks, even though the average desk has 100 times more bacteria than a kitchen table and 400 times more bacteria than the average toilet," Dr Gerba said. "Without cleaning, a small area on your desk or phone can sustain millions of bacteria that could potentially cause illness," he added.

Dr Gerba also warned that workers with a cold or flu virus can also pass it on through office equipment such as photocopiers and microwaves.

"When someone is infected with a cold or flu bug, the surfaces they touch during the day become germ transfer points," he said.

"Because some cold and flu viruses can survive on surfaces for up to 72 hours, an office can become an incubator."

In addition to germs in the workplace, the most frequent household bugs include campylobacter, listeria, salmonella (all three can be found in undercooked meat), botulism and e-coli.