Smartphones, tablet computers and office keyboards are riddled with more dangerous bacteria than toilet seats, it is claimed.
Watchdogs said routine swab tests revealed "hazardous" levels of germs that can cause vomiting, diarrohea and even harbour infections such as e.coli.
Which? took swabs from 30 smartphones, tablets and keyboards. One iPad had 600 units of Staphylococcus aureus, which creates toxins that can lead to food poisoning.
This compared with less than 20 units of Staphylococcus per swab of an office toilet, 140 on a smartphone and 480 on the dirtiest keyboard.
Which? said the results stem from today's hectic lifestyles, with grubby fingers, snacking while typing and rushed toilet breaks all to blame. Part of the problem is down to people taking their must-have tech gadgets into the bathroom with them.
James Francis, the microbiologist that carried out the resaearch, said: "A count of 600 on a plastic device of any sort is incredibly high. It indicates that some people don't wash their hands a lot.
"In the food industry, if we found those levels of bacteria from a hand swab of a food handler, they'd have to be taken out of the workplace and retrained in basic hygiene."
Tests for Enterobacteria revealed 15,000 of the bacteria on one tablet, four smartphones and five keyboards. There were less than ten on the toilet seat and flush handle. Fortunately the Enterobacteria tests came up clean for both e.coli and salmonella.
Earlier this summer media regulator Ofcom revealed that we are so addicted to our smartphones and tablet computers that over one in ten - 11pc - now view video content on a device such as the iPad in the bathroom. Some 20pc of 18 to 24 year-olds do so.
Which? said it was essential to keep devices clean by using anti-bacterial wipes.
Keyboard users should tip them upside down and shake them to "dislodge any old food crumbs, dust and skin flakes". Damp, soft, lint-free cloths should be used to remove streaks from phones and tablets.
Apple advises that fans of its products do not use alcohol-based cleaners on iPhones or iPads. Which? added: "Don't rely on wiping your phone on a shirt sleeve or dry cloth."