And when looking into the issue of cleanliness further, there are a host of other surfaces that return scarily high levels of bacteria when swabbed and tested.
Adam Savage and Jamie Hyneman of the popular TV series Myth Busters conducted thorough research into the topic years ago, producing some scary results.
The scientifically minded duo tested 8 everyday objects to measure their cleanliness, including money, kitchen sponge, keyboard, light switch, mobile phone, shopping cart, TV remote and the toilet seat.
To determine cleanliness, Savage and Hyneman swabbed the surfaces for 10 seconds, and then created Petri dishes to be left overnight, in order to determine which surface returned the greatest number of bacterial colonies.
Enlisting the help of biology students from the University of California, Berkeley, to validate their results, they received some shocking results. Surprisingly, the toilet seat had the lowest colony count, with the kitchen sponge returning the highest result.
These are their findings, ranked dirtiest to cleanest, based on the experiment.
- Kitchen sponge
- Light switch
- TV remote
- Shopping cart
- Toilet seat