Many objects that people touch every day are dirtier than a toilet seat.confirmed
Adam and Jamie chose a total of 8 objects to test for cleanliness: toilet seat, money, kitchen sponge, hotel room remote, computer keyboard, light switch, cell phone, and shopping cart. They swabbed each surface for 10 seconds and created Petri dishes from the swabs that incubated overnight. Their first method of measurement was to count the number of microorganism colonies on each dish. They found that the toilet seat sample actually had the fewest colonies, while the kitchen sponge sample had more than they could count:
- kitchen sponge (most colonies)
- money
- light switch
- computer keyboard
- hotel remote
- shopping cart
- cell phone
- toilet seat (fewest colonies)
However, they always wanted to account for the “nastiness” or harmfulness of the types of organisms on each Petri dish, so they had a microbiologist re-rank the samples. The list was as follows.
- kitchen sponge (most nasty)
- money
- light switch
- computer keyboard
- toilet seat
- cell phone
- shopping cart
- hotel remote (least nasty)
Finally, Adam and Jamie decided they needed a larger sample size to provide better results. They enlisted a group of biology students at UC Berkeley to collect more samples from the top five dirtiest surfaces. After collecting and analyzing these samples, the final list was as follows.
- kitchen sponge (most dirty)
- money
- computer keyboard
- toilet seat
- light switch (least dirty)