These numbers represent colony-forming units (CFUs) per square inch. A CFU is a measurement of microbial organisms. The surfaces tested in our study contained everyday bacteria―most of which are not harmful to healthy people―and no traces of serious germs, like E. coli.
Store shopping cart: 2
Restaurant-restroom door handle: 4
Children’s library book: 7
Stuffed toy in a doctor’s office: 8
School-desk surface: 12
School computer mouse: 23
Store floor: 33
Public-park swing: 59
Restaurant tray: 204
School musical instrument: 262
Video-game controller in an arcade: 551
Public-park sandbox: 7,440
Classroom faucet handle: 32,000
Cafeteria water-fountain spigot: 62,000
Research was performed by NSF International Swab Testing, with thanks to Greta Houlahan and Robin Bechanko.