A Rossen Reports investigation at five of the top hotel chains in the country revealed the cleanest spot in a typical hotel room — and the dirtiest.

The Rossen Reports team booked rooms at five top hotel chains across the country. After maids had cleaned up the rooms, bacteria expert Dr. Luisa Ikner, a microbiologist at the University of Arizona Gerba Lab, applied test swaps to various areas of the rooms.

A meter provided instant readouts of the bacteria counts. Anything over 100 on the scale was considered an unacceptable level of bacteria. (In addition to bacteria, other types of germs such as viruses can also be spread by contact with the skin.)