Bad news: The soles of your shoes are completely disgusting. That's what microbiologist Charles P. Gerba of the University of Arizona's Department for Soil, Water and Environment Science discovered when shoe company Rockport asked him whether washing shoes in a washing machine made hygienic sense.
Gerba tested 26 different pairs of shoes and discovered that 421,000 bacterial units per square centimeter had collected on the soles. Specifically, Gerba found coliform, a bacterium originating in fecal matter, and E. coli, an intestinal bacterium found in animals.
As we walk along, our shoes pick up food and other debris that bacteria can digest. As Gerba put it, our soles become a "bacteria cafeteria." To combat shoe goo, Paul Rodman, a serial entrepreneur who founded the business that became Staples, has announced the release of a new product called "The Sole Sanitizer." The Sole Sanitizer is a floor mat that removes bacteria and viruses from the bottom of people's shoes. As people step on the mat, they activate UVC light technology that's designed to kill germs and prevent them from being tracked into a building.
Bacteria are simple single-cell organisms that store DNA in their nuclei. Viruses are actually made up of strands of RNA or DNA surrounded by some kind of protein coating; they aren't complex enough to be classified as cells. UV light kills bacteria and viruses by damaging their DNA. Specifically, UV light creates a reaction between some of the thymine molecules that make up the DNA double helix. Although the bacteria or virus can usually repair these molecular lesions easily, when the damage is extensive, the cell usually dies.
While the UV technology in The Shoe Sanitizer could feasibly damage some germs, author Anne Maczulak, author of "The 5-Second Rule and Other Myths About Germs," told NPR's "Sound Medicine" that UV light needs to be directed toward germs for about two minutes to completely kill them."Here’s the thing that’s a bit of a caveat," said Maczulak. "Usually you have to hold it in place for at least two minutes to really be assured that you’re killing germs in the very spot you’re focusing on." The best solution for defeating shoe-borne germs is to leave shoes by the door when entering a space. Of course, if you take your shoes off at the airport or in a restaurant, your fellow patrons may object. But don't worry—Gerba says that the insides of our shoes are much cleaner. They only average about 11,000 bacterial units per square centimeter.
Edited by
Cassandra Tucker
