Missy Koch & Kelsey Rehwaldt '09

Risk of Cross Contamination from Computer Keyboards

Computer keyboards in college institutions can be contaminated with microbes because of multiple users and are rarely cleaned or sanitized. Microbes on keyboards can be transferred to hands and then to food, causing illness.  Reducing cross-contamination is possible with proper hand-washing techniques, but less than 50% of college-aged students frequently or always wash their hands before eating. (American Journal of Infection control, (37)1:70-72, 2009).

Purpose: To assess the effectiveness of UV-C light wands as a sanitizing tool for computer keyboards in comparison to Clorox disinfecting wipes.

Methods: Random selection of sixteen computer keyboards in a public computer lab at the college were initially dry-swabbed using 3M Quick Swabs. Half of each keyboard was treated with a Clorox disinfecting wipe and re-swabbed. The other half of the same keyboard was treated with a UV-C light wand for ten seconds two inches above the keyboard [manufacturer's directions] and re-swabbed. The media from the Quick Swabs was transferred to 3M Petrifilm Aerobic Count Plates and samples were incubated at 37degrees Celsius for 48 hours. Microbial growth was assessed using the Interpretation Guide included with the Petrifilm instructions.

Results: 100% of computer keyboards sampled contained microbial growth. Clorox disinfecting wipes killed an average of 90% microbial growth on computer keyboards; exposure to UV-C light for ten seconds killed an average of 60% microbial growth.

Conclusion: The UV-C light wand [used according to manufacturer's directions] was not as effective at sanitizing computer keyboards as the Clorox disinfecting wipes.  Given the results, individuals should always wash their hands after using public access computers and consider Clorox wipes or another comparable sanitizing product to prevent cross contamination.

Kelsey Rehwaldt and Missy Koch presenting their research at the Minnesota Dietetics Association annual Meeting May 7, 2009, St. Cloud, MN

Kelsey presented a shared research project with Missy Koch at Scholarship and Creativity Day 2009

To view Poster, click on link below:

Risk of Cross Contamination from Computer Keyboards

Research Advisor: Amy Olson, PhD, RDN, LD