Prevalence of Fecal Indicators and Viruses on Touchscreens and Other High-Touch Surfaces in Retail Food Establishments in the United States.

Electronic touchscreens are common in retail food settings, though little is known about their microbial profile. In this study, electronic touchscreens were sampled in retail food establishments in four states spread across the U.S. to assess the prevalence of fecal indicators and microbes. Surface swabs of touchscreens and other high-touch surfaces (ATMs, credit card machines, restroom door handles, and employee phones; n = 175) were collected from grocery and convenience stores, and from quick service and casual dining restaurants. Heterotrophic plate counts (HPCs), coliforms, and Escherichia coli were enumerated using culture methods. Target gene sequences specific to adenoviruses, noroviruses (GI and GII), and human parainfluenza virus type 1 (HPIV-1), as well as Clostridium coccoides (human fecal bacterium) were amplified using molecular methods. Grocery and convenience stores had significantly higher HPC and coliform levels than the other food service establishment types (p < 0.05), while E. coli was not detected. Grocery store touchscreens yielded the highest level of coliforms (1.54 log10 MPN) compared to restroom door handles (0.91 log10 MPN; p < 0.05). Grocery and convenience stores demonstrated the highest detection frequency of C. coccoides, which was identified in 40.6% and 75.8% of samples, respectively. For convenience stores, 88.9% of touchscreens were positive for C. coccoides. Adenovirus was detected in 10.5% of samples, the majority corresponding to touchscreens. The detection of norovirus (GI and GII) and HPIV-1 was relatively low (1.2-1.7%). These results suggest that electronic touchscreen devices are fomite reservoirs and can become contaminated with fecal indicators and viruses during use. Knowledge gaps pertaining to the types and quantities of microbes present on these surfaces can inform future studies and risk models. Touchscreen cleaning and disinfection, plus safe hand hygiene practices after usage, are highly recommended in public settings.