In the initial phase of our study 598 staff members were observed entering the carpark. 21.6% of them put their parking ticket in their mouth | Journal of Hospital Infection
Using UV dye we successfully demonstrated card-to-card cross-contamination. Swabs of the ticket machine yielded commensal bacteria: coagulase negative staphylococci and a Bacillus species.
After placing a poster on the ticket-reading machine highlighting this potential infection risk, a further 1366 observations resulted in a statistically significant and persistent decline in the proportion of staff putting their carpark tickets in their mouths (p<0.001).
Full reference: Groves, J. et al. (2017) Reducing the Risk of Mouth to Mouth Transmission of Pathogens Via Reusable, Machine-read, Parking Tickets. An observational cohort study. Journal of Hospital Infection. Published online: June 08, 2017