Application times for surface disinfectants

In surface disinfection, exposure times and concentrations depend on the risk assessment and the manufacturers' instructions. For high-risk areas, for example operating theatres, recommendations state an application time of at least one hour. After all routine surface disinfection measures, the surface can be used again as soon as it is visibly dry– independent of the recommended application time. As the microorganisms are inactivated exponentially, the most are killed at the beginning of the exposure time. The surface disinfectant continues to inactivate the pathogens until the end of the application time, even though the surface is already dry.

In order to protect patients against the transmission of pathogens, the surface may not be reused before the end of the exposure time in the following situations:

• Disinfection procedures requiring products listed by the RKI (e.g. epidemics acc. to the Federal Law on the Prevention of Infectious Diseases in Humans (IfSG))
• Targeted disinfection procedures when there is a potential for microorganisms entering the human body (e.g. via wounds) directly from the surface (e.g. bed of patients with burns)
• Disinfection procedures with final water rinses (e.g. in kitchens, bathtubs).

Sources:

1. Kramer A. et al. (2006) How long do nosocomial pathogens persist on inanimate surfaces? A systematic review. BMC Infect Dis 6:130
2. Riddell S. et al. (2020) The effect of temperature on persistence of SARS-CoV-2 on common surfaces. Virol J 17(1):145
3. Wißmann JE. et al. (2021) Persistence of pathogens on inanimate surfaces: A narrative review. Microorganisms 9(2):343