What is contact time and what happens if the surface dries before the stated contact time on a Sani-Cloth® product label?

The contact time listed on the product label is the total amount of time that it takes to inactivate ALL of the microorganisms listed on the product label. This time is typically referred to in minutes, and should be communicated to staff members that are utilizing the disinfectant.

Per EPA guidance, treated surfaces must remain visibly wet for the full stated contact time in order to achieve the efficacy claims on the label. If a surface dries too quickly, additional wipes may be needed to keep the surface wet. The overall contact time itself does not change.

Surfaces may sometimes dry before the stated contact time due to factors such as airflow and ventilation, temperature, humidity, or the material/porosity of the surface. This is not uncommon in healthcare environments, which often have high air exchanges and low relative humidity.

While the EPA requires that treated environmental surfaces remain wet for the full contact time, some leading researchers in infection prevention have offered an alternate view. In a commentary published in Infection Control and Hospital Epidemiology (March 2018, vol. 39, no. 3, pp 229–231), Dr. W.A. Rutala and Dr. D.J. Weber suggested that contact time and treatment time are mutually exclusive, and that treatment time — regardless of visible wetness — may be sufficient for wipes (except bleach products). PDI continues to monitor this research closely and will provide customers with the latest information as regulations permit.