A single wipe with liquid soap followed by a wipe with 250-ppm free chlorine solution was sufficient to reduce residual contamination to below the target level for most tested pathogens.
A two-step cleaning process using liquid soap followed by 250-ppm free chlorine is sufficient to reduce residual viral and bacterial contamination on stainless steel surfaces below target levels for most tested pathogens.
Effect estimate: 1 to 4 log10 reduction
Environmental surfaces contaminated with pathogens can be sources of indirect transmission, and cleaning and disinfection are common interventions focused on reducing contamination levels. We determined the efficacy of cleaning and disinfection procedures for reducing contamination by noroviruses, rotavirus, poliovirus, parechovirus, adenovirus, influenza virus, Staphylococcus aureus, and Salmonella enterica from artificially contaminated stainless steel surfaces. After a single wipe with water, liquid soap, or 250-ppm free chlorine solution, the numbers of infective viruses and bacteria were reduced by 1 log(10) for poliovirus and close to 4 log(10) for influenza virus. There was no significant difference in residual contamination levels after wiping with water, liquid soap, or 250-ppm chlorine solution. When a single wipe with liquid soap was followed by a second wipe using 250- or 1,000-ppm chlorine, an extra 1- to 3-log(10) reduction was achieved, and except for rotavirus and norovirus genogroup I, no significant additional effect of 1,000 ppm compared to 250 ppm was found. A reduced correlation between reduction in PCR units (PCRU) and reduction in infectious particles suggests that at least part of the reduction achieved in the second step is due to inactivation instead of removal alone. We used data on infectious doses and transfer efficiencies to estimate a target level to which the residual contamination should be reduced and found that a single wipe with liquid soap followed by a wipe with 250-ppm free chlorine solution was sufficient to reduce the residual contamination to below the target level for most of the pathogens tested.
Tuladhar et al. (Sat,) conducted a other in Environmental surfaces contaminated with pathogens. Cleaning and disinfection procedures (water, liquid soap, or free chlorine solution) vs. Water or liquid soap alone was evaluated on Reduction in numbers of infective viruses and bacteria (1 to 4 log10 reduction). A single wipe with liquid soap followed by a wipe with 250-ppm free chlorine solution was sufficient to reduce residual contamination to below the target level for most tested pathogens.