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Evaluation of steam heat as a decontamination approach for SARS-CoV-2 when applied to common transit-related materials
Citation:
Richter, W., M. Sunderman, D. Schaeufele, Z. Willenberg, K. Ratliff, Michael Calfee, AND L. Oudejans. Evaluation of steam heat as a decontamination approach for SARS-CoV-2 when applied to common transit-related materials. JOURNAL OF APPLIED MICROBIOLOGY. Blackwell Publishing, Malden, MA, 134(3):lxad053, (2023). https://doi.org/10.1093/jambio/lxad053
Impact/Purpose:
SARS-CoV-2, the causative virus of the CoVID-19 pandemic, is by now a highly studied pathogen. Alternative approaches to chemical disinfection of surfaces are of interest to mitigate the dangers associated with the extensive use of chemical fumigants or liquids to clean surfaces. This work describes the research on the inactivation of SARS-CoV-2 by steam using a commercial off the shelf product. This information provides a first guidance on the ability of steam to inactivate SARS-CoV-2 on surfaces. These results are of high relevancy to researchers, transportation authorities, and other stakeholders including the general public that may consider steam as a mode of disinfection of their spaces.
Description:
Aims: The purpose of this study was to evaluate the efficacy of steam heat for inactivation of SARS-CoV-2 when applied to materials common in mass transit installations. Methods and Results: SARS CoV-2 (USA-WA1/2020) was resuspended in either cell culture media or synthetic saliva, inoculated (approximately 1×106 TCID50) onto porous and nonporous materials commonly found in transit systems (e.g., stainless steel, ABS plastic, or bus seat fabric), and subjected to steam inactivation efficacy tests as either wet or dried droplets. The inoculated test materials were placed on a custom steam test fixture and exposed to steam heat ranging from 70-90°C. The amount of infectious SARS-CoV-2 remaining after various exposure durations ranging from 1 to 60 seconds was assessed. Higher steam heat application resulted in higher inactivation rates at short contact times. Steam applied at 1 inch distance (~90°C at the surface) resulted in complete inactivation for dry inoculum within 2 seconds of exposure (excluding two outliers of 19 test samples at the 5 second duration) and within 2 to 30 seconds of exposure for wet droplets. Increasing the distance to 2 inches (~70°C) also increased the exposure time required to achieve complete inactivation to 15 or 30 seconds for materials inoculated with saliva or cell culture media, respectively. Conclusions: Steam heat can provide high levels of decontamination (>3 log reduction) for transit-related materials contaminated with SARS-CoV-2 using a commercially available steam generator with a manageable exposure time of 2 to 5 seconds. Significance and Impact of the Study: These results provide information on the performance of steam heat against SARS-CoV-2 on surfaces. These data may aid response decision makers and industry managing surface decontamination as it relates to the ongoing COVID-19 pandemic.
URLs/Downloads:
DOI: Evaluation of steam heat as a decontamination approach for SARS-CoV-2 when applied to common transit-related materials
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