Capturing coronavirus: Comparison and optimization of methods for recovery of infectious coronavirus from environmental surfaces

Abstract

The unprecedented global impact of the COVID-19 pandemic posed unparalleled challenges to modern-day public health, necessitating the development of effective prevention and control measures across various settings. A critical need has been the development of rigorous and reliable environmental monitoring (EM) strategies to help understand and mitigate viral transmission, especially in crowded working conditions. COVID-19 outbreaks disproportionately affected meat and poultry (M&P) processing facilities early in the pandemic, endangering human and animal health and disrupting the food supply chain. Moreover, an increased reliance on viral RNA detection as a proxy for infectious virus particles has potentially led to inaccurate assessments of the risk of SARS-CoV-2 infection in these environments. Therefore, I evaluated commonly used EM sampling materials and innovative alternatives to identify the most effective material for recovering infectious SARS-CoV-2 particles from non-uniformly inoculated, stainless-steel surfaces, similar to those found in these facilities. Utilizing a systematic approach, I compared the performance of cellulose acetate, hydrophilic polyurethane, and a novel hydrophobic polymer material (MANO) sponge across different sampling sizes and with a variety of eluants. I found significant variations in different materials’ efficacy to recover or release SARS-CoV-2 particles. Polyurethane consistently outperformed the other materials, particularly when compared to MANOs. Specifically, surface sampling with polyurethane at 929 cm2 and 1,858 cm2 using a pH 7 beef extract buffer (BEB) solution yielded significantly superior recovery of infectious virus particles compared to MANO recovery from similar surface areas, supporting polyurethane’s potential as a preferred material for SARS-CoV-2 EM in M&P environments. Conversely, no statistically significant differences were observed in the comparisons between cellulose and polyurethane at various sizes, as well as between cellulose and MANO at certain sizes, highlighting the complexity of material performance and the need for nuanced, application-specific considerations. This research provides empirical evidence to guide the selection of EM materials for infectious SARS-CoV-2 recovery, thereby enhancing the efficiency and reliability of viral detection and surface decontamination strategies. By aligning these insights with the overarching goal of developing, validating, and delivering science-based cleaning and disinfection solutions, this thesis contributes to the broader public health effort to safeguard workers in M&P settings from SARS-CoV-2 exposure.