Effect of Surface Sampling and Recovery of Viruses and Non-Spore-Forming Bacteria on a Quantitative Microbial Risk Assessment Model for Fomites

Quantitative microbial risk assessment (QMRA) is a powerful decision analytics tool, yet it faces challenges when modeling health risks for the indoor environment. One limitation is uncertainty in fomite recovery for evaluating the efficiency of decontamination. Addressing this data gap has become more important as a result of response and recovery from a potential malicious pathogen release. To develop more accurate QMRA models, recovery efficiency from non-porous fomites (aluminum, ceramic, glass, plastic, steel, and wood laminate) was investigated. Fomite material, surface area (10, 100, and 900 cm2), recovery tool (swabs and wipes), initial concentration on the fomites and eluent (polysorbate 80, trypticase soy broth, and beef extract) were evaluated in this research. Recovery was shown to be optimized using polysorbate 80, sampling with wipes, and sampling a surface area of 10–100 cm2. The QMRA model demonstrated, through a relative risk comparison, the need for recovery efficiency to be used in these models to prevent underestimated risks.