Purpose: The goal is to evaluate virus recoveries from inoculated abiotic plastics such as polyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC) with smooth or rough surfaces.
Methods: Smooth polymer sheets were made by injection molding, and some were mechanically abraded with sanding paper to produce roughened surfaces. Virus surrogate MS2 suspension was used for inoculation. To arrive at similar drying times, the virus sample was split into two to three aliquots to enhance drying for more hydrophobic surfaces. Inoculated sheets were air-dried (minimum 30 min) and cold stored 24 h before virus elution. The elution started by shaking the sheets twice in an eluent for 10 min at 10°C. Viruses in eluates were filtered through 0.22-µm-pore-size filters before being plaque-assayed.
Results: Among 10 trials comparing the virus recoveries from glass, PVC, and PE surfaces, no significant differences via ANOVA were observed in the recovery immediately after inoculation and one minute drying. The drying time of virus inoculum seemed to impact the recovery: longer drying time resulted in a lower percentage of virus recovered. With controlled drying, the recoveries from smooth high density PE or PP surfaces (after 24 h cold storage) were greater than those from the same materials after roughening with sand paper (up to 50% more recoveries from smooth surfaces, P<0.05). To understand any potential recovery change by the surface charge of viral capsid proteins, the virus suspension with alternative pH will be tested in additional experiments.
Significance: The chemical and physical characteristics of abiotic polymer surfaces are illustrated. The data may assist in selecting appropriate food contact surfaces for potentially reduced virus retention and transmission.