SARS-CoV-2, the virus that causes COVID-19, is primarily spread through airborne respiratory droplets, but several studies have also explored the possibility of the virus surviving on surfaces and in other environments. Ongoing research on possible SARS-CoV-2 transmission routes can help inform control strategies and guidance on safety and sanitation measures in workplaces, public venues, private households and in industry. A recent study conducted by researchers at Campbell University, the Texas Tech University Health Science Center and the University of North Carolina at Chapel Hill found that SARS-CoV-2 surrogates could survive for up to a month on both refrigerated and frozen meat products, suggesting that these products could be a potential source of virus exposure.
The study was conducted using chicken, beef, pork and salmon and surrogate viruses with surface spikes similar to those on SARS-CoV-2. These included the lipid enveloped RNA bacteriophage Phi 6, as well as murine hepatitis virus (MHV) and transmissible gastroenteritis virus (TGEV), which are both animal coronaviruses. The meat products inoculated with virus surrogates were stored at both refrigeration (4°C) and freezing (−20°C) temperatures for 30 days and subsequently analyzed for the presence of live viruses using a double agar layer (DAL) overlay plaque assay method for Phi 6 and a most probable number (MPN) cell culture assay for MHV and TGEV.
The researchers found that the surrogate viruses could survive for the full 30-day period on both refrigerated and frozen products, although different extents of virus reduction were observed among the four foods, and a greater reduction was seen at the refrigerated temperature than the frozen temperature. Greater reductions of Phi 6 and TGEV were seen on chicken and salmon at frozen temperatures than on beef and pork, while MHV showed much greater reductions than the other two viruses after seven days of freezer storage. In refrigerated products, MHV also saw the most extensive reduction compared to Phi 6 and TGEV. TGEV reduction was similar across all the meats, while Phi 6 saw a significantly lower reduction on beef compared to the other products. This study was published in Applied and Environmental Microbiology.
“Continued efforts are needed to prevent contamination of foods and food processing surfaces, worker hands and food processing utensils such as knives,” the investigators wrote. They added, “the lack of, or inadequate disinfection of these foods prior to packaging needs to be addressed.”
The team first undertook their research following COVID-19 outbreaks in Southeast Asia absent prior community transmission. Reports from those communities “suggested that packaged meat products, produced in areas where SARS-CoV-2 was circulating, could have been the source of the virus,” said first author Emily S. Bailey, an assistant professor in the Department of Public Health, College of Pharmacy and Health Sciences at Campbell University.
“Our goal was to investigate whether or not similar viruses could survive in this environment,” Bailey said.