In light of growing evidence, researchers say that SARS-CoV-2 virus transmission via contaminated surfaces, and in particular, frozen foods and products that are transported while keeping them at low temperatures, should be taken into account when devising prevention strategies.
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is usually spread by airborne transport. When an infected person sneezes, coughs, talks, or breathes, the virus present in aerosol droplets can be transmitted. Hence, the main strategies to curb its spread have been social distancing and ensuring well-ventilated indoor spaces.
SARS-CoV-2 is stable on various surfaces for different times. The virus's half-life on plastic and stainless steel is about six hours. On the skin, the virus is stable for 96 hours at 22 °C and 14 days at 4 °C. Studies have shown that the virus can be isolated from surfaces such as glass, paper, and banknotes, up to 28 days after infection.
The virus is very stable at low temperatures and can remain on the packaging of cold-chain products, and transportation of these products can lead to viral spreading. Reports from China in the last few months indicate several infections, mainly asymptomatic, caused by imported cold-chain products. The live virus was isolated from the packaging of imported-cold chain products in Qingdao, raising the possibility that trade may be causing virus spread.
Virus can stay alive on surfaces for many days
In a previous study, researchers reported that livestock processing industries contribute significantly to SARS-CoV-2 transmission. For the United States, the authors estimated that for a county with the presence of livestock processing plants, excess COVID-19 cases were 6 to 8% of all the cases in the country, with the vast majority of cases occurring in people not working at the plants.
One reason for the increase in transmission risk in livestock plants is the low indoor temperature. After slaughter, the meat processing area is generally kept between 0 and 12 °C, which allows the virus to remain stable.
Another study reported the stability of SARS-CoV-2 on a variety of surfaces. They found that the presence of a tiny protein in respiratory droplets that can prolong the life of the virus on many different surfaces. Thus, viruses in aerosol droplets from infected persons that settle on surfaces can stay alive, sometimes for more than four days, and transmit the virus when people contact the contaminated surfaces.
Cold-chain virus transport
All these reports provide growing evidence of how SARS-CoV-2 can be transmitted by trade, particularly when the transported goods are maintained at low temperatures.
In a letter published in the Proceedings of the National Academy of Sciences, researchers from Jilin University in China argue that livestock plants and cold-chain industries play a key role in virus transmission and should be taken into account when implementing COVID-19 prevention strategies.
Thus, supervising meatpacking and scattered small-scale meat production could help disease prevention. The authors suggest that the environment in these plants and cold-chain industries should be tested regularly along with frequent disinfection. Imported cold-chain or frozen products should also be sampled and tested to identify any contaminated products and take control measures in time.
Furthermore, any personnel handling such goods should wear personal protective equipment, including masks and gloves. Such personnel should also be screened routinely for the virus. Wiping all frozen packages using disinfectant wipes may also be useful in eliminating the virus.