The COVID-19 virus, SARS-CoV-2, can survive in freezing temperatures. Freezing does not eliminate or inactivate the virus; instead, it tends to preserve it. This means the virus remains viable at cold temperatures, impacting how frozen items are handled.
How Freezing Affects the Virus
Viruses are not living organisms that can be “killed” by freezing. SARS-CoV-2 consists of genetic material encased within a protein shell, often with an outer lipid envelope. Freezing temperatures slow the degradation of this viral structure, preventing its rapid breakdown.
When a virus is frozen, its components are held in a stable, inactive state. This suspension of activity allows the viral structure to remain largely intact. Upon thawing, if the viral structure is still sound, the virus can regain its ability to become active and potentially infectious. This principle is why laboratories often store viruses at very low temperatures for long-term preservation.
How Long the Virus Remains Viable
Research indicates that SARS-CoV-2 can remain viable for extended periods in frozen conditions. Studies using surrogate viruses have shown survival on meat products for up to 30 days when stored at freezer temperatures of -20°C (or -4°F). Some studies found SARS-CoV-2 to remain infectious for more than 21 days on various foods, when kept under refrigerated (4°C) and frozen (-10°C to -80°C) conditions.
The persistence of SARS-CoV-2 on surfaces is longer at lower temperatures. On non-porous surfaces, the virus has been found viable for up to 5 days at -20°C, with little to no reduction in infectivity. While the risk of transmission via food consumption is considered low, the presence of the virus on frozen food surfaces or packaging has been identified.
Safety When Handling Frozen Items
SARS-CoV-2 can persist on frozen surfaces, so practicing good hygiene when handling frozen items is important, although the primary mode of transmission remains respiratory droplets. While the risk of contracting COVID-19 from food or food packaging is low, standard food safety measures should be applied.
Wash hands with soap and water before and after handling groceries, especially frozen items. Surfaces where frozen groceries have been placed should be cleaned and disinfected. If possible, unpack groceries directly into storage areas to minimize contact with other surfaces.
Cooking food to appropriate temperatures will inactivate the virus. Coronaviruses can be inactivated at temperatures such as 60°C or 80°C, with specific durations reducing viral load. For example, 60°C for 30 minutes or 80°C for 1 minute can achieve substantial thermal disinfection. High temperatures, like 95°C for 10 minutes, effectively inactivate SARS-CoV-2.