The public has often wondered about the risk of contracting COVID-19, caused by the SARS-CoV-2 virus, through refrigerated or frozen food products. This concern stems from the virus’s ability to survive on surfaces and the common use of freezing as a preservation method. Understanding the difference between viral preservation and inactivation at low temperatures is necessary to assess the actual risk associated with frozen foods.
Survival of SARS-CoV-2 in Cold Temperatures
Low temperatures, such as those found in refrigeration and freezers, are known to slow down the degradation of the SARS-CoV-2 virus, acting more like a preservative than a killer. Studies have demonstrated its remarkable stability in cold environments, which is a significant factor in its potential persistence on food and packaging. The virus can survive for an extended period at refrigerated temperatures, typically around 4°C (39.2°F), retaining infectivity for over two weeks.
When temperatures drop to freezing levels, such as -20°C (-4°F), the decay rate of the virus is significantly lower than at room temperature. For example, some studies using animal coronavirus surrogates on meat products found that the virus could be cultured after being stored at freezer temperatures for up to 30 days. This cold-chain environment effectively halts the processes that would normally cause the virus to break down quickly, allowing it to maintain its infectious capacity for weeks. The physical and chemical conditions within frozen materials help to protect the virus’s structure.
Freezing and Viral Inactivation
The act of freezing does not typically inactivate or “kill” viruses; rather, it suspends their activity and preserves their structure. Viruses, unlike bacteria, do not have metabolic processes that can be stopped by cold, meaning the freezing process simply puts them into a state of suspended animation. The physical structure of the SARS-CoV-2 virus is not sufficiently damaged by the transition to ice crystals to render it non-infectious.
Inactivation of SARS-CoV-2 relies on mechanisms that actively destroy the viral components, such as denaturing the proteins or breaking down the genetic material. High heat is a proven method of inactivation, with temperatures like 70°C (158°F) being sufficient to quickly kill the virus, often within minutes. Chemical disinfectants also work by disrupting the viral envelope and proteins. Freezing lacks this destructive power, making it an ineffective method for sanitizing food products that may have been contaminated during handling or processing.
Foodborne Transmission Risk and Safe Handling
While the virus can survive for extended periods on frozen food and packaging surfaces, foodborne transmission of COVID-19 is not considered a primary route of infection. Health organizations have consistently stated there is no evidence to suggest that people can catch the virus by ingesting it via food or food packaging. SARS-CoV-2 is a respiratory illness, and its main transmission route is through person-to-person contact via respiratory droplets.
The risk associated with food is generally connected to surface contamination, where viral particles land on packaging or the food itself after being expelled by an infected person. An individual could potentially become infected by touching a contaminated surface and then touching their mouth, nose, or eyes. Therefore, the focus remains on good hygiene practices during food preparation and handling, regardless of the food’s frozen status. Thoroughly cooking food to recommended internal temperatures, such as at least 70°C (158°F), is a proven method to inactivate any potential viral contamination. Consumers should also prioritize frequent hand washing after handling food packaging and before eating.