If the goal of the environmental testing is to validate cleaning procedures in the food manufacturing or retail environment, then a coronavirus is an inappropriate marker for this purpose.
Fomites (infected surfaces or objects) are not currently believed to be a primary method of spread for COVID-19, though similar viruses have been shown to remain infective on surfaces and in unprocessed foods for up to 72 hours.
The virus is unlikely to be transmitted through food, however, and has limited survivability – due to the relative instability of the lipid membrane and of the spike glycoproteins, which are heavily influenced by environmental conditions. The lipid envelope is required to be intact to protect the nucleocapsid and RNA genome from nucleases, and correctly structured spike proteins are required for the entry of the virus into cells. Existing cleaning procedures, making use of surfactants and disinfectants, are sufficient to prevent the transmission of viruses from surface to surface, as they typically destroy both the envelope and the exposed proteins.
Similarly, heat treatment inactivates the virus, through the dehydration of the lipid envelope and the denaturation of proteins. Environmental testing for more robust pathogens (such as those that can form biofilms or DNA viruses) would be a more appropriate proxy for determining cleaning efficacy.
Importantly, the same considerations are relevant to surface testing in the retail setting – except with less control over access and testing conditions, and even less meaningful information obtained from a result. It is also worth bearing in mind that the environmental and clinical diagnostic tests are identical; so conducting questionable tests that make use of potentially supply-limited kits and reagents might be unhelpful at this time.
Furthermore, directing resources away from critical food safety activities and towards more speculative testing programmes could lead to unintended adverse outcomes.
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The FACTS team