7 May 2020

It is important at this time to question whether environmental testing for COVID-19 is a suitable approach for detecting the virus in your manufacturing or retail premises.

At the start of the spread of COVID-19, FACTS identified suitable testing methods for the SARS-CoV-2 virus. Based on scientific evidence, our understanding of the virus and the relevant applications in the food industry, we chose not to add this testing option to our testing catalogue.

Our rationale for doing so has since been shown to be in line with the US FDA:

“Currently there is no evidence of food or food packaging being associated with the transmission of COVID-19. Therefore, we do not believe there is a need to conduct environmental testing in food settings for the virus that causes COVID-19 for the purpose of food safety. Cleaning and sanitising the surfaces is a better use of resources than testing to see if the virus is present. Facilities are required to use personnel practices that protect against contamination of food, food contact surfaces and packaging, and to maintain clean and sanitised facilities and food contact surfaces.”

“Although it is possible that an infected worker may have touched surfaces in your facility, FDA-regulated food manufacturers are required to follow Current Good Manufacturing Practices (CGMPs). Maintaining CGMPs in the facility should minimise the potential for surface contamination and eliminate contamination when it occurs. With the detection of the coronavirus in asymptomatic people and studies showing survival of coronavirus on surfaces for short periods of time, as an extra precaution food facilities may want to consider a more frequent cleaning and sanitation schedule for high human-contact surfaces.”

Please read the summary below from our scientific officers and Professor Pieter Gouws from the Centre for Food Safety at Stellenbosch University, regarding testing.

Environmental testing for COVID-19: A scientific point of view

There are two potential reasons for testing surfaces in a food facility for COVID-19; to indirectly detect an infected individual, or to confirm the efficacy of cleaning procedures.

If the goal is to detect the presence of an infected individual, environmental testing is a poor substitute for other measures that could be used.

Whether testing surfaces or human beings, the assay for the novel coronavirus is a test for the presence of short stretches of DNA with the same sequence as the RNA genetic material of the virus. This RNA must be isolated using a swab, and transported in a nuclease-free solution, before being transcribed using an enzyme into DNA copies. Given the prevalence of RNAse enzymes in the environment, the results of an environmental swab are likely to be far more prone to false negatives than those taken directly from a human respiratory tract. The results from a surface swab would also only be available in 24-48 hours, severely limiting the value of this information.

Active/infectious virions may only be detected using culture-based techniques that are both costly and time-consuming. Instituting physical distancing in conjunction with the reinforcement of existing food safety hygiene and sanitation measures is effective for preventing the spread of the virus. Detecting the presence of an infected individual is most effectivity achieved by directly testing staff, and this should therefore take precedence over environmental sampling for COVID-19.

“It is highly unlikely that people can contract COVID-19 from food or food packaging. But it is imperative for the food industry to reinforce personal hygiene measures and provide refresher training on food hygiene principles to eliminate or reduce the risk of food surfaces and food packaging materials becoming contaminated. In addition, the food industry is strongly advised to introduce physical distancing and stringent hygiene and sanitation measures and promote frequent and effective handwashing and sanitation at each stage of food processing, manufacture and marketing.” – Professor Pieter Gouws, Centre for Food Safety, Stellenbosch University

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.

For a full list of references click here.

Kind regards,
The FACTS team

+27 21 882 9883 | [email protected] | www.factssa.com
Office 11, The Woodmill, Vredenburg Rd, Stellenbosch, Western Cape 7600, South Africa

Copyright © 2020 FACTSSA, All rights reserved.