SARS-CoV-2 Delta Variant Remains Viable in Environmental Biofilms found in Meat Packaging Plants

Chitlapilly Dass, S.; Featherstone, A. B.; Mathijssen, A. J.; Brown, A. C.

doi:10.1101/2023.06.15.545172

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bioRxiv · 10.1101/2023.06.15.545172

SARS-CoV-2 Delta Variant Remains Viable in Environmental Biofilms found in Meat Packaging Plants

Chitlapilly Dass, S.·Featherstone, A. B.·Mathijssen, A. J.·Brown, A. C.

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Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a coronavirus that directly infects human airway epithelial cells and caused the COVID-19 pandemic. At the start of the pandemic in 2020, meat-packaging plants saw a surge in SARS-CoV-2 cases, which forced many to temporarily close. To determine why SARS-CoV-2 appears to thrive specifically well in meat packaging plants, we used SARS-CoV-2 Delta variant and meat packaging plant drain samples to develop mixed-species biofilms on materials commonly found within meat packaging plants (stainless steel (SS), PVC, and ceramic tile). Our data provides evidence that SARS-CoV-2 Delta variant remained viable on all the surfaces tested with and without an environmental biofilm. We observed that SARS-CoV-2 Delta variant was able to remain infectious with each of the environmental biofilms, however, we detected a significant reduction in viability post-exposure to Plant B biofilm on SS, PVC, and on ceramic tile chips, and to Plant C biofilm on SS and PVC chips. The numbers of viable SARS-CoV-2 Delta viral particles was 1.81 - 4.57-fold high than the viral inoculum incubated with the Plant B and Plant C environmental biofilm on SS, and PVC chips. We did not detect a significant difference in viability when SARS-CoV-2 Delta variant was incubated with the biofilm obtained from Plant A on any of the materials tested and SARS-CoV-2 Delta variant had higher plaque numbers when inoculated with Plant C biofilm on tile chips, with a 2.75-fold difference compared to SARS-CoV-2 Delta variant on tile chips by itself. In addition, we detected an increase in the biofilm biovolume in response to SARS-CoV-2 Delta variant which is also a concern for food safety due to the potential for foodborne pathogens to respond likewise when they come into contact with the virus. These results indicate a complex virus-environmental biofilm interaction which correlates to the different bacteria found in each biofilm. Our results also indicate that there is the potential for biofilms to protect SARS-CoV-2 from disinfecting agents and remaining prevalent in meat packaging plants. With the highly infectious nature of some SARS-CoV-2 variants such as Delta, and more so with the Omicron variant, even a minimal amount of virus could have serious health implications for the spread and reoccurrence of SARS-CoV-2 outbreaks in meat packaging plants.

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Chitlapilly Dass, S., Featherstone, A. B., Mathijssen, A. J., Brown, A. C.. 2023-06-16. SARS-CoV-2 Delta Variant Remains Viable in Environmental Biofilms found in Meat Packaging Plants. https://doi.org/10.1101/2023.06.15.545172

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