COVID-19: Potential for Foodborne transmission of COVID-19

COVID-19: Potential for Foodborne transmission of COVID-19. Jefferson T Heneghan C.

https://www.cebm.net/study/covid-19-potential-for-foodborne-transmission-of-covid-19/

Published on July 2, 2020

Bottom Line

Extensive uncertainty on the ecology of SARS-CoV-2 makes it hard to make specific recommendations on handling and prevention of transmission. CoV are susceptible to heat, surfactants and low PH.

Evidence Summary

The best practice for reducing the risk of contamination of food products or packaging continues to be managing the risk of SARS-CoV-2 infection amongst workers. This includes workers informing their employer and seeking medical advice if they have any symptoms of respiratory illness. Employers can promote and implement good personal hygiene practices for all workers.

The primary transmission route for human infection with SARS-CoV-2 is via respiratory droplets. It may be possible that a person can be infected with SARS-CoV-2 by touching a surface or object that has the virus on it and then touching their own mouth, nose, or possibly their eyes, but this is not thought to be the main way the virus spreads. Infectious virus has been found in faeces of some infected people, raising the possibility of faecal-oral transmission via contaminated vehicles such as food, but there is no evidence for this having occurred.

No published studies of SARS-CoV-2 survival in or on food products were located. A study of MERS-CoV in various types of unpasteurised milk showed survival of the virus for up to 72 hours. Pasteurisation inactivated the virus

No published studies of SARS-CoV-2 survival on fresh food were located. A study of another coronavirus showed survival on lettuce for up to two days. This coronavirus could not be recovered after inoculation onto strawberries. 

No information was located on the likelihood of infection from consuming SARS-CoV-2 through food. Normal intestinal conditions (stomach acid and bile salts) are thought to inactivate SARS-CoV-2, but more research is needed.

The situation in which a food handler is found to be positive would need to be assessed on a case-by-case basis.

What did they do?

The study is the second update of a systematic review with searches up to 4th of May 2020. The review aimed to answer 7 questions:

  1. What is international best practice regarding reducing the likelihood that food products or packaging are vectors for COVID-19? In this context, sources of COVID-19 may be production or supply chain workers?
  2. What is international best practice for mitigation options to reduce the transfer of COVID-19 from workers to food products?
  3. What is the latest information on the routes of transmission for COVID-19 (including anything that implicates food as a vector)?
  4. What is the international consensus on survival rates of SARS-CoV-2 in food products?
  5. What is the international consensus on survival rates of SARS-CoV-2 on surfaces of fresh food especially if the food is consumed fresh and not cooked?
  6. What is the likelihood of a person becoming infected with coronavirus from consuming the virus?
  7. What are the risk management options for companies when a worker is identified as having COVID-19?

A systematic approach was undertaken to identify relevant literature from electronic scientific databases. 

Information and advice was also obtained from public websites over the dates 6-27 March 2020, including:  

Study reliability

The authors make the reasonable point that RT-PCR is unable to distinguish viable viruses from inactivated ones. This can only be done by culture and few studies have done so. 

In addition despite finding ACE2 receptors in the GIT, tongue and buccal mucosa, it is possible that nasal passage mucus ingestion may account for the findings of large concentrations of viral RNA.

Clearly defined setting Demographic characteristics described Follow-up length was sufficient Transmission outcomes assessed Main biases are taken into consideration
Yes Yes Yes Yes Partly

What else should I consider?

The review updates will be followed.

About the authors

Carl Heneghan

Carl Heneghan

Carl is Professor of EBM & Director of CEBM at the University of Oxford. He is also a GP and tweets @carlheneghan. He has an active interest in discovering the truth behind health research findings

Tom Jefferson

Tom Jefferson

Tom Jefferson is a senior associate tutor and honorary research fellow, Centre for Evidence-Based Medicine, University of Oxford.