Coronavirus (COVID-19): Briefing note
Posted on March 31, 2020 by biocheckuk.
- This information is compiled from online sources accessed on 31-March-2020:
- A new strain of virus is causing Severe Acute Respiratory Syndrome (SARS) in humans. The new SARS coronavirus (SARS-CoV), called SARS-CoV-2, from the Coronaviridae family of viruses that primarily infect birds and mammals, is a positive-strand RNA virus. It was first discovered in December 2019 in Wuhan, Hubei Province of China, and sequenced and isolated in January 2020. The resulting outbreak of SARS-CoV-2 has caused the coronavirus infectious disease 2019 (COVID-19). SARS-CoV-2 is not the same as an influenza virus, it belongs to a different family of RNA viruses. COVID-19 and influenza, both cause respiratory illnesses spread from person to person through tiny droplets containing the virus, during exhalation and in coughs and sneezes. The symptoms of the diseases have some important differences, including that SARS-CoV-2 spreads and potentially kills more readily. Globally, it has spread to be a pandemic (WHO, 11 March 2020). Unlike many respiratory viruses, it seems to infect both the upper and lower respiratory tract.
- Food has not been identified as a likely source or route of transmission of the virus according to EFSA. The virus is spread through direct contact with respiratory droplets from an infected person, as described above. Furthermore, it is believed that the virus is sensitive to heat and that the typical temperature and time regimes of cooking to ensure food safety are sufficient to inactive the virus and reduce the risk.
- Each spherical SARS-CoV-2 virus particle (about 80-90nm in size) consists of the RNA genome enclosed by a viral envelope, a lipid bilayer with structural proteins, including glycoprotein spikes that protrude from the particle surface to form a ‘corona’ or crown of spikes. The coronavirus spikes are known to play a key role in how it infects the host human cell. The viral envelope protects the virus when outside the host cell in the environment.
- With aerial (direct) and surface (indirect) transmission of the SARS-CoV-2 virus, the stability of SARS-CoV-2 has been reported by the New England Journal of Medicine to be more stable on plastic and stainless steel than on cardboard, and viable virus was detected up to 72 hours after application to these surface, although the virus titre was greatly reduced. On cardboard, no viable SARS-CoV-2 was measured after 24 hours. Results indicate that aerosol and indirect transmission by contaminated objects is plausible, since the virus can remain viable and infectious in aerosols for hours and on surfaces up to days (depending on the inoculum shed).
- Although it is unlikely that SARS-CoV-2 is spread by contaminated food it is advisable to ensure social distancing in a food plant together with robust personal (e.g. frequent handwashing and not touching the face) and food safety hygiene during food preparation to prevent cross-contamination (e.g. by handling and objects) and to heat food to reduce the risk when appropriate. Washing hands is believed to be effective at inactivating the virus, because the soap or liquid detergent disrupts the lipid bilayer of the SARS-CoV-2 causing the virus particle to disintegrate and be easily rinsed away. Although there have been no studies on the effectiveness of formulated disinfectants against SARS-CoV-2 on food contact surfaces (following the important detergent cleaning and rinsing stages), those with an oxidising nature such as hypochlorite, peracetic acid and hydrogen peroxide are likely to be effective at an appropriate working concentration (please discuss with your cleaning chemical supplier).
- Recently developed analytical methods for detecting SARS-CoV-2 in food and on food surfaces typically target at least two genes in the virus genome (e.g. coding for the envelope or the nucleocapsid). Following sampling and RNA extraction a sensitive Real-Time RT-PCR technique is employed for detection.
Please refer to the latest official guidance and peer reviewed references when formulating policy, practices and procedures on mitigating the risks posed by COVID-19. Some helpful references and hyperlinks are listed below:
Walls et al., 2020 Structure, Function, and Antigenicity of the SARS-CoV-2 Spike Glycoprotein Cell online, open access 9 March 2020 https://doi.org/10.1016/j.cell.2020.02.058
Van Doremalen et al., (2020) Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1 The New England Journal of Medicine, Letter to the Editor 17 March 2020 https://doi.org/10.1056/NEJMc2004973