Food safety risk assessment authorities have so far ruled out the possibility of Covid-19 being transmitted through food. This is what the Ministry of Health in Italy and EFSA(European Food Safety Authority) said back in the early days of the pandemic.
There has already been an analysis of best practices to follow, in handling raw and fresh food as in food delivery. This is followed by a brief scientific review about the persistence of SARS-CoV-2 on materials, food technologies and disinfection of materials, new opportunities.
Food and food packaging
Risk assessment on food and MOCAs (Materials and Objects intended for Food Contact) required revisiting the available literature on other coronaviruses, such as SARS-CoV-1 and MERS. And the risk of its transmission via contaminated food or packages turns out to be extremely low. (1) Be it where the oro-fecal cycle is considered. (2)
The concentration of the virus in food has so far not been found to be sufficient or otherwise capable of triggering contagions through food matrices. (3) Scrupulous application of good hygiene practices-as part of self-control and food safety management systems-is therefore the optimal strategy for mitigating risk. (4)
Survival and inactivation of virus on inanimate surfaces
Transmission of the virus, like other pathogens, can occur indirectly through fomites (inanimate materials). In the event that you touch your eyes, nose, mouth without first washing your hands after coming into contact with them. (5) Therefore, the surfaces of worktops, utensils and and materials used to produce and package food are taken into consideration. In addition to PPE (personal protective equipment) and personal hygiene precautions (see OSHA guidelines).
Several tests were conducted in the laboratory to evaluate the survival times and temperatures of various coronavirus strains, with SARS-Cov-2-like characteristics, on a variety of surfaces:
– HuCoV-229E, SARS-CoV-1 and MERS. Human coronavirus 229E showed the ability to persist for up to 5 days on Teflon, PVC, glass, silicone rubber, and ceramic tiles. Other strains persist on metal, plastic and glass for up to 9 days. The time is shortened at temperatures >30 °C and can increase, up to 28 days, at +4 °C, (6)
– SARS-CoV-2 can survive 4 hours on copper, 24 hours on cardboard, 72 hours on plastic and stainless steel, at 21-23 °C and 40% relative humidity. (7) In another experiment, at 22 °C, greater persistence was observed on smooth surfaces. Up to 4 days on glass and banknotes, 7 days on plastic and stainless steel. (8)
PPE fabrics, artificial light
Treating PPE fabrics with silicon nitride particles is one of the most promising treatments, an interesting hypothesis for containing the spread of the virus in work environments. Against the ability of this substance to inactivate up to 99% of SARS-CoV-2 with only 1 minute. (9)
Artificial light has in turn proven effective. Inactivating in about 7 minutes the virus on artificial saliva deposited on steel plates. (10) This experiment offers interesting insights, which deserve further study, into the ability of light (natural and artificial) to reduce the persistence (and perhaps even the viral load) of SARS-CoV-2.
Food processing technologies
In the food industry, inactivation of viruses and pathogenic microorganisms is achieved by thermal (wet or dry) and nonthermal treatments. Exposure to temperatures of 63 °C for 4 minutes-the time considered sufficient to inactivate SARS-CoV-2-is a widely exceeded parameter in food cooking. (11)
The cold chain, conversely, has no effectiveness in destroying the virus under investigation or other pathogens that may contaminate food. A stress-test-performed by inoculating Covid-19 on chicken, pig and salmon-showed its ability to survive at temperatures of +4, -20 and -80 °C for as long as three weeks. (12)
Numerous nonthermal treatments include the use of UV light, pH control (< 3 and >12), pulsed light, ionizing radiation, high hydrostatic pressures, and cold plasma. (13) The latter technique is innovative and prized for being eco-friendly and chemical-free. The combination of inert gas and high voltage help inactivate numerous microorganisms from solid and liquid foods, with excellent potential against SARS-CoV-2. (14)
Fig. 1. Schematic diagram of the operation of a cold plasma plant (A,B) and some food matrices (C) subjected to treatment with this technology (Filipič et al., 2020)
Disinfection of food contact surfaces
All surfaces with which food comes into contact during production, packaging and preparation-in industrial, restaurant and household activities-can become contaminated with SARS-CoV-2. Therefore, proper disinfection is necessary to avoid infection through subsequent contact with eyes, mouth or nose before washing hands. (15) Although the biology of SARS-CoV-2 is still poorly known it too, like other coronaviruses, shows good sensitivity to several disinfectants including sodium hypochlorite (bleach), hydrogen peroxide (hydrogen peroxide) and ethyl alcohol, which can greatly reduce its surface presence even after only one minute of treatment at room temperature. (16)
UV light is widely used in the food industry to disinfect surfaces after they have been properly cleaned and rinsed to leave no residue. (17) UV can also be used for microbiological air control, in addition to filters that need to be replaced regularly, to reduce the risk of the presence of the virus (and other pathogens), as well as food contamination. (18)
Fig. 2. Some disinfectant agents that can disinfect coronaviruses (Anelich et al., 2020)
Interim conclusions
The evidence to date shows that SARS-CoV-2 does not represent a cause of foodborne illness. This virus, on the other hand, has caused serious uncertainties in the global food supply chain and its workers. Therefore, it seems useful to devise new strategies to better prevent and manage situations similar to the one that is still going on. (19)
To explore the topic in its complexity, we refer to the ebooks ‘
Covid-19, ABC – Volume I, People
‘, ‘
Covid-19, ABC – Volume II, Society
‘, ‘
Covid-19, ABC – Volume III, Planet
‘.
Dario Dongo and Andrea Adelmo Della Penna
Notes
(1) World Health Organization (2020). COVID-19 and Food Safety: Guidance for Food Businesses. https://www.who.int/publications/i/item/covid-19-and-food-safety-guidance-for-food-businesses
(2) Lamers et al. (2020). SARS-CoV-2 productively infects human gut enterocytes. Science 1:eabc1669, doi:10.1126/science.abc1669
(3) Wang et al. (2020). Clinical characteristics and fecal-oral transmission potential of patients with COVID19. medRxiv, doi:10.1101/2020.05.02.20089094
(4) Dario Dongo, Fabrizio De Stefani, Andrea Gazzetta (2020). Covid-19 and food safety, preventive and corrective actions. GIFT (Great Italian Food Trade). 6.5.20, https://www.greatitalianfoodtrade.it/sicurezza/covid-19-e-sicurezza-alimentare-azioni-preventive-e-correttive
(5) Centers for Disease Control and Prevention (2020). Updates COVID-19 Transmission Webpage to Clarify Information About Types of Spread. https://www.cdc.gov/media/releases/2020/s0522-cdc-updates-covid-transmission.html
(6) Warnes et al. (2015). Human coronavirus 229E remains infectious on common touch surface materials. MBio 6:e01691-15, doi:10.1128/mBio.01697-15
(7) Van Doremalen et al. (2020). Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1. N. Engl. J. Med. 382:1564-7, doi:10.1056/NEJMc2004973
(8) Chin et al. (2020). Stability of SARS-CoV-2 under different environmental conditions. Lancet Microbe. 1:e10, https://doi.org/10.1016/S2666-5247(20)30003-3
(9) Pezzotti et al. (2020). Rapid inactivation of SARS-CoV-2 by silicon nitride, copper, and alluminium nitride. bioRxiv, doi:10.1101/2020.06.19.159970
(10) Shumate et al. (2020). Simulated sunlight rapidly inactivates SARS-CoV-2 on surfaces. J. Infect. Dis. 222:214-22, doi:10.1093/infdis/jiaa274/5841129
(11) ANSES (2020). Opinion on an Urgent Request to Assess Certain Risks Associated with COVID-19. https://www.anses.fr/en/system/files/SABA2020SA0037-1.pdf
(12) Fisher et al. (2020). Seeding of outbreaks of COVID-19 by contaminated fresh and frozen food. bioRxiv, doi:10.1101/2020.08.17.255166
(13) Deng et al. (2019). Emerging chemical and physical disinfection technologies of fruits and vegetables: a comprehensive review. Crit. Rev. Food Sci. Nutr. 60:2481-508, doi:10.1080/10408398.2019.1649633
(14) Filipić et al. (2020). Cold plasma, a new hope in the field of virus inactivation. Trends Biotechnol. 38:1278-91, doi:10.1016/j.tibtech.2020.04.003
(15) Sohrabi et al. (2020). World health organization declares global emergency: a review of the 2019 novel coronavirus (COVID-19). Int. J. Surg. 76:71-76, doi:10.1016/j.ijsu.2020.02.034
(16) Kampf et al. (2020). Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents. J. Hosp. Infect. 104:246-51, doi:10.1016/j.jhin.2020.01.022
(17) Skara et al. (2016). Emerging methods and principles in food contact surface decontamination/prevention environmental factors in infectious disease. Innovation and Future Trends in Food Manufacturing and Supply Chain Technologies 151-72, doi:10.1016/B978-1-78242-447-5.00006-X
(18) Nardell et al. (2020). Airborne spread of SARS-CoV-2 and a potential role for air disinfection. JAMA 324:141-2, doi:10.1001/jama.2020.7603
(19) Anelich et al. (2020). SARS-CoV-2 and Risk to Food Safety. Front. Nutr. 7:580551, doi:10.3389/fnut.2020.580551
Dario Dongo, lawyer and journalist, PhD in international food law, founder of WIISE (FARE - GIFT - Food Times) and Égalité.
Graduated in Food Technologies and Biotechnologies, qualified food technologist, he follows the research and development area. With particular regard to European research projects (in Horizon 2020, PRIMA) where the FARE division of WIISE Srl, a benefit company, participates.
