COVID-19 is an acute infectious disease of the respiratory tract (which can be severe), caused by a new type of coronavirus designated SARS-CoV-2 ( Severe Acute Respiratory Syndrome Coronavirus 2) . This is the third highly pathogenic coronavirus in the last 20 years that has been able to cross the species barrier and reach the human population, although its intermediate host is still unknown. The outbreak caused by this coronavirus began in Wuhan province in China, but quickly spread to a large number of countries, leading to the declaration of a pandemic by the World Health Organization (WHO) on March 11, 2020. As a global public health concern impacting all activities, including the food sector, this study aimed to gather existing knowledge about SARS-CoV-2 and its potential impact on the food preparation and distribution environment, as well as hygiene and food safety recommendations developed by various reference entities in the context of the COVID-19 pandemic.
How is SARS-CoV-2 infection transmitted?
Although knowledge about the origin and transmission routes of this new coronavirus is still limited, the rapid and efficient spread of COVID-19 is due to the fact that SARS-CoV-2 has a high capacity to infect humans (invasion of respiratory tract cells) and person-to-person transmission. The main route of transmission is through the inhalation of respiratory droplets that infected people emit when they sneeze, cough, or talk (direct route). Additionally, these droplets containing SARS-CoV-2 can infect another person through hand contact with surfaces and objects (frequently touched) contaminated with viral particles and then with the mouth, nose, or eyes (indirect route). Regarding foodborne transmission , health authorities such as the European Food Safety Authority (EFSA) and the WHO consider it highly unlikely that a virus causing respiratory illness can be transmitted through the food chain (food and packaging), and to date there is no evidence of infection through the consumption of food (raw or cooked), similar to the coronaviruses associated with previous outbreaks (SARS-CoV and MERS-CoV ( Middle East Respiratory Syndrome Coronavirus )). The differences in the epidemiological characteristics of this pandemic are probably related to other factors, such as the high viral load present in the upper respiratory tract and the potential for people infected with SARS-CoV-2 to transmit the virus while asymptomatic . Although the presence of SARS-CoV-2 (RNA) has been detected in stool samples from infected patients, there is (still) no evidence of transmission via the fecal-oral route . Therefore, since there is no vaccine or specific treatment for this infection, it is imperative that measures to prevent the transmission of the virus be reinforced, including personal hygiene and food hygiene principles, in order to eliminate or reduce the risk of contamination of surfaces/objects in the food area, hands, and food packaging materials.
What do we know about coronaviruses that is relevant to the food industry?
Coronaviruses (CoVs) belong to a family of viruses that cause respiratory illnesses in humans, ranging from the common cold to rarer and more severe diseases such as SARS and MERS (both with high mortality rates, first detected in 2003 and 2012, respectively). Like other viruses, coronaviruses do not multiply in food, as they need to infect cells of the animal or human host (obligate intracellular parasites). Coronaviruses are RNA viruses (single-stranded) with a helical nucleocapsid, which is coated by an envelope (consisting of a lipid bilayer derived from intracellular membrane systems of host cells). The presence of an envelope makes them susceptible to agents that dissolve "fat," such as dishwashing detergents, hand soaps, and alcohols. However, the stability of coronaviruses in the environment depends on several factors, such as temperature, air humidity, and surface type, in addition to the amount of virus and strain. The survival time and conditions affecting the viability of SARS-CoV-2 are still unknown. Studies evaluating the environmental stability of coronaviruses have shown that they can survive for several days in the environment and on different surfaces. A review, published during the pandemic, on the survival of known coronaviruses (SARS-CoV and MERS-CoV) on inert surfaces showed, for example, that the viruses can persist on metal, glass, or plastic (and remain infectious) at room temperature for an average of four to five days (possibly up to nine days). More recently, the first results regarding SARS-CoV-2 were published, showing that the virus can remain viable for up to 72 hours on plastic and stainless steel, up to 24 hours on cardboard, and up to four hours on copper surfaces . The interpretation of this data should be done with caution, since viruses usually become non-infectious after the first 24 hours on surfaces and there is little evidence that viral particles can cause infection through this route . In any case, this initial data on the stability of SARS-CoV-2 suggests the possibility of dissemination of these viruses through contact with surfaces , reinforcing the importance of hand hygiene and cleaning of surfaces/objects.
Regarding the effects of biocidal agents commonly used for chemical disinfection (disinfectants), the survey conducted by Kampf et al (2020) showed that coronaviruses can be inactivated through surface disinfection procedures with agents based on ethanol (62-71%), hydrogen peroxide (0.5%) or sodium hypochlorite (0.1%), highlighting the importance of applying appropriate concentrations to reduce the number of viral particles. The results with other biocidal agents tested, such as benzalkonium chloride (0.05-0.2%) and chlorhexidine digluconate (0.02%), demonstrated effectiveness, although less than the biocides mentioned above. Alcohol-based hand sanitizers ( 80% ethanol and 75% 2-propanol formulations recommended by the WHO) have also recently been tested against SARS-CoV-2, demonstrating their ability to inactivate the virus, as is already known for other coronaviruses.
Thus, in food production and distribution units, the WHO recommends that good hygiene and food safety practices be maintained, ensuring regular and correct cleaning and disinfection procedures for surfaces (facilities, equipment, and frequently touched points such as counters, worktops, tongs and other utensils and door handles), as well as proper hand washing (soap and water for at least 20 seconds; hand sanitizers can be used as an additional measure, but should not replace hand washing) combined with the frequent use of alcohol-based disinfectants (disposable gloves should not be used as a substitute for hand washing). For disinfecting small surfaces in the food area, alcohol-based disinfectants (ethanol, 2-propanol, 1-propanol) at concentrations of 70 to 80% are recommended, as they significantly reduce the infectivity of enveloped viruses such as SARS-CoV-2. Other commonly used disinfectants with active ingredients based on quaternary ammonium compounds or chlorine (e.g., 0.1% sodium hypochlorite - 1:50 dilution of 5% common bleach) also have virucidal properties (if prepared according to the manufacturer's instructions) and are recommended, as they are for the health sector and other locations . A list of disinfectants that meet the EPA (Environmental Protection Agency) criteria for use against SARS-CoV-2 the US Department of Agriculture website . More specific guidance for the professional sector is available on the websites of the Directorate-General of Health ( DGS – Guidance No. 014/2020 of 21/03/2020 ) and the Food and Drug Administration (FDA).
How can we prevent the spread of SARS-CoV-2 during food preparation and consumption?
Currently, there is no evidence that human infection with the novel coronavirus SARS-CoV-2 can occur through the consumption of food, contact with contaminated food/packaging, or cutlery/dishes . Therefore, food is not considered a source or route of transmission of this virus ( EFSA , BfR , USDA ). In fact, experience from previous outbreaks caused by other coronaviruses, SARS-CoV and MERS-CoV, showed that transmission did not occur through food consumption. According to current knowledge, there is also no evidence that livestock used for meat production can be infected with SARS-CoV-2, so transmission of the virus to humans through this route is unlikely ( BfR ). However, some national entities such as the Food and Economic Security Authority ( ASAE ) and the DGS (Directorate- General of Health), applying the precautionary principle, suggest reinforcing hygiene and cleaning measures during the preparation, cooking, and consumption of food, since good practices lead to a reduction in the number of viruses and effectively decrease the probability of contamination. Among these measures, the correct handwashing and hygiene of inert surfaces, cooking food (e.g., meat and poultry) at appropriate temperatures (the virus is sensitive to heat), and avoiding cross-contamination between raw and cooked foods stand out – measures framed within the WHO's "Five Keys to Safer Food" . Other international entities have published complementary information that can minimize possible (and undescribed) contamination through contact with the surface of ready-to-eat foods. Regarding raw plant-based products (usually displayed in retail establishments), it is recommended that general hygiene rules be followed, including washing fruits and vegetables with running drinking water before consumption (including those whose peel is not consumed), frequent hand washing during handling, and keeping hands away from the face (Bfr, WHO , FDA ). Regarding dishwashing/cutlery , although there is no specific data for SARS-CoV-2, it is very likely that detergents (containing surfactants that dissolve grease) will inactivate it, particularly if the dishes are washed and dried in a dishwasher at 60°C ( BfR ). Like other viruses, it is possible that SARS-CoV-2 can survive on surfaces in the food preparation environment, but being an enveloped virus (sensitive to common disinfectants), basic hygiene procedures applied to ensure food safety should be sufficient to prevent its spread. Frequent washing and sanitizing of surfaces is recommended using commercially available disinfectant products (following the manufacturer's instructions) or homemade disinfectants (e.g., the DGS recommends 4 teaspoons of approximately 10ml of bleach per 1 liter of water ). Additional recommendations regarding the purchase of food products in retail establishments are available.
In summary, there is no evidence that the SARS-CoV-2 coronavirus can be transmitted through food, but it is recommended to maintain and reinforce preventive measures for personal hygiene and hygiene of the food preparation, distribution and consumption environment, in order to eliminate or reduce the risk of contamination of inert surfaces/objects in the food area, hands and food packaging materials.
