Microbiological risk in foods
Every year we face the emergence of pathogens that put plant health at risk (Avila-Quezada et al., 2018) along with human health (Chowell et al., 2009), due to their quick spread and mortality. The recent emergence caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has alarmed the global population. Among these alarms are the speculations around the risk of contagion by foods. So far, there have been no reports of a direct relation, therefore regulatory and health authorities have declared the non-existence of evidence to indicate that foods are a means of transmission of SARS-CoV-2 (CDC, 2020; OMS, 2020; FDA, 2020).
However, the known means of transmission are person-to-person contact, contaminated surfaces (Han et al., 2021), exposure to high levels of microparticles in the air and aerosols (Li et al., 2020; Roviello, 2020) which, combined in places in which foods are handled, may be a potential risk for the transmission of the virus (Han et al., 2021). This premise rises from isolated incidents in which frozen foods and their packages were found to be carriers of SARS-CoV-2, being the first, and so far, the only reported cases (SMHC, 2020). In this sense, refrigerated and frozen foods must follow adequate hygiene protocols.
Storage temperature and latency of the virus
The low temperatures in refrigerators, warehouses and transportation vehicles for food may extend the viability of SARS-CoV-2. Chin et al. (2020), Aboubakr et al. (2020) and Matson et al. (2020) measured the stability of the virus at different temperatures and found that it is stable at 4 °C. Depending on the type of surface, environment, pH, temperature and humidity, the coronaviruses may remain viable for up to 28 days (Casanova et al., 2010; Lai et al. 2005), confirming the presence of the virus in frozen foods, packages and storage settings Han et al. (2021). This suggests that before storing foods in low temperatures, they must undergo an appropriate and efficient disinfection treatment.
Person-to-food contamination
People infected with SARS-CoV-2 and are not adequately protected may release the virus when breathing, coughing, sneezing, or talking (Morawska and Milton, 2020). Therefore, when they are handling foods, they will contaminate them, along with the packages. Morawska et al. (2009) documented that the droplets released by a person can remain in the air and become a risk of exposure at distances higher than 2 m away from the infected person. At typical indoor air speeds, a 5 μm droplet will travel dozens of meters from a height of 1.5 m before landing on the ground (Matthews et al., 1989). Here is where the measures regarding covering one’s face and social distancing come into play as key factors to reduce the rate of contagion and thus reduce the risk of contamination of foods (Li et al., 2020).
Recommendations and perspectives
Although further studies are required on the stability of SARS-CoV-2 and its viral load on foods to induce infections on humans, it is recommendable for the workers involved in preparing, packaging and distributing foods to take precautions (Eslami and Jalili, 2020). The action protocols established in some food plants in several countries consist in workers taking turns for lunch breaks and avoiding speaking in this period to reduce the risk of contaminating the foods they and other employees will eat. Other measures are the procedures for the hygiene and disinfection of equipment, facilities and frequently touched surfaces. These protocols have given good results as measures of precaution and are easy to follow in other areas related to the production, packaging and storage of foods. In general terms, these measures are widely used in food packaging plants operated under strict ISO certification models and adequate manufacturing practices.