A review of epidemic investigation on cold-chain food-mediated SARS-CoV-2 transmission and food safety consideration during COVID-19 pandemic

A narrative review of alternative transmission routes of COVID 19: what we know so far

The Coronavirus disease 19 (COVID-19) pandemics, caused by severe acute respiratory syndrome coronaviruses, SARS-CoV-2, represent an unprecedented public health challenge. Beside person-to-person contagion via airborne droplets and aerosol, which is the main SARS-CoV-2's route of transmission, alternative modes, including transmission via fomites, food and food packaging, have been investigated for their potential impact on SARS-CoV-2 diffusion. In this context, several studies have demonstrated the persistence of SARS-CoV-2 RNA and, in some cases, of infectious particles on exposed fomites, food and water samples, confirming their possible role as sources of contamination and transmission. Indeed, fomite-to-human transmission has been demonstrated in a few cases where person-to-person transmission had been excluded. In addition, recent studies supported the possibility of acquiring COVID-19 through the fecal-oro route; the occurrence of COVID-19 gastrointestinal infections, in the absence of respiratory symptoms, also opens the intriguing possibility that these cases could be directly related to the ingestion of contaminated food and water. Overall, most of the studies considered these alternative routes of transmission of low epidemiological relevance; however, it should be considered that they could play an important role, or even be prevalent, in settings characterized by different environmental and socio-economic conditions. In this review, we discuss the most recent findings regarding SARS-CoV-2 alternative transmission routes, with the aim to disclose what is known about their impact on COVID-19 spread and to stimulate research in this field, which could potentially have a great impact, especially in low-resource contexts.

Detection rates of norovirus gastroenteritis and factors associated with the infection before and during COVID-19 pandemic: a secondary analysis of surveillance data in Guangxi Zhuang Autonomous Region, Southern China

Background: Changes in oral and hand hygiene behaviors have been reported during the COVID-19 pandemic in 2020 which may be associated with the incidence of the norovirus infection, a common cause of gastroenteritis. Objective: To estimate the trends of detection rates of norovirus gastroenteritis and associated factors before COVID-19 in 2015-2019 and during the COVID-19 in 2020 in Guangxi, China. Methods: A secondary analysis of Guangxi surveillance data of gastroenteritis patients was conducted. The detection rate in 2020 was predicted using an autoregressive integrated moving average modeland associated factors were analyzed using multiple logistic regression adjusted for interaction effects. Results: Of 7,903 gastroenteritis patients, the overall detection rate of norovirus gastroenteritis was 12.8%, (14.3% before and 6.1% during COVID-19). Detection rates gradually decreased from 2015 to 2020, of which the slope of predicted line was slightly flatter than the actual line. The odds ratios of detection were double to triple increase during COVID-19 in the younger age group and having food intake outside their homes. Tourist city, season, and types of food were independent associated factors. Conclusion: The detection rates were higher during the COVID-19 year among the population aged 45 years or less and those who consumed food outside their home.

SARS-CoV-2 Survival on Surfaces. Measurements Optimisation for an Enthalpy-Based Assessment of the Risk

The present work, based on the results found in the literature, yields a consistent model of SARS-CoV-2 survival on surfaces as environmental conditions, such as temperature and relative humidity, change simultaneously. The Enthalpy method, which has recently been successfully proposed to investigate the viability of airborne viruses using a holistic approach, is found to allow us to take a reasoned reading of the data available on surfaces in the literature. This leads us to identify the domain of conditions of lowest SARS-CoV-2 viability, in a specific enthalpy range between 50 and 60 kJ/Kg_dry-air. This range appears well-superimposed with the results we previously obtained from analyses of coronaviruses' behaviour in aerosols, and may be helpful in dealing with the spread of infections. To steer future investigations, shortcomings and weaknesses emerging from the assessment of viral measurement usually carried out on surfaces are also discussed in detail. Once demonstrated that current laboratory procedures suffer from both high variability and poor standardisation, targeted implementations of standards and improvement of protocols for future investigations are then proposed.

High-Intensity Ultraviolet-C Irradiation Efficiently Inactivates SARS-CoV-2 Under Typical Cold Chain Temperature

SARS-CoV-2 contaminated items in the cold chain becomes a threat to public health, therefore the effective and safe sterilization method fit for the low temperature is needed. Ultraviolet is an effective sterilization method while its effect on SARS-CoV-2 under low-temperature environment is unclear. In this research, the sterilization effect of high-intensity ultraviolet-C (HIUVC) irradiation against SARS-CoV-2 and Staphylococcus aureus on different carriers at 4 °C and - 20 °C was investigated. The results showed that dose of 15.3 mJ/cm2 achieved more than 3 log reduction of SARS-CoV-2 on gauze at 4 °C and - 20 °C. The vulnerability of coronavirus to HIUVC under - 20 °C was not significantly different than those under 4 °C. Four models including Weibull, biphasic, log-linear tail and log linear were used to fit the survival curves of SARS-CoV-2 and Staphylococcus aureus. The biphasic model fitted best with R2 ranging from 0.9325 to 0.9878. Moreover, the HIUVC sterilization correlation between SARS-CoV-2 and Staphylococcus aureus was established. This paper provides data support for the employment of HIUVC under low-temperature environment. Also, it provides a method of using Staphylococcus aureus as a marker to evaluate the sterilization effect of cold chain sterilization equipment.

Effects of E-beam irradiation on the physicochemical properties of Atlantic cod (Gadus morhua)

Electron beam (E-beam) irradiation can effectively inactivate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in cold-chain seafood. This study evaluated the effects of E-beam irradiation at doses killing SARS-CoV-2 on quality indicators of Atlantic cod. The cod samples were exposed to 0, 2, 4, 7, and 10 kGy E-beam irradiation, and nutrition, texture, color, and sensory attributes were investigated. The results showed that E-beam irradiation significantly increased thiobarbituric acid (TBA) value and decreased hardness, chewiness, and a* value of Atlantic cod (P < 0.05). E-beam irradiation with 10 kGy significantly lowered total volatile base nitrogen (TVB-N) and reducing sugar content while increasing moisture and ash content (P < 0.05). A significant color change was observed after irradiation with 2 kGy-7 kGy E-beam (P < 0.05). E-beam irradiation had no effects on sensory attributes (P > 0.05). A dose of 4 kGy was recommended considering the keeping quality in Atlantic cod.

Design of UVC Surface Disinfection Robot with Coverage Path Planning Using Map-Based Approach At-The-Edge

In response to the issue of virus contamination in the cold-chain warehouse or hospital environment under the influence of the COVID-19, we propose the design work of a disinfection robot based on the UVC radiation mechanism using the low-computational path optimization at-the-edge. To build a surface disinfection robot with less computing power to generate a collision-free path with shorter total distance in studies, a 2D map is used as a graph-based approach to automatically generate a closed-loop disinfection path to cover all the accessible surfaces. The discrete disinfection points from the map are extracted with effective disinfection distances and sorted by a nearest-neighbor (NN) search over historical trajectory data and improved A * algorithm to obtain an efficient coverage path to all accessible boundaries of the entire area. The purpose of improved A * algorithm with NN is not to find the optimal path solution but to optimize one with reasonable computing power. The proposed algorithm enhances the path-finding efficiency by a dynamically weighted heuristic function and reduces the path turning angles, which improves the path smoothness significantly requiring less computing power. The Gazebo simulation is conducted, and the prototype disinfection robot has been built and tested in a real lab environment. Compared with the classic A * algorithm, the improved A * algorithm with NN has improved the path-finding efficiency and reduced the path length while covering the same area. Both the simulation and experimental results show that this approach can provide the design to balance the tradeoffs among the path-finding efficiency, smoothness, disinfection coverage, and computation resources.

Point-of-care CRISPR/Cas biosensing technology: A promising tool for preventing the possible COVID-19 resurgence caused by contaminated cold-chain food and packaging

The ongoing coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused great public health concern and has been a global threat due to its high transmissibility and morbidity. Although the SARS-CoV-2 transmission mainly relies on the person-to-person route through the respiratory droplets, the possible transmission through the contaminated cold-chain food and packaging to humans has raised widespread concerns. This review discussed the possibility of SARS-CoV-2 transmission via the contaminated cold-chain food and packaging by tracing the occurrence, the survival of SARS-CoV-2 in the contaminated cold-chain food and packaging, as well as the transmission and outbreaks related to the contaminated cold-chain food and packaging. Rapid, accurate, and reliable diagnostics of SARS-CoV-2 is of great importance for preventing and controlling the COVID-19 resurgence. Therefore, we summarized the recent advances on the emerging clustered regularly interspaced short palindromic repeats (CRISPR)/Cas system-based biosensing technology that is promising and powerful for preventing the possible COVID-19 resurgence caused by the contaminated cold-chain food and packaging during the COVID-19 pandemic, including CRISPR/Cas system-based biosensors and their integration with portable devices (e.g., smartphone, lateral flow assays, microfluidic chips, and nanopores). Impressively, this review not only provided an insight on the possibility of SARS-CoV-2 transmission through the food supply chain, but also proposed the future opportunities and challenges on the development of CRISPR/Cas system-based detection methods for the diagnosis of SARS-CoV-2.

Consideration of COVID-19 beyond the human-centred approach of prevention and control: the ONE-HEALTH perspective

Most of the new emerging and re-emerging zoonotic virus outbreaks in recent years stem from close interaction with dead or alive infected animals. Since late 2019, the coronavirus disease 2019 (COVID-19) has spread into 221 countries and territories resulting in close to 300 million known infections and 5.4 million deaths in addition to a huge impact on both public health and the world economy. This paper reviews the COVID-19 prevalence in animals, raise concerns about animal welfare and discusses the role of environment in the transmission of COVID-19. Attention is drawn to the One Health concept as it emphasizes the environment in connection with the risk of transmission and establishment of diseases shared between animals and humans. Considering the importance of One Health for an effective response to the dissemination of infections of pandemic character, some unsettled issues with respect to COVID-19 are highlighted.

The Multifaceted Relationship between the COVID-19 Pandemic and the Food System

The SARS-CoV-2 pandemic is being questioned for its possible food transmission, due to several reports of the virus on food, outbreaks developed in food companies, as well as its origins linked to the wet market of Wuhan, China. The purpose of this review is to analyze the scientific evidence gathered so far on the relationship between food and the pandemic, considering all aspects of the food system that can be involved. The collected data indicate that there is no evidence that foods represent a risk for the transmission of SARS-CoV-2. In fact, even if the virus can persist on food surfaces, there are currently no proven cases of infection from food. Moreover, the pandemic showed to have deeply influenced the eating habits of consumers and their purchasing methods, but also to have enhanced food waste and poverty. Another important finding is the role of meat processing plants as suitable environments for the onset of outbreaks. Lessons learned from the pandemic include the correct management of spaces, food hygiene education for both food workers and common people, the enhancement of alternative commercial channels, the reorganization of food activities, in particular wet markets, and intensive farming, following correct hygiene practices. All these outcomes lead to another crucial lesson, which is the importance of the resilience of the food system. These lessons should be assimilated to deal with the present pandemic and possible future emergencies. Future research directions include further investigation of the factors linked to the food system that can favor the emergence of viruses, and of innovative technologies that can reduce viral transmission.

Investigating the microbial inactivation effect of low temperature high pressure carbon dioxide and its application in frozen prawn (Penaeus vannamei)

During the pandemic of coronavirus disease 2019, the fact that frozen foods can carry the relevant virus raises concerns about the microbial safety of cold-chain foods. As a non-thermal processing technology, high pressure carbon dioxide (HPCD) is a potential method to reduce microbial load on cold-chain foods. In this study, we explored the microbial inactivation of low temperature (5-10 °C) HPCD (LT-HPCD) and evaluated its effect on the quality of prawn during freeze-chilled and frozen storage. LT-HPCD treatment at 6.5 MPa and 10 °C for 15 min could effectively inactivate E. coli (99.45%) and S. aureus (94.6%) suspended in 0.85% NaCl, SARS-CoV-2 Spike pseudovirus (>99%) and human coronavirus 229E (hCoV-229E) (>1-log virus tilter reduction) suspended in DMEM medium. The inactivation effect of LT-HPCD was weakened but still significant when the microorganisms were inoculated on the surface of food or package. LT-HPCD treatment at 6.5 MPa and 10 °C for 15 min achieved about 60% inactivation of total aerobic count while could maintain frozen state and quality of prawn. Moreover, LT-HPCD treated prawn exhibited significant slower microbial proliferation and no occurrence of melanosis compared with the untreated samples during chilled storage. A comprehensive quality investigation indicated that LT-HPCD treatment could maintain the color, texture and sensory of prawn during chilled or frozen storage. Consequently, LT-HPCD could improve the microbial safety of frozen prawn while maintaining its original quality, and could be a potential method for food industry to improve the microbial safety of cold-chain foods.

Persistence of avian influenza virus (H9N2) on plastic surface

Plastics have been found to be colonized with pathogens and may become vectors for transmission of diseases. In this study, we evaluated the persistence of H9N2 avian influenza virus (AIV) on the surfaces of various plastics (PP, PE, PS, PET, PVC, PMMA) under different environmental conditions using glass and stainless steel for comparison. Our results showed that the RNA abundance of AIV on plastics was decreased over time but still detectable 14 days after AIV had been dropped on plastic surfaces. Low temperature (4 °C) was more favorable for AIV RNA preservation and infectivity maintenance. The abundance of AIV RNA was significantly greater on polyethylene terephthalate (PET) than that on glass and stainless steel at higher temperature (i.e., 25 °C and 37 °C) and lower humidity (<20% and 40-60%) (p < 0.05). Infectivity assay showed that AIV infectivity was only maintained at 4 °C after 24 h of incubation. Taken together, the persistence of AIV was more affected by environmental factors than material types. Plastics were able to preserve viral RNA more effectively in relatively high-temperature or low-humidity environments. Our study indicates that environmental factors should be taken into consideration when we evaluate the capacity of plastics to spread viruses.

Truths and myths about superfoods in the era of the COVID-19 pandemic

Nowadays, during the current COVID-19 pandemic, consumers increasingly seek foods that not only fulfill the basic need (i.e., satisfying hunger) but also enhance human health and well-being. As a result, more attention has been given to some kinds of foods, termed "superfoods," making big claims about their richness in valuable nutrients and bioactive compounds as well as their capability to prevent illness, reinforcing the human immune system, and improve overall health.This review is an attempt to uncover truths and myths about superfoods by giving examples of the most popular foods (e.g., berries, pomegranates, watermelon, olive, green tea, several seeds and nuts, honey, salmon, and camel milk, among many others) that are commonly reported as having unique nutritional, nutraceutical, and functional characteristics.While superfoods have become a popular buzzword in blog articles and social media posts, scientific publications are still relatively marginal. The reviewed findings show that COVID-19 has become a significant driver for superfoods consumption. Food Industry 4.0 innovations have revolutionized many sectors of food technologies, including the manufacturing of functional foods, offering new opportunities to improve the sensory and nutritional quality of such foods. Although many food products have been considered superfoods and intensively sought by consumers, scientific evidence for their beneficial effectiveness and their "superpower" are yet to be provided. Therefore, more research and collaboration between researchers, industry, consumers, and policymakers are still needed to differentiate facts from marketing gimmicks and promote human health and nutrition.

Microfluidic Paper-Based Analytical Devices for the Determination of Food Contaminants: Developments and Applications

Food safety is an issue that cannot be ignored at any time because of the great impact of food contaminants on people's daily life, social production, and the economy. Because of the extensive demand for high-quality food, it is necessary to develop rapid, reliable, and efficient devices for food contaminant detection. Microfluidic paper-based analytical devices (μPADs) have been applied in a variety of detection fields owing to the advantages of low-cost, ease of handling, and portability. This review systematically discusses the latest progress of μPADs, including the fundamentals of fabrication as well as applications in the detection of chemical and biological hazards in foods, hoping to provide suitable screening strategies for contaminants in foods and accelerating the technology transformation of μPADs from the lab into the field.

A narrative review on the role of temperature and humidity in COVID-19: Transmission, persistence, and epidemiological evidence

Since December 2019, the 2019 coronavirus disease (COVID-19) outbreak has become a global pandemic. Understanding the role of environmental conditions is important in impeding the spread of COVID-19. Given that airborne spread and contact transmission are considered the main pathways for the spread of COVID-19, this narrative review first summarized the role of temperature and humidity in the airborne trajectory of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Meanwhile, we reviewed the persistence of the virus in aerosols and on inert surfaces and summarized how the persistence of SARS-CoV-2 is affected by temperature and humidity. We also examined the existing epidemiological evidence and addressed the limitations of these epidemiological studies. Although uncertainty remains, more evidence may support the idea that high temperature is slightly and negatively associated with COVID-19 growth, while the conclusion for humidity is still conflicting. Nonetheless, the spread of COVID-19 appears to have been controlled primarily by government interventions rather than environmental factors.

The Safety of Cold-Chain Food in Post-COVID-19 Pandemic: Precaution and Quarantine

Since the outbreak of coronavirus disease-19 (COVID-19), cold-chain food contamination caused by the pathogenic severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has attracted huge concern. Cold-chain foods provide a congenial environment for SARS-CoV-2 survival, which presents a potential risk for public health. Strengthening the SARS-CoV-2 supervision of cold-chain foods has become the top priority in many countries. Methodologically, the potential safety risks and precaution measures of SARS-CoV-2 contamination on cold-chain food are analyzed. To ensure the safety of cold-chain foods, the advances in SARS-CoV-2 detection strategies are summarized based on technical principles and target biomarkers. In particular, the techniques suitable for SARS-CoV-2 detection in a cold-chain environment are discussed. Although many quarantine techniques are available, the field-based quarantine technique on cold-chain food with characteristics of real-time, sensitive, specific, portable, and large-scale application is urgently needed.

Mass Spectrometry Approaches for SARS-CoV-2 Detection: Harnessing for Application in Food and Environmental Samples

The public health crisis caused by the emergence of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in 2019 has drastically changed our lifestyle in virtually all contexts around the world. SARS-CoV-2 is mainly airborne, transmitted by the salivary droplets produced when infected people cough or sneeze. In addition, diarrhea symptoms and the detection of SARS-CoV-2 in feces suggest a fecal-oral route of contagion. Currently, the high demand for SARS-CoV-2 diagnosis has surpassed the availability of PCR and immunodetection probes and has prompted the development of other diagnostic alternatives. In this context, mass spectrometry (MS) represents a mature, robust alternative platform for detection of SARS-CoV-2 and other human viruses. This possibility has raised great interest worldwide. Therefore, it is time for the global application of MS as a feasible option for detecting SARS-CoV-2, not only in human fluids, but also in other matrices such as foods and wastewater. This review covers the most relevant established methods for MS-based SARS-CoV-2 detection and discusses the future application of these tools in different matrices. Significance: The Coronavirus Disease 2019 (COVID-19) pandemic highlighted the pros and cons of currently available PCR and immunodetection tools. The great concern over the infective potential of SARS-CoV-2 viral particles that can persist for several hours on different surfaces under various conditions further evidenced the need for reliable alternatives and high-throughput methods to meet the needs for mass detection of SARS-CoV-2. In this context, MS-based proteomics emerging from fundamental studies in life science can offer a robust option for SARS-CoV-2 detection in human fluids and other matrices. In addition, the substantial efforts towards detecting SARS-CoV-2 in clinal samples, position MS to support the detection of this virus in different matrices such as the surfaces of the packing food process, frozen foods, and wastewaters. Proteomics and mass spectrometry are, therefore, well positioned to play a role in the epidemiological control of COVID-19 and other future diseases. We are currently witnessing the opportunity to generate technologies to overcome prolonged pandemics for the first time in human history.

Investigation of mouse hepatitis virus strain A59 inactivation under both ambient and cold environments reveals the mechanisms of infectivity reduction following UVC exposure

The surface contamination of SARS-CoV-2 is becoming a potential source of virus transmission during the pandemic of COVID-19. Under the cold environment, the infection incidents would be more severe with the increase of virus survival time. Thus, the disinfection of contaminated surfaces in both ambient and cold environments is a critical measure to restrain the spread of the virus. In our study, it was demonstrated that the 254 nm ultraviolet-C (UVC) is an efficient method to inactivate a coronavirus, mouse hepatitis virus strain A59 (MHV-A59). The inactivation rate to MHV-A59 coronavirus was up to 99.99% when UVC doses were 2.90 and 14.0 mJ/cm² at room temperature (23 °C) and in cold environment (-20 °C), respectively. Further mechanistic study demonstrated that UVC could induce spike protein damage to partly impede virus attachment and genome penetration processes, which contributes to 12% loss of viral infectivity. Additionally, it can induce genome damage to significantly interrupt genome replication, protein synthesis, virus assembly and release processes, which takes up 88% contribution to viral inactivation. With these mechanistic understandings, it will greatly contribute to the prevention and control of the current SARS-CoV-2 transmissions in cold chains (low temperature-controlled product supply chains), public area such as airport, school, and warehouse.

Time course and epidemiological features of COVID-19 resurgence due to cold-chain food or packaging contamination

Contaminations in frozen food imported from countries with ongoing COVID-19 epidemics have been reported in China. However, the epidemiological features of the outbreaks initiated by material-to-human transmission were less reported. The risk of this route of transmission remains unclear, and strategies to prevent resurgence could be flawed.

We aimed to demonstrate the existence of cold-chain food or packaging contamination transmission and describe the time course and epidemiological features associated with the transmission in China. This review was based on the official reports or literature for resurging COVID-19 events that were related to cold-chain food or packaging contamination in China and other countries. Although SARS-CoV-2 on the material surface is not the main source of infection, the closed and humid environment for food packaging and transportation is a place favoring the material-to-human spread of SARS-CoV-2. In this transmission mode, patient zero is often hidden and difficult to detect, such that the outbreak usually can only be perceived after a period of a secret epidemic. Regular testing for high-risk populations and imported cold-chain products, proper disinfection of imported products, and protection of susceptible population while working remain an effective way to detect and prevent SARS-CoV-2 spread.

The efficacy of different sanitizers against MS2 bacteriophage introduced onto plastic or stainless steel surfaces

The virucidal activities of 11 prepared disinfectant solutions (active ingredients of household sanitizers) and 10 household sanitizers against bacteriophage MS2 on plastic and stainless steel surfaces were studied. Among the prepared sanitizers, 70-90% ethanol and ethanol-based disinfectants resulted in 1-2.5 log PFU/mL reductions on both surfaces. The 70% isopropanol and isopropanol-based formula reduced MS2 by 0.7-1.5 log PFU/mL on both surfaces. Other disinfectants, containing 0.1% benzalkonium chloride (BAC), 0.5% hydrogen peroxide, or 4% acetic acid, showed significant (P < 0.05) lower log reductions (-0.17-0.55 log PFU/mL) compared with other treatments. At room temperature, the virucidal activities of 70% ethanol on plastic (1.46-1.64 log PFU/mL reductions) and stainless steel (0.84-0.93 log PFU/mL reductions) surfaces were not significantly (P > 0.05) affected by the treatment time (30-600 s). However, 85% ethanol-treated groups showed significant (P < 0.05) higher log reductions in 60 and 600 s treated groups (1.69-2.24 log PFU/mL) compared with those in 30 s treated groups (0.92-1.32 log PFU/mL). Their virucidal activities were further examined at low temperatures (4 and 8 °C). We observed that the surface inactivation efficacies were not affected by the low temperatures. In addition, the virucidal activities of household sanitizers revealed that sanitizers with 1.84% (pH = 12.5, ∼17,500 ppm free-chlorine concentrations) or 3% (pH = 13.1, ∼38,100 ppm free-chlorine concentrations) sodium hypochlorite (NaClO) reduced 4.15-6.23 log PFU/mL MS2 on hard surfaces after 60 s contact time. Furthermore, an approximately 1.5 log PFU/mL reduction was observed in groups treated by sanitizer H (active ingredients: 58% ethanol + 0.1% quaternary ammonium compound). Household products with BAC or organic acid resulted in -0.28-0.33 log reductions on two surfaces after 30 or 60 s treatment. Therefore, the use of ethanol and NaClO-based products should be considered as a potential surface decontamination strategy in the food industry.