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.

Investigation on contamination of SARS-CoV-2 in cold chain food and key environment in Nantong

Objective To understand the contaminations of SARS-CoV-2 of imported frozen food and corresponding ke;environments in Nantong Farmers’ Wholesale Market. Methods The samples of imported frozen food, surface samples of key environmental objects and throat swabs, anal swabs and blood samples from employees were collected randomly, SARS-CoV-2 nucleic acid testing as well as specific serum antibody IgM and IgG testing were implemented. Results A total of 1 685 sample: of imported frozen food in Nantong, 2 432 samples from key environment, and 1 539 samples of anal swabs and throat swabs fron key practitioners were collected, all samples were confirmed to be negative for SARS-CoV-2 nucleic acid testing. A total of 299 blood samples were collected from key employees, and virus specific serum antibodies IgM and IgG were negative. Conclusion The imported frozen food and key environment sold in the Nantong have not been contaminated with SARS-CoV-2 temporarily, and it remains being necessary to further implements surveillance and control of Corona Virus Disease 2019(COVID-19). © 2022, Editorial Department of Medical Pest Control. All rights reserved.

Sensitive fluorescence biosensor for SARS-CoV-2 nucleocapsid protein detection in cold-chain food products based on DNA circuit and g-CNQDs@Zn-MOF.

SARS-CoV-2 isolation from cold-chain food products confirms the possibility of outbreaks through cold-chain food products. RNA extraction combined with RT-PCR is the primary method currently utilized for the detection of SARS-CoV-2. However, the requirement of hours of analytical time and the high price of RT-PCR hinder its worldwide implementation in food supervision. Here, we report a fluorescence biosensor for detection of SARS-CoV-2 N protein. The fluorescence biosensor was fabricated by aptamer-based conformational entropy-driven circuit where molecular beacon strands were labeled with graphitic carbon nitrides quantum dots@Zn-metal-organic framework (g-CNQDs@Zn-MOF) and Dabcyl. The detection of the N protein was achieved via swabbing followed by competitive assay using a fixed amount of N-48 aptamers in the analytical system. A fluorescence emission spectrum was employed for the detection. The detection limit of our fluorescence biosensor was 1.0 pg/mL for SARS-CoV-2 N protein, indicating very excellent sensitivity. The fluorescence biosensor did not exhibit significant cross-reactivity with other N proteins. Finally, the biosensor was successfully applied for the detection of SARS-CoV-2 N protein in actual cold-chain food products showing same excellent accuracy as RT-PCR method. Thus, our fluorescence biosensor is a promising analytical tool for rapid and sensitive detection of SARS-CoV-2 N protein.

Ultrafast and absolute quantification of SARS-CoV-2 on food using hydrogel RT-LAMP without pre-lysis.

With rapid growing of environmental contact infection, more and more attentions are focused on the precise and absolute quantification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus on cold chain foods via point-of-care test (POCT). In this work, we propose a hydrogel-mediated reverse transcription loop-mediated isothermal amplification (RT-LAMP) for ultrafast and absolute quantification of SARS-CoV-2. Cross-linked hydrogel offers opportunities for digital single molecule amplification in nanoconfined spaces, facilitating the virus lysis, RNA reverse transcription and amplification process, which is about 3.4-fold faster than conventional bulk RT-LAMP. Ultrafast quantification of SARS-CoV-2 is accomplished in 15 min without virus pre-lysis and RNA extraction. The sensitivity can accurately quantify SARS-CoV-2 down to 0.5 copy/µL. Furthermore, the integrated system has an excellent specificity, reproducibility and storage stability, which can be also used to test SARS-CoV-2 on various cold chain fruits. The developed ultrafast and simple hydrogel RT-LAMP will be an enormous potential for surveillance of virus or other hazardous microbes in environmental, agricultural and food industry.

SARS-CoV-2 Spreads Globally Through the Object-to-Human Transmission of Cross-Border Logistics.

With globalization, the demand for transnational logistics is growing rapidly. However, the object-to-human transmission of SARS-CoV-2 has been reported in transnational logistics production, transportation, storage, sales, and consumption. Every link of transnational logistics has the risk of spreading the COVID-19 pandemic. It is concluded that low temperatures, dry environments, and smooth surfaces are conducive to the long-term survival of SARS-CoV-2 on the surface of transnational goods. Epidemiological investigation and big data analysis show that the object-to-human transmission route of direct contact with contaminated cold chain goods plays a key role in the outbreak and transmission of the COVID-19 pandemic. This may be the most crucial reason for the global spread of SARS-CoV-2 caused by transnational logistics. It is an effective way to prevent the spread of SARS-CoV-2 from object-to-human through transnational logistics by strengthening the management of employees in all aspects of transnational logistics, carrying out comprehensive disinfection and quarantine of and guiding consumers to handle transnational goods properly.

Transmission of SARS-CoV-2 on Cold-Chain Food: Precautions Can Effectively Reduce the Risk.

The COVID-19 pandemic has generated a new era in the world, also in the food safety. Up to now, there is no evidence to suggest that people can infect COVID-19 via food contaminated by SARS-CoV-2. Here, we analyzed the results of regular SARS-CoV-2 nucleic acid testing of considerable cold-chain food practitioners, cold-chain food surfaces, and their internal or external packaging as well as their associated environments, aiming to explore the risk of cold-chain food being contaminated by SARS-CoV-2 and the probability of people infecting COVID-19 through contaminated cold-chain food in the context of COVID-19 epidemic. This study found that only two batches of cold-chain food were contaminated by SARS-CoV-2, none of the cold-chain food handler were infected due to effective regulatory measures for cold-chain food. Therefore, effective supervision and preventive methods could effectively reduce the transmission risk of SARS-CoV-2 on cold-chain food.

Surveillance of SARS-CoV-2 Contamination in Frozen Food-Related Samples - China, July 2020 - July 2021.

Introduction: Current evidence shows that coronavirus disease 2019 (COVID-19) is neither a food safety issue nor a foodborne disease. However, the outbreaks of this disease in workers of meat- or poultry-processing plants and food markets have been reported in many countries. Systematic reports on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) contamination in food-related samples worldwide are lacking so far. This study aimed to survey and monitor SARS-CoV-2 contamination in samples of foods or their packaging, storage environment, and employees, as well as explore the possible potential for virus transmission via frozen foods. Methods: Swabs of frozen food-related samples were collected between July 2020 and July 2021 in 31 provincial-level administrative divisions (PLADs) and Xinjiang Construction Corps in China. The SARS-CoV-2 RNAs were extracted and analyzed by real-time quantitative polymerase chain reaction using the commercially available SARS-CoV-2 nucleic acid test kit. Results: More than 55.83 million samples were analyzed, and 1,455 (0.26 per 10,000) were found to be positive for SARS-CoV-2 nucleic acid. Among the virus-positive samples, 96.41% (1,398/1,450) and 3.59% (52/1,450) were food/food packaging materials and environment, respectively. As for 1,398 SARS-CoV-2-positive food and food packaging materials, 99.50%, (1,391/1,398) were imported and 7 were domestic. The outer packaging of food was frequently contaminated by the virus 78.75% ( 1,101/1,398). Conclusions: Our study supported speculation that cold-chain foods might act as the SARS-CoV-2 carrier, and food handlers/operators were at high risk of exposure to the virus. It is necessary to carry out a comprehensive mass testing for SARS-CoV-2 nuclei acid, along with contact tracing and symptom screening in cold-chain food handlers and processors so as to identify high proportions of asymptomatic or pre-symptomatic infections. Meanwhile, research and development of effective self-protection equipment available at a temperature below -18 ℃ is urgent.

Traceability Analysis of Cold Chain Food under COVID-19 Based on Block Chain Technology

The distributed accounting method of blockchain, together with its decentralized and tamper proof characteristics, can solve the problem of lack of food safety traceability data and low credibility, which enable the traceability requirements of food chain traceability, problem food recall, food circulation information query. It also improves the food flow mode, and establishes a new food safety ecosystem. This paper innovatively integrates the principle of blockchain into the traceability and circulation process of Hebei cold chain food. In order to find the proportion and distribution of various types of commodities in the circulation of imported and domestic cold chain food in Hebei Province, the combination of qualitative and quantitative analysis methods, chi square test, association rules and other analysis methods are used. The results show that the demand for cold chain food in Hebei Province is mainly domestic food and supplemented by imported food. Cold chain poultry is the main need and other cold chain food is supplement. The flow of imported cold chain food is mainly from the surrounding provinces and cities. Furthermore, in the process of tracing the positive commodities, it is found that there are four main modes of commodity circulation in Hebei Province, namely, family model from farmer, wholesale market, new retail and multi-level sales model. The new retail and multi-level sales model fill the gap in the distribution and circulation of cold chain goods in Hebei Province. © 2021 ACM.

LAMP Assay for On-site Detection of SARS-CoV-2 and Its Application in Cold-chain Food Analysis

A highly sensitive visualization method for SARS-CoV-2 detection, based on loop-mediated isothermal amplification (LAMP) and molecular light switch [Ru(phen)2dppz]2+, was established. In this design, insulation cups replaced laboratory thermostats and blue flashlights replaced blue transilluminators, to realize the rapid on-site visual LAMP detection of SARS-CoV-2. Specific primers were designed for the N gene of SARS-CoV-2. LAMP amplification products were detected by [Ru(phen)2dppz]2+ with molecular light switch characteristics. Red fluorescence could be directly detected by naked eye using blue light flashlight. Single copy number SARS-CoV-2 gene fragments were detected with high specificity. The detection was rapid, requiring only 40 minutes to visually observe the results. The LAMP detection results for food samples artificially contaminated with SARS-CoV-2 pseudovirus were 100% consistent with the current gold-standard real-time fluorescent quantitative PCR method for SARS-CoV-2 detection. This method requires only insulation cups and blue flashlight, and can be used to supplement the real-time fluorescent PCR method to provide a fast and efficient on-site screening of food for SARS-CoV-2. © 2022, Editorial Board of Modern Food Science and Technology. All right reserved.

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 global concern of food security during the COVID-19 pandemic: Impacts and perspectives on food security.

COVID-19 is having a far-reaching negative impact on global economic and social development. One of the challenges arising from the pandemic is ensuring food security, especially with respect to cold chain food. Given the current situation of high contagion and large numbers of infected people, the perspective briefed emergency management measures of cold chain food, compared the development of accurate and rapid detection methods of COVID-19 and hazards in foods. In addition, we proposed three-dimensional-printing of foods as a promising candidate for ensuring food security during the current pandemic because it uses locally-obtained raw materials and does not need long-distance cold chain transportation.

Geographical and Epidemiological Characteristics of Sporadic Coronavirus Disease 2019 Outbreaks From June to December 2020 in China: An Overview of Environment-To-Human Transmission Events.

China quickly brought the severe acute respiratory syndrome coronavirus 2 under control during the early stage of 2020; thus, this generated sufficient confidence among the public, which enabled them to respond to several sporadic coronavirus disease 2019 outbreaks. This article presents geographical and epidemiological characteristics of several sporadic coronavirus disease 2019 outbreaks from June to December 2020 in China. The data show that the coronavirus disease may be transmitted by imported cold-chain food and international exchange, and this viewpoint deserves our great attention.