The coronavirus disease 2019 (COVID-19) has brought speculations on possible transmission routes of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of the pandemic. Air pollution has been linked to increased risks of COVID-19 infection and mortality rates in regions with poor air quality, yet no retrospective study has been reported on foodborne transmission of COVID-19. While studies have shown that low temperature could dramatically prolong the persistence on SARS-CoV-2 and other coronaviruses, frozen and refrigerated foods have been widely overlooked as potential vectors in policy frameworks and risk mitigation strategies. Food transmission evidence has been disclosed in China early July 2020 by the detection of SARS-CoV-2 on frozen foods, including their packaging materials and storage environments, with two re-emergent outbreaks linked to contaminated food sources. The contamination risk is augmented by a complex farm-to-table process, which favors exposure to food workers and ambient environments. Moreover, the food cold-chain also promotes contamination because laboratory studies showed that SARS-CoV-2 remained highly stable under refrigerated, at 4 °C, and freezing conditions, from − 10 to − 80 °C, on fish, meat, poultry, and swine skin, during 14-21 days. While data are lacking on long-term survival and infectivity under these conditions, ample evidence has been shown on other coronaviruses, including SARS-CoV-1. We therefore hypothesize that contaminated cold-storage foods may present a systematic risk for SARS-CoV-2 transmission between countries and regions. Here, we review the evidence, risk factors, current policy and knowledge gaps, on food contamination and foodborne transmission of SARS-CoV-2. Keywords Refrigerated • Frozen • Food • Coronavirus • Cold chain • Logistics Abbreviations ATP Agreement concerning the international carriage of perishable footstuffs and on the special equipment to be used for such carriage BCoV-88 Bovine coronavirus strain 88 CDC

The relationship between outdoor atmospheric pollution by particulate matter and the morbidity and mortality of coronavirus disease 2019 (COVID-19) infections was recently disclosed, yet the role of indoor aerosols is poorly known. Since people spend most of their time indoor, indoor aerosols are closer to human occupants than outdoors, thus favoring airborne transmission of COVID-19. Therefore, here we review the characteristics of aerosol particles emitted from indoor sources, and how exposure to particles affects human respiratory infections and transport of airborne pathogens. We found that tobacco smoking, cooking, vacuum cleaning, laser printing, burning candles, mosquito coils and incenses generate large quantities of particles, mostly in the ultrafine range below 100 nm. These tiny particles stay airborne, are deposited in the deeper regions of human airways and are difficult to be removed by the respiratory system. As a consequence, adverse effects can be induced by inhaled aerosol particles via oxidative stress and inflammation. Early epidemiological evidence and animal studies have revealed the adverse effects of particle exposure in respiratory infections. In particular, inhaled particles can impair human respiratory systems and immune functions, and induce the upregulation of angiotensin-converting enzyme 2, thus inducing higher vulnerability to COVID-19 infection. Moreover, co-production of inflammation mediators by COVID-19 infection and particle exposure magnifies the cytokine storm and aggravates symptoms in patients. We also discuss the role of indoor aerosol particles as virus carriers. Although many hypotheses were proposed, there is still few knowledge on interactions between aerosol articles and virus-laden droplets or droplet nuclei.

During the current pandemic, chemical disinfectants are ubiquitously and routinely used in community environments, especially on common touch surfaces in public settings, as a means of controlling the virus spread. An underappreciated risk in current regulatory guidelines and scholarly discussions, however, is that the persisting input of chemical disinfectants can exacerbate the growth of biocide-tolerant and antibiotic-resistant bacteria on those surfaces and allow their direct transfers to humans. For COVID-19, the most commonly used disinfecting agents are quaternary ammonium compounds, hydrogen peroxide, sodium hypochlorite, and ethanol, which account for two-thirds of the active ingredients in current EPA-approved disinfectant products for the novel coronavirus. Tolerance to each of these compounds, which can be either intrinsic or acquired, has been observed on various bacterial pathogens. Of those, mutations and horizontal gene transfer, upregulation of efflux pumps, membrane alteration, and biofilm formation are the common mechanisms conferring biocide tolerance in bacteria. Further, the linkage between disinfectant use and antibiotic resistance was suggested in laboratory and real-life settings. Evidence showed that substantial bacterial transfers to hands could effectuate from short contacts with surrounding surfaces and further from fingers to lips. While current literature on disinfectant-induced antimicrobial resistance predominantly focuses on municipal wastes and the natural environments, in reality the community and public settings are most severely impacted by intensive and regular chemical disinfecting during COVID-19 and, due to their proximity to humans, biocide-tolerant and antibiotic-resistant bacteria emerged in these environments may pose risks of direct transfers to humans, particularly in densely populated urban communities. Here we highlight these risk factors by reviewing the most pertinent and up-to-date evidence, and provide several feasible strategies to mitigate these risks in the scenario of a prolonging pandemic.

Abrupt changes in food preferences and eating habits have induced an overlooked health risk during the coronavirus disease pandemic (COVID-19). Indeed, emerging evidence points to a major shift to consumption of high-sodium foods during the pandemic lockdowns in the population from different countries and cultures. High-sodium foods have sodium contents exceeding 500 mg per 100 g, and many processed and preserved foods fall into this category. Excessive dietary sodium intake is associated with chronic diseases including hypertension, cardiovascular diseases, and kidney diseases, and thus poses confounding risks during the pandemic. Here, we review food categories in consumers’ shopping lists and food parcels delivered to people who needed assistance during the pandemic, when frozen meals, canned foods, instant foods, snacks, and other high-sodium foods gained substantial popularity. Such change in consumers’ behavior is driven by several factors: the perceived risk of viral infection in grocery shopping trips, limited supplies and inflated prices of fresh produce, preference on foods with long shelf lives, and emotional eating. Moreover, the general low awareness of sodium contents in food has contributed to the increased consumption of high-sodium foods during the pandemic. We also discuss the possible effects on COVID-19 infection and severity caused by excessive sodium intake. We conclude that the public should be educated to maintain a healthy sodium intake during the pandemic, and measures should be adopted by governments and private donors in procuring food parcels with more balanced sodium contents to lower the risks of prolonged and excessive sodium intakes in the vulnerable population.

Bone char was prepared from bovine bone for the removal of methylene blue from aqueous solution. The effects of particle size, contact time, and adsorption temperature on the removal rate of methylene blue were investigated. It was found that bone char particle size had an insignificant effect. The equilibration time was found at approximately 80 min. The removal rate decreased with an increase in temperature. The intraparticle diffusion was the main rate-limiting step. The experimental data was analyzed by kinetic, isotherm, and thermodynamic equations. The results show that the pseudo-second-order kinetic model and Freundlich, Temkin, and Dubinin–Kaganer–Radushkevich isotherm models are true of the adsorption process. The spontaneous and exothermic ion-exchange adsorption process was certified by the negative values of free energy change and enthalpy change, and 13.29 kJ mol−1 of adsorption energy.