A Critical Review of Disinfection Processes to Control SARS-CoV-2 Transmission in the Food Industry

The use of in vitro bioassays and chemical screening to assess the impact of a minimally processed vegetable facility on wastewater quality

Fruit- and vegetable-processing facilities may contaminate wastewater via contaminants found in the produce and disinfecting chemicals used. These contaminants may include agrochemicals, pesticides, and disinfectants such as chlorine and quaternary ammonium compounds (QACs). Some compounds may exhibit harmful endocrine-disrupting activity. This study investigated the impact of a minimally processed vegetable facility on wastewater quality via in vitro bioassays and chemical screening. Estrogen activity was assessed via a yeast estrogen screen (YES), and (anti-)androgenic and glucocorticoid activities were evaluated via an MDA-kb2 reporter gene assay. The samples were screened via gas and liquid chromatography-tandem mass spectrometry (GC-MS/MS and LC-MS/MS) to identify target compounds, and GC coupled with time-of-flight mass spectrometry (GC-TOFMS) was used for non-targeted screening. Sample complexity and chemical profiles were assessed using GC-TOFMS. Estrogenic activity was detected in 16 samples (n = 24) with an upper limit of 595 ± 37 ng/L estradiol equivalents (EEqs). The final wastewater before discharge had an EEq of 0.23 ng/L, which is within the ecological effect-based trigger value range for the estrogenic activity of wastewater (0.2-0.4 ng/L EEq). Androgenic activity was detected in one sample with a dihydrotestosterone equivalent (DHTEq) value of 10 ± 2.7 ng/L. No antiandrogenic activity was detected. The GC-MS/MS and LC-MS/MS results indicated the presence of multiple pesticides, nonylphenols, triclocarban, and triclosan. Many of these compounds exhibit estrogenic activity, which may explain the positive YES assay findings. These findings showed that wastewater from the facility contained detergents, disinfectants, and pesticides and displayed hormonal activity. Food-processing facilities release large volumes of wastewater, which may affect the quality of the water eventually being discharged into the environment. We recommend expanding conventional water quality monitoring efforts to include additional factors like endocrine activity and disinfectant byproducts.

Impact of benzalkonium chloride on anaerobic granules and its long-term effects on reactor performance

This study assessed the inhibitory and performance-degrading effects induced by the cationic surfactant benzalkonium chloride (BAC) on anaerobic granules during the long-term operation of a laboratory-scale expanded granular sludge bed (EGSB) reactor. To address the critical scientific problem of how BAC affects the efficiency of EGSB reactors, this research uniquely evaluated the long-term stress response to BAC by systematically comparing continuous and discontinuous inhibitor exposure scenarios. The novel comparison demonstrated that inhibitor concentration is of minor relevance compared to the biomass-specific cumulative inhibitor load in the reactor. After exceeding a critical biomass-specific cumulative inhibitor load of 6.1-6.5 mg BAC/g VS, continuous and discontinuous exposure to BAC caused comparable significant deterioration in reactor performance, including accumulation of volatile fatty acids (VFA), decreased removal efficiency, reduced methane production, as well as the wash-out, flotation, and disintegration of anaerobic granules. BAC exposures had a more detrimental effect on methanogenesis than on acidogenesis. Moreover, long-term stress by BAC led to an inhibition of protein production, resulting in a decreased protein-to-polysaccharide ratio of extracellular polymeric substances (EPS) that promoted destabilizing effects on the granules. Finally, hydrogenotrophic methanogenesis was triggered. Reactor performance could not be restored due to the severe loss of granular sludge.

Antimicrobial Activity of Hydrogen Peroxide for Application in Food Safety and COVID-19 Mitigation: An Updated Review

Hydrogen peroxide (H2O2) is a well-known agent with a broad-spectrum antimicrobial activity against pathogenic bacteria, fungi, and viruses. It is a colorless liquid and commercially available in aqueous solution over a wide concentration range. It has been extensively used in the food industry by virtue of its strong oxidizing property and its ability to cause cellular oxidative damage in microbial cells. This review comprehensively documents recent research on the antimicrobial activity of H2O2 against organisms of concern for the food industry, as well as its effect against SARS-CoV-2 responsible for the COVID-19 pandemic. In addition, factors affecting the antimicrobial effectiveness of H2O2, different applications of H2O2 as a sanitizer or disinfectant in the food industry as well as safety concerns associated with H2O2 are discussed. Finally, recent efforts in enhancing the antimicrobial efficacy of H2O2 are also outlined.

Synergistic Bactericidal Effects of Quaternary Ammonium Compounds with Essential Oil Constituents

Antimicrobial tolerance is a significant concern in the food industry, as it poses risks to food safety and public health. To overcome this challenge, synergistic combinations of antimicrobials have emerged as a potential solution. In this study, the combinations of two essential oil constituents (EOCs), namely carvacrol (CAR) and eugenol (EUG), with the quaternary ammonium compounds (QACs) benzalkonium chloride (BAC) and didecyldimethylammonium chloride (DDAC) were evaluated for their antimicrobial effects against Escherichia coli and Bacillus cereus, two common foodborne bacteria. The checkerboard assay was employed to determine the fractional inhibitory concentration index (FICI) and the fractional bactericidal concentration index (FBCI), indicating the presence of bactericidal, but not bacteriostatic, synergy in all QAC-EOC combinations. Bactericidal synergism was clearly supported by Bliss independence analysis. The bactericidal activity of the promising synergistic combinations was further validated by time-kill curves, achieving a >4-log10 reduction of initial bacterial load, which is significant compared to typical industry standards. The combinations containing DDAC showed the highest efficiency, resulting in the eradication of bacterial population in less than 2-4 h. These findings emphasize the importance of considering both bacteriostatic and bactericidal effects when evaluating antimicrobial combinations and the potential of EOC-QAC combinations for sanitization and disinfection in the food industry.

Biosecurity in the workplace and a QMS during the COVID-19 pandemic: a survey for Peruvian goods companies

Objectives. This study analyzes the differences between goods companies with a Standard No. ISO 9001:2015 quality management system (QMS) and those without, in terms of implementation of biosecurity measures during the COVID-19 pandemic. The study shows whether having a QMS helped companies to implement the biosecurity measures required to continue operating during a pandemic. Methods. The sample was composed of 145 Peruvian goods companies. The empirical data were collected through a questionnaire sent to company presidents, general managers and department heads. The questionnaire focused on four biosecurity dimensions in the workplace: protocols, preventive actions, biosecurity processes and risk management. Results. The study found that companies with a QMS (Standard No. ISO 9001:2015) significantly differed from companies without in the implementation of three of the four biosecurity dimensions. Conclusions. This study is useful for academia and companies because it identifies the main differences between certified and non-certified companies, in terms of adoption of biosecurity measures. This study highlights the importance of a QMS to respond to hazardous situations like a global health crisis, but also provides useful information for the strategic decision-making process of companies.

Lesson learned from COVID-19 pandemic for the future of food industry

With WHO announcing COVID-19 no longer as a public health emergency of international concern (PHEIC) on May 5, 2023, coupled with the fact that the majority of the countries of the world have dropped strict city lockdown or border closure, this perhaps signals the end of the COVID-19 crisis caused by the SARS-CoV-2 virus. However, the COVID-19 pandemic has resulted in far-reaching effects affecting nearly every aspect of our lives and society. Notably, the food industry including agriculture, food manufacturers, food logistics, distributors and retailers have all felt the profound impact and had experienced significant stress during the pandemic. Therefore, it is essential to retrospect the lessons that can be learned from this pandemic for the food industry. This short review aims to address the food safety issues related to the COVID-19 pandemic by focusing on its foodborne transmission potential, innovations of virus detection strategies suitable for food industry; development of phathogenicaidal methods and devices to inactivate SARS-CoV-2 virus (particularly in industrial scale); and the set-up of related food regulations and guidelines as preventive and control measures for preventing the spread of SARS-CoV-2 virus through the food supply chain during the pandemic. This article may provide useful references for the food industry to minimize the food safety impact of COVID-19 (as well as other respiratory virus) and allows them to better prepare for similar future challenges.

The Effect of Water Hardness and pH on the Efficacy of Peracetic Acid and Sodium Hypochlorite against SARS-CoV-2 on Food-Contact Surfaces

Sodium hypochlorite (NaOCl) and peracetic acid (PAA) are commonly used disinfectants with a maximum recommended concentration of 200 ppm for food-contact surfaces. The objectives of this study were to assess the effect of pH and water hardness on NaOCl and PAA efficacy against SARS-CoV-2 on stainless steel (SS). The two disinfectants were prepared at 200 ppm in water of hardness 150 or 300 ppm with the final pH adjusted to 5, 6, 7, or 8. Disinfectants were applied to virus-contaminated SS for one minute at room temperature following the ASTM E2197 standard assay. SARS-CoV-2 infectivity was quantified using TCID50 assay on Vero-E6 cells. In general, increasingly hard water decreased the efficacy of NaOCl while increasing the efficacy of PAA. Hard water at 300 ppm significantly increased virus log reduction with PAA at pH 8 by ~1.5 log. The maximum virus log reductions were observed at pH 5 for both NaOCl (~1.2 log) and PAA (~2 log) at 150 and 300 ppm hard water, respectively. In conclusion, PAA performed significantly better than NaOCl with harder water. However, both disinfectants at 200 ppm and one minute were not effective (≤3 log) against SARS-CoV-2 on contaminated food-contact surfaces, which may facilitate the role of these surfaces in virus transmission.

Mechanisms of Listeria monocytogenes Disinfection with Benzalkonium Chloride: From Molecular Dynamics to Kinetics of Time-Kill Curves

Unravelling the mechanisms of action of disinfectants is essential to optimise dosing regimes and minimise the emergence of antimicrobial resistance. In this work, we examined the mechanisms of action of a commonly used disinfectant-benzalkonium chloride (BAC)-over a significant pathogen-L. monocytogenes-in the food industry. For that purpose, we used modelling at multiple scales, from the cell membrane to cell population inactivation. Molecular modelling revealed that the integration of the BAC into the membrane requires three phases: (1) the approaching of BAC to the cellular membrane, (2) the absorption of BAC to its surface, and (3) the integration of the compound into the lipid bilayer, where it remains at least for several nanoseconds, probably destabilising the membrane. We hypothesised that the equilibrium of adsorption, although fast, was limiting for sufficiently large BAC concentrations, and a kinetic model was derived to describe time-kill curves of a large population of cells. The model was tested and validated with time series data of free BAC decay and time-kill curves of L. monocytogenes at different inocula and BAC dose concentrations. The knowledge gained from the molecular simulation plus the proposed kinetic model offers the means to design novel disinfection processes rationally.

Effects of specific doses of E-beam irradiation which inactivated SARS-CoV-2 on the nutrition and quality of Atlantic salmon

The contamination of Atlantic salmon with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has impeded the development of the cold-chain food industry and posed possible risks to the population. Electron beam (E-beam) irradiation under 2, 4, 7, and 10 kGy can effectively inactivate SARS-CoV-2 in cold-chain seafood. However, there are few statistics about the quality changes of salmon exposed to these irradiation dosages. This work demonstrated that E-beam irradiation at dosages capable of killing SARS-CoV-2 induced lipid oxidation, decreased vitamin A content, and increased some amino acids and ash content. In addition, irradiation altered the textural features of salmon, such as its hardness, resilience, cohesiveness, and chewiness. The irradiation considerably affected the L*, a*, and b* values of salmon, with the L* value increasing and a*, b* values decreasing. There was no significant difference in the sensory evaluation of control and irradiated salmon. It was shown that irradiation with 2-7 kGy E-beam did not significantly degrade quality. The inactivation of SARS-CoV-2 in salmon is advised at a dose of 2 kGy.

Quaternary ammonium compounds of emerging concern: Classification, occurrence, fate, toxicity and antimicrobial resistance

Amplified hygiene and precautionary measures are of utmost importance to control the spread of COVID-19 and future infection; however, these changes in practice are projected to trigger a rise in the purchase, utilisation and hence, discharge of many disinfectants into the environment. While alcohol-based, hydrogen peroxide-based, and chlorine-based compounds have been used widely, quaternary ammonium compounds (QACs) based disinfectants are of significant concern due to their overuse during this pandemic. This review presents the classification of disinfectants and their mechanism of action, focusing on QACs. Most importantly, the occurrence, fate, toxicity and antimicrobial resistance due to QACs are covered in this paper. Here we collated evidence from multiple studies and found rising trends of concern, including an increase in the mass load of QACs at a wastewater treatment plant (WWTP) by 331% compared to before the COVID-19 pandemic, as well as an increases in the concentration of 62% in residential dust, resulting in high concentrations of QACs in human blood and breast milk and suggesting that these could be potential sources of persistent QACs in infants. In addition to increased toxicity to human and aquatic life, increased use of QACs and accelerated use of antibiotics and antimicrobials during the COVID-19 pandemic could multiply the threat to antimicrobial resistance.

Inactivation of two SARS-CoV-2 virus surrogates by electron beam irradiation on large yellow croaker slices and their packaging surfaces

The detection of infectious SARS-CoV-2 in food and food packaging associated with the cold chain has raised concerns about the possible transmission pathway of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in foods transported through cold-chain logistics and the need for novel decontamination strategies. In this study, the effect of electron beam (E-beam) irradiation on the inactivation of two SARS-CoV-2surrogate, viruses porcine epidemic diarrhea virus (PEDV) and porcine transmissible gastroenteritis virus (TGEV), in culture medium and food substrate, and on food substrate were investigated. The causes of virus inactivation were also investigated by transmission electron microscopy (TEM) and Quantitative Real-time PCR (QRT-PCR). Samples packed inside and outside, including virus-inoculated large yellow croaker and virus suspensions, were irradiated with E-beam irradiation (2, 4, 6, 8, 10 kGy) under refrigerated (0 °C)and frozen (-18 °C) conditions. The titers of both viruses in suspension and fish decreased significantly (P < 0.05) with increasing doses of E-beam irradiation. The maximum D10 value of both viruses in suspension and fish was 1.24 kGy. E-beam irradiation at doses below 10 kGy was found to destroy the spike proteins of both SARS-CoV-2 surrogate viruses by transmission electron microscopy (TEM) and negative staining of thin-sectioned specimens, rendering them uninfectious. E-beam irradiation at doses greater than 10 kGy was also found to degrade viral genomic RNA by qRT-PCR. There were no significant differences in color, pH, TVB-N, TBARS, and sensory properties of irradiated fish samples at doses below 10 kGy. These findings suggested that E-beam irradiation has the potential to be developed as an efficient non-thermal treatment to reduce SARS-CoV-2 contamination in foods transported through cold chain foods to reduce the risk of SARS-CoV-2 infection in humans through the cold chain.

Kinetics of Bacterial Adaptation, Growth, and Death at Didecyldimethylammonium Chloride sub-MIC Concentrations

Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) are standard indexes for determining disinfection effectiveness. Nevertheless, they are static values disregarding the kinetics at sub-MIC concentrations where adaptation, growth, stationary, and death phases can be observed. The understanding of these dynamic mechanisms is crucial to designing effective disinfection strategies. In this study, we studied the 48 h kinetics of Bacillus cereus and Escherichia coli cells exposed to sub-MIC concentrations of didecyldimethylammonium chloride (DDAC). Two mathematical models were employed to reproduce the experiments: the only-growth classical logistic model and a mechanistic model including growth and death dynamics. Although both models reproduce the lag, exponential and stationary phases, only the mechanistic model is able to reproduce the death phase and reveals the concentration dependence of the bactericidal/bacteriostatic activity of DDAC. This model could potentially be extended to study other antimicrobials and reproduce changes in optical density (OD) and colony-forming units (CFUs) with the same parameters and mechanisms of action.

Cold Chain Food and COVID-19 Transmission Risk: From the Perspective of Consumption and Trade

Since the outbreak of the coronavirus disease 2019 (COVID-19), political and academic circles have focused significant attention on stopping the chain of COVID-19 transmission. In particular outbreaks related to cold chain food (CCF) have been reported, and there remains a possibility that CCF can be a carrier. Based on CCF consumption and trade matrix data, here, the "source" of COVID-19 transmission through CCF was analyzed using a complex network analysis method, informing the construction of a risk assessment model reflecting internal and external transmission dynamics. The model included the COVID-19 risk index, CCF consumption level, urbanization level, CCF trade quantity, and others. The risk level of COVID-19 transmission by CCF and the dominant risk types were analyzed at national and global scales as well as at the community level. The results were as follows. (1) The global CCF trade network is typically dominated by six core countries in six main communities, such as Indonesia, Argentina, Ukraine, Netherlands, and the USA. These locations are one of the highest sources of risk for COVID-19 transmission. (2) The risk of COVID-19 transmission by CCF in specific trade communities is higher than the global average, with the Netherlands-Germany community being at the highest level. There are eight European countries (i.e., Netherlands, Germany, Belgium, France, Spain, Britain, Italy, and Poland) and three American countries (namely the USA, Mexico, and Brazil) facing a very high level of COVID-19 transmission risk by CCF. (3) Of the countries, 62% are dominated by internal diffusion and 23% by external input risk. The countries with high comprehensive transmission risk mainly experience risks from external inputs. This study provides methods for tracing the source of virus transmission and provides a policy reference for preventing the chain of COVID-19 transmission by CCF and maintaining the security of the global food supply chain.

Comprehensive Risk Pathway of the Qualitative Likelihood of Human Exposure to Severe Acute Respiratory Syndrome Coronavirus 2 from the Food Chain

ABSTRACT

A group of experts from all Canadian federal food safety partners was formed to monitor the potential issues relating to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) food contamination, to gather and consider all of the relevant evidence and to determine the impact for Canadian food safety. A comprehensive risk pathway was generated to consider the likelihood of a SARS-CoV-2 contamination event at any of the relevant steps of the food processing and handling chain and the potential for exposure and transmission of the virus to the consumer. The scientific evidence was reviewed and assessed for each event in the pathway, taking into consideration relevant elements that could increase or mitigate the risk of contamination. The advantage of having an event-wise contextualization of the SARS-CoV-2 transmission pathway through the food chain is that it provides a systematic and consistent approach to evaluate any new data and communicate its importance and impact. The pathway also increases the objectivity and consistency of the assessment in a rapidly evolving and high-stakes situation. Based on our review and analysis, there is currently no comprehensive epidemiological evidence of confirmed cases of SARS-CoV-2, or its known variants, causing coronavirus disease 2019 from transmission through food or food packaging. Considering the remote possibility of exposure through food, the likelihood of exposure by ingestion or contact with mucosa is considered negligible to very low, and good hygiene practices during food preparation should continue to be followed.

HIGHLIGHTS

Efficacy of frontline chemical biocides and disinfection approaches for inactivating SARS-CoV-2 variants of concern that cause coronavirus disease with the emergence of opportunities for green eco-solutions

The emergence of severe acute respiratory disease (SARS-CoV-2) variants that cause coronavirus disease is of global concern. Severe acute respiratory disease variants of concern (VOC) exhibiting greater transmissibility, and potentially increased risk of hospitalization, severity and mortality, are attributed to molecular mutations in outer viral surface spike proteins. Thus, there is a reliance on using appropriate counter-disease measures, including non-pharmaceutical interventions and vaccination. The best evidence suggests that the use of frontline biocides effectively inactivate coronavirus similarly, including VOC, such as 202012/01, 501Y.V2 and P.1 that have rapidly replaced the wild-type variant in the United Kingdom, South Africa and Brazil, respectively. However, this review highlights that efficacy of VOC-disinfection will depend on the type of biocide and the parameters governing the activity. VOC are likely to be similar in size to the wild-type strain, thus implying that existing guidelines for use and re-use of face masks post disinfection remain relevant. Monitoring to avoid injudicious use of biocides during the coronavirus disease era is required as prolonged and excessive biocide usage may negatively impact our receiving environments; thus, highlighting the potential for alternative more environmental-friendly sustainable biocide solutions. Traditional biocides may promote cross-antimicrobial resistance to antibiotics in problematical bacteria. The existing filtration efficacy of face masks is likely to perform similarly for VOC due to similar viral size; however, advances in face mask manufacturing by way incorporating new anti-viral materials will potentially enhance their design and functionality for existing and potential future pandemics.