Frozen Food Industry Research Articles

Decontamination of frozen cherries by innovative light-based technologies: Assessment of microbial inactivation and quality changes

Foodborne pathogen L. monocytogenes is a major concern in the frozen food industry. In this study, the decontamination efficiency of UV-C and HIPL for the inactivation of L. monocytogenes on frozen cherries was evaluated for the first time. Frozen cherries were exposed to light treatments at various light doses (3, 6, 9, 12 J/cm 2 ) and lamp distances (10 and 20 cm). Moreover, samples were washed with/without chlorine solution (300 ppm) for 60 s as a commercial treatment. The highest reduction of L.innocua was observed as 2.90 log CFU/g by HIPL (9 J/cm 2 -20 cm). The HIPL inactivation kinetic data of L. innocua were well described using the Log-Linear equation. D value (J/cm 2 ) required to reduce the Listeria population by 90% was 5.42 J/cm 2 (at 10 cm). Unlike UV-C, the surface temperature of samples did not exceed 0 °C during HIPL at all parameters. The experiments show that HIPL treated cherries had statistically lower total anthocyanin and higher total phenolics than the untreated control. • Study of surface decontamination methods of frozen cherries inoculated with L. innocua . • Inactivation level was increased as the fluence increased up to 9 J/cm 2 . • HIPL exhibited a high level of microbial inactivation (up to 2.90 log cycles). • At the same energy doses, HIPL required shorter treatment times compared to UV-C • The surface temperature of cherries did not exceed 0 °C by HIPL.

Effects of polysaccharides autoclave extracted from Flammulina velutipes mycelium on freeze-thaw stability of surimi gels

Quality deterioration caused by ice formation and growth is a prevailing problem in frozen food, therefore, exploration of natural cryoprotectants has been attracting more attention. In this study, Flammulina velutipes mycelium polysaccharides (FVP) were obtained by autoclave extraction and their effect on freeze-thaw stability of surimi gels were investigated. The results showed that FVP consisted mainly (59.02%) of high-molecular-weight polysaccharides (>450 kDa), and were composed of Glu, Xyl, Man, Gal, and Fuc in a molar ratio of 33.4: 28.72: 26.31: 8.01: 3.55. FVP (1.0 mg/mL) showed superior Ice Recrystallization Inhibition (IRI) activity. Freeze-thaw stability tests demonstrated that frozen-thawed surimi gels with FVP addition exhibited a more uniform and continuous matrices than the control ones. FVP could significantly improve the water holding capacity, the hardness, springiness and cohesiveness of surimi gels during the repeated freeze-thaw cycles. Studies on water state and properties showed that FVP could decrease the freezable water content, restrict water mobility, and inhibit water migration in frozen surimi gels. These results suggest the potential of FVP as a promising cryoprotectant candidate in the frozen food industry.

Birdseye’s Frosted Possession: Processing, Storing, and Transmitting the Gift of Inuit Thermocultural Knowledge,

On August 12, 1930, Clarence Birdseye patented his “Method of Preparing Food Products,” a “quick” freezing machine that “for the first time produced ... a compacted, quick frozen block of comestibles ... which can be stored ... transported ... and ... after being thawed, reassumes its original condition.” Birdseye’s innovation in the frozen food industry is typically historicized as a progress narrative, wherein the lone inventor masters the molecular forces of water, salts, metal, cardboard, flesh, and plant matter. This teleology is further contextualized within an exploration account, wherein Birdseye’s curiosity is piqued during his years as a fur trader who observes the Labrador Inuit practice of quick-freezing fish. In this article, I use Goenpul scholar Aileen Moreton-Robinson’s concept of “white possessive logics” to interrogate how Birdseye’s racialized assumption of ownership dislocated Inuit epistemologies into industrial metanarratives. To trace the possession, but also the survivance, of Labrador Inuit thermoculture, I reconsider frozen food as a communication system, characterized by dynamics of processing, storage, and transmission. Within this system, food is thinkable as data—information and gift—and frozen food is understandable as an Inuit gift of knowledge and sustenance provided to, and unreciprocated by, Birdseye. Comparatively reading Birdseye’s papers and patents with ethnographical and autobiographical Labrador Inuit and Inuit-Metis narratives, I rethink the historic event of knowledge-sharing that gave Birdseye his thermocultural inspiration. Furthermore, I consider how Labrador Inuit communities reappropriate the mechanical freezer as a traditional technology, and I argue that the globalization of frozen food technology poses an ongoing challenge of reciprocity for Birdseye’s white possession.

Tandem mass tag-based proteomics analysis of protein changes in the freezing and thawing cycles of Trachurus murphyi.

We investigated the proteome variations in Trachurus murphyi with different cycles of freezing and thawing (FT) under frozen storage. A total of 2,482 proteins were assessed quantitatively, of which 269 proteins were recognized as differential abundance proteins during the second FT cycle until the eighth FT cycle. Bioinformatics analysis on gene ontology (GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes pathway analyses of Differential Analysis of Proteins (DAPs) indicated multiple DAPs engaged with the protein structure, metabolic enzymes, and protein turnover. In addition, some of the observed proteins were probably the underlying markers of protein oxidation (PO). The analysis of PO sites revealed the sites of PO, such as amino adipic semialdehydes, γ-glutamic semialdehydes, and Schiff bases. Bioinformatics analyses demonstrated the involvement of differentially expressed proteins in the Hippo signaling pathway (Ko04390), indicating strong protein degradation with greater numbers of FT cycles under frozen storage. It provides an insight into quality stability from a proteomics quality perspective at the molecular level. The results obtained have deepened our current understandings of the mechanisms that reveal variations in proteomes and quality, as well as help promote quality control of T. murphyi across the cold transportation chain. PRACTICAL APPLICATION: Temperature fluctuation is one of the core issues during frozen food storage and distribution faced by the frozen food industry. Fluctuation may result in microstructural changes, ice recrystallization, and protein change in frozen food products. Tandem mass tag-based methods were adopted to study proteome variations in Trachurus murphyi muscles under different cycles of freezing and thawing under frozen storage conditions in this paper. The results obtained have deepened our current understandings of the mechanisms that reveal variations in proteomes and quality, as well as help promote quality control of T. murphyi across the cold transportation chain.

A lauded refrigeration technique and resource-efficiency of frozen food industry

BackgroundAn emerging mode of refrigerated preservation has recently been advertised as an allegedly game-changing means to improve the overall sustainability of global frozen food industry. Scope and approachIsochoric low-temperature pressure-aided supercooling (named ‘isochoric freezing’) creates exciting expectations, associated with reduced or eliminated ice crystallisation and resulting finer food structure, along with savings of cold energy for phase change. A simplified technology assessment has been carried out by comparing this emerging modality with the conventional isobaric freezing for a typical lab-scale scenario. Key findings and conclusionsExcept several niche applications, in general the lauded method appears to underperform classical isobaric freezing in terms of applicability, and overall usage of resources and energy.

Utilizing energy transition to drive sustainability in cold supply chains: a case study in the frozen food industry

In alignment with the ever-growing interest in adopting sustainable practices, this paper devises a cold supply chain (CSC) planning model that integrates the three pillars of sustainability into the decision-making process while accounting for the shift towards clean energy sources. Interrelated decisions pertaining to production-distribution strategy, backorder and inventory levels, choice of truck type, and selection of third-party logistics (3PLs) providers are jointly optimized. For global CSCs in specific, such decisions are particularly sensitive to the energy sources of the refrigerated facilities and the accompanying levels of CO2 emissions generated. As such, a multi-objective mixed-integer non-linear programming (MINLP) model is developed and then solved via the weighted-sum method. In essence, the model seeks to operationalize sustainability goals by considering the rapidly evolving transition in energy sources across different regions when deciding on which 3PLs to engage in a contractual agreement with while adjusting the production and distribution strategy accordingly. The practical relevance of the model is illustrated using a case study drawn from the North American frozen food industry. The conducted trade-off analysis indicates the possibility of obtaining a drastic improvement of 86% in jobs’ stability levels (social measure) with a maximum cost increase of around 9% as compared to the economic measure. Furthermore, the analysis reveals that it is possible to reduce 71% of CO2 emissions while attaining 63% reduction in worker variations at the expense of only 4.47% cost increase once compared to solely optimizing the economic objective.

Bio-inspired eutectogels enabled by binary natural deep eutectic solvents (NADESs): Interfacial anti-frosting, freezing-tolerance, and mechanisms

To explore food-grade anti-freezing strategies for the frozen food industry, three bio-inspired binary natural deep eutectic solvents (NADESs) comprising proline, glucose, and sorbitol were prepared. Besides, through gelling the NADESs, two-dimensional planar film-like eutectogels (PG53, PG11, and PS11) showing sandwich-like structures were fabricated, of which basic characteristics, anti-frosting capacities and freezing-tolerance were investigated. Results indicated that the eutectogels possessing plenty of hydroxy groups within systems could show more hydrophilic surfaces (47.6°–55.7°) as compared with the control group (69.1°). Besides, PS11 showed the best anti-frosting capacity, exhibiting only 36.31% frost-covered area after 120 min under extreme conditions, probably due to its more rugged surface possessing more and spikier hill-like profiles. For freezing-tolerance, all the eutectogels could stay flexible at −40 °C and show stable mechanical strengths before (stress: 3.1–4.4 MPa, strain: 82.6%–104.7%) and after (stress: 2.5–3.9 MPa, strain: 71.9%–96.5%) extreme temperature fluctuation. Given this, an absorption-inhibition hypothesis was proposed and verified by gradient moisture absorption test and cooling-heating cyclic test, through which critical absorption relative humidity (CARH) and glass transition temperature (Tg) were obtained, which suggested that the eutectogels firstly absorbed the ambient moisture easily (CARH: 49% RH ∼ 55% RH) and subsequently inhibited the crystallization through immobilizing the moisture within the NADESs systems (Tg: −58.6 °C ∼ −50.5 °C), endowing them with great potentials for interfacial anti-frosting. It is hoped that this work could broaden the field of bio-inspired anti-freezing materials in a greener and eco-friendly way.

The Structural Equation Model of Causal Factors Affecting on The Customer Satisfaction Level to Transportation Providers of Fruits in Thailand

The Structural Equation Model of Causal Factors Affecting on The Customer Satisfaction Level to Transportation Providers of Fruits in Thailand

Ice structuring protein extract of Hordeum vulgare var. dolma grain reduces drip loss and loss of soluble vitamin content in peas during frozen storage

The Himalayan plants face low temperature during their life cycle and are expected to possess antifreeze proteins. The present work describes screening of six plant species that grow in Himalayas, for their ice structuring properties with an aim to provide a vegetarian source of ice structuring proteins. The ice-structuring protein extract of barley [Hordeum vulgare; variety Dolma (HvISE)] and wheat [Triticum aestivum; variety Him Pratham DH 114 (TaISE) ]showed inhibition of growth of ice crystals during the process of recrystallization. This property was analyzed for its application in frozen peas by pretreatment with HvISE before freezing. The drip loss was measured in frozen peas after thawing. Further, the water-soluble vitamins; thiamine, pyridoxine, riboflavin, and ascorbic acid were quantified before and after freezing of green peas by UHPLC-PDA. The pretreatment with HvISE reduced the loss of ascorbic acid, riboflavin, and pyridoxine during their frozen storage. The present study identified barley as a remarkable source of ice structuring proteins and validated its potential for frozen peas. The work has enormous implications in frozen food industry, in general.

Impact of temperature fluctuations on quality changes of frozen green beans and carrots during storage.

The quality of vegetables during frozen storage and distribution chain is affected by fluctuating temperature regimes. The temperature variations influence ice-water displacement due to ice crystal growth and ice-sublimation. Hence, the description of quality changes of frozen vegetables during temperature fluctuations is indispensable in the frozen food industry. In this context, frozen carrots and green beans were stored under four different temperatures: -8 °C ± 3 °C, -12 °C ± 3 °C, -18 °C ± 3 °C and -23 °C ± 3 °C for 12 months. In each storage condition, two different partitions were created to achieve different amplitudes of temperature fluctuations, namely low (±0.3 °C) and large (±2 °C). The evolution of frost forming and drip loss in green beans and carrots were analysed in addition to the changes of ascorbic acid in green beans. The results indicated that high mean storage temperature and large amplitude of fluctuation significantly affect the quality indicators. The quality data for drip loss and ascorbic acid were fitted to a first-order kinetic model. An Arrhenius model was applied to describe the temperature dependency by incorporating the temperature fluctuation scenarios. A simplified physical model was used to simulate frost formation during frozen storage in green beans and carrots. Finally, the models were validated using the data collected at -18 °C and -12 °C with low and large amplitudes of fluctuation.

Makin Dirasa Makin Terasa: the case of Mamart Food

Learning outcome At the end of this case study, students should be able to identify issues relating to the external and internal environment of a business; explain how traditional marketing differ to social media marketing strategy and how digital marketing could be applied for frozen food company, identify alternatives to address the production capacity issue and challenges of contract manufacturing; identify and discuss measures that a company could adopt to effectively manage the working capital; apply various business management tools, concepts and theories in different decision-making settings – tools or concepts such as Porter’s five forces, SWOT analysis, PESTEL; and use analytical and logical skills through problem solving. Case overview/synopsis This case presents Khir, CEO of Mamart Food, facing several challenges in the post Covid-19 pandemic. Mamart Food is a SME manufacturing company located in Peninsular Malaysia. It competes in a frozen food industry. The case highlights the turbulence which Khir had to face due to the production capacity issue. He had the dilemma of balancing between the opportunity to boost sales and the capacity to meet demand. The dilemma emerged during the Movement Control Order in place and was expected to continue in the post MCO period. Quite a number of frustrated stockists over the unmet demand have started to aggressively voice out their dissatisfaction. Seeing the growing number of complaints, Khir had to act fast. Being the CEO, Khir must resolve the tension between Suliana, the production manager and Hisham, the sales and marketing manager. Failing which, it could be detrimental to the survival of Mamart Food. The most effective strategy for Mamart Food therefore needs to be formulated immediately. Complexity academic level This case is designed mainly for final year students in Accounting or Business undergraduate programmes. Supplementary materials Teaching notes are available for educators only. Subject code CSS 11: Strategy.

A review of natural polysaccharides for food cryoprotection: Ice crystals inhibition and cryo-stabilization

Although freezing is by far the most common method of food preservation, deteriorative changes in food quality are inevitable because of the formation of ice crystals and other physicochemical reactions. In recent years, cryoprotective agents from natural sources have attracted great interest and been applied to the frozen food industry to overcome freezing damage. Natural polysaccharides have been proved to inhibit ice crystals formation. They possess cryo-stabilized effects due to their rheological properties and antioxidant activity, thus showing great potential in food to achieve the desired cryoprotection levels. In this review, we first summarized the quality damage of food during freezing and frozen storage. Next, the effects of natural polysaccharides on the formation of ice crystals were discussed from the three aspects of ice nucleation, growth, and ice recrystallization. The review focused on the action mechanism of polysaccharides on ice recrystallization inhibition (IRI), in which the polysaccharide-ice interaction and the water perturbation by hydration of polysaccharides might play critical roles in the IRI. Moreover, the cryo-stabilized effects of polysaccharides on food systems were discussed. This review is expected to shed new light on the antifreeze mechanism of natural polysaccharides, inspiring further research into exploring and applying new polysaccharide resources for food cryoprotection.

Safety and health risks for workers exposed to cold thermal environments: A frozen food processing industry perspective.

Environmental temperatures in the fresh food industry vary from 0°C to 10°C, and go below -20°C for the frozen food industry, representing risk for the health and safety of workers involved. The aim of this work was to evaluate the cold thermal stress risks for workers working in a frozen food industry. A total of 27 acclimatized workers (13 male and 14 female) participated in a study which was conducted during 11 working days. The thermal sensation questionnaire and the cold work health questionnaire (CWHQ) were applied to all participants. Additionally, 4 workers were chosen to be fully monitored with a thermometer telemetry capsule for measuring the intra-abdominal temperature and 8 skin temperature sensors. The lowest recorded hand temperature was 14.09°C, lowest forehead 18.55°C, mean skin temperature had variations of 1.10 to 3.20°C along the working period. Highest and most frequent fluctuations were found in the hand and forehead skin temperatures, small changes were found in mean skin temperature. Answers to the CWHQ increase concern on clinical forms of "a frigore", and in two cases the mean body temperature decreased below 35.0°C, which is defined in the current literature as a mild form of hypothermia.

Changes of quality and free radical scavenging activity of strawberry and raspberry frozen under different conditions

The effects of different freezing methods and long-term frozen storage on quality of strawberry and raspberry were investigated, that is, the retention of initial property and free radical scavenging (AO) activity after individual quick freezing (IQF) and conventional (discontinuous) freezing. The physicochemical properties, vitamin C, and AO activity were more affected by long-term frozen storage than by freezing itself; however, their better retention was obtained after IQF. Moreover, AO activity was found to be higher in frozen samples compared to fresh fruits, but significant decrease was detected after 8 months of frozen storage. Despite the significantly higher initial content of vitamin C in strawberry, it demonstrated a lower AO activity than raspberry. Sensory attributes were significantly affected by freezing; the most considerable changes were recorded on their texture/firmness, especially after conventional (slow) freezing. Therefore, IQF can generally be suggested as a more suitable method of preserving these delicate fruits than slow freezing. Practical applications Nowadays, consumers are increasingly interested in foods that possess not only good nutritional value but also health-promoting property. Berries are known as rich sources of micronutrients and antioxidant compounds, but consumption of fresh strawberry and raspberry fruits may be limited because of seasonal and market availability; therefore, they must be preserved commonly by freezing. Frozen food industry is of crucial importance for developing countries, in which the fast freezing industry is rapidly developed. Investigation of the effect of industrial freezing and frozen storage on retention of the quality-related property and antioxidant activity is important for providing the best quality for consumers and health benefits, as well as international fruit trade. In addition, the results obtained in this study could provide best practice and guidance for the frozen fruit industry.

Development of natural deep eutectic solvents (NADESs) as anti-freezing agents for the frozen food industry: Water-tailoring effects, anti-freezing mechanisms and applications

Nature-inspired natural deep eutectic solvents (NADESs) as anti-freezing agents including Pro:Glc (5:3), Pro:Glc (1:1), Pro:Sor (1:1), and Urea:Glc:CaCl2 (3:6:1) were prepared. Viscosity (η), conductivity (σ), activation energy of viscous flow (Eη) and conduction (Eᴧ), transverse relaxation time (T2), thermal behaviours, and anti-freezing capacities of the NADESs were investigated. A critical T2 of 24.60 ms for η changes was obtained, and the relationship between η and T2 was determined as lnη = -1.398lnT2 + 10.688. Differentialscanningcalorimetry and low-field nuclear magnetic resonance analyses indicated NADESs could hinder the molecular motion as temperature decreased through enhancing the hydrogen-bonding strength, endowing them with excellent anti-freezing capacity. NADESs showed varied Eη (41.58 ∼ 45.72 kJ mol−1) and Eᴧ (48.31 ∼ 63.08 kJ mol−1), of which Pro:Sor (1:1) possessed the greatest ones, showing its greatest temperature sensitivity and best anti-frosting capacity. Applications in frozen chicken breast further announced the potentials of NADESs as anti-freezing agents for the industry.

Analysis of global energy savings in the frozen food industry made possible by transitioning from conventional isobaric freezing to isochoric freezing

An efficient global cold food chain is critical to the sustainability of the growing world population, and it is anticipated that the global frozen food market will reach $404.8 billion by 2027. Frozen foods are typically stored under conventional industry-standard isobaric (constant-pressure) conditions at sub-freezing temperatures, however, which can degrade the textural and nutritional quality of the food and comes at high energetic and carbon costs. While efforts to reduce this energetic toll have traditionally targeted the devices used to generate refrigeration, we herein identify that significant energy savings may be attainable by altering the fundamental thermodynamics of the freezing process itself. Here we show that preserving frozen food under isochoric (constant-volume) thermodynamic conditions, as opposed to conventional isobaric conditions, may theoretically reduce annual global energy consumption by as much as 6.49 billion kWh, with accompanying carbon emission savings of 4.59 billion kg. Importantly, these savings can be achieved rapidly and inexpensively, without any costly changes to the current global refrigeration infrastructure. Furthermore, early studies demonstrate that isochoric freezing results in substantially improved food quality, extends the preservable lifetime of fresh and otherwise delicate food products, and has cross-cutting biopreservation applications in domains as diverse as medicine, biology, and pharmaceuticals.

An innovative water-assisted UV-C disinfection system to improve the safety of strawberries frozen under cryogenic conditions

Strawberries inoculated with Salmonella enterica, Listeria monocytogenes (108 CFU/mL, 50 μL) and murine norovirus (MNV-1; 106 TCID50/mL, 50 μL), were washed for 2 min in a water-assisted UV-C light tank (WUVC) combined or not with 40 mg/L of peracetic acid (WUVC+PA), and 200 mg/L of free chlorine solution (NaClO) with the UV-C lamps switched off. Moreover, a ‘conventional’ dry UV-C treatment (DUVC) was also tested. After 2-min exposure, washing sanitization with chemical agents gave the highest reduction for both bacteria (ca. ≥ 3.3 log CFU/g) and MNV-1 (≥1.8 log TCID50/mL). DUVC treatment proved to be the least effective technology (≤0.6 log CFU/g for bacteria and 1.5 log TCID50/mL for MNV-1). Regarding wash water, no presence of L. monocytogenes and S. enterica were reported with WUVC+PA and NaClO sanitization. After disinfection, samples were frozen at −70 ± 2 °C in a cryogenic freezing cabinet with liquid nitrogen (N2). For both pathogens, frozen storage after washing substantially enhanced their inactivation in the first 3 days (1.1–4.9 log UFC/g) compared to the reductions obtained the following sampling points (0.0–0.8 log UFC/g). After 90 days, L. monocytogenes and S. enterica were not detected on the samples treated with water-assisted methodologies (WUVC, WUVC+PA and NaClO treatments), whilst MNV-1 was little affected. Further studies are needed to improve norovirus inactivation on frozen strawberries. Industrial relevanceThe present work provides relevant information to the frozen food industry regarding a suitable decontamination alternative to chlorine sanitation. Low-dose immersion-assisted UV-C allows inactivation and inhibition of pathogenic microbiota while generates non-toxic byproducts and allows reusing the process water, contributing to the so-called “smart green growth” attended to provide a more innovative and sustainable future for the food industry.

The Effect of Multiple Freeze-Thaw Cycles on the Microstructure and Quality of Trachurus murphyi.

Temperature fluctuation in frozen food storage and distribution is the perpetual and core issue faced by the frozen food industry. Ice recrystallisation induced by temperature fluctuations under cold storage causes microstructural changes in fish products and irreversible damages to cells and tissues, which lower the frozen fish quality in the food chain. This study is intended to explore how repeated freezing–thawing affected the microstructure and quality of Trachurus murphyi during its frozen storage. The results showed the consistency between the increase in ice crystal diameter, volume, and porosity in frozen fish and the increase in centrifugal loss (from 22.4% to 25.69%), cooking loss (from 22.32% to 25.19%), conductivity (from 15.28 Ms/cm to 15.70 Ms/cm), TVB-N (from 16.32 mg N/100 g to 19.94 mg N/100 g), K-value (from 3.73% to 7.07%), and amino acid composition. The muscle structure change observed by Fourier-Transform Infrared spectroscopy (FT-IR) showed that the content of α-helix reduced from 59.05% to 51.83%, while the β-sheet fraction grew from 15.44% to 17.11%, β-turns increased from 5.45% to 7.58%, and random coil from 20.06% to 23.49%. Moreover, muscular structure exhibited varying degrees of deterioration with increasing cycles of freezing and thawing as shown by scanning electron microscopy (SEM). We studied the muscular morphology, which included the measurement of porosities (%) of pore that increased (from 1.4% to 4.3%) and pore distribution, by X-ray computed tomography (uCT). The cycles of the freeze–thaw resulted in structural changes, which seemed to be closely associated with ultimate quality of frozen fish products.

The Effect of Product Innovation on Interest with Satisfaction as Mediation

In the future, the food and beverage industry is very promising for industry players due to the trend growth of the food and beverage industry in Indonesia. The food and beverage business is starting to grow rapidly in Indonesia so that it attracts many people to innovate. One form of innovation is the frozen food industry. This study aims to determine the effect of product innovation on repurchase interest by looking at consumer satisfaction as a mediating effect on the frozen food industry. The population in this study were 147 people who were frozen food consumers. Sei. By using a purposive sampling approach and using the Slovin formula, it was determined that the number of samples in this study were 108 respondents. The results of this study indicate that product innovation has a positive and significant effect on customer satisfaction. Product innovation and customer satisfaction have a significant effect on repurchase interest. Consumer satisfaction can mediate the effect of product innovation on consumer repurchase interest.
 Keywords: Product Innovation; Consumer Satisfaction; Repurchase Interest; Mediation; frozen food.

Cold-chain transportation in the frozen food industry may have caused a recurrence of COVID-19 cases in destination: Successful isolation of SARS-CoV-2 virus from the imported frozen cod package surface

Coronavirus disease 2019 (COVID-19) pandemic has spread in 220 countries/regions to wreak havoc to human beings around the world. At present, the second wave of COVID-19 has begun in many European countries. The complete control of COVID-19 is very urgent. Although China quickly brought the virus under control, there have been eight sporadic outbreaks in China since then. Both in Xinfadi of Beijing and Dalian outbreak of COVID-19, environmental swab samples related to imported cold chain food were tested nucleic acid positive for SARS-CoV-2. In this outbreak in Qingdao, we directly isolated SARS-CoV-2 from the cod outer package's surface swab samples. This is the first time worldwide, SARS-CoV-2 were isolated from the imported frozen cod outer package's surface, which showed that imported frozen food industry could import SARS-CoV-2 virus.