Effectiveness of the online-eLearning program KeepCoool at improving the vaccine cold chain in general practices.

BACKGROUND: Protecting vaccines from freeze damage is a poorly addressed problem. We describe the effectiveness of the eLearning KeepCoool on cold chain maintenance in general practices. METHODS: For this intervention study, temperatures of vaccine refrigerators were logged at one-minute intervals. Personnel from practices with cold chain breaches was offered the eLearning. The primary outcome was the intervention's effectiveness to achieve temperatures in the target range (2 to 8°C) in the sixth week (follow-up) compared to the first (baseline). Using continuous temperature data, a generalized additive model for location, scale and shape was estimated. RESULTS: The practice response rate was 38% (64 of 168). At baseline, 73% of the practices and 68% of the refrigerators (51 of 75) showed cold chain breaches. 47% of the practices (n = 22 with 24 refrigerators) participated in the eLearning (55 physicians and practice assistants). At follow-up, 17% of those refrigerators were in the target range continuously, 38% reached targets 95% of the time while always >0°C, and temperatures ≤0°C decreased by 63%. Based on 2 million temperature data, the average Euclidian distance based on regression showed a significant improvement (p<0.05). CONCLUSION: The eLearning KeepCoool improved the practices´ vaccine cold chain. It is freely available at https://keepcoool.ukbonn.de.

Research on risk factor filtering and rating of cold chain logistics from the perspective of root-state risk identification.

The natural attributes of perishable and vulnerable cold chain products make the cold chain have more risks than the general supply chain. The attribute characteristics and internal relations of various risks increase the complexity of risk analysis. The purpose of this paper is to study the horizontal and vertical assessment of various risk factors. The multi-dimensional risk measurement model is used to integrate the assessment of multiple risk factors of human, machine, environment, and management, and the cold chain risk management is discussed from the perspective of risk factor classification. The root-state risk identification (RSRI) method was used to identify potential risks. Based on the double standard filtering and multiple criteria, the filtering of irrelevant risks and screening of uncontrollable risks were evaluated, and the triangular fuzzy number method was used to quantitatively evaluate the controllable risk factors. A total of 223 potential risks, 18 important risks, and 6 key risks were identified, followed by inspection and quarantine reports, pesticide residues, improper loading and unloading operations, unqualified centralized environment, unqualified pre-cooling technology of carriages, and unreasonable storage temperature. According to the analysis results, targeted control measures are proposed to better prevent risks and reduce the probability of cold chain accidents. The traditional risk assessment method can only assess the impact of a single risk factor on the system. This assessment method overcomes this limitation and provides a new perspective for cold chain risk management. PRACTICAL APPLICATION: This study laid the foundation for further risk safety management of cold chain logistics.

Stability of Genotube® Swabs for African Swine Fever Virus Detection Using Loop-Mediated Isothermal (LAMP) Laboratory Testing on Samples Stored without Refrigeration.

African swine fever (ASF) is a transboundary viral disease which causes high mortality in pigs. In many low- and middle-income countries and in remote areas where diagnostic surveillance for ASF virus (ASFV) is undertaken, access to trained animal health technicians, sample collection, cold chain storage and transport of samples to suitably equipped laboratories can be limiting when traditional sampling and laboratory tests are used. Previously published studies have demonstrated that alternative sampling matrices such as swabs and filter papers can be tested using PCR without refrigeration for up to a week. This study used Genotube® swabs stored in temperate and tropical climates without refrigeration for four weeks after collection to demonstrate there was no change in test performance and results using loop-mediated isothermal amplification (LAMP) ASFV detection on a series of pig serum samples including serum spiked with a synthetic ASFV positive control, naturally acquired ASFV positive serum from Timor-Leste and negative ASFV serum samples. The use of Genotube® swabs for ASFV detection for surveillance purposes, coupled with testing platforms such as LAMP, can provide an alternative to traditional testing methodology where resources are limited and time from collection to testing of samples is prolonged.

Magnetocaloric effect modeling of dysprosium-transition metal based intermetallic alloys for magnetic refrigeration application using hybrid genetic algorithm based support vector regression intelligent method.

Intermetallic alloy containing rare earth dysprosium ions with the associated unfilled 4f shell electrons and sub-lattice of 3d-transition metal, results into fascinating magnetic properties which are useful for green refrigeration technological application. Magnetocaloric effect remains the fundamental principle upon which magnetic refrigeration technology is based while this cooling technology has advantages of cost effectiveness, high efficiency and environmental friendliness as compared with the existing conventional gas compression systems. Maximum magnetic entropy change (which controls the hugeness of magnetocaloric effect) of intermetallic alloy Dy-T-X (where T = transition metal and X = any other metal or nonmetal) is modeled in this work using hybrid genetic algorithm based support vector regression (GSVR) computational intelligent method with applied magnetic field, ionic concentration and ionic radii descriptors. The developed GSVR-G model with kernel Gaussian function outperforms GSVR-P model with polynomial function with improvement of 85.23%, 78.82% and 78.67% on the basis of the computed correlation coefficient (CC), mean absolute error (MAE) and root mean square error (RMSE) on testing sample, respectively. The developed model further investigates the influence of applied external magnetic field on magnetocaloric effect of DyCuAl intermetallic alloy. The developed models in this work circumvent experimental challenges of magnetocaloric effect determination while the recorded precision of the developed model further opens doors for possible exploration of these intermetallic compounds for addressing environmental challenges associated with the present system of cooling.

Piloting delivery of PfSPZ vaccines for malaria through a cryogenic vaccine cold chain to travel and military medicine clinics.

BACKGROUND: PfSPZ vaccines comprising Plasmodium falciparum (Pf) sporozoites (SPZ) have demonstrated > 90% protection against variant Pf malaria infections for at least 12 weeks; they are the only vaccines with the level of efficacy necessary to protect travellers. PfSPZ are eukaryotic cells stabilized by cryopreservation and distributed using a cryogenic (below -150 °C) cold chain. The Ebola vaccine and mRNA vaccines against SARS-CoV-2 pioneered uptake of vaccines requiring non-standard ultra-low temperature cold chains. The cryogenic cold chain using liquid nitrogen (LN2) vapour phase (LNVP) cryoshippers, is simpler, more efficient than -80, -20 or 2-8 °C cold chains, and does not use electricity. This study was conducted to evaluate implementation and integration of a cryogenically distributed vaccine at travel and military immunization clinics. METHODS: We conducted sequential 28-day studies evaluating vaccine shipping, storage, maintenance and accession at two US military and two civilian travel health/immunization clinics. In each clinic, personnel were trained in equipment use, procurement and handling of LN2, temperature monitoring and inventory record keeping by in-person or video instruction. RESULTS: Sites required 2-4 h/person for two persons to assimilate and develop the expertise to manage vaccine storage and LNVP operations. LN2 for recharging cryoshippers was delivered every 1-2 weeks. Vaccine ordering, receipt, storage and inventory control was conducted effectively. Simulated single dose vaccine cryovial retrieval and thawing were performed successfully in different travel clinic settings. Continuous temperature monitoring at each site was maintained with only one short excursion above -150 °C (-145 °C) through shipping, use and reverse logistics. Staff, during and at study conclusion, provided feedback that has been incorporated into our models for cold chain logistics. CONCLUSIONS: These studies demonstrated that the training in delivery, storage, administration and integration of PfSPZ vaccines can be successfully managed in different immunization clinic settings for travellers and military personnel.

Temperature status of domestic refrigerators and its effect on the risk of listeriosis from ready-to-eat (RTE) cooked meat products.

Inadequate domestic refrigeration is frequently cited as a factor that contributes to foodborne poisoning and infection, and consumer behaviour in this regard can vary largely. This study provides insight into the temperature profiles of domestic refrigerators in the Netherlands and the impact on the number of listeriosis cases related to ready-to-eat (RTE) cooked meat products. A survey was conducted among Dutch consumers (n = 1020) to assess their knowledge and behaviour related to refrigerators. Out of these participants, 534 measured their refrigerator's temperature, revealing an average temperature of 5.7 °C (standard deviation (SD) of 2.2 °C) with a maximum of 17 °C. Elderly people (65 years and older) had refrigerators with temperatures that were on average 0.6 °C higher than those of younger people (35 years or younger). The 24-hour temperature profiles of an additional set of actively surveyed refrigerators (n = 50) showed that the temperature measured on the upper shelf was significantly higher (mean 7.7 °C, SD 2.7 °C) than the temperature measured on the bottom shelf (5.7 °C, SD 2.1 °C). Quantitative Microbiological Risk Assessment (QMRA) predicted that the primary factors contributing to the risk of listeriosis were the initial concentration and the time and temperature during household storage. Scenario analysis revealed that storing opened RTE cooked meat products at home for either <7 days or at temperatures <7 °C resulted in a significant reduction of over 80 % in predicted illness cases. Among all illness cases, the elderly represented nearly 90 %. When assessing the impact of the disease in terms of Years of Life Lost (YLL), the contribution of the elderly was 59 %. Targeted communication, particularly directed towards the elderly, on the importance of storing RTE cooked meat products at the recommended temperature on the bottom or middle shelf as well as consuming within two to three days after opening, holds the potential to significantly reduce the number of cases.

Low-Temperature Adaptive Single-Atom Iron Nanozymes against Viruses in the Cold Chain.

Outbreaks of viral infectious diseases, such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A virus (IAV), pose a great threat to human health. Viral spread is accelerated worldwide by the development of cold chain logistics; Therefore, an effective antiviral approach is required. In this study, it is aimed to develop a distinct antiviral strategy using nanozymes with low-temperature adaptability, suitable for cold chain logistics. Phosphorus (P) atoms are added to the remote counter position of Fe-N-C center to prepare FeN4P2-single-atom nanozymes (SAzymes), exhibiting lipid oxidase (OXD)-like activity at cold chain temperatures (-20, and 4 °C). This feature enables FeN4P2-SAzymes to disrupt multiple enveloped viruses (human, swine, and avian coronaviruses, and H1-H11 subtypes of IAV) by catalyzing lipid peroxidation of the viral lipid envelope. Under the simulated conditions of cold chain logistics, FeN4P2-SAzymes are successfully applied as antiviral coatings on outer packaging and personal protective equipment; Therefore, FeN4P2-SAzymes with low-temperature adaptability and broad-spectrum antiviral properties may serve as key materials for developing specific antiviral approaches to interrupt viral transmission through the cold chain.

Changes in properties of human milk under different conditions of frozen storage.

Human milk is the best source of nutrition for infants. Lower freezing temperatures and faster freezing rates allow for better preservation of human milk. However, research on the freezing conditions of human milk is limited. This study investigated the effectiveness of quick freezing and suitable freezing conditions for home preservation. Human milk was stored under different freezing conditions (-18 °C, -18 °C quick freezing, -30 °C, -40 °C, -60 °C, and - 80 °C) for 30, 60, and 90 days and then evaluated for changes in the microbial counts, bioactive protein, and lipid. The results showed that the total aerobic bacterial and Bifidobacteria counts in human milk after storage at freezing temperatures of - 30 °C and lower were closer to those of fresh human milk compared to - 18 °C. Furthermore, the lysozyme loss, lipid hydrolysis degree, and volatile organic compound production were lower. However, -18 °C quick freezing storage was not markedly different from -18 °C in maintaining human milk quality. Based on the results, for household and environmental reasons, the recommended temperature for storing human milk is suggested as -30 °C.

Short- and long-term effects of essential oils on swine spermatozoa during liquid phase refrigeration.

The application of essential oils as potential alternatives to antibiotics in swine semen storage is promising, due to their antioxidant and antibacterial properties. However, detrimental effects on spermatozoa should be clarified first. The aim of this study was to evaluate 9 essential oils (EOs; Satureja montana, Pelargonium graveolens, Cymbopogon nardus, Melaleuca leucadendron, Eucaliptus globulus, Citrus limon, Lavandula angustifolia, Lavandula hybrida, Mentha piperita) and a blend (GL mix) on key morpho-functional parameters of swine spermatozoa. Test compounds were firstly chemo-characterized and experimental doses were prepared by suspending a fixed number of spermatozoa with 3 different concentrations (0.1, 0.5, 1 mg/mL) of EOs. Experimental doses were stored at 16 °C and sampled after 3 and 120 h for analysis. Overall, S. montana, P. graveolens and L. angustifolia EOs induced the strongest alterations, with C. nardus and E. globulus EOs being the best tolerated. Swine spermatozoa represent a good preliminary testing platform to screen toxicity and its different patterns. The comprehensive overview on the potential mechanisms of action of some of the most common EOs, despite of the direct aim of the study being swine reproduction, may be exploited in other fields of research within both veterinary and human medicine.

Evaluation of Lipid Oxidation Characteristics in Salmon after Simulation of Cold Chain Interruption Using Rapid Evaporation Ionization Mass Spectrometry.

Temperature fluctuations occurring during the cold chain logistics of salmon contribute to lipid oxidation. This study aimed to simulate cold chain interruption through freeze-thaw operations and evaluate the lipidomics data from salmon samples subjected to different numbers of freeze-thaw cycles by using rapid evaporative ionization mass spectrometry (REIMS) combined with an intelligent surgical knife (iKnife). The results indicated significant differences in the relative abundance of characteristic ions among the samples (p < 0.05). A total of 34 ions with variable importance for the projection values ≥1 were identified as potential biomarkers, including m/z 719.4233 ([PCC36:5-NH(CH3)3]-), m/z 337.3134 ([FAC22:1]-), m/z 720.4666 ([PEC35:6-H]-), m/z 309.2780 ([FAC20:1]-), m/z 777.4985 ([PCC40:4-NH(CH3)3]-), m/z 745.4421 ([PCC38:6-NH(CH3)3]-/[PEC38:6-NH3]-), m/z 747.4665 ([PCC38:5-NH(CH3)3]-/[PEC38:5-NH3]-), etc. The degree of lipid oxidation was found to be associated with the number of freeze-thaw cycles, exhibiting the most significant alterations in the relative abundance of lipid ions in the 8T samples. Additionally, sensory evaluation by the CIE-L*a*b* method and volatile analysis by headspace solid-phase microextraction gas chromatography-mass spectrometry demonstrated significant differences (p < 0.05) in color and odor among the salmon samples, with a correlation to the number of freeze-thaw cycles. The primary compounds responsible for alterations in salmon odor were aldehydes with lower odor thresholds. In summary, the iKnife-REIMS method accurately differentiated salmon muscle tissues based on varying levels of lipid oxidation, thus expanding the application of REIMS.

Effect of feruloylated arabinoxylan on the retrogradation and digestibility properties of pea starch during short-term refrigeration: Dependence of polysaccharide structure and bound ferulic acid content.

In this study, arabinoxylans (AX) with various molecular weights (Mw) and bound ferulic acid (FA) contents were prepared to compare their effects on the gelatinization, short-term retrogradation and digestive properties of pea starch (PeS). The results indicated that all AX samples could obviously impede the pasting process of PeS and inhibit the short-term retrogradation of PeS-based gels during refrigeration by hindering the rearrangement and double helical associations of amylose. More precisely, AXs with low Mw and the highest FA content (H-FAX) exhibited the strongest intervention ability on PeS compared with the other samples. According to the Fourier transform infrared spectroscopy and X-ray diffraction results, it might be due to the unique role of bound FA as a noncovalent cross-linking agent, which enhanced the association between AX and starch molecules through extra hydrogen bonding interactions and entanglement behaviour. On these bases, H-FAX clearly improved the hardness, chewiness, moisture content, and sensory acceptance of PeS-base gels (pea jelly), and could also regulate its starch composition during short-term refrigeration to delay starch digestion. Overall, AXs with appropriate structural features might obviously improve the quality and storage stability of PeS-based foods.

Study of vapor compression refrigeration system with suspended nanoparticles in the low GWP refrigerant.

The rising global temperatures, attributed to the high global warming potential (GWP) of conventional refrigerants, necessitate the adoption of low-GWP alternatives in HVAC systems. However, these low-GWP refrigerants often exhibit high toxicity and flammability, limiting their usage. To address these challenges, compact heat exchangers incorporating blended refrigerants have been introduced to enhance HVAC system performance. Researchers have also made significant strides in improving HVAC system efficiency by introducing the concept of suspending nanolubricants and nanorefrigerants within the system. This review paper seeks to comprehensively assess the potential of alternative refrigerants containing suspended nanoparticles, commonly referred to as nanorefrigerants. The paper reviews various mechanisms and potential combinations of different nanorefrigerants employed to enhance refrigeration system effectiveness and efficiency. A detailed examination of key heat transfer parameters and the performance predictions of low-GWP refrigerants, including those from the hydrofluoroolefin (HFO) and hydrocarbon (HC) classes, is conducted through energy and exergy analyses. Commercial refrigerants like R-134a, R-290, R-600, R-600a, R-123, R-125, R-22, R-141b, R-152, R-11, R-113, R-404a, R-407c, R-502, R-600a, R-507a, R-1234yf, R-1234ze, 1336mzz(Z), and R-410a are evaluated in conjunction with suspended nanoparticles, considering their specific properties. The findings indicate that the utilization of nanorefrigerants leads to notable improvements in overall system performance, characterized by reduced compressor workloads and increased heat transfer rates. Consequently, the integration of blended nanoparticles into refrigerants holds significant promise for advancing the HVAC field.

Continuous monitoring of temperature and freshness in cold chain transport based on the dual-responsive fluorescent hydrogel.

Comprehensive attention should be paid to the potential food spoilage in food transport. However, there is a problem of freshness destruction by repeated freezing and thawing during the cold chain transport. Herein, a fluorescent hydrogel with N-doped green-emitting carbon dots (N-GCDs), bovine serum albumin-gold nanoclusters (BSA-AuNCs) as fluorescent probes and polyvinyl alcohol-sodium alginate hydrogel as carrier matrix was developed to continuously detect temperature and freshness. Due to the solvatochromic effect of N-GCDs, when the temperature surpassed the threshold, the mixture of water and dimethyl sulfoxide underwent a phase transition and melted into the gel, changing the fluorescence color to realize the temperature monitoring. Then, due to the pH effect of BSA-AuNCs, the gel could respond to pH changes in food deterioration to monitor the food freshness. Thus, the changes of both fluorescence color and intensity of the hydrogel provides a new method for visual and portable authenticity of food freshness.

Appropriate handling and storage reduce the risk of bacterial growth in enteral feeding systems reused within 24 hours.

BACKGROUND: Enteral tube feeding can require considerable amounts of plastic equipment including delivery sets and containers, often disposed of after a single feeding session because of bacterial contamination concerns. The aim of this research was to assess whether reuse of delivery sets and containers for up to 24 h is safe from a microbiological perspective. METHODS: Four enteral tube feeding systems (FS) were tested under hygienic controlled or repeated inoculation challenge conditions using key foodborne pathogens, to assess bacterial growth over time (FS1: ready-to-hang, closed 1-L system with delivery set reused, stored at room temperature [RT]; FS2: a prepared, powdered, open 1-L system with delivery set and container reused, stored at RT; FS3 and FS4: prepared, powdered, open 200-ml bolus systems with delivery set and container reused, stored at RT [FS3] and refrigeration [FS4]). Feed samples were cultured at 0.5, 6.5, 12.5, 18.5, and 24.5 h with >2 Δlog considered significant bacterial growth. RESULTS: Under hygienic control, FS1, FS3, and FS4 were below the level of enumeration (<5 CFU/g) for all bacteria tested, at all time points. In FS2, significant bacterial growth was observed from 18.5 h. Under repeated bacterial inoculation challenge, no significant growth was observed in FS1 and FS4 over 24.5 h; however, significant growth was observed in FS2 after 6.5 h and in FS3 after 10-12 h. CONCLUSION: With hygienic handling technique, there is limited bacterial growth with reuse of delivery sets and containers over 24 h. Refrigeration between feeding sessions and using boluses of reconstituted powdered feed reduce bacterial growth risk.

One-week storage of refrigerated bovine milk does not affect the size, concentration, or molecular properties of extracellular vesicles.

Milk extracellular vesicles (EV) have gained extensive attention as promising diagnostic and therapeutic tools. Pre-analytical raw milk storage at low temperatures is an ordinary and usually necessary step after sample collection. It is known that direct freezing of unprocessed whole milk contaminates the native pool of milk EV with other cell structures. However, less evidence is available regarding prolonged cooling at 4°C. The current study assessed whether pre-analytical storage of bovine raw milk for several days affected EV isolation and further analysis. To confirm the independence from the health status of the mammary gland, we analyzed milk samples stored at 4°C for 1, 2, 3, and 7 d past collection, respectively, from 2 quarters of the same cow with different somatic cell counts (SCC). Seven days of refrigeration did not change the milk EV size, concentration, or morphology. We did not detect any changes in the EV cargo regarding the amount of protein and RNA, nor in the specific EV markers TSG101, CD9, and CD81 in milk from quarters with high and low SCC. Overall, we observed fewer CD81 and CD9 markers in quarters with high SCC. Moreover, we found no reduction in the mastitis-related miRNA bta-miR-223-3p, suggesting that refrigeration for several days up to 1 wk is a possible storage option compatible with further EV analyses. The findings of this study enhance the confidence that milk EV are highly stable in the raw milk matrix.

Estabilidad fisicoquímica y microbiológica de un colirio de insulina 10 UI/mL / Physicochemical and microbiological stability of a 10 IU/mL insulin eye drop

Objetivo: Los pacientes con defectos epiteliales corneales persistentes son, a menudo, refractarios a los tratamientos convencionales. La insulina tópica surge como una posible alternativa, habiendo demostrado su efectividad y seguridad. Sin embargo, en la bibliografía actual disponible, hay una falta de estudios de estabilidad. El objetivo del presente trabajo fue evaluar la estabilidad fisicoquímica y microbiológica de un colirio de insulina 10 UI/ml durante 28 días. Método: Estudio de estabilidad fisicoquímica y microbiológica. Se elaboraron 2 lotes (A y B) de colirios de insulina 10 UI/ml, manteniendo el lote B cerrado hasta el día 15. Las variables fisicoquímicas analizadas fueron la concentración de insulina mediante inmunoanálisis quimioluminiscente, pH y osmolaridad. El estudio microbiológico se realizó mediante pruebas de esterilidad mientras que el estudio descriptivo se analizó mediante visualización directa. Resultados: No se observaron cambios significativos de concentración (±10%) en los colirios a excepción de 2 valores en una de las muestras del lote B. El pH y la osmolaridad se mantuvieron dentro de los rangos fisiológicos del ojo. No se observó crecimiento microbiano ni cambios en las características organolépticas. Conclusiones: Se puede considerar al colirio de insulina 10 UI/ml estable durante 28 días en refrigeración manteniendo el frasco abierto desde el día de su elaboración.(AU)

Objective: Patients with persistent corneal epithelial defects are often refractory to conventional treatments. Topical insulin emerges as a possible alternative of proven effectiveness and safety. However, in the current available literature, there is a lack of stability studies. The main objective of this study was to evaluate the physicochemical and microbiological stability of a 10 IU/ml insulin eye drop for 28 days. Methods: Physicochemical and microbiological stability study. Two batches (A and B) of 10 IU/ml insulin eye drops were prepared, keeping batch B closed until day 15. The physicochemical variables analysed were insulin concentration by chemiluminescent immunoassay, pH and osmolarity. The microbiological study was performed by sterility tests while the descriptive study was assessed by direct visualization. Results: No significant concentration changes (±10%) were observed in the eye drops except for 2 values in one of the samples from batch B. The pH and osmolarity remained within the physiological ranges of the eye. No microbiological growth or changes in organoleptic characteristics were observed. Conclusions: Insulin 10 UI/ml eye drops can be considered stable for 28 days under refrigeration if the bottle is kept open from the day of its preparation.(AU)

The survival of murine hepatitis virus (a surrogate of SARS-CoV-2) on conventional packaging materials under cold chain conditions.

Introduction: The cold chain conditions have been suggested to facilitate long-distance transmission of SARS-CoV-2, but it is unclear how viable the virus is on cold chain packaging materials. Methods: This study used the MHV-JHM strain of murine hepatitis virus as a model organism to investigate the viability of SARS-CoV-2 on foam, plastic, cardboard, and wood sheets at different temperatures (-40°C, -20°C, and 4°C). In addition, the ability of peracetic acid and sodium hypochlorite to eliminate the MHV-JHM on plastic and cardboard sheets were also evaluated. Results: The results indicate that MHV-JHM can survive on foam, plastic, or cardboard sheets for up to 28 days at -40°C and -20°C, and up to 14 days on foam and plastic surfaces at 4°C. Although viral nucleic acids were still detectable after storing at 4°C for 28 days, the corresponding virus titer was below the limit of quantification (LOQ). Discussion: The study highlights that a positive nucleic acid test result may not indicate that the virus is still viable, and confirms that peracetic acid and sodium hypochlorite can effectively eliminate MHV-JHM on packaging materials under cold chain conditions.

Demand forecasting of cold-chain logistics of aquatic products in China under the background of the Covid-19 post-epidemic era.

In the background of the post-epidemic era, the consumption demand and market scale of cold chain logistics in China are expanding, but there is still an obvious gap with developed countries. To complete the balance between the supply and demand for aquatic products and the rational allocation of logistics resources and promote the rapid development trend of aquatic product cold chain logistics, it is particularly important to forecast and analyze the demand for aquatic product cold chain logistics. This article selects six main factors that affect the demand for aquatic products in cold chain logistics, uses the traditional grey model and the grey-BP neural network model to simulate and predict the demand for aquatic products in cold chain logistics in China from 2012 to 2021, and compares and analyzes the simulation results. Generally speaking, the demand for aquatic products from Chinese residents is on the rise. In the simulation prediction process, the prediction error of the grey-BP neural network is reduced compared to the traditional grey model, and the processing ability of the nonlinear system is ideal. The results show that the grey-BP neural network model is an effective method to predict the demand for cold chain logistics of aquatic products. Finally, suggestions are made on the future development of aquatic cold chain logistics in the post-epidemic era from the economic, social, and environmental aspects, which provide valuable decision-making reference for the development of marine aquaculture enterprises and cold chain logistics industry.