Method for keeping oysters alive without water at high temperature in summer

Abstract

According to the invention, pacific oysters are taken as research objects, and a water-free keep-alive oyster transportation technology in summer is constructed through pretreatment before transportation and optimization of a packaging mode. Specifically, the research finds that after fresh oysters are temporarily cultured at 15 DEG C, purified for 40 minutes under the conditions that the water temperature is 15 DEG C and the ozone concentration is 0.3-0.4 mg / L and then transited for 2 hours in seawater at 20 DEG C, the simulated transportation survival rate (88.33 + / -9.35%) and the 24-hour rehydration survival rate (79.58 + / -13.46%) of the oysters are the highest, and the weight loss rate is the lowest (8.81 + / -2.48%). Besides, under the same transportation pretreatment mode and simulated transportation conditions, the influence of different ice bag forms and placement positions on the anhydrous transportation survival rate, the weight loss rate and the 24-hour rehydration survival rate of the pacific oysters is compared and analyzed; it is found that the survival rate (94.54 + / -4.45%) and the 24h rehydration survival rate (81.50 + / -15.63%) of the oysters are the highest and the weight loss rate (6.96 + / -1.92%) of the oysters are the lowest in the packaging mode that the ice bags with the same mass are all flatly laid and clamped among all the oysters in a bulk mode.

Description

Technical Field

[0001] The invention relates to the technical field of marine product transportation, and in particular to a method for circulating oysters at high temperatures in summer without water to keep them alive. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] The shellfish live circulation model, led by oysters, has generally undergone three stages of development and evolution. In the initial stage of shellfish circulation, shellfish raw materials were directly put into the market after being salvaged. During the entire storage, transportation and sales process, no measures were taken to keep shellfish alive. Due to changes in living conditions, shellfish often died partially or completely, resulting in economic losses. In the second stage, shellfish raw materials were put into the market after purification, which partially solved the problem of shellfish edible safety, but the survival rate (liveliness) and quality (shelf life) of shellfish could not be guaranteed. Although traditional live storage methods such as ice padding and oxygenation were adopted, the effect was not ideal. The problem of shellfish death was very serious, and some nutrients and flavor components were lost in large quantities. In the shellfish processing stage, there were also problems such as aging of meat, hardening, decreased water holding capacity, residue feeling when eating, discoloration and taste change. The low-temperature live technology problem of shellfish during storage, transportation and sales has not been completely solved. The shellfish live circulation mode has developed to the third stage. After the shellfish raw materials are purified, they are kept alive and circulated at ecological ice temperature, that is, the temperature is controlled within the temperature range from the ecological critical temperature to the freezing point (ecological ice temperature) to put the shellfish in a semi-hibernation or full hibernation state, thereby reducing metabolic weightlessness and mechanical damage, effectively prolonging the survival time, and achieving the purpose of live transportation or storage. This can not only solve the problem of food safety, but also effectively maintain a high survival rate and high quality, achieving the purpose of safety, survival, and quality preservation.

[0004] However, although the shellfish survival circulation model has developed to the third stage, the traditional transportation method is mainly cold chain transportation. Considering the relatively high cost of cold chain logistics, how to ensure that oysters have a high survival rate and nutritional quality without being affected in the conventional transportation environment with high temperatures in summer is still a challenge. Summary of the invention

[0005] In order to overcome the above problems, the present invention provides a method for circulating oysters in a waterless environment at high temperature in summer.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0007] A method for keeping oysters alive and circulating under high temperature and without water in summer, comprising the following steps:

[0008] (1) After the cleaned fresh oysters are temporarily stored, they are purified and then transferred;

[0009] (2) The oysters are packaged after the transition and circulated alive under the ecological ice temperature conditions of the oysters.

[0010] In one or more embodiments, in step (1), the cleaning method includes: manually or mechanically cleaning the oysters to remove debris attached to the oysters and to wash away mud, sand and mucus.

[0011] In one or more embodiments, in step (1), the temporary culture conditions are: a temperature of 10 to 20°C, preferably 15°C; a salinity of 28 to 30‰, and artificial seawater with a dissolved oxygen content of 7.5 to 8.0 mg / L;

[0012] The holding time is 6 to 12 hours.

[0013] In one or more embodiments, in step (1), the purification conditions are: a temperature of 10 to 20°C, preferably 15°C; an ozone concentration of 0.1 to 0.5 mg / L, and artificial seawater with a salinity of 28 to 30‰;

[0014] The purification time is 20 to 60 minutes, preferably 40 minutes.

[0015] In one or more embodiments, in step (1), the transition conditions are: temperature of 10-20°C, preferably 15°C; salinity of 28-30‰, dissolved oxygen of 7.5-8.0 mg / L artificial seawater;

[0016] The transition time is 2 to 3 hours, preferably 2 hours.

[0017] In one or more embodiments, in step (2), the method of packaging the oysters after transition and keeping them alive and circulating them under the condition of oyster ecological ice temperature includes:

[0018] Put the transitioned oysters, cold storage ice packs and transitioned oysters in the insulation bag from bottom to top; seal the insulation bag and place it in an insulation box, and seal the insulation box for transportation.

[0019] Preferably, in step (2), the mass ratio of oysters to cold storage ice is 5 to 6:1.

[0020] Preferably, in step (2), the cold storage ice is bulk biological ice bags.

[0021] Preferably, in step (2), the material of the thermal insulation box includes polyethylene; the material of the thermal insulation bag includes tin foil.

[0022] Preferably, in step (2), the packaging weight is 5 to 6 kg.

[0023] In one or more embodiments, in step (1), the size of the oysters is 2 to 5 per kilogram.

[0024] The beneficial effects of the present invention are:

[0025] (1) This study uses Pacific oysters as the research object, and constructs a waterless transportation technology for oysters in summer by optimizing pre-transportation treatment and packaging methods. Specifically, the present invention found that after fresh oysters were temporarily stored at 15°C, purified for 40 minutes under the conditions of water temperature of 15°C and ozone concentration of 0.3-0.4 mg / L, and then transitioned in 20°C seawater for 2 hours, the simulated transportation survival rate (88.33±9.35%) and 24h rehydration survival rate (79.58±13.46%) of oysters were the highest, and the weight loss rate was the lowest (8.81±2.48%). In addition, under the same pre-transportation treatment method and simulated transportation conditions, a comparative analysis was conducted on the effects of different ice pack shapes and placement positions on the survival rate, weight loss rate and 24-hour rehydration survival rate of Pacific oysters during waterless transportation. It was found that the oyster survival rate (94.54±4.45%) and 24-hour rehydration survival rate (81.50±15.63%) were the highest, and the weight loss rate (6.96±1.92%) was the lowest when ice packs of the same mass were laid flat in bulk and sandwiched between all oysters.

[0026] (2) In order to evaluate the effect of the circulation method provided by the present invention on the transportation effect of oysters, the texture, quality, oxidase reaction and nutritional value of oysters were analyzed. The results showed that the transportation method would not have a significant effect on the texture and color difference of the oyster closing muscle and soft tissue. The changes in the muscle fibers of the oyster closing muscle under the waterless transportation method and the traditional transportation method were similar. Compared with before transportation, the gaps between the closing muscle fibers increased and a small amount of fiber breakage occurred after transportation. The study of oxidative stress kinases found that compared with the traditional transportation method, the CAT and T-AOC of oysters under the pre-treatment method of the waterless transportation method were relatively high, and the temporary storage treatment had a significant positive effect on alleviating the oxidative stress during the transportation process of oysters. By detecting the glycogen and total amino acid content in different tissue parts of oysters under different transportation methods, it was found that the total amino acids of each tissue of each experimental oyster had no significant effect. Compared with the traditional transportation method, the waterless transportation method had less effect on glycogen.

[0027] (2) Oysters are warm-water shellfish. The seawater temperature in summer is generally 24-26°C. Under the dual effects of high temperature and spawning in early summer, the physical condition of oysters is affected, which can easily cause large-scale mortality. After the oysters are harvested, the traditional method of direct transportation with ice bags will cause stress to the oysters, which is easy to die, affecting sales and customer taste. In addition, the traditional transportation method is mainly cold chain transportation. Considering the relatively high cost of cold chain logistics, how to develop small-package transportation so that oysters not only have a higher survival rate in the conventional transportation environment of high temperature in summer, but also have unaffected nutritional quality is an urgent problem to be solved. The present invention uses a complete processing chain of "cleaning the shell surface after oyster fishing-temporary storage-ozone purification-transition-packaging and transportation" to ensure that during the transportation of oysters, bacteria and viruses attached to the shell surface cannot breed, and will not consume too much oxygen in the packaging box and cause oyster death; through purification and transition, the oysters gradually adapt to the low temperature environment in the packaging box, reduce metabolic activity, and do not affect the taste. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0029] Figure 1 The change of Vibrio colony number over time in seawater with ozone concentration of 0.3-0.4 mg / L;

[0030] Figure 2 The figure below shows the life characteristics of oysters in different ozone concentrations. The left figure shows the state of oysters in ozone concentrations of 0.1-0.2 mg / L and 0.4-0.5 mg / L, and the right figure shows the state of oysters in ozone concentrations of 0.7-0.8 mg / L. The red circle indicates the phenomenon of oysters ovulating sperm and eggs.

[0031] Figure 3 The sterilization rate of oyster surface changes with time at different temperatures and ozone concentrations;

[0032] Figure 4 The sterilization rate of the whole oyster organs changes with time at different temperatures and ozone concentrations. The upper left is 20℃ ozone concentration of 0.1-0.2 mg / L, the upper right is 20℃ ozone concentration of 0.3-0.4 mg / L, the lower left is 15℃ ozone concentration of 0.3-0.4 mg / L, and the lower right is 10℃ ozone concentration of 0.3-0.4 mg / L.

[0033] Figure 5 The effect of transition temperature on the waterless transportation of oysters;

[0034] Figure 6 The effects of whole ice and loose ice packaging on the waterless and live transportation of oysters;

[0035] Figure 7 The effect of ice pack placement on waterless oyster transportation;

[0036] Figure 8 To investigate the effects of different optimization methods on the waterless and alive transportation of oysters;

[0037] Fig. 9 The texture changes of the soft part and closed muscle of the oyster, the left picture shows hardness, and the right picture shows adhesion;

[0038] Fig.10 The color difference of the oyster mantle changes;

[0039] Fig.11 The microscopic structural changes of the oyster closing muscle;

[0040] Fig.12 The effects of different treatments on superoxide dismutase (SOD) activity in different tissues of oysters;

[0041] Fig.13 The effects of different treatments on the catalase (CAT) activity in different tissues of oysters;

[0042] Fig.14 The effects of different treatments on the total antioxidant capacity (T-AOC) activity of oyster tissues;

[0043] Fig.15 The effects of different treatments on the glycogen content of oyster tissues;

[0044] Fig.16 This is the effect of different treatments on the total amino acid content of glycogen in oyster tissue. DETAILED DESCRIPTION

[0045] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0046] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0047] The experimental animals, Pacific oysters, were purchased from a marine aquaculture farm in Weihai City, Shandong Province, with an average shell length of 10.67±2.76cm, a shell width of 6.44±0.88cm, and an average wet weight of 153.10±20.59g. The unwashed oysters were directly placed in a polyvinyl chloride box with a 500g ice bag in the box, and transported to the laboratory after 1-2 hours of waterless transportation. When they arrived at the laboratory, they were unpacked and checked. The unpacking temperature was 27±2.72℃, and the overall survival rate of oysters was >95%. The oysters were rinsed with a high-pressure seawater gun, and the oysters that were obviously dead were selected again. The remaining oysters were then placed in a 15℃ water pool for temporary storage.

[0048] Unless otherwise specified in the following examples, the seawater is artificial seawater, and the salinity of the artificial seawater is 28-30‰ and the dissolved oxygen is 7.5-8.0 mg / L.

[0049] Example 1

[0050] Ozone sterilization effect experiment:

[0051] Fill the artificial seawater with ozone to make the ozone concentration in the seawater reach 0.3-0.4 mg / L. Take 1L of seawater containing ozone into a conical flask and add 1mL of ozone with a concentration of about 3.18×10 9 CFU / mL of Vibrio harveyi was mixed evenly, and 10 μL was dropped into the Vibrio identification culture dish every 0.5 or 1 minute starting from 0 min after addition to observe the dynamic changes in the number of Vibrio harveyi.

[0052] The results are as follows Figure 1 As shown, from Figure 1 It can be seen that when the ozone concentration is 0.3-0.4 mg / L, the Vibrio content in seawater decreases with the increase of ozone addition time, and the sterilization rate reaches more than 99% within 5 minutes.

[0053] Example 2

[0054] Exploration of purification methods before transportation:

[0055] A total of 135 individuals of uniform size were selected and divided into three groups, with 45 oysters in each group. Each group of oysters was temporarily cultured for 12 hours under the following conditions: seawater with a water temperature of 15°C, a salinity of 28-30‰, and a dissolved oxygen content of 7.5-8.0 mg / L. The ozone concentration in the seawater was then adjusted to 0.1-0.2 mg / L, 0.4-0.5 mg / L, and 0.7-0.8 mg / L, respectively. The changes in the vital activities of the oysters were observed to determine the range of ozone concentration in the purification treatment.

[0056] In order to further determine the effects of seawater temperature and ozone concentration on the purification effect of oyster surface and whole organs, the purified seawater temperature was set at 20℃, 15℃ and 10℃, and the ozone concentration was set at 0.1-0.2mg / L and 0.3-0.4mg / L, respectively, and divided into 4 seawater temperature-ozone concentration groups. Three parallels were set in each group, and 30 oysters were selected in each parallel to purify in the culture ponds with corresponding temperature and ozone concentration. The survival status of oysters was observed at 0min, 10min, 30min, 1h and 2h after the start of purification, and 4 oysters were randomly selected at each time point. The microorganisms on the surface of oysters were brushed with a sterile brush, and then rinsed with 20mL sterile PBS solution to obtain the bacterial solution; the whole organs of oysters were dissected and placed in a sterile culture dish, weighed and homogenized to obtain the oyster organ homogenate. The microbial samples of the surface and whole organs of the four oyster shells were mixed and stored in a 4℃ refrigerator, and the microbial colony culture was completed within 1 hour. Three parallel samples were set up for each mixed sample to detect the bacterial colony count. The determination method was based on "GB4789.2-2022 Determination of total colony count in food microbiology inspection". The oyster-purified seawater temperature and ozone concentration were determined based on the sterilization effect.

[0057] Results: By comparing the effects of different ozone concentrations on oyster life at 15°C water temperature, Figure 2 As shown in the figure, it was found that when the ozone concentration was 0.1-0.2 mg / L and 0.4-0.5 mg / L, the purified water was transparent and the oysters had no obvious abnormal life activity characteristics. When the ozone concentration was 0.7-0.8 mg / L, the oysters showed sperm and ovulation, and the purified water was turbid, indicating that the high ozone concentration in the seawater may irritate the oysters and affect their normal life activities. The reason for this result may be that when the ozone concentration is higher than 0.5 mg / L, the ozone in the water will react in a short time to produce compounds such as sulfites, olefin fatty hydrocarbons, phenols, polyaromatic hydrocarbons, organic amines and sulfides, which will be toxic to shellfish. The above results show that when using ozone to purify oysters, the ozone concentration should not be higher than 0.5 mg / L, so in subsequent experiments, only 0.1-0.2 mg / L and 0.3-0.4 mg / L ozone concentrations were used to affect the purification effect of oyster surfaces and organs.

[0058] Effects of different temperatures and ozone concentrations on the purification and sterilization rate of oyster shell surfaces Figure 3As shown in the results, the oyster surface sterilization rate was 85.20% after 10 minutes when the ozone concentration was 0.3-0.4 mg / L, and the oyster shell surface sterilization rate was greater than 86.98% after 30 minutes; when the ozone concentration was 0.1-0.2 mg / L, the sterilization rate was 18.64% after 10 minutes, and the oyster shell surface sterilization rate was 81.42% after 30 minutes. The experimental results show that under the temperature condition of 20℃, the sterilization rate of the ozone concentration of 0.3-0.4 mg / L group increased significantly within 10 minutes, and the sterilization effect was significant, while when the ozone concentration was 0.1-0.2 mg / L, the sterilization rate did not increase significantly until 30 minutes after the purification started. This shows that under the same temperature conditions, the ozone concentration of 0.3-0.4 mg / L sterilizes the oyster surface faster than 0.1-0.2 mg / L seawater, and can achieve a good sterilization effect in a shorter time. The effect of different temperatures on the sterilization effect of oysters was studied under the condition of ozone concentration of 0.3-0.4 mg / L. It was found that except for the 20℃+0.3-0.4 mg / L group, the sterilization rate of oyster shell surface in all groups increased with the increase of purification time, and after 30 minutes of purification, the sterilization rate of oyster shell surface could reach more than 82.68%; after 2 hours of purification, the sterilization rate of oyster shell surface in each group reached more than 88%. Under the condition of ozone concentration of 0.3-0.4 mg / L, the sterilization rate of the 15℃+0.3-0.4 mg / L group in the first 10 minutes was always higher than that of other groups in different temperature groups. The sterilization rate of the 20℃+0.3-0.4 mg / L group showed a downward trend in the first hour of purification, and the sterilization rate increased significantly in the second hour. The sterilization rate of the 10℃+0.3-0.4 mg / L group increased with time from 0 to 2 hours, but was always lower than that of the 15℃+0.3-0.4 mg / L group until the second hour, which was close to other groups. In the end, from the overall point of view, the 15℃+0.3-0.4 mg / L group had the best surface sterilization effect on oysters, but it was not much different from the 20℃+0.3-0.4 mg / L group.

[0059] Effects of different temperatures and ozone concentrations on the sterilization rate of oyster organs Figure 4As shown in the figure, the sterilization effect of oyster meat after 2 hours of ozone purification was not obvious compared with the surface of oyster shell. The colony count of oyster meat in the 20℃+0.1~0.2mg / L group did not change significantly in each time period of the 2h purification process (p>0.05); the colony count of oyster meat in the 20+0.3~0.4g / L group increased at 30min of purification, and then decreased with time, and the number of bacterial colonies after 2h of purification was significantly lower than that in other time periods (p<0.05); the colony count of oyster meat in the 15℃+0.3~0.4mg / L group increased at 10min of purification, and then decreased with time, and the colony count of oyster meat at 2h was significantly lower than that of oyster meat at 10min (p<0.05); the colony count of oyster meat in the 10℃+0.3~0.4mg / L group decreased from the beginning of purification, but the colony count did not change significantly during the whole purification process (p>0.05).

[0060] In general, the bactericidal effect of different temperature and ozone concentration treatment groups on the whole organs of oysters did not change significantly over time. This may be because oysters mainly rely on gills and mantle to filter seawater. When stimulated by the external environment, the oysters close their double shells and reduce their daily activities. During the period when the ozone concentration is stable, the ozone seawater cannot enter the oyster shell, resulting in the inability of ozone seawater to fully sterilize the inside of the oysters. At the same time, due to the needs of experimental operation, all oysters in different experimental groups were not from the same batch at the same time, so the total number of bacterial colonies in the whole organs of oysters in each experimental group was different. Moreover, since the number of bacterial colonies in the whole organs of oysters is greatly affected by the individual differences of oysters, the change pattern of the number of colonies is inconsistent with the change of experimental conditions.

[0061] Finally, considering the sterilization effect of ozone seawater at different temperatures on the oyster shell surface and the whole oyster organs and the stimulation of temperature changes on oysters, the oyster purification water temperature was determined to be 15°C and the ozone concentration was 0.3-0.4 mg / L. Since the number of colonies on the oyster shell surface has been significantly reduced after purification for more than 30 minutes, while the number of colonies in the whole oyster organs has not changed significantly over time, and considering the convenience of actual operation in the future production process, the purification time before the waterless oyster alive transportation is determined to be 40 minutes.

[0062] Example 3

[0063] Research on transition methods before transportation

[0064] In order to alleviate the stimulation of purification treatment on oysters, based on the best purification treatment results of oysters, the purified oysters were placed in 25℃, 20℃, 15℃ and 10℃ seawater for 2h. Five parallels were set for each temperature, and 30 oysters were placed in each parallel culture pond. After 2h, the waterless survival transportation was simulated according to the conventional transportation packaging method. The specific method is: first put the oysters and ice bags (2×500g) into aluminum foil insulation bags, and then put them into polyvinyl chloride insulation boxes (36cm×21cm×24cm, wall thickness 5cm) for sealing. The insulation box was placed in a constant temperature box, set the temperature to 30℃, and simulated waterless survival transportation for 48h to calculate the survival rate of oysters. The oysters were weighed before and after packaging and transportation as m0 and m, and the weight loss rate of oysters was calculated. In addition, the surviving oysters were cultured in 15℃ seawater, and the rehydration survival rate was calculated after 24h. The optimal transition temperature before oyster transportation was determined based on the survival rate, weight loss rate and rehydration survival rate of oysters after treatment at different transition temperatures. The calculation formula for the weight loss rate (Y) of oysters before and after simulated transportation is:

[0065]

[0066] Transition is an important processing method for seafood before transportation. Studies have shown that proper transition treatment can improve the survival rate of seafood in waterless transportation and help maintain its quality during transportation. Figure 5 The results show the changes in the survival rate, weight loss rate and 24h rehydration survival rate of oysters after 48h of simulated waterless transportation at 30℃, after being purified at 15℃ and ozone concentration of 0.3-0.4mg / L for 40min and then packed in seawater of different temperatures for 2h.

[0067] The results showed that the survival rate, weight loss rate and 24h rehydration survival rate of different transition temperatures were different, indicating that different transition temperatures would have a certain impact on the oyster transportation survival rate. The oyster survival rate of the 20℃ group, 15℃ group and 10℃ group decreased with the increase of transition temperature. Among them, the survival rate of waterless transportation under 20℃ precooling conditions was 88.33±9.35%, and the rehydration survival rate was 79.58±13.46%, which were slightly higher than those of other experimental groups; the weight loss rate was 8.81±2.48%, which was slightly lower than that of other experimental groups except the 10℃ group. The oyster unpacking survival rate in the 25℃ transition group was 73.75±19.45%, and the 24h rehydration survival rate was 71.00±11.53%, which were significantly lower than those of other groups, while the weight loss rate was 10.81±1.72%, which was higher than those of other groups.

[0068] In this study, after temporary culture at 15℃ and seawater purification with the same temperature and ozone concentration, the oysters that transitioned for 2h in seawater at 20℃ had the highest survival rate and the lowest weight loss rate after 48h of simulated transportation, compared with the oysters that transitioned for 2h in seawater at 15℃ and 10℃ under the same conditions. This may be because the oysters were temporarily cultured in 15℃ seawater for a long time before transportation and have adapted to the 15℃ living environment. The respiration and metabolic rates of oysters are at their best at this temperature. When the transition temperature is 15℃, the respiration and metabolic rates of oysters remain unchanged, but the oxygen demand in the waterless transportation environment is large, and the waterless environment cannot meet the demand, resulting in the death of oysters due to lack of oxygen. When the transition temperature is 10℃, it may be because the temperature is lowered before transportation, and the temperature of oysters increases over time during transportation. The oysters increase their energy consumption before and after transportation to adapt to the repeated temperature changes, which eventually leads to their death during the waterless transportation process.

[0069] Example 4

[0070] Exploration of packaging methods before transportation:

[0071] Based on the thermal insulation effect of cold storage ice bags in summer transportation, the effects of the size and placement of cold storage ice bags on the transportation effect are compared.

[0072] (1) Effect of ice size in cold storage ice packs on waterless transportation of oysters in summer. The ice is 1 kg as the standard and is divided into whole ice group and loose ice group. The whole ice group (WI) uses 1 bag of ice pack with a mass of 1 kg, and the loose ice group (BI) uses 5 bags of ice packs with a mass of 200 g each. That is, the total amount of ice in the two groups is the same, both 1 kg, but the packaging method is different. They are laid on the top layer of all oysters. Each experiment is set up with 5 parallels. (2) Effect of ice pack placement on waterless transportation of oysters in summer. The ice pack with a total mass of 1 kg is divided into 5 bags of ice packs with a mass of 200 g. According to different placement methods, they are divided into dispersed control (DC) group, one layer type (OLT) group, two layer type (TLT) group, and three layer type (RLT) group. Each experimental group is set up with 5 parallels. The dispersed group placed five bags of ice bags on the four walls of the packaging box and in the middle of the oysters; the one-layer (OLT) group first put a layer of oysters in the box and then laid all 5 bags of ice bags on the bottom layer of oysters before placing the remaining oysters; the two-layer (TLT) group first put a layer of oysters in the box and then laid 3 bags of ice bags on the bottom layer of oysters, then placed the remaining oysters, and then laid the remaining 2 bags of ice bags on top of the oysters; the three-layer (RLT) group first put 1 bag of ice bags at the bottom of the box, then put a layer of oysters and laid 3 bags of ice bags, then placed the remaining oysters, and placed the remaining ice bags on top of all oysters. Except for the ice bags, other packaging methods and transportation environment settings are consistent with those in Example 3. The optimal oyster transportation packaging method is determined based on indicators such as oyster survival rate, weight loss rate, and 24h rehydration survival rate.

[0073] The results are as follows Figure 6 As shown in the study, it was found that under the same total mass of ice packs, the survival rate of the loose ice group was 86.90±12.54%, the rehydration survival rate was 71.07±21.81%, and the weight loss rate was 5.79±4.06%; the survival rate of the whole ice group was 74.37±6.88%, the rehydration survival rate was 65.55±23.19%, and the weight loss rate was 5.79±4.06%. The survival rate and rehydration survival rate of the loose ice group were higher than those of the whole ice group, while its weight loss rate was lower than that of the whole ice group. This may be because under the same mass, the surface area of ​​loose ice is greater than that of whole ice, and the loose ice melts faster, resulting in a larger heat absorption area, which can further reduce the temperature in the box.

[0074] The effects of different placement positions of ice packs of the same total mass on the waterless transportation of oysters were studied. Figure 7As shown in the figure, compared with other packaging methods, the unpacking survival rate and rehydration survival rate of oysters in the one-layer (OLT) packaging method were 94.54±4.45% and 81.50±15.63%, respectively, which were higher than those in other groups. Under the dispersed (DC) ice pack packaging method, the unpacking survival rate and rehydration survival rate of oysters were significantly lower than those in other groups, which were 79.90±14.51% and 68.16±18.76%, respectively. The weight loss rates among the groups were significantly different, among which the weight loss rate under the two-layer (TLT) packaging method was 5.90±2.70%, slightly lower than that of other groups. This may be because the contact area between the ice bag and the air is larger than that of the one-layer ice bag packaging method in other packaging methods, resulting in the melting of the ice bag to absorb the heat of the surrounding air, causing the loss of heat absorption efficiency, while under the one-layer packaging method, the ice bag is in full contact with the oyster, and the melting of the ice bag absorbs the heat of the oyster to the greatest extent, maintaining a relatively low temperature during the transportation of the oyster. In summary, this study determined that the optimal packaging method was 5 bags of loose ice with a total mass of 1 kg. A layer of oysters was first placed on the bottom of the box, followed by a layer of ice packs and finally the remaining oysters.

[0075] Example 5

[0076] Considering that the power consumption of temperature control in actual operation has a great impact on transportation costs, and the water temperature of 20 and 15°C has little difference in the purification effect on oysters under the condition of ozone concentration of 0.3-0.4 mg / L, this experiment changes the water temperature of temporary culture and purification from 15°C to 20°C, which saves more electricity, and compares the effects of different transition temperatures on the survival rate of oysters in waterless transportation, etc., and optimizes the scheme obtained in the experiment in Example 3. By comparing the oyster transportation survival rate, 24h rehydration survival rate and weight loss rate under five transportation treatment schemes of temporary culture at 20°C, different transition temperatures (20°C, 15°C and 10°C) after purification, temporary culture at 15°C, transition at 20°C after purification, and direct transportation without any pre-treatment, the optimal pre-transportation pretreatment method with relatively high transportation survival rate and relatively low cost is obtained.

[0077] 30 oysters were randomly selected from 150 oysters and directly simulated for transportation without temporary culture, as the control group (CG). 90 oysters were randomly selected and temporarily cultured at 20℃ and then randomly divided into 3 experimental groups, which were respectively transitioned in 20℃, 25℃ and 20℃ seawater for 2h, and grouped according to "temporary culture temperature-transition temperature", namely 20-20℃ group, 20-15℃ group and 20-10℃ group for pretreatment before transportation. The remaining 30 oysters were temporarily cultured and purified at 15℃, and then transitioned in 20℃ water temperature for 2h, namely 15-20℃ group. After the transition treatment of each experimental oyster, it was simulated for 48h under the same conditions as in Example 3. The above experiments were repeated three times, and the survival rate, 24h rehydration survival rate and weight loss rate of each group of oysters before and after transportation were finally statistically analyzed.

[0078] Results: The above-obtained pre-transportation treatment methods were optimized, and the survival rate, 24-hour rehydration survival rate and weight loss rate of oysters after waterless transportation were compared in the 20°C temporary culture temperature treatment groups, the control group (CG group) without temporary culture, and the 15°C temporary culture and 20°C transition treatment groups (15-20 groups). Figure 8 After analysis, it was found that the survival rate and rehydration survival rate of the CG group were 77.85±7.52% and 57.09±17.10%, respectively, which were lower than those of all other groups, while its weight loss rate was 7.92±3.45%, which was higher than that of all other groups; when the temporary temperature was 20℃, the unpacking survival rate and 24h water survival rate increased with the decrease of precooling temperature, and the 20-10℃ group had the highest survival rate and retest survival rate, which were 95.65±5.50% and 7.02±8.79%, respectively. The weight loss rate slowly decreased with the decrease of transition temperature, and the lowest was 5.741±1.89% in the 20-10℃ group. Comparing the 20-10℃ group and the 15-20℃ group, it was found that the out-of-box survival rate, rehydration survival rate and weight loss rate of the 20-10℃ group were slightly higher than those of the 15-20 group. The survival rate of the 15-20 group was 93.79±5.60%, the 24h rehydration survival rate was 85.77±3.43%, and the weight loss rate was 4.79±2.19%.

[0079] Under the temporary culture condition of 20℃, when the transition temperature was 10℃, the oyster transportation survival rate was the highest, and the oyster anhydrous survival transportation survival rate under this temporary culture temperature increased with the decrease of transition temperature, and this result pattern was different from that under the temporary culture condition of 15℃. This may be because the temperature difference between 20℃ and 10℃ is large, and the rapid cooling is equivalent to cold shock treatment, which reduces the respiration and metabolic rate of oysters, which is conducive to anhydrous survival transportation.

[0080] By comparing the 20-10℃ group and the 15-20℃ group, it was found that the transportation effect of 20℃ temporary storage and 10℃ purification was slightly better than that of 15℃ temporary storage and purification and 20℃ transition. However, considering that the cost of the transition temperature of 10℃ is much higher than that of 15℃, it is more conducive to actual transportation operations. Finally, the temporary storage and ozone purification temperature was determined to be 15℃, and the transition temperature was 20℃.

[0081] In summary, according to the optimization scheme for keeping oysters alive and transporting in Examples 1 to 5, the effect was evaluated, and the temporary holding condition was determined to be 15° C., and the purification and pre-cooling conditions were determined to be: purification for 40 minutes under an ozone concentration of 0.3 to 0.4 mg / L, and then pre-cooling in 20° C. seawater for 2 to 3 hours; the packaging method was to first put a tin foil insulation bag in an insulation box, and the oysters were put into a tin foil bag. Each box contained about 30 oysters (5 to 6 kg), first placed a layer of oysters at the bottom of the package, and then added 5 bags of 200 g (1 kg in total) ice bags and laid them flat as a layer, and then placed the remaining oysters on top of the ice bags so that all the ice bags were placed in the middle of the oysters.

[0082] Example 6

[0083] According to the different treatment methods and characteristics of different stages of oysters, the sample collection was divided into 5 groups, namely control group (CG), temporary culture group (TG), depuration and transition group (DT), transportation control group (TC), and transportation treatment group (TT). The control group (CG) samples refer to oysters purchased from the farm and cleaned in the laboratory; the temporary culture group (TG) samples refer to oysters after being temporarily cultured in clean seawater; the depuration and transition group (DT) samples refer to oysters purified in seawater with an ozone concentration of 0.3-0.4 mg / L and a water temperature of 15°C and then transitioned to seawater at a water temperature of 20°C. The transportation control group (TC) samples refer to clean oysters that are directly packaged and transported in a 30°C constant temperature box for 48 hours, and the transportation treatment group (TG) samples refer to clean oysters that are treated with the pre-treatment and packaging methods specified in Example 5 and transported in a 30°C constant temperature box for 48 hours.

[0084] 6.1 Texture and color difference determination

[0085] Six oysters were randomly selected from each group to dissect all the organs and closed muscle tissues of the oysters. The texture of the soft part outside the gonad and the adductor muscle of the oysters was analyzed using the TMS-PRO texture analyzer. The surface moisture of the sample was dried with absorbent paper. In the TPA mode, a cylindrical probe with a diameter of 8 mm was used to vertically squeeze the sample. The probe descended at a constant speed of 30 mm / s, with an initial force of 0.3 N. After the deformation of the sample reached 60%, the probe moved up. Two different sites were measured for each sample, and the average values ​​of the adhesiveness (N) and hardness (N) of the two points were calculated as the final value of the sample. A handheld colorimeter was used to perform colorimetric analysis on the surface of the soft part outside the gonad of the oyster sample. After the instrument was calibrated, the brightness difference (ΔL * ), redness difference (Δa * ) and yellowness difference (Δb * ), calculate the total color difference (ΔE * ):

[0086]

[0087] Texture analyzers can provide time series data of product deformation, and thus various texture attributes can be calculated based on force-time or force-displacement data. They are widely used to quantify food texture and are considered to be one of the indicators for quantifying the chewing quality of food. Fig. 9As shown in the figure, in the comparison of closing muscle hardness, the hardness of the closing muscle of the TG and DT groups was lower than that of the CG group, while the hardness of the closing muscle of the TC and TT groups was close to that of the CG group, and the hardness of the closing muscle of the TT group was slightly higher than that of the TC group. In addition, the hardness of the closing muscle of the TT group was significantly greater than that of the TG and TC groups (p<0.05); compared with the control group, the hardness of the soft parts of the oysters in the TG group increased significantly (p<0.05), while the changes in other experimental groups were not obvious; compared with the TC group, the hardness of the soft parts of the oysters in the TT group also remained almost unchanged.

[0088] Adhesion of the soft part and closing muscle of oysters in each experimental group Fig. 9 As shown in the figure, the adhesion of the oyster closed muscle in the TG and DT groups was slightly higher than that in the CG group. After simulated transportation, the adhesion of the oyster closed muscle showed a downward trend. The adhesion of the closed muscle in the TT group was lower than that in the TC group, but there was no significant difference. Compared with the CG group, the adhesion of the soft parts of the oysters in the other TG and DT groups decreased, but there was no significant difference (p>0.05). The adhesion of the soft parts of the TC and TT groups decreased significantly compared with the TG group (p<0.05), and the TT group was slightly higher than the TC group, but there was no significant difference between the two (p>0.05). This shows that under the new transportation method, the hardness of the oyster closed muscle after temporary storage and purification pre-cooling treatment decreased compared with the control group, and the hardness of the oyster closed muscle increased after simulated transportation. At the same time, temporary storage treatment may cause the hardness of the oyster soft tissue to increase. In addition, the various treatment methods have no significant effect on the adhesion of the oyster closed muscle, but will affect the adhesion of the oyster. It may be that the environmental stress during transportation will cause the oyster soft tissue to lose water and increase adhesion, which will affect the oyster's taste.

[0089] Effects of various pre-transportation treatment methods and waterless simulated transport on the color difference of oyster soft parts Fig.10 As shown, compared with the control group, the color difference ΔE of oysters showed an upward trend, and L* showed a downward trend, but the various treatments and simulated transportation methods had no significant effect on the color difference and brightness of oysters (p<0.05).

[0090] From the above results, it can be seen that after temporary culture at 15℃, temporary culture and purification under the condition of ozone concentration of 0.3-0.4 mg / L for 40 minutes, and then pre-cooling in 20℃ seawater for 2-3 hours before packing, and simulated transportation at 30℃ for 48 hours, the color difference of oysters did not change significantly; although the texture of oysters changed during the new treatment process, compared with the traditional transportation method, the new transportation method after temporary culture, purification and other treatments will not have adverse effects on the texture of oysters.

[0091] 6.2 Preparation of microscopic tissue sections

[0092] Three oysters were randomly selected from each group and dissected to obtain 5 mm 3The adductor muscles were fixed in 4% paraformaldehyde solution and stored in a refrigerator at 4°C. When making tissue sections, the fixative was first rinsed with running water, and then dehydrated with 50%, 70%, 80%, and 95% ethanol in a gradient manner. Then, xylene was used for transparent treatment, and conventional paraffin was used for embedding and sectioning. After hematoxylin-eosin (HE) staining, histological observation was performed using an optical microscope at 100 times.

[0093] In order to further understand the effects of various treatments on oyster muscle tissue, we conducted structural and ultrastructural analyses of the oyster closing muscles in different experimental groups. Fig.11 It can be seen that the oyster closing muscle fibers in the CG group were arranged tightly and evenly, with certain gaps but small widths; the number and width of gaps in the oyster closing muscle fibers in the TG group increased to a certain extent, and there were 1 to 2 muscle fiber breaks, but the overall muscle fibers were arranged tightly and there was no obvious change in the microstructure; the changes in the microstructure of the oyster closing muscle fibers in the DT group were significantly different from those in the CK and TG groups. The number of muscle fiber gaps in this group increased and the width increased significantly, accompanied by multiple muscle fiber breaks; compared with the CK group, the oyster muscle fibers in the TT group had multiple cracks and significantly increased fiber gaps. Compared with the TC group, the width of the muscle fiber gaps in the TT group did not change much, but there were multiple obvious fiber breaks, which was consistent with the DT group. The microstructure of the oyster muscle fibers was obviously damaged.

[0094] It can be inferred that the muscle fiber damage in the purification precooling group may be due to the damage caused by the closed muscles contacting with ozone seawater during the purification process. The muscle fiber damage in the transportation control group may be caused by the dehydration and metabolic changes of the body caused by the long-term high temperature, anhydrous and hypoxic environment during transportation. The muscle fiber changes in the transportation experimental group may be due to the fact that the body was subjected to both the stress of ozone seawater and the stress of dehydration, hypoxia and high temperature during the water-free transportation.

[0095] 6.3 Antioxidant enzyme activity and nutrient determination

[0096] Six oysters were randomly selected from each group, and all viscera and closed muscle tissues of the oysters were dissected. The surface moisture of the oyster meat was wiped clean with absorbent paper, and samples of oyster gills, closed muscles, visceral masses and mantle were taken respectively, and placed in 2mL centrifuge tubes, which were quickly frozen with liquid nitrogen and stored in a -80℃ refrigerator. During the measurement, the samples were accurately weighed using a balance and placed in a 1.5ml homogenate tube, and double distilled water was added according to the mass (g): volume (mL) = 1:9, and centrifuged at 4000 rpm for 2min under ice bath conditions, and the supernatant was taken for use.

[0097] (1) During the anhydrous preservation and transportation of products, factors such as hypoxia and temperature can easily cause the body to be subjected to harmful stress and produce oxidative stress, which in turn produces oxidative free radicals (ROS) that reduce cell activity or damage function. Therefore, oxidase activity is a key indicator in the study of the physiological and biochemical mechanisms of environmental stress, among which antioxidant-related enzymes play a key role in anhydrous preservation and transportation. Common antioxidant enzymes include superoxide dismutase (SOD) and catalase (CAT), which play a key role in scavenging oxidative free radicals (ROS). The free radical metabolism in the body and the oxidative damage of tissues can be accurately reflected through the dynamic changes of the two enzymes, thereby judging the impact of anhydrous preservation and transportation on the health status of the body.

[0098] The results of antioxidant enzyme activities in different tissues of oysters at each treatment stage are as follows Fig.12 As shown in the results, there was no significant difference in the superoxide dismutase activity in the oyster closed muscle and mantle during the various treatment stages of waterless live transport (p>0.05). Compared with the closed muscle and mantle, waterless live transport and treatment methods at various stages had a greater impact on the superoxide dismutase activity in the oyster gills, among which the superoxide dismutase activity in the gills of the TC group was significantly higher than that of the CK group (p<0.05), but there was no significant difference with the TT group (p>0.05), and the superoxide dismutase activity in the TG group was significantly lower than that of the TC group and the TT group (P<0.05).

[0099] In this experiment, the activity of oxide dismutase in the TG group was lower than that in the CG group, and was significantly lower than that in the TT group, indicating that temporary storage treatment may be beneficial to alleviate the body's oxidative stress response and have a positive effect on the waterless transportation of oysters. At the same time, although there was no significant difference in the activity of oxide dismutase between the TT group and the TC group (p>0.05), the activity of oxide dismutase in the TT group was lower than that in the TC group, indicating that the pre-transportation treatment method can alleviate the oxidative stress of oysters during waterless transportation to a certain extent. In addition, some studies have pointed out that different tissues of the body have different responses to oxidative stress, which may be due to differences in different tissue structures and functions. In this experiment, the results showed that there were differences in the effects of changes in SOD enzyme activity in the gills, closed muscles and mantle of oysters, and the effects of environmental changes on gill enzyme activity were more obvious than those on closed muscles and mantle.

[0100] (2) Effects of different treatments on CAT activity in different tissues of oysters Fig.13As shown in the figure, the CAT activity of the control group in each tissue of oysters was higher than that of other groups. This may be due to the fact that the oysters had a certain stress response due to environmental changes such as hypoxia and temperature during the transportation from the breeding site to the laboratory. According to the results, the CAT activity of each TG group was lower than that of the CG group, and the CAT activity of oysters in the temporary culture group of oyster gills and closed muscles was significantly lower than that of the control group (p<0.05), which further shows that temporary culture can effectively alleviate the oxidative transport of oysters.

[0101] This study also found that the CAT activity in the purification and pre-cooling group increased compared with the temporary storage group, and the gills increased significantly (p<0.05). It is inferred that this may be because the ozone in the purification process or the temperature change during pre-cooling has a certain stimulation on the oysters, resulting in oxidative stress, thereby changing the CAT activity. Compared with the DT group, the CAT activity of the gills and closed muscles in the TT group decreased but there was no significant difference, but the CAT activity of the gills and closed muscles in the TC group was significantly higher than that in the TT group, indicating that the pre-transportation treatment method and the new packaging method are conducive to alleviating the oxidative stress damage of oysters during waterless transportation. In addition, compared with the gills and closed muscles, there was no significant difference in the CAT of the oyster mantle between the groups (p>0.05), indicating that the catalase activity in the oyster mantle is not sensitive to external stimuli.

[0102] (3) Total antioxidant capacity (T-AOC) includes other antioxidant enzymes, such as superoxide dismutase, anti-superoxide anion free radical (ASAFR), glutathione peroxidase, etc., as well as non-enzymatic antioxidants. It reflects the activity of antioxidants in organisms and is a comprehensive indicator of the body's antioxidant capacity. It can reflect the ability of the body's antioxidant defense system to cope with external stress. An increase in total antioxidant capacity indicates that the body may not be able to withstand stress.

[0103] Effects of various treatments on the total antioxidant capacity of different tissues of oysters Fig.14As shown in the figure, the results showed that each treatment had little effect on the T-AOC of different tissues of oysters. Compared with the CG group, temporary storage and purification precooling treatments had almost no effect on the total antioxidant capacity of the oyster gills and mantle, but the T-AOC of the oyster closed muscle in the DT group was higher than that in the CG and TG groups, and was significantly different from that in the TG group (p<0.05), which indicated that temporary storage could reduce the oxidative stress response of the oyster closed muscle to a certain extent, and purification precooling might have a certain effect on the oyster closed muscle. The antioxidant capacity of each tissue of oyster in TC group was higher than that in CG group and TT group, and the T-AOC in gills of TC group was significantly higher than that in CG group (p<0.05), the total antioxidant capacity of closed muscle of TC group was significantly higher than that in TT group (p<0.05), and the T-AOC of mantle of TC group was significantly higher than that in TG group (p<0.05), indicating that the traditional waterless transportation method caused oysters to suffer from external adverse stresses such as hypoxia or high temperature, resulting in an increase in total antioxidant capacity to alleviate the body damage caused by external stress; while the T-AOC of TT group did not change significantly compared with CG group (p>0.05), and decreased in closed muscle and mantle, indicating that the new waterless transportation method is highly feasible and has relatively little effect on the oxidative stress of oysters.

[0104] (4) Glycogen is the most direct and effective energy storage substance in the oyster body. When subjected to stress such as temperature and feed deficiency, the body maintains a relatively stable blood sugar concentration by breaking down glycogen. Therefore, during the waterless transportation process, the body's glycogen content will tend to decrease over time. Glycogen is also one of the main flavor substances that affect the fatness of oyster meat. Its content directly affects the flavor and nutritional quality of oysters, so it is often used as an important criterion for judging the quality of oyster meat.

[0105] Effects of various treatments on glycogen in different tissues of oysters Fig.15 As shown in the data, the glycogen content of oyster mantle was significantly higher than that of oyster gills and closing muscles, and the different treatments of temporary culture and purification pre-cooling had little effect on oysters. Although the glycogen content of TG group and DT group in gills and mantle was lower than that of the control group, there was no significant difference (p>0.05), which indicated that temporary culture and purification pre-cooling had no significant effect on the glycogen content of oysters.

[0106] In the results of this experiment, after 72 hours of waterless transportation, the glycogen content of the oyster mantle in the TC group was significantly lower than that in the CG group (p<0.05), which was consistent with the above experimental results; while the decrease in glycogen content in the TT group was less than that in the TC group, and there was no significant difference with the CG group (p>0.05), which shows that the new waterless transportation packaging method can effectively reduce the glycogen consumption of oysters compared with the traditional packaging method, and maintain the nutritional quality of oysters before and after transportation.

[0107] (5) The richness of amino acids in muscle determines the quality and nutritional value of muscle and is the most important nutritional indicator for evaluating muscle quality. The content of free amino acids is also an important factor affecting the flavor of crustaceans. Fig.16 As shown in the figure, the difference of total amino acid in oysters is manifested in different tissues. The total amino acid content in oyster closed muscle is relatively low, while the total amino acid content in gills and mantle is relatively high. The amino acid content in different tissues of organisms responds differently to the same external conditions. At the same time, whether it is oyster gills, closed muscle or mantle, the amino acid content of oysters under different treatments has no significant change (P>0.05), which shows that the amino acid composition in oysters is relatively stable, and the water-free survival treatment method before transportation has little effect on the total amino acid content of oysters, which is feasible.

[0108] In order to evaluate the effect of the new waterless transportation method on the transportation effect of oysters, the texture, quality, oxidase reaction and nutritional value of oysters were analyzed. The results showed that the new transportation method would not have a significant effect on the texture and color difference of the oyster closing muscle and soft tissue. The changes in the muscle fibers of the oyster closing muscle under the new waterless transportation method and the traditional transportation method were similar. Compared with before transportation, the gaps between the closing muscle fibers increased and a small amount of fiber breakage occurred after transportation. The study of oxidative stress kinases found that compared with the traditional transportation method, the CAT and T-AOC of oysters under the new waterless transportation pre-treatment method were relatively high, and temporary storage treatment had a significant positive effect on alleviating oxidative stress during oyster transportation. By detecting the glycogen and total amino acid content in different tissues of oysters under different transportation methods, it was found that the total amino acids of each tissue of the experimental oysters had no significant effect. Compared with the traditional transportation method, the new transportation method had little effect on glycogen.

[0109] In summary, under the new waterless live-keeping transportation method, oysters can maintain high vitality and nutritional quality, which shows that the new transportation method has certain feasibility and has a certain positive effect on reducing the mortality rate of oysters.

[0110] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for keeping oysters alive and circulating under high temperature in summer without water, characterized in that: The steps include: (1) After the cleaned fresh oysters are temporarily stored, they are purified and then transferred; (2) The oysters are packaged after the transition and circulated alive under the ecological ice temperature conditions of the oysters.

2. The method for keeping oysters alive at high temperature in summer without water as claimed in claim 1, characterized in that: In step (1), the cleaning method includes: manually or mechanically cleaning the oysters, removing debris attached to the oysters, and washing away mud, sand and mucus.

3. The method for keeping oysters alive without water in summer at high temperature as claimed in claim 1, characterized in that: In step (1), the temporary culture conditions are: a temperature of 10 to 20°C, preferably 15°C; a salinity of 28 to 30‰, and artificial seawater with a dissolved oxygen content of 7.5 to 8.0 mg / L; The holding time is 6 to 12 hours.

4. The method for keeping oysters alive at high temperature in summer without water as claimed in claim 1, characterized in that: In step (1), the purification conditions are: temperature of 10-20°C, preferably 15°C; ozone concentration of 0.1-0.5 mg / L, artificial seawater with a salinity of 28-30‰; The purification time is 20 to 60 minutes, preferably 40 minutes.

5. The method for keeping oysters alive without water in summer at high temperature as claimed in claim 1, characterized in that: In step (1), the transition conditions are: temperature of 10-20°C, preferably 15°C; salinity of 28-30‰, and artificial seawater of 7.5-8.0 mg / L of dissolved oxygen; The transition time is 2 to 3 hours, preferably 2 hours.

6. The method for keeping oysters alive without water in summer at high temperature as claimed in claim 1, characterized in that: In step (2), the method of packaging the oysters after transition and keeping them alive and circulating them under the condition of oyster ecological ice temperature includes: Put the transitioned oysters, cold storage ice packs and transitioned oysters in the insulation bag from bottom to top; seal the insulation bag and place it in an insulation box, and seal the insulation box for transportation.

7. The method for keeping oysters alive without water in summer at high temperature as claimed in claim 6, characterized in that: In step (2), the mass ratio of oysters to cold storage ice is 5 to 6:1; Or, in step (2), the cold storage ice is bulk biological ice bags.

8. The method for keeping oysters alive without water in summer at high temperature as claimed in claim 6, characterized in that: In step (2), the material of the thermal insulation box includes polyethylene; the material of the thermal insulation bag includes tin foil.

9. The method for keeping oysters alive without water in summer at high temperature as claimed in claim 1, characterized in that: In step (2), the packaging weight is 5 to 6 kg.

10. The method for keeping oysters alive without water in summer at high temperature as claimed in claim 1, characterized in that: The size of oysters is 2 to 5 pieces per pound.

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