Lactic acid bacteria preparation capable of being stored for long time at normal temperature and preparation method thereof

Abstract

The invention provides a lactic acid bacteria preparation capable of being preserved for a long time at normal temperature and a preparation method thereof, and relates to the technical field of microorganisms, the lactic acid bacteria preparation successfully realizes long-time stable preservation at normal temperature through an optimized strain combination, an elaborately-prepared protective agent and an advanced preparation process, and the lactic acid bacteria preparation can be stored for a long time at normal temperature. Compared with a lactic acid bacteria preparation in the prior art that the activity is greatly reduced in a short time at normal temperature and the storage life is limited, the preparation disclosed by the invention can be stably stored for at least 9-15 months, so that the shelf life of the product is greatly prolonged, the high survival rate and stability of lactic acid bacteria are guaranteed, and the product quality is improved by accurately controlling the activation and culture conditions of the strain. According to the present invention, the temperature, the time and the bacterial liquid concentration are determined, the good growth state and the good activity of the lactic acid bacteria at the initial stage are ensured, the optimized bacterial strain combination enhances the product performance, and the specific combination of the lactobacillus plantarum, the lactobacillus acidophilus and the bifidobacterium is adopted to achieve the synergistic effect of the different bacterial strains;

Description

Technical Field

[0001] The present invention belongs to the field of microbial technology, and more specifically, particularly relates to a lactic acid bacteria preparation that can be stored for a long time at room temperature and a preparation method thereof. Background Art

[0002] As a beneficial microorganism, lactic acid bacteria plays an important role in promoting human health and maintaining ecological balance. In the food industry, lactic acid bacteria are often used to ferment dairy products and beverages to improve the taste and nutritional value of products; in the medical field, lactic acid bacteria help regulate intestinal flora and enhance immunity; in the agricultural field, lactic acid bacteria can be used as biological fertilizers and feed additives to promote the growth of plants and animals.

[0003] However, the activity and stability of lactic acid bacteria are extremely sensitive to environmental conditions, especially temperature. At room temperature, lactic acid bacteria are easily affected by factors such as oxygen, moisture, and temperature changes, causing their activity to drop rapidly and their survival time to shorten. This characteristic greatly limits the scope of application and market promotion of lactic acid bacteria preparations.

[0004] At present, most lactic acid bacteria preparations on the market need to be stored at low temperatures, which not only increases storage and transportation costs, but also limits their use in some areas without refrigeration conditions. Moreover, even when stored at low temperatures, the shelf life of many lactic acid bacteria preparations is still relatively short, which cannot meet the needs of consumers and related industries for long-term stable supply.

[0005] In addition, the existing lactic acid bacteria preparations have poor stability at room temperature, and are prone to problems such as reduced numbers of live bacteria and changes in metabolites, which affect their functions and effects. For example, in food processing, lactic acid bacteria preparations stored at room temperature may not be able to ferment effectively, resulting in unstable product quality; in medical applications, lactic acid bacteria preparations with reduced activity may not play the expected role in regulating intestinal flora.

[0006] Therefore, developing a lactic acid bacteria preparation that can be stored for a long time at room temperature and maintain high activity and stability and its preparation method has become a key issue that needs to be solved in the current field of lactic acid bacteria applications. This will not only help reduce production costs and expand the scope of market application, but also provide strong support for the development of related industries and meet people's demand for high-quality, convenient and efficient lactic acid bacteria products. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a lactic acid bacteria preparation that can be stored for a long time at room temperature and a preparation method thereof, so as to solve the above problems.

[0008] Lactic acid bacteria preparations that can be stored for a long time at room temperature contain the following ingredients:

[0009] Lactic acid bacteria strain combination: Lactobacillus plantarum, Lactobacillus acidophilus and Bifidobacterium, and the quantity ratio of Lactobacillus plantarum, Lactobacillus acidophilus and Bifidobacterium is (1.5-2.5):(0.5-1.5):(0.5-1.5);

[0010] Protective agent: trehalose, sucrose and mannitol, the weight ratio of which is (2-4):(1-3):(0.5-1.5);

[0011] Nutrients: yeast extract and peptone, weight ratio is (0.5-1.5):(0.5-1.5).

[0012] Preferably, in the lactic acid bacteria preparation, the total viable count of lactic acid bacteria is not less than 5×10^8-2×10^9 CFU / g.

[0013] Preferably, at 25°C, the activity of lactic acid bacteria is maintained above 70%.

[0014] Preferably, the lactic acid bacteria preparation is treated in an environment with a pH value of 2.5-3.5 for 2-4 hours, and the survival rate is not less than 60%.

[0015] Preferably, the lactic acid bacteria preparation is treated in a 0.2%-0.4% bile salt environment for 3-5 hours, and the survival rate is not less than 50%.

[0016] A method for preparing a lactic acid bacteria preparation that can be stored for a long time at room temperature comprises the following steps:

[0017] S1: Activation and cultivation of bacteria: select high-quality lactic acid bacteria strains, activate and cultivate them in MRS medium at a temperature of 35-39°C for 22-26 hours until the OD600 value of the bacterial solution reaches 0.6-1.2;

[0018] S2: collecting the cultured lactic acid bacteria by centrifugation at a speed of 3500-4500 rpm for 10-20 minutes;

[0019] S3: adding protective agent, the collected bacteria are mixed with the pre-prepared protective agent solution in a volume ratio of 1:(2-4), and stirred evenly at a stirring speed of 150-250 rpm for 20-40 minutes;

[0020] S4: Drying treatment, using vacuum freeze drying technology to dry the mixed solution, the drying time T = K1 × V, where T is the drying time (unit: hour), K1 is the drying time coefficient (value 0.4-1.2), and V is the volume of the mixed solution (unit: liter);

[0021] S5: packaging the preparation, packaging the dried lactic acid bacteria preparation in an aluminum foil bag.

[0022] Preferably, in S1, the pH value of the MRS culture medium is 6.0-6.8.

[0023] Preferably, in S3, the stirring speed calculation formula is V=K2×(M1+M2), wherein V is the stirring speed (unit: revolutions per minute), K2 is the stirring speed coefficient (range: 80-180), M1 is the bacterial weight (unit: gram), and M2 is the protective agent solution weight (unit: gram).

[0024] Preferably, in S4, the drying time coefficient K1 takes a value of 0.6-1.0.

[0025] Preferably, in S5, the thickness of the aluminum foil bag is 0.08-0.25 mm.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. Significantly improve the shelf life at room temperature: The lactic acid bacteria preparation of the present invention has successfully achieved long-term stable storage at room temperature (25°C) through optimized strain combinations, carefully formulated protective agents and advanced preparation processes. Compared with the prior art where the activity of lactic acid bacteria preparations at room temperature drops significantly in a short period of time and the shelf life is limited, the preparation of the present invention can be stably stored for at least 9-15 months, greatly extending the shelf life of the product. This significant advantage not only reduces the dependence on low-temperature storage conditions and reduces storage and transportation costs, but also increases the market circulation and availability of the product, creating favorable conditions for the widespread application of lactic acid bacteria preparations. The long-term room temperature storage ability enables lactic acid bacteria preparations to be more conveniently used in various scenarios, whether it is distribution in remote areas or at sales points without refrigeration facilities. The quality and activity of the product can be guaranteed, thereby meeting the needs of more consumers and expanding the market coverage.

[0028] 2. Ensure the high survival rate and stability of lactic acid bacteria: By precisely controlling the conditions for activation and cultivation of the strains, such as temperature, time and bacterial liquid concentration, ensure that lactic acid bacteria have a good growth state and vitality in the initial stage. In the process of collecting bacteria, the appropriate centrifugal speed and time are used to minimize the damage to the bacteria and retain its integrity and activity. The unique protective agent addition steps, including the selection of protective agent types and proportions, provide an effective protective barrier for lactic acid bacteria and reduce the adverse effects of the external environment on the bacteria. In the drying process, the application of vacuum freeze-drying technology and the precise calculation of drying time further reduce the damage to the activity of lactic acid bacteria and maintain its physiological function and metabolic capacity. The selection of appropriate packaging materials during the packaging process effectively blocks the invasion of external factors such as oxygen, moisture and microorganisms, creating a stable microenvironment for lactic acid bacteria. The combined effect of these measures enables lactic acid bacteria to maintain a high survival rate and stability in the preparation, ensuring the quality and efficacy of the product throughout the shelf life.

[0029] 3. Optimized strain combination enhances product performance: A specific combination of Lactobacillus plantarum, Lactobacillus acidophilus and Bifidobacterium is used to bring into play the synergistic effect between different strains. This synergistic effect not only enhances the tolerance of lactic acid bacteria preparations to the gastrointestinal environment, such as acid resistance and bile salt resistance, enabling them to survive and function under the action of gastric acid and bile, but also improves their ability to regulate the balance of intestinal flora. The optimized strain combination also improves the adaptability of lactic acid bacteria preparations in different application scenarios. Whether used for food processing, feed additives or health care product manufacturing, they can show excellent performance and efficacy, providing strong support for the quality improvement and functional optimization of related products.

[0030] 4. Expand the application field of lactic acid bacteria: Since the problem of room temperature storage is solved, the lactic acid bacteria preparation of the present invention can be more widely used in the food industry. In the production of products such as yogurt and beverages, there is no need for complex cold chain transportation and storage, which reduces production costs, while ensuring the activity and function of lactic acid bacteria in the product, providing consumers with healthier and higher-quality food choices. In the field of feed, as an additive, it can improve animal intestinal health, increase feed utilization and animal growth performance, reduce the occurrence of diseases, and bring economic and environmental benefits to the breeding industry. In the health care product market, it can regulate the balance of human intestinal flora, enhance immunity, prevent and improve a variety of intestinal-related diseases, meet people's pursuit of health, and improve the quality of life.

[0031] 5. Reduce costs and improve economic benefits: The room temperature storage characteristics reduce the demand for refrigeration equipment and cold chain logistics, and significantly reduce energy consumption and cost investment in storage and transportation. At the same time, the extended shelf life reduces product losses due to expiration or reduced activity, improves the product's qualification rate and utilization rate, and the stable high survival rate and performance ensure the quality consistency of the product, reducing the cost of quality control and testing. In the production process, the optimized preparation method improves production efficiency, reduces labor and raw material waste, and further improves economic benefits. The wide range of applications and the increase in market demand have brought more business opportunities and profit margins to enterprises, and promoted the development and innovation of related industries.

[0032] 6. Promote technological progress in the industry: This invention provides an innovative solution for the field of lactic acid bacteria preparations, breaks through the technical bottleneck of room temperature storage, and sets a new benchmark for the industry. This will encourage other researchers and companies to increase their R&D investment in related technical fields, promote technological progress and product upgrades in the entire industry, and promote the cross-integration of microbial preparation technology with other related fields such as food science, animal nutrition and medicine, laying the foundation for the development of more efficient, safer and more innovative products and applications, and is expected to lead the industry in a healthier and more sustainable direction.

[0033] 7. Environmental friendliness and sustainable development: It reduces the use of refrigeration equipment, reduces dependence on refrigerants such as Freon, reduces damage to the ozone layer and greenhouse gas emissions, and has positive environmental significance. Lower energy consumption and resource waste are in line with the concept of sustainable development, and help build a green, low-carbon production and consumption model, and promote the sustainable development of the entire society.

[0034] 8. Enhance consumer trust and market competitiveness: Provide consumers with a convenient and reliable lactic acid bacteria product, and enhance consumers' trust and acceptance of lactic acid bacteria preparations. Stable quality and efficacy can meet consumers' needs for health and quality, enhance brand image and reputation. In the market competition, lactic acid bacteria preparations with room temperature storage advantages and excellent performance will be more competitive, which can help enterprises stand out in the fierce market competition, occupy a larger market share, and promote the healthy development and healthy competition of the industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the components and preparation method of the present invention. DETAILED DESCRIPTION

[0036] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0037] Lactic acid bacteria preparations are increasingly used in the fields of food, medicine and feed, but the problem of storage at room temperature has always restricted their wider application. The present invention aims to provide a lactic acid bacteria preparation that can be stored for a long time at room temperature and a preparation method thereof, and verify its effectiveness and superiority through a series of experiments and examples.

[0038] Experimental materials: lactic acid bacteria strains (Lactobacillus plantarum, Lactobacillus acidophilus, Bifidobacterium), culture medium (MRS culture medium), protective agents (trehalose, sucrose, mannitol), nutrients (yeast extract, peptone), other reagents and materials (hydrochloric acid, bile salt, aluminum foil bag);

[0039] Experimental equipment: constant temperature incubator, centrifuge, vacuum freeze dryer, pH meter, and viable bacteria counter.

[0040] The method is as follows: the lactic acid bacteria strains are inoculated into MRS culture medium respectively, cultured in a constant temperature incubator at 37°C for 24 hours for activation, the activated strains are inoculated into fresh MRS culture medium according to a certain proportion, and the culture is continued until the OD600 value of the bacterial solution reaches a specified range, the cultured bacterial solution is centrifuged at 4000 rpm for 15 minutes, the bacteria are collected, a protective agent solution is prepared according to a predetermined proportion, the collected bacteria are mixed with the protective agent solution in a volume ratio, the mixture is stirred at a stirring speed of 200 rpm for 30 minutes, the mixed solution is dried by vacuum freeze drying technology, the drying time is calculated according to a formula, and the dried lactic acid bacteria preparation is packaged in an aluminum foil bag.

[0041] Embodiment 1:

[0042] Lactobacillus plantarum: Lactobacillus acidophilus: Bifidobacterium = 1.5:1:0.5, trehalose: sucrose: mannitol = 2:1:0.5, culture temperature 35°C, culture time: 22 hours, OD600 value: 0.6, centrifugal speed 3500 rpm, time: 10 minutes, bacteria: protective agent solution = 1:2, stirring speed: 150 rpm, time: 20 minutes, drying time coefficient K1 = 0.4, aluminum foil bag thickness 0.08 mm.

[0043] Embodiment 2:

[0044] Lactobacillus plantarum: Lactobacillus acidophilus: Bifidobacterium = 2:1:1, trehalose: sucrose: mannitol = 3:2:1, culture temperature 37°C, culture time: 24 hours, OD600 value: 0.8, centrifugal speed 4000 rpm, time: 15 minutes, bacteria: protective agent solution = 1:3, stirring speed: 200 rpm, time: 30 minutes, drying time coefficient K1 = 0.8, aluminum foil bag thickness 0.15 mm.

[0045] Embodiment 3:

[0046] Lactobacillus plantarum: Lactobacillus acidophilus: Bifidobacterium = 2.5:1.5:1.5, trehalose: sucrose: mannitol = 4:3:1.5, culture temperature 39°C, culture time: 26 hours, OD600 value: 1.2, centrifugal speed 4500 rpm, time: 20 minutes, bacteria: protective agent solution = 1:4, stirring speed: 250 rpm, time: 40 minutes, drying time coefficient K1 = 1.2, aluminum foil bag thickness 0.25 mm.

[0047] Example 4, as control group 1:

[0048] The lactic acid bacteria strain combination only used Lactobacillus plantarum, trehalose: sucrose: mannitol = 1:1:1, culture temperature 37°C, culture time: 24 hours, OD600 value: 0.8, centrifugation speed 4000 rpm, time: 15 minutes, bacteria: protective agent solution = 1:3, stirring speed: 200 rpm, time: 30 minutes, drying time coefficient K1 = 0.8, and aluminum foil bag thickness 0.15 mm.

[0049] Example 5, as control group 2:

[0050] Lactobacillus plantarum: Lactobacillus acidophilus: Bifidobacterium = 2:1:1, only trehalose is used as the protective agent, the culture temperature is 37°C, the culture time is 24 hours, the OD600 value is 0.8, the centrifugal speed is 4000 rpm, the time is 15 minutes, the bacteria: the protective agent solution = 1:3, the stirring speed is 200 rpm, the time is 30 minutes, the drying time coefficient K1 is 0.8, and the thickness of the aluminum foil bag is 0.15 mm.

[0051] Verification experiment:

[0052] 1. Determination of viable count: The viable count of the lactic acid bacteria preparation of each embodiment was determined at 0 day, 1 month, 3 months, 6 months, 9 months and 12 months after preparation. The results are shown in the following table:

[0053]

[0054] 2. Acid resistance test: The lactic acid bacteria preparations of each embodiment were placed in an environment with a pH value of 2.5, 3.0 and 3.5 for 2 hours, 3 hours and 4 hours, respectively, and the survival rate was measured. The results are shown in the following table:

[0055]

[0056] 3. Bile salt tolerance test: The lactic acid bacteria preparations of each embodiment were placed in 0.2%, 0.3% and 0.4% bile salt environments for 3 hours, 4 hours and 5 hours, respectively, and the survival rates were measured. The results are shown in the following table:

[0057]

[0058] 4. Room temperature storage stability test: The lactic acid bacteria preparations of each example were stored at room temperature (25° C.) and their appearance, odor and viable bacteria count were observed. The results are shown in the following table:

[0059]

[0060] By analyzing and comparing the experimental results of the five embodiments, the following conclusions can be drawn:

[0061] 1. From the results of viable bacteria count determination, the viable bacteria count of Examples 1-3 remained at a relatively high level during the 12-month storage period, while the viable bacteria count of the control group Examples 4 and 5 decreased significantly. This shows that a reasonable combination of lactic acid bacteria strains and protective agent ratio are crucial to maintaining the viable bacteria count;

[0062] 2. In the acid resistance experiment, the survival rates of Examples 1-3 after being treated for different time periods in a lower pH environment were significantly higher than those of the control group, indicating that the preparation of the present invention has good acid resistance;

[0063] 3. The results of the bile salt tolerance test showed that the survival rates of Examples 1-3 after being treated for different periods of time in an environment with a higher bile salt concentration were better than those of the control group, which demonstrated the good adaptability of the preparation of the present invention in a bile salt environment;

[0064] 4. The room temperature storage stability experiment showed that the stability of Examples 1-3 in appearance, odor and viable bacteria count was better than that of the control group, further proving that the lactic acid bacteria preparation of the present invention has excellent storage performance at room temperature.

[0065] In summary, the lactic acid bacteria preparation and preparation method of the present invention effectively solves the problem that lactic acid bacteria are difficult to preserve for a long time at room temperature by optimizing the strain combination, protective agent formula and process parameters, improves the survival rate and stability of lactic acid bacteria, and has significant advantages and application value.

[0066] The lactic acid bacteria preparation and preparation method thereof which can be stored for a long time at room temperature of the present invention have shown excellent performance through a series of experiments and examples. In future applications, it is expected to provide more convenient, efficient and stable lactic acid bacteria preparation products for the fields of food, medicine and feed, and promote the development of related industries.

[0067] The lactic acid bacteria preparation of the present invention has successfully achieved long-term stable storage at room temperature (25°C) through optimized strain combinations, carefully formulated protective agents and advanced preparation processes. Compared with the prior art where the activity of lactic acid bacteria preparations at room temperature drops significantly in a short period of time and the shelf life is limited, the preparation of the present invention can be stably stored for at least 9-15 months, greatly extending the shelf life of the product. This significant advantage not only reduces the dependence on low-temperature storage conditions and reduces storage and transportation costs, but also increases the market circulation and availability of the product, creating favorable conditions for the widespread application of lactic acid bacteria preparations. The ability to store at room temperature for a long time enables lactic acid bacteria preparations to be more conveniently used in various scenarios, whether it is distribution in remote areas or at sales points without refrigeration facilities, the quality and activity of the product can be guaranteed, thereby meeting the needs of more consumers and expanding market coverage.

[0068] By precisely controlling the conditions for activation and cultivation of the strains, such as temperature, time, and bacterial liquid concentration, it is ensured that the lactic acid bacteria have a good growth state and vitality at the initial stage. In the process of collecting bacteria, the appropriate centrifugal speed and time are used to minimize the damage to the bacteria and retain its integrity and activity. The unique protective agent addition step, including the selection of protective agent types and proportions, provides an effective protective barrier for lactic acid bacteria and reduces the adverse effects of the external environment on the bacteria. In the drying process, the application of vacuum freeze-drying technology and the precise calculation of drying time further reduce the damage to the activity of lactic acid bacteria and maintain its physiological function and metabolic capacity. The selection of appropriate packaging materials during the packaging process effectively blocks the invasion of external factors such as oxygen, moisture and microorganisms, creating a stable microenvironment for lactic acid bacteria. The combined effect of these measures enables lactic acid bacteria to maintain a high survival rate and stability in the preparation, ensuring the quality and efficacy of the product throughout the shelf life.

[0069] The specific combination of Lactobacillus plantarum, Lactobacillus acidophilus and Bifidobacterium is used to bring into play the synergistic effect between different strains. This synergistic effect not only enhances the tolerance of lactic acid bacteria preparations to the gastrointestinal environment, such as acid resistance and bile salt resistance, enabling them to survive and function under the action of gastric acid and bile, but also improves their ability to regulate the balance of intestinal flora. The optimized strain combination also improves the adaptability of lactic acid bacteria preparations in different application scenarios. Whether used in food processing, feed additives or health care product manufacturing, they can show excellent performance and efficacy, providing strong support for the quality improvement and functional optimization of related products.

[0070] Since the problem of room temperature storage is solved, the lactic acid bacteria preparation of the present invention can be more widely used in the food industry. In the production of products such as yogurt and beverages, there is no need for complex cold chain transportation and storage, which reduces production costs, while ensuring the activity and function of lactic acid bacteria in the product, providing consumers with healthier and higher-quality food choices. In the field of feed, as an additive, it can improve the intestinal health of animals, increase the utilization rate of feed and the growth performance of animals, reduce the occurrence of diseases, and bring economic and environmental benefits to the breeding industry. In the health care product market, it can regulate the balance of human intestinal flora, enhance immunity, prevent and improve a variety of intestinal-related diseases, meet people's pursuit of health, and improve the quality of life.

[0071] The room temperature storage feature reduces the demand for refrigeration equipment and cold chain logistics, significantly reducing energy consumption and cost investment in storage and transportation. At the same time, the extended shelf life reduces product losses due to expiration or reduced activity, improves product qualification rate and utilization rate, and the stable high survival rate and performance ensure product quality consistency and reduce quality control and testing costs. In the production process, the optimized preparation method improves production efficiency, reduces labor and raw material waste, and further improves economic benefits. The wide range of applications and increased market demand have brought more business opportunities and profit margins to enterprises, and promoted the development and innovation of related industries.

[0072] The present invention provides an innovative solution for the field of lactic acid bacteria preparations, breaks through the technical bottleneck of room temperature storage, and sets a new benchmark for the industry. This will encourage other researchers and enterprises to increase R&D investment in related technical fields, promote technological progress and product upgrades in the entire industry, promote the cross-integration of microbial preparation technology with other related fields such as food science, animal nutrition and medicine, and lay the foundation for the development of more efficient, safer and more innovative products and applications. It is expected to lead the industry in a healthier and more sustainable direction, reduce the use of refrigeration equipment, reduce dependence on refrigerants such as Freon, reduce damage to the ozone layer and greenhouse gas emissions, and have positive environmental significance. Lower energy consumption and resource waste are in line with the concept of sustainable development, which helps to build a green and low-carbon production and consumption model and promote the sustainable development of the entire society.

[0073] The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. A lactic acid bacteria preparation that can be stored for a long time at room temperature, characterized in that: Contains the following ingredients: Lactic acid bacteria strain combination: Lactobacillus plantarum, Lactobacillus acidophilus and Bifidobacterium, and the quantity ratio of Lactobacillus plantarum, Lactobacillus acidophilus and Bifidobacterium is (1.5-2.5):(0.5-1.5):(0.5-1.5); Protective agent: trehalose, sucrose and mannitol, the weight ratio of which is (2-4):(1-3):(0.5-1.5); Nutrients: yeast extract and peptone, weight ratio is (0.5-1.5):(0.5-1.5).

2. The lactic acid bacteria preparation that can be stored for a long time at room temperature according to claim 1, characterized in that In the lactic acid bacteria preparation, the total viable count of lactic acid bacteria is not less than 5×10^8-2×10^9 CFU / g.

3. The lactic acid bacteria preparation that can be stored for a long time at room temperature according to claim 1, characterized in that At 25°C, the activity of lactic acid bacteria remains above 70%.

4. The lactic acid bacteria preparation that can be stored for a long time at room temperature according to claim 1, characterized in that The lactic acid bacteria preparation is treated in an environment with a pH value of 2.5-3.5 for 2-4 hours, and the survival rate is not less than 60%.

5. The lactic acid bacteria preparation that can be stored for a long time at room temperature according to claim 1, characterized in that: The lactic acid bacteria preparation is treated in a 0.2%-0.4% bile salt environment for 3-5 hours, and the survival rate is not less than 50%.

6. A method for preparing a lactic acid bacteria preparation that can be stored for a long time at room temperature as claimed in claim 1, characterized in that: The following steps are involved: S1: Activation and cultivation of bacteria: select high-quality lactic acid bacteria strains, activate and cultivate them in MRS medium at a temperature of 35-39°C for 22-26 hours until the OD600 value of the bacterial solution reaches 0.6-1.2; S2: collecting the cultured lactic acid bacteria by centrifugation at a speed of 3500-4500 rpm for 10-20 minutes; S3: adding protective agent, the collected bacteria are mixed with the pre-prepared protective agent solution in a volume ratio of 1:(2-4), and stirred evenly at a stirring speed of 150-250 rpm for 20-40 minutes; S4: Drying treatment, using vacuum freeze drying technology to dry the mixed solution, the drying time T = K1 × V, where T is the drying time, K1 is the drying time coefficient, and V is the volume of the mixed solution; S5: packaging the preparation, packaging the dried lactic acid bacteria preparation in an aluminum foil bag.

7. The method for preparing a lactic acid bacteria preparation that can be stored for a long time at room temperature according to claim 6, characterized in that: In the S1, the pH value of the MRS culture medium is 6.0-6.

8.

8. The method for preparing a lactic acid bacteria preparation that can be stored for a long time at room temperature according to claim 6, characterized in that: In S3, the stirring speed calculation formula is V=K2×(M1+M2), wherein V is the stirring speed, K2 is the stirring speed coefficient, M1 is the weight of the bacteria, and M2 is the weight of the protective agent solution.

9. The method for preparing a lactic acid bacteria preparation that can be stored for a long time at room temperature according to claim 6, characterized in that: In S4, the drying time coefficient K1 takes a value of 0.6-1.

0.

10. The method for preparing a lactic acid bacteria preparation that can be stored for a long time at room temperature according to claim 6, characterized in that: In S5, the thickness of the aluminum foil bag is 0.08-0.25 mm.

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