Fruit and vegetable fresh-keeping method for inhibiting microorganisms through magnetic field treatment

Abstract

The invention relates to the technical field of fruit and vegetable preservation, and discloses a fruit and vegetable preservation method for inhibiting microorganisms through magnetic field treatment, which comprises the following operation steps: putting precooled and vacuum packaged fruit and vegetable products into a magnetic field treatment device comprising a magnetic field generator, a control system and a fruit and vegetable treatment cavity for magnetic field treatment, the magnetic field intensity is accurately controlled within the range of 50-300 millitesla, the frequency fluctuates between 5-50 Hz, and the action time is set to be 2-6 hours. By systematically comparing growth conditions of microorganisms in fruits and vegetables under different parameter combinations, a magnetic field parameter combination capable of effectively inhibiting microorganism breeding and keeping fruit and vegetable cell structures complete is finally screened out. The fruit and vegetable fresh-keeping method for inhibiting microorganisms through magnetic field treatment aims to overcome the limitation of the existing physical, chemical and biological fresh-keeping technology, and provides a fruit and vegetable fresh-keeping solution which is more efficient, more environmentally friendly and wide in applicability.

Description

Technical Field

[0001] The invention relates to the technical field of fruit and vegetable preservation, and in particular to a fruit and vegetable preservation method for inhibiting microorganisms through magnetic field treatment. Background Art

[0002] Fruit and vegetable preservation is an extremely complex and crucial process. It has a profound impact on maintaining the quality, nutritional value, market life of fruits and vegetables, and the health of consumers. Given the diversity of fruit and vegetable types, including fruits, vegetables, meat, seafood, and grains, each type of fruit and vegetable presents unique characteristics in terms of preservation needs and technical applications. The main function of preservation technology is to delay the spoilage process of fruits and vegetables, ensure that their color, taste, flavor and nutritional value are maintained for a long time, thereby improving consumer satisfaction with the food. At the same time, through scientific preservation treatment, fruits and vegetables can remain fresh for a longer time in the market, which not only extends the sales cycle and brings higher income to farmers, but also effectively reduces the waste caused by corruption.

[0003] Existing food preservation technologies cover three major methods: physical, chemical and biological. However, these methods all have certain defects and shortcomings. Physical preservation methods, such as low-temperature preservation, modified atmosphere packaging and vacuum preservation, mainly rely on changing the storage environment of food to extend its shelf life. Low-temperature preservation slows down the spoilage of food by lowering the storage temperature, but this method has high energy consumption, and long-term low-temperature storage may cause changes in food texture and taste. Modified atmosphere packaging inhibits the growth of microorganisms by adjusting the gas composition in the package, but the operation is relatively complicated and requires special packaging equipment and materials. Vacuum preservation reduces food oxidation by extracting the air in the package, but it also has the problems of high equipment cost and inconvenient operation. Chemical preservation relies on preservatives to inhibit microbial growth. The growth and reproduction of organisms, thereby extending the shelf life of food, although this method is effective, long-term use of chemical preservatives is likely to produce chemical residues in food, these residues may cause potential harm to human health, in addition, the use of chemical preservatives may also affect the flavor and taste of food, biological preservation method uses natural substances or microbial metabolites to inhibit the growth of microorganisms in food, so as to achieve the purpose of preservation, this method is relatively environmentally friendly, but the cost is high, and the scope of application is limited, for example, some biological preservatives may only be suitable for specific types of food, or need to be under specific storage conditions to play the best effect, so there are certain defects, so a magnetic field treatment to inhibit microorganisms in fruit and vegetable preservation method is proposed to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to overcome the limitations of existing physical, chemical and biological preservation technologies, and to provide a more efficient, environmentally friendly and widely applicable fruit and vegetable preservation solution, and to propose a fruit and vegetable preservation method using a magnetic field to treat and inhibit microorganisms.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A method for preserving fruits and vegetables by treating with a magnetic field to inhibit microorganisms, comprising the following steps:

[0007] S10, Magnetic field parameter optimization and determination stage: A large number of experiments were conducted to verify the best magnetic field parameter combination for specific types of fruits and vegetables. During the experiment, the magnetic field intensity was precisely controlled within the range of 50 to 300 millitesla, the frequency fluctuated between 5 and 50 Hz, and the action time was set to 2 to 6 hours. By systematically comparing the growth of microorganisms in fruits and vegetables under different parameter combinations, a magnetic field parameter combination that can effectively inhibit the growth of microorganisms while maintaining the integrity of the fruit and vegetable cell structure was finally selected;

[0008] S20, fruit and vegetable pretreatment stage: Before the magnetic field treatment, a strict pretreatment process was implemented for the fruits and vegetables. The pretreatment steps included lowering the temperature of the fruits and vegetables to a state close to the freezing point but avoiding freezing. The precooling treatment was aimed at reducing the respiration and water evaporation rate of the fruits and vegetables, thereby extending their shelf life. At the same time, vacuum packaging technology was introduced to effectively remove oxygen in the packaging, build a low-oxygen environment, and further inhibit the growth of microorganisms. The synergistic effect of precooling treatment and vacuum packaging provided initial conditions for subsequent treatments.

[0009] S30, magnetic field treatment device design and application stage: In order to meet the preservation requirements of different types of fruits and vegetables, a special magnetic field treatment device with adjustable magnetic field strength and frequency is designed. The device consists of three parts: a magnetic field generator, a control system, and a fruit and vegetable treatment chamber. The magnetic field generator is responsible for generating a magnetic field with specific parameters, and the control system is used to accurately adjust these parameters to ensure the optimization of the treatment effect. The fruit and vegetable treatment chamber is used to accommodate the fruits and vegetables to be treated. Its design ensures that the magnetic field can act evenly and fully on the surface of the fruits and vegetables. During the magnetic field treatment process, the pre-treated fruits and vegetables are placed in the treatment chamber and accurately treated according to the previously determined magnetic field parameters to achieve effective inhibition of microorganisms;

[0010] S40. Subsequent storage management and testing stage: After magnetic field treatment, fruits and vegetables are placed in a low-temperature, low-humidity, low-oxygen storage environment, where the temperature is precisely controlled within the range of 0 to 5°C and the humidity is maintained between 85% and 90%. This storage condition can further inhibit the growth of microorganisms and maintain the quality of fruits and vegetables. At the same time, in order to comprehensively evaluate the preservation effect, the microbial content of fruits and vegetables, including the number of E. coli, the number of molds, etc., as well as quality indicators such as hardness, color, taste, etc., are regularly tested. According to the test results, the magnetic field treatment parameters and storage conditions are adjusted in time to ensure the continuity and stability of the preservation effect.

[0011] Based on the above technical solution, the present invention can also be improved as follows.

[0012] Furthermore, the step S10 specifically includes the following steps:

[0013] S101. Experimental design and planning. Clarify the magnetic field parameters that need to be optimized, including magnetic field intensity, frequency and action time. According to the experimental requirements, select representative fruit and vegetable species as experimental objects to ensure the freshness and consistency of the samples. Based on previous research and literature research, set the magnetic field intensity to be in the range of 50 to 300 millitesla, the frequency to be between 5 and 50 Hz, and the action time to be between 2 and 6 hours.

[0014] S102. Experimental preparation: ensure that the magnetic field treatment device can accurately adjust the magnetic field intensity, frequency and action time to meet the experimental requirements; prepare tools for detecting the growth of microorganisms in fruits and vegetables, such as microscopes, colony counters, culture media, etc.; pre-treat the selected fruit and vegetable samples, such as washing, peeling, slicing, etc., to ensure the consistency and accuracy of the experiment;

[0015] S103, data collection and analysis, record in detail the growth of microorganisms in fruits and vegetables under each parameter combination, including colony count, growth rate, etc., use statistical methods to analyze the collected data, and find out the magnetic field parameter combination that can effectively inhibit the growth of microorganisms while maintaining the integrity of the fruit and vegetable cell structure.

[0016] Furthermore, the step S20 specifically includes the following steps:

[0017] S201, precooling treatment, according to the type, shape and size of fruits and vegetables, select the most suitable precooling method, ensure the cleanliness and hygiene of the precooling equipment, and set it to a temperature close to the freezing point but avoiding freezing, preliminarily wash the fruits and vegetables, remove the dirt and impurities on the surface, and ensure the integrity of the fruits and vegetables to avoid damage, put the fruits and vegetables into the precooling equipment, set the appropriate precooling time according to the type and quantity of fruits and vegetables, until the temperature of the fruits and vegetables drops to a state close to the freezing point but avoiding freezing, and continuously monitor the temperature of the fruits and vegetables during the precooling process to ensure that the temperature is uniform and within the set range;

[0018] S202, vacuum packaging technology, select vacuum packaging materials suitable for fruits and vegetables, ensure that the materials have good air permeability and sealing properties, further arrange the pre-cooled fruits and vegetables, such as removing excess moisture, and cutting them if necessary, to ensure space utilization and oxygen removal effect in the package, put the arranged fruits and vegetables into vacuum packaging bags, use vacuum packaging machines to package them, ensure that oxygen in the package is effectively removed, and build a low-oxygen environment. After packaging, check the sealing of the packaging bags to ensure that there is no leakage or damage, and store the vacuum-packed fruits and vegetables under appropriate temperature and humidity conditions to maintain their freshness and extend the shelf life;

[0019] S203. Synergistic effect and subsequent preparation. During the pretreatment process, the status and changes of fruits and vegetables are continuously monitored, and relevant data such as temperature, humidity, oxygen content, etc. are recorded. The effect of pretreatment is evaluated by checking the appearance, texture and smell of fruits and vegetables to ensure that the fruits and vegetables are in the best condition. After the pretreatment is completed, the fruits and vegetables are prepared for subsequent magnetic field treatment.

[0020] Furthermore, in step S201, the precooling methods include cold air cooling and cold storage cooling. Cold air cooling precooling is more suitable for fruits and vegetables with thin skin and easy to be damaged, such as strawberries, grapes and lettuce. When the number of fruits and vegetables is large or the shape is large and cold air needs to be blown evenly, this method is more suitable. In addition, when the temperature of fruits and vegetables is moderate and gentle cooling is required, cold air cooling precooling can also be selected. Cold storage cooling precooling is suitable for most fruits and vegetables, especially those that need to be stored for a long time. When the number of fruits and vegetables is large and they need to be kept at a low temperature for a long time, this method is particularly suitable.

[0021] Furthermore, the step S30 specifically includes the following steps:

[0022] S301. Device design and assembly. According to the required magnetic field strength and frequency range, design the core components of the magnetic field generator, such as electromagnets or permanent magnets, determine the size, shape and power of the magnetic field generator to ensure that it can generate a stable and adjustable magnetic field, develop a control system that can accurately adjust the magnetic field strength and frequency, and the control system should include a user-friendly interface to facilitate operators to set and monitor magnetic field parameters. According to the type and size of fruits and vegetables, design the size and shape of the fruit and vegetable processing chamber, ensure that the interior of the processing chamber is smooth and easy to clean to avoid contamination of fruits and vegetables, design appropriate ventilation or cooling systems to prevent excessive heat from being generated during the processing process, assemble the magnetic field generator, control system and fruit and vegetable processing chamber, ensure that the connection between the various parts is tight and stable, and perform necessary debugging and testing to ensure that the device can work properly.

[0023] S302, setting and optimizing magnetic field parameters, setting initial values ​​of magnetic field strength and frequency according to previous research or experimental results, which should be able to cover the preservation requirements of most types of fruits and vegetables, and subjecting different types of fruits and vegetables to magnetic field treatment through experiments or simulations to observe their effects on microbial inhibition, and adjusting the parameters of magnetic field strength and frequency according to the experimental results to find the best preservation effect;

[0024] S303, pre-processing fruits and vegetables and operating the device, classifying and arranging the fruits and vegetables to ensure that their surfaces are clean and easy to handle, placing the fruits and vegetables at appropriate locations in the fruit and vegetable processing chamber according to their types and sizes, turning on the control system, setting the required magnetic field strength and frequency parameters, starting the magnetic field generator, and starting to generate a magnetic field. During the processing, pay close attention to the display data of the control system to ensure that the magnetic field parameters are stable and meet expectations. If any abnormality is found, the processing should be stopped immediately and the device should be checked. When the predetermined processing time or effect is reached, the magnetic field generator is turned off, the fruit and vegetable processing chamber is opened, and the processed fruits and vegetables are taken out;

[0025] S304. Subsequent processing and evaluation: Carry out necessary cleaning, disinfection or packaging of the processed fruits and vegetables to ensure that the processed fruits and vegetables meet food safety and hygiene standards. Evaluate the effect of magnetic field treatment on the preservation of fruits and vegetables through laboratory tests or consumer feedback. Based on the evaluation results, further optimize the magnetic field parameters and processing procedures.

[0026] Furthermore, during the processing, key information such as magnetic field parameters, processing time, types and quantities of fruits and vegetables are recorded, and the preservation effect of the processed fruits and vegetables is evaluated. Through data analysis, key factors affecting the preservation effect are found out, providing data support for further optimization of magnetic field parameters and processing procedures.

[0027] Furthermore, the step S40 specifically includes the following steps:

[0028] S401, storage environment setting and monitoring, accurately control the temperature of the storage environment within the range of 0 to 5°C, maintain the humidity of the storage environment between 85% and 90%, and equip with humidity sensors and displays to monitor and record humidity data in real time, reduce the oxygen concentration in the storage environment by nitrogen filling or other means to further inhibit the growth of microorganisms and the respiration of fruits and vegetables. This usually requires the use of professional gas conditioning equipment, equipped with oxygen concentration sensors and displays, regular inspections of the storage environment, check whether the equipment is operating normally, record the temperature, humidity and oxygen concentration data of the storage environment, and conduct regular analysis to evaluate whether the storage environment is stable, and make necessary adjustments based on the analysis results;

[0029] S402. Fruit and vegetable quality inspection and evaluation. Regularly randomly sample stored fruits and vegetables to ensure that the samples are representative. Use professional microbial inspection equipment and methods, such as microscopic observation, culture method, PCR method, etc., to inspect the number of E. coli, mold count and other microbial contents in the samples. Record the inspection results and conduct regular analysis to evaluate the changing trend of microbial content. Perform necessary treatment according to the analysis results, such as strengthening cleaning, disinfection or adjusting magnetic field treatment parameters. Use equipment such as hardness tester to inspect the hardness of fruits and vegetables to evaluate their freshness and texture. Use equipment such as colorimeter to inspect the color of fruits and vegetables to evaluate their appearance quality. Use sensory evaluation or instrumental analysis to inspect the taste of fruits and vegetables, such as sweetness, acidity, crispness, etc. Record the inspection results and conduct regular analysis to evaluate the changing trend of fruit and vegetable quality. Perform necessary treatment according to the analysis results, such as adjusting storage conditions or magnetic field treatment parameters.

[0030] S403, parameter adjustment and optimization, according to the test results of microbial content and quality indicators, analyze the influence of magnetic field treatment parameters on the preservation effect, such as magnetic field intensity, frequency and treatment time, etc., according to the analysis results, adjust the magnetic field treatment parameters to optimize the preservation effect, according to the change trend of fruit and vegetable quality and the monitoring data of storage environment, analyze the influence of storage conditions on the preservation effect, such as temperature, humidity and oxygen concentration, etc., according to the analysis results, adjust the storage conditions to optimize the preservation effect;

[0031] S404. Record and report. Save all data, records and reports related to storage management and testing, including temperature, humidity, oxygen concentration data, microbial content test results, quality index test results, magnetic field treatment parameter adjustment records, etc. Regularly prepare storage management and testing reports to summarize the stability of the storage environment, the changing trend of microbial content, the changes in fruit and vegetable quality, and the adjustments of magnetic field treatment parameters and storage conditions.

[0032] Furthermore, in step S40, a complete data management and analysis system needs to be established to store, query and analyze storage environment data, microbial detection results, quality assessment data, magnetic field processing parameters and other information, and use data analysis tools such as statistical software and machine learning algorithms to conduct in-depth analysis of the collected data to explore the patterns and trends behind the data, so as to provide a scientific basis for optimizing storage conditions, magnetic field processing parameters and detection strategies.

[0033] Compared with the prior art, the technical solution of this application has the following beneficial technical effects:

[0034] The present invention has accurately screened out the best magnetic field parameter combination for specific types of fruits and vegetables through a large number of experimental verifications, including magnetic field strength, frequency and action time. This step not only ensures the effectiveness of magnetic field treatment, that is, it can effectively inhibit the growth of microorganisms, but also maintains the integrity of the cell structure of fruits and vegetables, avoiding the changes in food texture and taste caused by environmental changes in traditional physical preservation methods. The precise control of magnetic field parameters enables this method to inhibit the growth of microorganisms while retaining the original quality of fruits and vegetables to the maximum extent. Pre-cooling treatment and vacuum packaging technology are also introduced to provide ideal initial conditions for magnetic field treatment. Pre-cooling treatment reduces the respiration and water evaporation rate of fruits and vegetables, thereby extending the shelf life; while vacuum packaging creates a low-oxygen environment, further inhibiting the growth of microorganisms. The synergistic effect of this pretreatment process and magnetic field treatment significantly improves the preservation effect and reduces the difficulty and cost of subsequent treatment. At the same time, a method with adjustable magnetic field strength and frequency is designed. A special magnetic field treatment device not only meets the preservation needs of different types of fruits and vegetables, but also ensures the optimization of the treatment effect by precisely adjusting the magnetic field parameters. In addition, the design of the device ensures that the magnetic field can act evenly and fully on the surface of fruits and vegetables, thereby improving the efficiency and effect of the treatment. Finally, by precisely controlling the temperature, humidity and oxygen content of the storage environment, the growth of microorganisms is further inhibited, and the quality of fruits and vegetables is maintained. At the same time, the microbial content and quality indicators are regularly tested, and the magnetic field treatment parameters and storage conditions are adjusted in time according to the test results to ensure the continuity and stability of the preservation effect. This step not only improves the reliability of the preservation effect, but also provides data support for subsequent optimization and improvement. In summary, by precisely controlling the magnetic field parameters, optimizing the pretreatment process, designing a special magnetic field treatment device, and carefully managing the storage conditions, the defects of the traditional preservation method are effectively overcome, showing the beneficial effects of high efficiency, environmental protection, wide applicability and significant preservation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a flow chart of a method for preserving fruits and vegetables by using a magnetic field to inhibit microorganisms;

[0036] Figure 2 This is a schematic structural diagram of a magnetic field treatment device of a method for preserving fruits and vegetables by using magnetic field treatment to inhibit microorganisms according to the present invention;

[0037] Figure 3 This is a comparison diagram of the results of reducing the gray mold infection rate of strawberry fruit by magnetic field treatment in a strawberry embodiment of a method for preserving fruits and vegetables by magnetic field treatment to inhibit microorganisms of the present invention;

[0038] Figure 4 This is a comparison diagram of the results of reducing the length of gray mold hyphae in strawberry fruit by magnetic field treatment in a strawberry embodiment of a method for preserving fruits and vegetables by inhibiting microorganisms through magnetic field treatment of the present invention. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Combination Figures 1 to 4 As shown, a method for preserving fruits and vegetables by treating with a magnetic field to inhibit microorganisms of the present invention comprises the following steps:

[0041] S10, Magnetic field parameter optimization and determination stage: A large number of experiments were conducted to verify the best magnetic field parameter combination for specific types of fruits and vegetables. During the experiment, the magnetic field intensity was precisely controlled within the range of 50 to 300 millitesla, the frequency fluctuated between 5 and 50 Hz, and the action time was set to 2 to 6 hours. By systematically comparing the growth of microorganisms in fruits and vegetables under different parameter combinations, a magnetic field parameter combination that can effectively inhibit the growth of microorganisms while maintaining the integrity of the fruit and vegetable cell structure was finally selected;

[0042] Step S10 specifically includes the following steps:

[0043] S101. Experimental design and planning. Clarify the magnetic field parameters that need to be optimized, including magnetic field intensity, frequency and action time. According to the experimental requirements, select representative fruit and vegetable species as experimental objects to ensure the freshness and consistency of the samples. Based on previous research and literature research, set the magnetic field intensity to be in the range of 50 to 300 millitesla, the frequency to be between 5 and 50 Hz, and the action time to be between 2 and 6 hours.

[0044] S102. Experimental preparation: ensure that the magnetic field treatment device can accurately adjust the magnetic field intensity, frequency and action time to meet the experimental requirements; prepare tools for detecting the growth of microorganisms in fruits and vegetables, such as microscopes, colony counters, culture media, etc.; pre-treat the selected fruit and vegetable samples, such as washing, peeling, slicing, etc., to ensure the consistency and accuracy of the experiment;

[0045] S103, data collection and analysis, record in detail the growth of microorganisms in fruits and vegetables under each parameter combination, including colony count, growth rate, etc., use statistical methods to analyze the collected data, and find out the magnetic field parameter combination that can effectively inhibit the growth of microorganisms while maintaining the integrity of the fruit and vegetable cell structure.

[0046] In the S101 stage, the pertinence and practicality of the experiment were ensured by clarifying the magnetic field parameters that needed to be optimized (magnetic field intensity, frequency and action time) and selecting representative types of fruits and vegetables as experimental objects. At the same time, the parameter range set based on previous research and literature research provided a scientific basis for the experiment and avoided blindness. In the S102 stage, the meticulous preparation of the experiment ensured that the magnetic field treatment device could accurately adjust the magnetic field parameters to meet the experimental needs. In addition, the pretreatment of fruit and vegetable samples also ensured the consistency and accuracy of the experiment, providing a reliable basis for subsequent data collection and analysis. Most importantly, in the S103 stage, by recording the growth of microorganisms in fruits and vegetables under each parameter combination in detail and using statistical methods to conduct in-depth analysis of the data, we finally found a combination of magnetic field parameters that can effectively inhibit the growth of microorganisms while maintaining the integrity of the fruit and vegetable cell structure. This discovery not only overcomes the limitations of traditional preservation methods, but also provides a new, more efficient and environmentally friendly solution for the field of fruit and vegetable preservation.

[0047] S20, fruit and vegetable pretreatment stage: Before the magnetic field treatment, a strict pretreatment process was implemented for the fruits and vegetables. The pretreatment steps included lowering the temperature of the fruits and vegetables to a state close to the freezing point but avoiding freezing. The precooling treatment was aimed at reducing the respiration and water evaporation rate of the fruits and vegetables, thereby extending their shelf life. At the same time, vacuum packaging technology was introduced to effectively remove oxygen in the packaging, build a low-oxygen environment, and further inhibit the growth of microorganisms. The synergistic effect of precooling treatment and vacuum packaging provided initial conditions for subsequent treatments.

[0048] Step S20 specifically includes the following steps:

[0049] S201, precooling treatment, according to the type, shape and size of fruits and vegetables, select the most suitable precooling method, ensure the cleanliness and hygiene of the precooling equipment, and set it to a temperature close to the freezing point but avoiding freezing, preliminarily wash the fruits and vegetables, remove the dirt and impurities on the surface, and ensure the integrity of the fruits and vegetables to avoid damage, put the fruits and vegetables into the precooling equipment, set the appropriate precooling time according to the type and quantity of fruits and vegetables, until the temperature of the fruits and vegetables drops to a state close to the freezing point but avoiding freezing, and continuously monitor the temperature of the fruits and vegetables during the precooling process to ensure that the temperature is uniform and within the set range;

[0050] S202, vacuum packaging technology, select vacuum packaging materials suitable for fruits and vegetables, ensure that the materials have good air permeability and sealing properties, further arrange the pre-cooled fruits and vegetables, such as removing excess moisture, and cutting them if necessary, to ensure space utilization and oxygen removal effect in the package, put the arranged fruits and vegetables into vacuum packaging bags, use vacuum packaging machines to package them, ensure that oxygen in the package is effectively removed, and build a low-oxygen environment. After packaging, check the sealing of the packaging bags to ensure that there is no leakage or damage, and store the vacuum-packed fruits and vegetables under appropriate temperature and humidity conditions to maintain their freshness and extend the shelf life;

[0051] S203. Synergistic effect and subsequent preparation. During the pretreatment process, the status and changes of fruits and vegetables are continuously monitored, and relevant data such as temperature, humidity, oxygen content, etc. are recorded. The effect of pretreatment is evaluated by checking the appearance, texture and smell of fruits and vegetables to ensure that the fruits and vegetables are in the best condition. After the pretreatment is completed, the fruits and vegetables are prepared for subsequent magnetic field treatment.

[0052] In the S201 pre-cooling treatment stage, the most suitable pre-cooling method is selected according to the type, shape and size of fruits and vegetables, and the temperature is set to a temperature close to the freezing point but avoiding freezing, ensuring the temperature control of fruits and vegetables during the preservation process, which not only reduces the respiration and water evaporation rate of fruits and vegetables, but also avoids cell damage caused by freezing. At the same time, the temperature of fruits and vegetables is continuously monitored to ensure that the temperature is uniform and within the set range, further improving the preservation effect. In the S202 vacuum packaging technology stage, vacuum packaging materials suitable for fruits and vegetables are selected, and through further sorting, such as removing excess moisture and cutting, the space utilization in the package is ensured. The rate and oxygen removal effect of the vacuum packaging machine, the effective use of which builds a low-oxygen environment, further inhibits the growth of microorganisms and extends the shelf life of fruits and vegetables. In addition, the sealing of the packaging bags is checked to ensure the integrity of the packaging and the preservation effect. In the S203 synergy and subsequent preparation stage, by continuously monitoring the status and changes of fruits and vegetables, recording relevant data, and evaluating the effect of pretreatment, it is ensured that the fruits and vegetables are in the best condition, providing ideal initial conditions for subsequent magnetic field treatment. This step not only improves the sophistication of the preservation process, but also provides a scientific basis for subsequent optimization and improvement through data recording and effect evaluation.

[0053] In step S201, the precooling methods include cold air cooling and cold storage cooling. Cold air cooling precooling is more suitable for fruits and vegetables with thin skin and easy to be damaged, such as strawberries, grapes and lettuce. When the number of fruits and vegetables is large or the shape is large and cold air needs to be blown evenly, this method is more suitable. In addition, when the temperature of fruits and vegetables is moderate and gentle cooling is required, cold air cooling precooling can also be selected. Cold storage cooling precooling is suitable for most fruits and vegetables, especially those that need to be stored for a long time. When the number of fruits and vegetables is large and they need to be kept at a low temperature for a long time, this method is particularly suitable.

[0054] By proposing scientific and reasonable pre-cooling plans based on the characteristics and needs of different fruits and vegetables, the scientificity and effectiveness of pre-cooling treatment have been significantly improved. This technical feature not only optimizes the process of the pretreatment stage of fruit and vegetable preservation, but also significantly improves the preservation effect and quality of fruits and vegetables, providing new ideas and methods for the field of fruit and vegetable preservation.

[0055] S30, magnetic field treatment device design and application stage: In order to meet the preservation requirements of different types of fruits and vegetables, a special magnetic field treatment device with adjustable magnetic field strength and frequency is designed. The device consists of three parts: a magnetic field generator, a control system, and a fruit and vegetable treatment chamber. The magnetic field generator is responsible for generating a magnetic field with specific parameters, and the control system is used to accurately adjust these parameters to ensure the optimization of the treatment effect. The fruit and vegetable treatment chamber is used to accommodate the fruits and vegetables to be treated. Its design ensures that the magnetic field can act evenly and fully on the surface of the fruits and vegetables. During the magnetic field treatment process, the pre-treated fruits and vegetables are placed in the treatment chamber and accurately treated according to the previously determined magnetic field parameters to achieve effective inhibition of microorganisms;

[0056] Step S30 specifically includes the following steps:

[0057] S301. Device design and assembly. According to the required magnetic field strength and frequency range, design the core components of the magnetic field generator, such as electromagnets or permanent magnets, determine the size, shape and power of the magnetic field generator to ensure that it can generate a stable and adjustable magnetic field, develop a control system that can accurately adjust the magnetic field strength and frequency, and the control system should include a user-friendly interface to facilitate operators to set and monitor magnetic field parameters. According to the type and size of fruits and vegetables, design the size and shape of the fruit and vegetable processing chamber, ensure that the interior of the processing chamber is smooth and easy to clean to avoid contamination of the fruits and vegetables, design appropriate ventilation or cooling systems to prevent excessive heat from being generated during the processing process, assemble the magnetic field generator, control system and fruit and vegetable processing chamber, ensure that the connection between the various parts is tight and stable, and perform necessary debugging and testing to ensure that the device can work properly. Figure 21 is the entire device body, 2 is the adjustable magnetic field generator, 3 is the processing chamber, 4 is the ventilation device, 5 is the user interaction interface, and a corresponding cabinet door (not shown) is also provided. During use, fruits and vegetables can be placed inside the processing chamber, and then processed by the adjustable magnetic field generator, and the excess heat can be dissipated by the ventilation device;

[0058] S302, setting and optimizing magnetic field parameters, setting initial values ​​of magnetic field strength and frequency according to previous research or experimental results, which should be able to cover the preservation requirements of most types of fruits and vegetables, and subjecting different types of fruits and vegetables to magnetic field treatment through experiments or simulations to observe their effects on microbial inhibition, and adjusting the parameters of magnetic field strength and frequency according to the experimental results to find the best preservation effect;

[0059] S303, pre-processing fruits and vegetables and operating the device, classifying and arranging the fruits and vegetables to ensure that their surfaces are clean and easy to handle, placing the fruits and vegetables at appropriate locations in the fruit and vegetable processing chamber according to their types and sizes, turning on the control system, setting the required magnetic field strength and frequency parameters, starting the magnetic field generator, and starting to generate a magnetic field. During the processing, pay close attention to the display data of the control system to ensure that the magnetic field parameters are stable and meet expectations. If any abnormality is found, the processing should be stopped immediately and the device should be checked. When the predetermined processing time or effect is reached, the magnetic field generator is turned off, the fruit and vegetable processing chamber is opened, and the processed fruits and vegetables are taken out;

[0060] S304. Subsequent processing and evaluation: Carry out necessary cleaning, disinfection or packaging of the processed fruits and vegetables to ensure that the processed fruits and vegetables meet food safety and hygiene standards. Evaluate the effect of magnetic field treatment on the preservation of fruits and vegetables through laboratory tests or consumer feedback. Based on the evaluation results, further optimize the magnetic field parameters and processing procedures.

[0061] A highly customized and powerful magnetic field processing device is proposed. This device can not only be precisely designed according to the required range of magnetic field strength and frequency, but also enables operators to easily set and monitor magnetic field parameters by developing a user-friendly control system. In addition, the device is designed with fruit and vegetable processing chambers of appropriate size and shape for different types of fruits and vegetables to ensure the hygiene and efficiency of the processing process. The addition of ventilation or cooling systems can effectively avoid overheating problems that may occur during the processing process and ensure the stable operation of the device. This series of design optimizations not only improves the processing efficiency, but also significantly enhances the practicality and reliability of the device. It also emphasizes setting the initial values ​​of magnetic field strength and frequency according to previous research or experimental results, and performing magnetic field treatment on different types of fruits and vegetables through experiments or simulations to find the best preservation effect. This parameter optimization method based on data and experiments not only improves the targetedness of magnetic field treatment, but also ensures the maximization of preservation effect. By continuously adjusting and optimizing the magnetic field Field parameters provide a flexible and efficient preservation strategy. In the pre-treatment of fruits and vegetables and the operation of the device in S303, the key steps such as the classification, sorting and placement of fruits and vegetables are elaborated in detail to ensure the accuracy and consistency of the processing process. At the same time, by paying close attention to the display data of the control system, the operator can monitor the magnetic field parameters in real time, discover and deal with abnormal situations in time, thereby ensuring the safety and stability of the processing process. The refinement of this step not only improves the processing efficiency, but also significantly reduces the difficulty of operation and the error rate. Finally, in the subsequent processing and evaluation stage of S304, it is emphasized that the processed fruits and vegetables should be cleaned, disinfected or packaged as necessary to ensure that they meet food safety and hygiene standards. At the same time, the effect of magnetic field treatment on the preservation of fruits and vegetables is evaluated through laboratory tests or consumer feedback, and the magnetic field parameters and processing flow are further optimized based on the evaluation results. The addition of this step not only improves the safety and quality of the product, but also provides a scientific basis for subsequent continuous optimization.

[0062] During the processing, key information such as magnetic field parameters, processing time, types and quantities of fruits and vegetables are recorded, and the preservation effect of the processed fruits and vegetables is evaluated. Through data analysis, the key factors affecting the preservation effect are found out, providing data support for further optimization of magnetic field parameters and processing procedures.

[0063] During the processing, it is emphasized to record key information such as magnetic field parameters, processing time, types and quantities of fruits and vegetables. This practice provides a detailed data basis for the subsequent preservation effect evaluation. By accurately recording this information, operators can clearly understand the specific conditions of each treatment, thereby ensuring the accuracy and reliability of the evaluation results. The addition of this step not only improves the scientific nature of the preservation effect evaluation, but also provides strong data support for the subsequent parameter optimization. Further, it is required to evaluate the preservation effect of the treated fruits and vegetables. This step conducts a comprehensive and multi-dimensional evaluation of the treated fruits and vegetables through laboratory tests, sensory evaluation or consumer feedback to find the best preservation effect. By comparing the preservation effects under different treatment conditions, operators can intuitively understand the effects of factors such as magnetic field parameters and processing time on the preservation effect, thereby providing a basis for further optimizing parameters. More importantly, it is also emphasized to find out the key factors affecting the preservation effect through data analysis. This step uses methods such as statistics or machine learning to conduct in-depth analysis of the recorded key information and dig out the core factors affecting the preservation effect. This practice not only improves the pertinence and efficiency of parameter optimization, but also provides the possibility for developing more intelligent and efficient preservation methods.

[0064] S40. Subsequent storage management and testing stage: After magnetic field treatment, fruits and vegetables are placed in a low-temperature, low-humidity, low-oxygen storage environment, where the temperature is precisely controlled within the range of 0 to 5°C and the humidity is maintained between 85% and 90%. This storage condition can further inhibit the growth of microorganisms and maintain the quality of fruits and vegetables. At the same time, in order to comprehensively evaluate the preservation effect, the microbial content of fruits and vegetables, including the number of E. coli, the number of molds, etc., as well as quality indicators such as hardness, color, taste, etc., are regularly tested. According to the test results, the magnetic field treatment parameters and storage conditions are adjusted in time to ensure the continuity and stability of the preservation effect.

[0065] Step S40 specifically includes the following steps:

[0066] S401, storage environment setting and monitoring, accurately control the temperature of the storage environment within the range of 0 to 5°C, maintain the humidity of the storage environment between 85% and 90%, and equip with humidity sensors and displays to monitor and record humidity data in real time, reduce the oxygen concentration in the storage environment by nitrogen filling or other means to further inhibit the growth of microorganisms and the respiration of fruits and vegetables. This usually requires the use of professional gas conditioning equipment, equipped with oxygen concentration sensors and displays, regular inspections of the storage environment, check whether the equipment is operating normally, record the temperature, humidity and oxygen concentration data of the storage environment, and conduct regular analysis to evaluate whether the storage environment is stable, and make necessary adjustments based on the analysis results;

[0067] S402. Fruit and vegetable quality inspection and evaluation. Regularly randomly sample stored fruits and vegetables to ensure that the samples are representative. Use professional microbial inspection equipment and methods, such as microscopic observation, culture method, PCR method, etc., to inspect the number of E. coli, mold count and other microbial contents in the samples. Record the inspection results and conduct regular analysis to evaluate the changing trend of microbial content. Perform necessary treatment according to the analysis results, such as strengthening cleaning, disinfection or adjusting magnetic field treatment parameters. Use equipment such as hardness tester to inspect the hardness of fruits and vegetables to evaluate their freshness and texture. Use equipment such as colorimeter to inspect the color of fruits and vegetables to evaluate their appearance quality. Use sensory evaluation or instrumental analysis to inspect the taste of fruits and vegetables, such as sweetness, acidity, crispness, etc. Record the inspection results and conduct regular analysis to evaluate the changing trend of fruit and vegetable quality. Perform necessary treatment according to the analysis results, such as adjusting storage conditions or magnetic field treatment parameters.

[0068] S403, parameter adjustment and optimization, according to the test results of microbial content and quality indicators, analyze the influence of magnetic field treatment parameters on the preservation effect, such as magnetic field intensity, frequency and treatment time, etc., according to the analysis results, adjust the magnetic field treatment parameters to optimize the preservation effect, according to the change trend of fruit and vegetable quality and the monitoring data of storage environment, analyze the influence of storage conditions on the preservation effect, such as temperature, humidity and oxygen concentration, etc., according to the analysis results, adjust the storage conditions to optimize the preservation effect;

[0069] S404. Record and report. Save all data, records and reports related to storage management and testing, including temperature, humidity, oxygen concentration data, microbial content test results, quality index test results, magnetic field treatment parameter adjustment records, etc. Regularly prepare storage management and testing reports to summarize the stability of the storage environment, the changing trend of microbial content, the changes in fruit and vegetable quality, and the adjustments of magnetic field treatment parameters and storage conditions.

[0070] In step S40, firstly, through the storage environment setting and monitoring of S401, a highly accurate and comprehensive environmental control strategy is proposed. By accurately controlling the temperature of the storage environment within the range of 0 to 5°C and maintaining the humidity between 85% and 90%, this strategy provides ideal storage conditions for fruits and vegetables and effectively extends the shelf life. At the same time, humidity sensors and displays are equipped to monitor and record humidity data in real time, and professional gas conditioning equipment is used to reduce oxygen concentration, further inhibiting the growth of microorganisms and the respiration of fruits and vegetables. These measures not only improve the stability of the storage environment, but also provide data support for subsequent parameter adjustments. In addition, the storage environment is regularly inspected to ensure the normal operation of the equipment, and relevant data is recorded and analyzed to make storage management more scientific and efficient. In the fruit and vegetable quality inspection and evaluation stage of S402, the importance of regularly randomly sampling samples from the stored fruits and vegetables for quality inspection is emphasized. By using professional microbial detection equipment and methods, as well as hardness meters, colorimeter and other equipment, the quality indicators of fruits and vegetables such as microbial content, hardness, color and taste are comprehensively evaluated. This step not only improves the quality of the products, but also provides data support for the subsequent parameter adjustment. The accuracy and reliability of quality detection also provide a scientific basis for subsequent parameter adjustments. At the same time, by regularly analyzing the test results, evaluating the changing trends of microbial content and quality indicators, and timely discovering and dealing with potential problems, the stability and safety of fruit and vegetable quality are ensured. In the parameter adjustment and optimization stage of S403, according to the test results of microbial content and quality indicators, the influence of magnetic field treatment parameters and storage conditions on the preservation effect is deeply analyzed. By adjusting parameters such as magnetic field intensity, frequency and treatment time, as well as storage conditions such as temperature, humidity and oxygen concentration, the preservation effect is optimized. This step not only improves the pertinence and effectiveness of the preservation effect, but also provides the possibility for the development of more intelligent and efficient preservation methods. Finally, in the recording and reporting stage of S404, the importance of preserving all data, records and reports related to storage management and testing is emphasized. By regularly compiling storage management and testing reports, summarizing the stability of the storage environment, the changing trends of microbial content, the changes in fruit and vegetable quality, and the adjustment of magnetic field treatment parameters and storage conditions, it provides strong data support and decision-making basis for subsequent storage management.

[0071] In step S40, a complete data management and analysis system needs to be established to store, query and analyze storage environment data, microbial detection results, quality assessment data, magnetic field processing parameters and other information. Data analysis tools, such as statistical software and machine learning algorithms, are used to conduct in-depth analysis of the collected data to explore the patterns and trends behind the data, so as to provide a scientific basis for optimizing storage conditions, magnetic field processing parameters and detection strategies.

[0072] The system can comprehensively store various relevant data, including parameters such as temperature, humidity, and oxygen concentration of the storage environment, results such as the number of E. coli and mold obtained from microbial testing, indicators such as hardness, color, and taste in quality assessment, and parameters such as the intensity, frequency, and time of magnetic field treatment. This comprehensive data storage provides a solid foundation for subsequent data query and analysis. More importantly, the system also uses data analysis tools such as statistical software and machine learning algorithms to conduct in-depth analysis of the collected data. By mining the laws and trends behind the data, it can more accurately understand the effects of storage conditions, magnetic field treatment parameters, and detection strategies on the preservation of fruits and vegetables. This scientific analysis based on data not only improves the accuracy and efficiency of decision-making, but also provides a strong scientific basis for optimizing storage conditions, magnetic field treatment parameters and detection strategies. In addition, the establishment of a complete data management and analysis system will also help to improve the level of intelligence in fruit and vegetable preservation, storage and magnetic field treatment. Through real-time monitoring and analysis of data, potential problems can be discovered and solved in a timely manner, such as unstable storage environment and excessive microbial content, thereby ensuring the quality and safety of fruits and vegetables. At the same time, the system can also provide rich data resources for research in the field of fruit and vegetable preservation, storage and magnetic field treatment, and promote the continuous progress and innovation of related technologies.

[0073] Embodiment 1: For apples, a specific fruit and vegetable, the magnetic field parameters that need to be optimized are clarified through detailed experimental design and planning, and representative apples are selected as experimental objects. In the experimental preparation stage, the accuracy of the magnetic field treatment device is ensured, and necessary detection tools are prepared. Subsequently, in the data collection and analysis stage, the growth of microorganisms in apples under each parameter combination is recorded in detail, and the data is analyzed using statistical methods. Finally, the optimal magnetic field parameter combination for apples is determined to be a magnetic field intensity of 150 millitesla, a frequency of 20 Hz, and an action time of 4 hours;

[0074] Select cold storage cooling as the precooling method, place the apples in a clean precooling device, set the temperature to a temperature close to freezing but avoiding freezing, and continuously monitor the temperature, then use vacuum packaging technology, select vacuum packaging materials suitable for apples, sort the precooled apples and put them into vacuum packaging bags, use vacuum packaging machines for packaging, and continuously monitor the status and changes of the apples during the synergy and subsequent preparation stages, evaluate the effect of the pretreatment, and prepare the apples for subsequent magnetic field treatment;

[0075] In order to meet the needs of apple preservation, a special magnetic field treatment device with adjustable magnetic field strength and frequency was designed, and the magnetic field treatment device design and application stage was entered. In the device design and assembly stage, the core components of the magnetic field generator were designed, and a control system for accurately adjusting the magnetic field strength and frequency was developed. At the same time, a fruit and vegetable processing chamber suitable for the size and shape of apples was designed. In the magnetic field parameter setting and optimization stage, the initial value was set according to the results of the previous study, and the apples were treated with the magnetic field to observe its effect on microbial inhibition. The magnetic field parameters were adjusted according to the experimental results. In the apple pretreatment and device operation stage, the apples were sorted and placed in the fruit and vegetable processing chamber, and the magnetic field generator was started. In the subsequent processing and evaluation stage, the treated apples were cleaned and packaged as necessary, and the effect of magnetic field treatment on the apple preservation effect was evaluated through laboratory tests, and the magnetic field parameters and processing flow were further optimized;

[0076] After magnetic field treatment, the apples were placed in a low-temperature, low-humidity, and low-oxygen storage environment, and regular storage management and testing were carried out. The subsequent storage management and testing stage was entered. In the storage environment setting and monitoring stage, the temperature of the storage environment was accurately controlled within the range of 0 to 5°C, and the humidity was maintained between 85% and 90%. Humidity sensors and displays were equipped to monitor and record humidity data in real time. Nitrogen was injected to reduce the oxygen concentration in the storage environment to ensure a stable storage environment. In the apple quality testing and evaluation stage, samples were randomly selected from the stored apples for testing on a regular basis. Professional microbial testing equipment and methods were used to test the microbial content in the samples. Hardness meters, colorimeter and other equipment were used to test the hardness and color of the apples. The taste of the apples was tested through sensory evaluation. The test results were recorded and analyzed regularly. In the parameter adjustment and optimization stage, the effects of magnetic field treatment parameters and storage conditions on the preservation effect were analyzed based on the test results of microbial content and quality indicators, and adjustments were made based on the analysis results. In the recording and reporting stage, all data, records and reports related to storage management and testing were saved, and storage management and testing reports were compiled regularly.

[0077] In addition, a complete data management and analysis system has been established to store, query and analyze storage environment data, microbial test results, quality assessment data, magnetic field treatment parameters and other information. Data analysis tools such as statistical software and machine learning algorithms are used to conduct in-depth analysis of the collected data to explore the laws and trends behind the data, providing a scientific basis for optimizing storage conditions, magnetic field treatment parameters and detection strategies.

[0078] Through the above detailed implementation process, the method of magnetic field treatment to inhibit microorganisms was successfully used to preserve apples, and a significant preservation effect was achieved. This method not only extended the shelf life of apples, but also maintained their good quality and taste.

[0079] Example 2: For strawberries, a specific fruit and vegetable, a detailed experimental design and planning was carried out to clarify and optimize the magnetic field treatment parameters to improve the preservation effect of strawberries. In the experiment, representative strawberries were selected as experimental objects, and these strawberries were consistent in appearance, size and maturity to ensure the accuracy of the experimental results.

[0080] In the experimental preparation stage, the magnetic field treatment device was first accurately calibrated to ensure that it could operate stably according to the preset parameters. At the same time, necessary testing tools were also prepared, including but not limited to microbial testing equipment, hardness tester, colorimeter, etc., to comprehensively evaluate the preservation effect of strawberries after magnetic field treatment.

[0081] Aiming at the most common microbial pathogen of strawberries after harvest, Botrytis cinerea B05.10, an infection and magnetic treatment experiment was designed. The experimental process is as follows:

[0082] Sample selection and disinfection: Select half-red strawberry fruits of similar size and appearance, without disease spots and mechanical injuries, and soak them in 0.5% (v / v) NaClO solution for four minutes for disinfection. After disinfection, soak them in ultrapure water twice, two minutes each time, to wash the fruits.

[0083] Preparation of Botrytis cinerea spore suspension: A conidia suspension of Botrytis cinerea was obtained from PDA medium grown on potato dextrose agar for 9 days using 0.01% (v / v) Triton X-100.

[0084] Control group setup: Use a sterile needle to make a 1mm×1mm (diameter×depth) wound on the dried strawberry fruit. Dilute the spore suspension to a concentration of 4.0×105cfu, and inoculate 4μL of spores at the 1mm×1mm wound site. After inoculation, the strawberries were pre-cooled and vacuum-packed, and then stored in a common incubator (4±1℃, 85% to 90% humidity), and the gray mold infection rate and lesion diameter were recorded.

[0085] Magnetic treatment group settings: pretreatment operation is the same as the control group, but after precooling and vacuum packaging, it is placed in the magnetic field treatment device for treatment. The magnetic field parameters are set to a magnetic field intensity of 200 millitesla, a frequency of 20 Hz, and an action time of 4 hours. After the treatment, it is stored in the same way as the control group, and the gray mold infection rate and lesion diameter are recorded.

[0086] During the data collection and analysis phase, the growth of microorganisms in strawberries under different magnetic field parameter combinations was recorded in detail. By comparing the gray mold infection rate and lesion diameter of the two groups of strawberries during storage, it was found that the gray mold infection rate of the magnetic treatment group was significantly reduced, and the lesion diameter was also significantly smaller than that of the control group. This result verifies the positive effect of magnetic field treatment on the preservation of strawberries.

[0087] In order to meet the needs of strawberry preservation, a special magnetic field processing device with adjustable magnetic field strength and frequency is designed. The core component of the device is the magnetic field generator, which can accurately adjust the magnetic field strength and frequency to meet the needs of different types of fruits and vegetables for preservation. At the same time, a fruit and vegetable processing chamber suitable for the size and shape of strawberries is also designed to ensure that the magnetic field can act evenly on the strawberry fruit.

[0088] After the magnetic field treatment, the strawberries were placed in a low-temperature, low-humidity, low-oxygen storage environment, and regular storage management and testing were carried out. The temperature, humidity and oxygen concentration of the storage environment were precisely controlled to ensure that the strawberries could maintain the best freshness during storage. At the same time, professional microbial testing equipment and methods were used to regularly test the microbial content in the strawberries to evaluate the preservation effect of the magnetic field treatment.

[0089] A complete data management and analysis system is established to store, query and analyze storage environment data, microbial test results, quality assessment data, magnetic field treatment parameters and other information. By using data analysis tools such as statistical software and machine learning algorithms, the collected data is deeply mined and analyzed, providing a scientific basis for optimizing storage conditions, magnetic field treatment parameters and detection strategies.

[0090] By implementing this technical solution, we successfully used magnetic field treatment to inhibit microorganisms to preserve strawberries, and achieved significant preservation effects. This method not only extends the shelf life of strawberries, but also maintains their good quality and taste. Specifically, magnetic field treatment can not only inhibit the growth of gray mold in strawberries, but also delay the decline in hardness and color changes of strawberries. In the future, we will continue to optimize magnetic field treatment parameters and preservation processes to further enhance the preservation effects of strawberries and other fruits and vegetables. Figure 3 As shown, the results of magnetic field treatment in strawberry embodiment for reducing the gray mold infection rate of strawberry fruit (ns indicates no significant difference, "**" indicates that the magnetic treatment group has a significant difference with respect to the control group and p < 0.01; "***" indicates that the magnetic treatment group has a very significant difference with respect to the control group and p < 0.001). Figure 4 As shown, it is the result of magnetic field treatment in strawberry embodiment reducing the length of gray mold hyphae in strawberry fruit (ns indicates no significant difference, "**" indicates that the magnetic treatment group is significantly different from the control group and p < 0.01; "***" indicates that the magnetic treatment group is extremely significantly different from the control group and p < 0.001).

[0091] In summary, this embodiment, through detailed experimental design and planning, clarified the optimal magnetic field treatment parameters for strawberries, and successfully verified the positive effect of magnetic field treatment on the preservation of strawberries. This study provides new ideas and methods for the preservation of fruits and vegetables, and has important application value.

[0092] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0093] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preserving fruits and vegetables by inhibiting microorganisms through magnetic field treatment, characterized in that: The steps include: S10, Magnetic field parameter optimization and determination stage: A large number of experiments were conducted to verify the best magnetic field parameter combination for specific types of fruits and vegetables. During the experiment, the magnetic field intensity was precisely controlled within the range of 50 to 300 millitesla, the frequency fluctuated between 5 and 50 Hz, and the action time was set to 2 to 6 hours. By systematically comparing the growth of microorganisms in fruits and vegetables under different parameter combinations, a magnetic field parameter combination that can effectively inhibit the growth of microorganisms while maintaining the integrity of the fruit and vegetable cell structure was finally selected; S20, fruit and vegetable pretreatment stage: Before the magnetic field treatment, a strict pretreatment process was implemented for the fruits and vegetables. The pretreatment steps included lowering the temperature of the fruits and vegetables to a state close to the freezing point but avoiding freezing. The precooling treatment was aimed at reducing the respiration and water evaporation rate of the fruits and vegetables, thereby extending their shelf life. At the same time, vacuum packaging technology was introduced to effectively remove oxygen in the packaging, build a low-oxygen environment, and further inhibit the growth of microorganisms. The synergistic effect of precooling treatment and vacuum packaging provided initial conditions for subsequent treatments. S30, magnetic field treatment device design and application stage: In order to meet the preservation requirements of different types of fruits and vegetables, a special magnetic field treatment device with adjustable magnetic field strength and frequency is designed. The device consists of three parts: a magnetic field generator, a control system, and a fruit and vegetable treatment chamber. The magnetic field generator is responsible for generating a magnetic field with specific parameters, and the control system is used to accurately adjust these parameters to ensure the optimization of the treatment effect. The fruit and vegetable treatment chamber is used to accommodate the fruits and vegetables to be treated. Its design ensures that the magnetic field can act evenly and fully on the surface of the fruits and vegetables. During the magnetic field treatment process, the pre-treated fruits and vegetables are placed in the treatment chamber and accurately treated according to the previously determined magnetic field parameters to achieve effective inhibition of microorganisms; S40. Subsequent storage management and testing stage: After magnetic field treatment, fruits and vegetables are placed in a low-temperature, low-humidity, low-oxygen storage environment, where the temperature is precisely controlled within the range of 0 to 5°C and the humidity is maintained between 85% and 90%. This storage condition can further inhibit the growth of microorganisms and maintain the quality of fruits and vegetables. At the same time, in order to comprehensively evaluate the preservation effect, the microbial content of fruits and vegetables, including the number of E. coli, the number of molds, etc., as well as quality indicators such as hardness, color, taste, etc., are regularly tested. According to the test results, the magnetic field treatment parameters and storage conditions are adjusted in time to ensure the continuity and stability of the preservation effect.

2. A method for preserving fruits and vegetables by inhibiting microorganisms through magnetic field treatment according to claim 1, characterized in that: The step S10 specifically includes the following steps: S101. Experimental design and planning. Clarify the magnetic field parameters that need to be optimized, including magnetic field intensity, frequency and action time. According to the experimental requirements, select representative fruit and vegetable species as experimental objects to ensure the freshness and consistency of the samples. Based on previous research and literature research, set the magnetic field intensity to be in the range of 50 to 300 millitesla, the frequency to be between 5 and 50 Hz, and the action time to be between 2 and 6 hours. S102. Experimental preparation: ensure that the magnetic field treatment device can accurately adjust the magnetic field intensity, frequency and action time to meet the experimental requirements; prepare tools for detecting the growth of microorganisms in fruits and vegetables, such as microscopes, colony counters, culture media, etc.; pre-treat the selected fruit and vegetable samples, such as washing, peeling, slicing, etc., to ensure the consistency and accuracy of the experiment; S103, data collection and analysis, record in detail the growth of microorganisms in fruits and vegetables under each parameter combination, including colony count, growth rate, etc., use statistical methods to analyze the collected data, and find out the magnetic field parameter combination that can effectively inhibit the growth of microorganisms while maintaining the integrity of the fruit and vegetable cell structure.

3. The method for preserving fruits and vegetables by inhibiting microorganisms through magnetic field treatment according to claim 1, characterized in that: The step S20 specifically includes the following steps: S201, precooling treatment, according to the type, shape and size of fruits and vegetables, select the most suitable precooling method, ensure the cleanliness and hygiene of the precooling equipment, and set it to a temperature close to the freezing point but avoiding freezing, preliminarily wash the fruits and vegetables, remove the dirt and impurities on the surface, and ensure the integrity of the fruits and vegetables to avoid damage, put the fruits and vegetables into the precooling equipment, set the appropriate precooling time according to the type and quantity of fruits and vegetables, until the temperature of the fruits and vegetables drops to a state close to the freezing point but avoiding freezing, and continuously monitor the temperature of the fruits and vegetables during the precooling process to ensure that the temperature is uniform and within the set range; S202, vacuum packaging technology, select vacuum packaging materials suitable for fruits and vegetables, ensure that the materials have good air permeability and sealing properties, further arrange the pre-cooled fruits and vegetables, such as removing excess moisture, and cutting them if necessary, to ensure space utilization and oxygen removal effect in the package, put the arranged fruits and vegetables into vacuum packaging bags, use vacuum packaging machines to package them, ensure that oxygen in the package is effectively removed, and build a low-oxygen environment. After packaging, check the sealing of the packaging bags to ensure that there is no leakage or damage, and store the vacuum-packed fruits and vegetables under appropriate temperature and humidity conditions to maintain their freshness and extend the shelf life; S203. Synergistic effect and subsequent preparation. During the pretreatment process, the status and changes of fruits and vegetables are continuously monitored, and relevant data such as temperature, humidity, oxygen content, etc. are recorded. The effect of pretreatment is evaluated by checking the appearance, texture and smell of fruits and vegetables to ensure that the fruits and vegetables are in the best condition. After the pretreatment is completed, the fruits and vegetables are prepared for subsequent magnetic field treatment.

4. The method for preserving fruits and vegetables by inhibiting microorganisms through magnetic field treatment according to claim 3, characterized in that: The precooling methods in step S201 include cold air cooling and cold storage cooling. Cold air cooling precooling is more suitable for fruits and vegetables with thin skin and easy to be damaged, such as strawberries, grapes and lettuce. When the number of fruits and vegetables is large or the shape is large and cold air needs to be blown evenly, this method is more suitable. In addition, when the temperature of fruits and vegetables is moderate and gentle cooling is required, cold air cooling precooling can also be selected. Cold storage cooling precooling is suitable for most fruits and vegetables, especially those that need to be stored for a long time. When the number of fruits and vegetables is large and they need to be kept at a low temperature for a long time, this method is particularly suitable.

5. The method for preserving fruits and vegetables by inhibiting microorganisms through magnetic field treatment according to claim 1, characterized in that: The step S30 specifically includes the following steps: S301. Device design and assembly. According to the required magnetic field strength and frequency range, design the core components of the magnetic field generator, such as electromagnets or permanent magnets, determine the size, shape and power of the magnetic field generator to ensure that it can generate a stable and adjustable magnetic field, develop a control system that can accurately adjust the magnetic field strength and frequency, and the control system should include a user-friendly interface to facilitate operators to set and monitor magnetic field parameters. According to the type and size of fruits and vegetables, design the size and shape of the fruit and vegetable processing chamber, ensure that the interior of the processing chamber is smooth and easy to clean to avoid contamination of fruits and vegetables, design appropriate ventilation or cooling systems to prevent excessive heat from being generated during the processing process, assemble the magnetic field generator, control system and fruit and vegetable processing chamber, ensure that the connection between the various parts is tight and stable, and perform necessary debugging and testing to ensure that the device can work properly. S302, setting and optimizing magnetic field parameters, setting initial values ​​of magnetic field strength and frequency according to previous research or experimental results, which should be able to cover the preservation requirements of most types of fruits and vegetables, and subjecting different types of fruits and vegetables to magnetic field treatment through experiments or simulations to observe their effects on microbial inhibition, and adjusting the parameters of magnetic field strength and frequency according to the experimental results to find the best preservation effect; S303, pre-processing fruits and vegetables and operating the device, classifying and arranging the fruits and vegetables to ensure that their surfaces are clean and easy to handle, placing the fruits and vegetables at appropriate locations in the fruit and vegetable processing chamber according to their types and sizes, turning on the control system, setting the required magnetic field strength and frequency parameters, starting the magnetic field generator, and starting to generate a magnetic field. During the processing, pay close attention to the display data of the control system to ensure that the magnetic field parameters are stable and meet expectations. If any abnormality is found, the processing should be stopped immediately and the device should be checked. When the predetermined processing time or effect is reached, the magnetic field generator is turned off, the fruit and vegetable processing chamber is opened, and the processed fruits and vegetables are taken out; S304. Subsequent processing and evaluation: Carry out necessary cleaning, disinfection or packaging of the processed fruits and vegetables to ensure that the processed fruits and vegetables meet food safety and hygiene standards. Evaluate the effect of magnetic field treatment on the preservation of fruits and vegetables through laboratory tests or consumer feedback. Based on the evaluation results, further optimize the magnetic field parameters and processing procedures.

6. The method for preserving fruits and vegetables by inhibiting microorganisms through magnetic field treatment according to claim 5, characterized in that: During the treatment process, key information such as magnetic field parameters, treatment time, types and quantities of fruits and vegetables are recorded, and the preservation effect of the treated fruits and vegetables is evaluated. Through data analysis, key factors affecting the preservation effect are found to provide data support for further optimization of magnetic field parameters and treatment processes.

7. The method for preserving fruits and vegetables by inhibiting microorganisms through magnetic field treatment according to claim 1, characterized in that: The step S40 specifically includes the following steps: S401, storage environment setting and monitoring, accurately control the temperature of the storage environment within the range of 0 to 5°C, maintain the humidity of the storage environment between 85% and 90%, and equip with humidity sensors and displays to monitor and record humidity data in real time, reduce the oxygen concentration in the storage environment by nitrogen filling or other means to further inhibit the growth of microorganisms and the respiration of fruits and vegetables. This usually requires the use of professional gas conditioning equipment, equipped with oxygen concentration sensors and displays, regular inspections of the storage environment, check whether the equipment is operating normally, record the temperature, humidity and oxygen concentration data of the storage environment, and conduct regular analysis to evaluate whether the storage environment is stable, and make necessary adjustments based on the analysis results; S402. Fruit and vegetable quality inspection and evaluation. Regularly randomly sample stored fruits and vegetables to ensure that the samples are representative. Use professional microbial inspection equipment and methods, such as microscopic observation, culture method, PCR method, etc., to inspect the number of E. coli, mold count and other microbial contents in the samples. Record the inspection results and conduct regular analysis to evaluate the changing trend of microbial content. Perform necessary treatment according to the analysis results, such as strengthening cleaning, disinfection or adjusting magnetic field treatment parameters. Use equipment such as hardness tester to inspect the hardness of fruits and vegetables to evaluate their freshness and texture. Use equipment such as colorimeter to inspect the color of fruits and vegetables to evaluate their appearance quality. Use sensory evaluation or instrumental analysis to inspect the taste of fruits and vegetables, such as sweetness, acidity, crispness, etc. Record the inspection results and conduct regular analysis to evaluate the changing trend of fruit and vegetable quality. Perform necessary treatment according to the analysis results, such as adjusting storage conditions or magnetic field treatment parameters. S403, parameter adjustment and optimization, according to the test results of microbial content and quality indicators, analyze the influence of magnetic field treatment parameters on the preservation effect, such as magnetic field intensity, frequency and treatment time, etc., according to the analysis results, adjust the magnetic field treatment parameters to optimize the preservation effect, according to the change trend of fruit and vegetable quality and the monitoring data of storage environment, analyze the influence of storage conditions on the preservation effect, such as temperature, humidity and oxygen concentration, etc., according to the analysis results, adjust the storage conditions to optimize the preservation effect; S404. Record and report. Save all data, records and reports related to storage management and testing, including temperature, humidity, oxygen concentration data, microbial content test results, quality index test results, magnetic field treatment parameter adjustment records, etc. Regularly prepare storage management and testing reports to summarize the stability of the storage environment, the changing trend of microbial content, the changes in fruit and vegetable quality, and the adjustments of magnetic field treatment parameters and storage conditions.

8. The method for preserving fruits and vegetables by inhibiting microorganisms through magnetic field treatment according to claim 7, characterized in that: In step S40, a complete data management and analysis system needs to be established to store, query and analyze storage environment data, microbial detection results, quality assessment data, magnetic field processing parameters and other information. Data analysis tools, such as statistical software, machine learning algorithms, etc., are used to conduct in-depth analysis of the collected data to explore the patterns and trends behind the data, so as to provide a scientific basis for optimizing storage conditions, magnetic field processing parameters and detection strategies.

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