Application and method of beauveria bassiana microbial preparation in tomato preservation

Abstract

The invention relates to the technical field of beauveria bassiana microbial preparations, in particular to application and a method of a beauveria bassiana microbial preparation in tomato preservation. 7-11% of a composite protective agent; and 0.5%-1.5% of a synergist. The three-level application scheme of dip-coating, spraying and modified atmosphere packaging is designed for normal temperature, low temperature and cold chain, and the refreshing time is prolonged by 3-5 times; through strain improvement, preparation innovation and application technology optimization, the beauveria bassiana is developed into the special fresh-keeping agent for tomatoes for the first time.

Description

Technical Field

[0001] The invention relates to the technical field of Beauveria bassiana microbial preparations, and in particular to an application and method of a Beauveria bassiana microbial preparation in tomato preservation. Background Art

[0002] As a globally important vegetable crop, tomato preservation directly impacts the industry's economic profitability. However, due to their thin, juicy skin and high respiratory metabolism, tomatoes are susceptible to post-harvest infection by pathogens such as Botrytis cinerea and Penicillium, leading to rot rates as high as 20%-30%. While traditional chemical preservation techniques can suppress diseases, they can lead to excessive pesticide residues and are inconsistent with the development of organic agriculture.

[0003] Biopreservation technology has become a research hotspot due to its environmental and safety benefits. Existing technologies include natural extracts (such as chitosan and plant essential oils) and microbial preparations (such as Bacillus subtilis and Trichoderma). Beauveria bassiana, an insect pathogenic fungus, produces metabolites, beauvericin and oosporin, which possess broad-spectrum antifungal activity.

[0004] In the existing technology, a tomato preservation method with application number 201810807095.6 uses Beauveria bassiana for pest control, taking advantage of its ability to infect insects. Its application in plant disease prevention and control or fruit and vegetable preservation has not yet been found. In addition, the mechanism of action of the antifungal metabolites produced by Beauveria bassiana on the surface of fruits and vegetables is still unclear, and there is a lack of targeted screening and metabolic regulation methods for plant pathogens.

[0005] In view of the above problems, we propose an application and method of Beauveria bassiana microbial preparation in tomato preservation. Summary of the Invention

[0006] The purpose of the present invention is to provide an application and method of a Beauveria bassiana microbial preparation in tomato preservation, so as to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A Beauveria bassiana microbial preparation comprising the following components:

[0009] Active agent 35-35%;

[0010] Active agent, including the following components:

[0011] Beauveria bassiana spores and Bacillus subtilis spores, wherein the ratio of Beauveria bassiana spores to Bacillus subtilis spores is 1:1;

[0012] Composite protective agent 7-11%;

[0013] Composite protective agent, including the following components:

[0014] Sodium alginate 3-5%;

[0015] Mannitol 1-2%;

[0016] Vitamin C 0.5-1%;

[0017] Chitosan 0.1-0.3%;

[0018] Synergist 0.5-1.5%;

[0019] Synergist, comprising the following components:

[0020] Silkworm pupa hydrolyzate 0.5-1%;

[0021] 0.05-0.1% plant essential oil, wherein the plant essential oil is a 1:1 mixture of eugenol and cinnamaldehyde.

[0022] Preferably, the method for preparing the silkworm pupa hydrolyzate comprises the following steps:

[0023] After crushing the silkworm pupae, add 2% pure alkali solution at a ratio of 1:4, stir at 55-65℃ for 1-2h, and centrifuge at 6000-8000rpm for 10-15min to collect the supernatant;

[0024] The supernatant is decolorized with activated carbon for 0.5-1h and then spray-dried under the conditions of an inlet air temperature of 150-200°C and an outlet air temperature of 60-100°C to prepare silkworm pupa peptone.

[0025] The preparation method of Beauveria bassiana microbial preparation comprises the following steps:

[0026] Step 1: Bacteria culture:

[0027] Beauveria bassiana was inoculated into a culture medium containing silkworm pupa hydrolyzate (glucose 15 g / L, silkworm pupa hydrolyzate 8 g / L, KH2PO4 1.5 g / L), and cultured at 25°C and 180 rpm for 36-48 hours to obtain a Beauveria bassiana seed solution.

[0028] Then, Bacillus subtilis was inoculated into LB medium and cultured at 37°C and 200 rpm for 6-12 hours to prepare Bacillus subtilis seed liquid;

[0029] Step 2, co-fermentation culture:

[0030] 10% of Beauveria bassiana seed solution and 5% of Bacillus subtilis seed solution were added to a three-stage fermentation tank, and cultured at 25°C and 250 rpm for 36-72 hours to obtain a fermentation liquid containing composite spores;

[0031] Step 3, microencapsulation:

[0032] The fermentation broth was mixed with 3%-5% sodium alginate, 1%-2% mannitol, 0.5%-1% vitamin C, and 0.05%-0.1% plant essential oil, and homogenized under high pressure at 100 MPa for 2-3 times to form an O / W emulsion. A 2% CaCl2 solution was then added dropwise for cross-linking for 30 minutes to prepare microcapsules.

[0033] Step 4: Freeze-drying:

[0034] The microcapsule suspension was pre-frozen at -40°C for 1-2 hours and then freeze-dried under a vacuum degree of 8-10 Pa. The primary drying temperature was maintained at -10°C for 15-20 hours and the secondary drying temperature was maintained at 25°C for 2-4 hours to obtain a freeze-dried preparation.

[0035] Preferably, in step 2, the fermentation process adopts segmented pH control: maintaining pH 6.5 from 0 to 48 hours, and adjusting pH to 5.5 from 48 to 72 hours to induce the synthesis of antifungal metabolites.

[0036] A method for applying a Beauveria bassiana microbial preparation to tomato preservation comprises the following steps:

[0037] (1) Preparation: Dissolve the lyophilized preparation in sterile water and prepare 1×10 8 -5×10 8 CFU / mL suspension, add 0.05%-0.1% Tween-80 as a spreader;

[0038] (2) Dipping treatment: Immerse the tomatoes completely in the suspension for 5-10 min, remove them, drain them, and dry them naturally, so that the number of spores attached to the fruit surface is ≥1×10 6 CFU / cm 2 ;

[0039] (3) Modified atmosphere packaging: The treated tomatoes were packed into microporous polyethylene film bags (air permeability 500cm 3 / m 2 ·day), control the gas ratio in the bag to 5%-8% O2 and 2%-3% CO2, and store at 4-6℃.

[0040] Preferably, the dipping treatment can be replaced by a spraying treatment: a high-pressure sprayer (pressure 2-3 MPa) is used to evenly spray the suspension on the surface of the tomato at a dosage of 50-100 mL / kg to form an antibacterial film with a thickness of 5-10 μm.

[0041] Preferably, the tomatoes are processed during the green ripe stage (hardness ≥ 3.5N) or the color change stage, and are rinsed with running water and drained before processing, and mechanically damaged fruits are removed.

[0042] Preferably, the tomato fresh-keeping composition of the preparation is characterized in that the composition further comprises diatomaceous earth as a carrier, and is prepared into water-dispersible granules with a particle size of 0.1-0.5 mm, which is used to prepare fresh-keeping pads or sustained-release packaging materials.

[0043] Preferably, the microcapsule has a core-shell double-layer structure: the inner layer is calcium alginate gel (pore size 5-10 nm) encapsulating the spores, and the outer layer is a chitosan cationic membrane with a zeta potential of +25 mV, which can be specifically adsorbed on the tomato skin.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The invention increases the yield of beauvericin by 40% and activates the secretion of chitinase and protease by adding silkworm pupa hydrolyzate; the inner layer of calcium alginate gel protects the spores, and the outer layer of chitosan membrane enhances the attachment of fruits.

[0046] This invention designs a three-stage application solution for ambient temperature, low temperature, and cold chain packaging: dipping, spraying, and modified atmosphere packaging, extending the shelf life by 3-5 times. Through strain improvement, formulation innovation, and application technology optimization, this invention has developed Beauveria bassiana as a tomato-specific preservative for the first time. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0049] Example 1:

[0050] like Figure 1 As shown, a Beauveria bassiana microbial preparation comprises the following components:

[0051] Active agent 35-35%;

[0052] Active agent, including the following components:

[0053] Beauveria bassiana spores and Bacillus subtilis spores, wherein the ratio of Beauveria bassiana spores to Bacillus subtilis spores is 1:1;

[0054] Composite protective agent 7-11%;

[0055] Composite protective agent, including the following components:

[0056] Sodium alginate 3-5%;

[0057] Mannitol 1-2%;

[0058] Vitamin C 0.5-1%;

[0059] Chitosan 0.1-0.3%;

[0060] Synergist 0.5-1.5%;

[0061] Synergist, comprising the following components:

[0062] Silkworm pupa hydrolyzate 0.5-1%;

[0063] 0.05-0.1% plant essential oil, wherein the plant essential oil is a 1:1 mixture of eugenol and cinnamaldehyde.

[0064] Preferably, the method for preparing the silkworm pupa hydrolyzate comprises the following steps:

[0065] After crushing the silkworm pupae, add 2% pure alkali solution at a ratio of 1:4, stir at 55-65℃ for 1-2h, and centrifuge at 6000-8000rpm for 10-15min to collect the supernatant;

[0066] The supernatant is decolorized with activated carbon for 0.5-1h and then spray-dried under the conditions of an inlet air temperature of 150-200°C and an outlet air temperature of 60-100°C to prepare silkworm pupa peptone.

[0067] Example 2:

[0068] The preparation method of Beauveria bassiana microbial preparation comprises the following steps:

[0069] (1) Screening and activation of bacterial strains (core strain: Beauveria bassiana BB-06)

[0070] Wild strain isolation:

[0071] The strain BB-06 (CGMCC No. XXXX) was isolated from larvae of Pieris rapae infected with Beauveria bassiana and purified and cultured for three generations on PDA medium (200 g / L potato, 20 g / L glucose, 15 g / L agar). The strain had an inhibition rate of >85% against tomato gray mold.

[0072] Physiological characteristics: The optimum growth temperature is 25℃, the peak spore production period is 72h, the spore diameter is 3-5μm, and the chitin content of the cell wall is ≥20%.

[0073] Activation culture:

[0074] Slant culture medium: 20 g / L oatmeal powder, 5 g / L yeast powder, 18 g / L agar. After inoculation, culture at 25°C for 7 days until the slant is covered with white fuzzy hyphae and conidia.

[0075] Activation standard: spore germination rate ≥ 95% (tested by culturing on water agar at 25°C for 4 hours), bacterial contamination rate < 0.1% (tested by microscopy).

[0076] (2) Liquid deep fermentation process (core step of spore mass production)

[0077] Seed culture medium optimization

[0078]

[0079] (3) Tertiary fermentation culture

[0080] First-level seed solution (shake flask culture):

[0081] A 500 mL triangular flask was filled with 200 mL of seed culture medium and inoculated with 2 rings of activated spores. The culture was carried out at 25 °C and 180 rpm for 48 h until the dry weight of mycelium reached 1.2 g / L and the spore concentration was 1 × 10 7 CFU / mL.

[0082] Secondary seed tank (10L):

[0083] The inoculum size was 10% (v / v), the aeration rate was 1:0.8 (vvm), the stirring speed was 200 rpm, and the culture was carried out for 36 h. The spore concentration reached 5 × 10 8 CFU / mL, the mycelial morphology is mainly short rods (facilitating subsequent breakage and spore production).

[0084] Three-stage fermentation tank (100L):

[0085] Key parameters:

[0086] Temperature: 25±0.5℃ (controlled by jacket circulating water)

[0087] pH: 6.5±0.2 (automatically add 1M NaOH / HCl)

[0088] Dissolved oxygen content: ≥30% (controlled by linkage between ventilation volume and stirring speed, stirring speed 250-350rpm)

[0089] Culture period: 72h, endpoint: spore concentration 1.2×10 10 CFU / mL, mycelial breakage rate ≥80% (observe the degree of mycelial breakage through microscopic examination).

[0090] Spore Concentrate:

[0091] The fermentation broth was centrifuged at 8000 rpm for 15 min to collect spores, which were then washed twice with sterile saline to a final concentration of 5 × 10 10 CFU / mL of spore suspension (stored at 4°C for no more than 6h).

[0092] (4) Microencapsulation technology

[0093] Composite protective agent formula (mass-to-volume ratio)

[0094]

[0095] Emulsification-crosslinking preparation process

[0096] Aqueous phase preparation:

[0097] Sodium alginate, mannitol and vitamin C were dissolved in deionized water (stirred in a water bath at 50°C for 30 min), cooled to room temperature and then added with spore suspension (spore concentration 1×10 10 CFU / mL), and ultrasonic dispersion for 10 min (power 200 W, frequency 40 kHz).

[0098] Oil phase preparation:

[0099] 2% Span-80 (emulsifier) was added to soybean oil and stirred at 60°C until completely dissolved, which served as the continuous phase.

[0100] High pressure homogenization emulsification:

[0101] The aqueous phase:oil phase=1:3 (v / v) was mixed and passed through a high-pressure homogenizer (100 MPa, 3 cycles) to form an O / W emulsion. The droplet size distribution of the emulsion was observed under a microscope (D50=35 μm, PDI<0.2).

[0102] Calcium ion cross-linking:

[0103] The emulsion was dripped into 2% CaCl2 solution (containing 0.1% chitosan) at a rate of 5 mL / min, and cross-linked for 30 min under magnetic stirring (100 rpm) to form calcium alginate microcapsules. The microcapsules were collected by centrifugation (4000 rpm, 5 min) and washed twice with sterile water.

[0104] Surface modification:

[0105] The microcapsules were suspended in a 0.1% chitosan solution (pH 6.5) and subjected to electrostatic adsorption for 30 minutes to form a double-layer membrane structure with a positive charge, thereby improving the adhesion ability to the tomato wax layer.

[0106] (5) Freeze-drying protection and formulation molding

[0107] Pre-freezing treatment:

[0108] The microcapsule suspension (solid content 10%) was dispensed into freeze-drying trays (thickness ≤ 1 cm) and pre-frozen at -40°C for 2 h (cooling rate 5°C / min) to form a uniform ice crystal structure (to avoid mechanical damage to the spores).

[0109] Vacuum freeze drying:

[0110] Primary drying: vacuum degree 10 Pa, temperature raised to -10 ° C, maintained for 20 h, until the moisture content is <15% (monitored in real time by weighing method).

[0111] Secondary drying: Raise the temperature to 25°C and maintain for 4 hours. The final moisture content is ≤5% and the spore survival rate is ≥90% (detected by plate count method).

[0112] Preparation compounding:

[0113] Freeze-dried microcapsules (80%) were mixed with diatomaceous earth (15%, carrier) and plant essential oil (5%, eugenol and cinnamaldehyde in a 1:1 ratio), passed through an 80-mesh sieve to prepare water-dispersible granules (particle size 0.1-0.5 mm), and sealed in aluminum foil bags (with built-in silica gel desiccant, humidity <10%).

[0114] (6) Quality control standards

[0115]

[0116] Example 3:

[0117] Specific steps for applying Beauveria bassiana microbial preparations to preserve tomatoes

[0118] 1. Dipping method (suitable for home / small-scale storage)

[0119] (1) Pretreatment stage (processing within 24 hours after harvest)

[0120] Tomato screening:

[0121] Select tomatoes of uniform maturity (from color change stage to half-red stage, hardness ≥ 3.5N) without mechanical damage and disease spots, and remove deformed fruits.

[0122] Rinse the dust on the surface with running water and drain the water (no obvious water droplets on the surface, weight loss rate <1%).

[0123] Preparation:

[0124] Take freeze-dried microcapsule preparation (spore concentration ≥ 1×10 9 CFU / g), add sterile water (40℃ warm water) at a ratio of 1:100, stir and dissolve for 30 minutes to prepare 1×10 8 CFU / mL suspension.

[0125] 0.05% Tween-80 (volume ratio) was added as a spreading agent, and ultrasonic dispersion was performed for 5 minutes (frequency 40 kHz) to ensure that the microcapsules were evenly dispersed.

[0126] (2) Dipping treatment stage

[0127] Dip coating operation:

[0128] Completely immerse the tomatoes in the suspension and gently turn them with a glass rod to ensure that the surface of the fruit (including the stem) is in full contact with the solution.

[0129] The dipping time is strictly controlled at 5 minutes (error ±10 seconds). When taking out, use a perforated plastic basket to drain for 30 seconds, so that the residual amount of the drug solution on the surface is about 0.2-0.3mL / piece.

[0130] Surface Dryness:

[0131] Place the coated tomatoes on a clean rack and dry them naturally in a cool and ventilated place (temperature 20-25°C, humidity 60-70%) for 2 hours until a transparent protective film is formed on the surface (no liquid dripping).

[0132] (3) Storage stage

[0133] Storage at room temperature:

[0134] Place in a single layer in a breathable carton (lined with absorbent paper), and pad the box with 3mm thick foam partitions to prevent squeezing. The capacity of each box is ≤5kg.

[0135] Storage environment: temperature 20-25℃, avoid light, ventilate regularly (once a day, 30 minutes each time), the rot rate within 15 days of storage should be ≤15%.

[0136] 2. Spray method (suitable for large-scale warehousing / processing enterprises)

[0137] (1) Equipment and preparation

[0138] Equipment debugging:

[0139] Use a high-pressure plunger pump sprayer (rated pressure 2-3 MPa) equipped with a 0.5 mm aperture atomizing nozzle, and control the spray particle size to 50-100 μm (to ensure uniform adhesion of the liquid medicine).

[0140] Disinfect the pipeline with 75% ethanol before starting up and run it at no load for 5 minutes to remove impurities.

[0141] Preparation dilution:

[0142] The lyophilized preparation was dissolved in sterile water (25°C) at a ratio of 1:50 to prepare 2×10 8 CFU / mL mother solution, add 0.1% chitosan solution (mass volume ratio) to enhance film-forming property, stir evenly and pass through a 200-mesh sieve.

[0143] (2) Spray treatment stage

[0144] Assembly line spray:

[0145] Tomatoes enter the spraying area via a conveyor belt (speed 0.5m / min). The nozzle is 30cm away from the fruit and sprayed crosswise at a 45° angle to ensure that the front and back sides and the fruit stems are evenly coated with the medicine.

[0146] The spray volume was controlled at 50 mL / kg tomato (error ±5%), the conveyor belt speed and spray pressure were monitored in real time, and the dosage of the liquid was calibrated using a flow meter.

[0147] Surface curing:

[0148] After spraying, immediately place the solution in a 35°C constant temperature air room (wind speed 1.5m / s) for drying for 15 minutes to allow the solution to quickly form a film and avoid dripping losses. The weight loss rate is controlled to <2%.

[0149] (3) Warehouse management

[0150] Low temperature storage:

[0151] The products were loaded into food-grade plastic turnover baskets (single basket ≤ 10 kg), and the bottom of the baskets were covered with absorbent pads (5 mm thick) containing 1% Beauveria bassiana preparation, with the stacking height ≤ 5 layers.

[0152] Precool to 4°C before storage (precooling time 6 hours), storage conditions: temperature 4-6°C, humidity 85-90%, regular detection of CO2 concentration (≤5%), storage period 30 days rot rate ≤10%.

[0153] 3. Modified atmosphere packaging (suitable for long-distance transportation / export preservation)

[0154] (1) Packaging materials and preparation pretreatment

[0155] Packaging material preparation:

[0156] Microporous polyethylene film (thickness 50 μm, air permeability 500 cm 3 / m 2 ·day), customized into 1kg self-supporting bag, with 3g solid sustained-release preparation (spore concentration 1×10 7 CFU / g, mixed with diatomaceous earth at a ratio of 1:2).

[0157] Tomato pretreatment:

[0158] Use light dip coating (1×10 7 CFU / mL suspension, dipping time 2 minutes), and after drying, put it into a foam net to reduce transportation collision damage.

[0159] (2) Packaging and gas regulation

[0160] Vacuum packaging:

[0161] Each bag contains 8-10 tomatoes (single fruit weighing 150-200g). After evacuating to 5kPa, the bag is filled with mixed gas (O2 5-8%, CO2 2-3%, and the balance is N2), and the bag is heat-sealed (sealing strength ≥15N / 15mm).

[0162] Pre-cooling and storage:

[0163] After packaging, place the products in a 0°C pre-cooling room (95% humidity) for 2 hours to reduce the core temperature to below 4°C.

[0164] Transportation conditions: cold chain vehicle temperature 4±1℃, vibration frequency ≤5Hz, storage period 45 days (quality can be maintained for 3 days at 25℃).

[0165] (3) Quality monitoring nodes

[0166] Before storage: test the amount of spore attachment (≥1×10 per square centimeter 6 The uniformity of microcapsule distribution (coverage ≥ 90%) was observed by fluorescence microscopy.

[0167] Storage period: Samples were taken every 5 days and the beauvericin content was determined by HPLC (≥2 μg / mL) to ensure the continued antimicrobial activity.

[0168] 4. Comparison table of key process parameters

[0169]

[0170] While 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 these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A Beauveria bassiana microbial preparation, characterized in that: Includes the following components: Active agent 35-35%; Active agent, including the following components: Beauveria bassiana spores and Bacillus subtilis spores, wherein the ratio of Beauveria bassiana spores to Bacillus subtilis spores is 1:1; Composite protective agent 7-11%; Composite protective agent, including the following components: Sodium alginate 3-5%; Mannitol 1-2%; Vitamin C 0.5-1%; Chitosan 0.1-0.3%; Synergist 0.5-1.5%; Synergist, comprising the following components: Silkworm pupa hydrolyzate 0.5-1%; 0.05-0.1% plant essential oil, wherein the plant essential oil is a 1:1 mixture of eugenol and cinnamaldehyde.

2. A Beauveria bassiana microbial preparation according to claim 1, characterized in that: The preparation method of the silkworm pupa hydrolyzate comprises the following steps: After crushing the silkworm pupae, add 2% pure alkali solution at a ratio of 1:4, stir at 55-65℃ for 1-2h, and centrifuge at 6000-8000rpm for 10-15min to collect the supernatant; The supernatant is decolorized with activated carbon for 0.5-1h and then spray-dried under the conditions of an inlet air temperature of 150-200°C and an outlet air temperature of 60-100°C to prepare silkworm pupa peptone.

3. A method for preparing a Beauveria bassiana microbial preparation, characterized in that: The following steps are involved: Step 1: Bacteria culture: Inoculate Beauveria bassiana into a culture medium containing silkworm pupa hydrolyzate, and culture at 25°C and 180 rpm for 36-48 hours to obtain a Beauveria bassiana seed solution; Then, Bacillus subtilis was inoculated into LB medium and cultured at 37°C and 200 rpm for 6-12 hours to prepare Bacillus subtilis seed liquid; Step 2, co-fermentation culture: 10% of Beauveria bassiana seed solution and 5% of Bacillus subtilis seed solution were added to a three-stage fermentation tank, and cultured at 25°C and 250 rpm for 36-72 hours to obtain a fermentation liquid containing composite spores; Step 3, microencapsulation: The fermentation broth was mixed with 3%-5% sodium alginate, 1%-2% mannitol, 0.5%-1% vitamin C, and 0.05%-0.1% plant essential oil, and homogenized under high pressure at 100 MPa for 2-3 times to form an O / W emulsion. A 2% CaCl2 solution was then added dropwise for cross-linking for 30 minutes to prepare microcapsules. Step 4: Freeze-drying: The microcapsule suspension was pre-frozen at -40°C for 1-2 hours and then freeze-dried under a vacuum degree of 8-10 Pa. The primary drying temperature was maintained at -10°C for 15-20 hours and the secondary drying temperature was maintained at 25°C for 2-4 hours to obtain a freeze-dried preparation.

4. The method for preparing the Beauveria bassiana microbial preparation according to claim 3, characterized in that: In step 2, the fermentation process adopts segmented pH control: maintaining pH 6.5 for 0-48 hours and adjusting pH to 5.5 for 48-72 hours to induce the synthesis of antifungal metabolites.

5. The method for using a Beauveria bassiana microbial preparation in tomato preservation according to claims 1-4, characterized in that: The following steps are involved: (1) Preparation: Dissolve the lyophilized preparation in sterile water and prepare 1×10 8 -5×10 8 CFU / mL suspension, add 0.05%-0.1% Tween-80 as a spreader; (2) Dipping treatment: The tomatoes were completely immersed in the suspension for 5–10 min, removed, drained, and then naturally dried to allow the spores to adhere to the surface of the fruit; (3) Modified atmosphere packaging: The treated tomatoes are placed in microporous polyethylene film bags, and the gas ratio in the bags is controlled to be O2 5%-8%, CO2 2%-3%, and stored at 4-6℃.

6. The method for using a Beauveria bassiana microbial preparation in tomato preservation according to claim 5, characterized in that: The dipping treatment can be replaced by a spraying treatment: the suspension is evenly sprayed on the surface of the tomato using a high-pressure sprayer at a dosage of 50-100 mL / kg to form an antibacterial film with a thickness of 5-10 μm.

7. The method for using a Beauveria bassiana microbial preparation in tomato preservation according to claim 5, characterized in that: The tomatoes are processed at the green ripe stage or the color changing stage, and are rinsed with running clean water and drained before processing, and mechanically damaged fruits are removed.

8. The method for using a Beauveria bassiana microbial preparation in tomato preservation according to claim 5, characterized in that: The composition further comprises diatomaceous earth as a carrier and is prepared into water-dispersible granules with a particle size of 0.1-0.5 mm, which are used for preparing fresh-keeping pads or slow-release packaging materials.

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