Composite starter for improving fermentation quality of sausages and application

Abstract

To provide a composite starter for improving the fermentation quality of sausages and applications therefor.SOLUTION: The invention relates to a composite starter that comprises Lactiplantibacillus plantarum YR07, Lactobacillus sakei L48, Staphylococcus xylosus S.14, and Staphylococcus sciuri S.18. The composite starter is a liquid microbial agent. The ratio of the effective viable counts of Lactiplantibacillus plantarum YR07, Lactobacillus sakei L48, Staphylococcus xylosus S.14, and Staphylococcus sciuri S.18 is 1: 1: (2-4): (2-4). Compared with traditional fermented sausages, the pH value of the sausages can be remarkably and rapidly reduced, growth of putrefying bacteria is inhibited, and the safety of the sausages is guaranteed.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to the technical field of meat starter, in particular to a composite starter and its application for improving the fermentation quality of sausage. [Background technology]

[0002] Fermented sausage refers to a kind of meat product that uses microbial fermentation under artificially controlled or natural environmental conditions to produce a unique flavor. Traditional fermented sausage is mainly fermented naturally by microorganisms in the production environment, and the product quality is unstable. Using artificial inoculation of pure microbial cultures to control fermentation can greatly improve the quality and safety of the product. Therefore, it has become a common practice to artificially inoculate meat products with pure microbial cultures or preparations (i.e., fermented meat product starters) to achieve industrial production.

[0003] Lactic acid bacteria and staphylococci are the most common microorganisms in fermented meat products, and are also often used as starters for fermented meat products. When inoculated with lactic acid bacteria, they can quickly metabolize carbohydrates to produce acid, lower the pH, inhibit the growth of spoilage and pathogenic microorganisms, and improve the safety of the product. Staphylococcus plays an important role in the flavor and color quality of fermented meat products, and generally has proteolytic enzyme, fat hydrolase, and nitrate reductase activity, which can affect the flavor characteristics of the product, promote the drying process of mature meat products, improve the texture, and at the same time promote the formation of nitrosomyoglobin, which is favorable for the formation and stability of good color of meat products. Fermented meat products require different microorganisms according to different flavors, and their applications are usually not limited to a single strain, and multiple strains are used in combination to make up for the monotony of a single strain.

[0004] Fermented meat products with targeted inoculation of bacterial strains can resolve the instability dependent on natural fermentation while ensuring texture and texture, and greatly improve the reliability of product safety and quality. In addition, the effect of combined inoculation of lactic acid bacteria and staphylococcus is better than that of single inoculation.

[0005] At present, starters used in domestic production are mainly produced by Western companies, such as BactofermTMF-1 from Chr Hansen, Germany, but have not yet been produced using domestic strains. Therefore, screening for lactic acid bacteria and coagulase-negative staphylococci with excellent fermentation and growth properties and applying them to fermented sausages is of great importance for the processing of sausages and meat products. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention aims to provide a composite starter and application for improving the fermentation quality of sausage. [Means for solving the problem]

[0007] To achieve the above objectives, the present invention provides the following technical solutions: A composite starter for improving the fermentation quality of sausage, comprising Lactiplantibacillus plantarum YR07, Lactiplantibacillus sakei L.48, Staphylococcus xylosus S.14, and Staphylococcus schiuri S.18; The Lactiplantibacillus plantarum YR07 was deposited at the China Center for Type Culture Collection (CCTCC), the date of deposit was August 18, 2022, and the strain deposit number is CTCCC NO: M20221303; The said Latilactobacillus sakei L.48 was deposited at the China Center for Type Culture Collection (CCTCC), the date of deposit is August 18, 2022, and the deposit number is CTCCC NO: M20221306; The Staphylococcus xylosus S.14 was deposited at the China Center for Type Culture Collection (CCTCC) on August 18, 2022, with the deposit number CTCCC NO:M 20221305; The Staphylococcus schiuri S.18 was deposited at the China Center for Type Culture Collection (CCTCC) on August 18, 2022, with the deposit number CTCCC NO:M20221304.

[0008] Furthermore, the complex starter is a liquid bacterial agent, and the ratio of effective live bacteria counts of Lactiplantibacillus plantarum YR07, Lactiplantibacillus sakei L.48, Staphylococcus xylosus S.14 and Staphylococcus schiuri is 1:1:2~4:2~4.

[0009] The complex starter according to the invention can be used in the production of fermented meat products.

[0010] wherein said fermented meat product is a fermented sausage.

[0011] The method for producing fermented sausages is as follows: (1) adding seasonings and auxiliary materials to raw meat and salting it to obtain pre-fermented meat; (2) inoculating the composite starter according to claim 1 or 2 into the fermented meat and mixing it uniformly, and stuffing the sausage; (3) a fermentation step in which the mixture is fermented for 20 to 40 hours under conditions of 25 to 35°C and RH 80 to 90%; and (4) an air-drying step of fermenting the mixture under conditions of 10 to 20°C and RH 40 to 50% for 10 to 20 days.

[0012] The composite starter is a liquid microbial agent, in which the ratio of effective viable bacteria counts of Lactiplantibacillus plantarum YR07, Lactiplantibacillus sakei L.48, Staphylococcus xylosus S.14 and Staphylococcus schiuri is 1:1:2~4:2~4.

[0013] In the step (1), the raw meat is obtained by removing and washing fresh lean pork thigh meat and back fat from which fascia, large tendons, and other parts are removed, grinding the meat, and then mixing the lean pork thigh meat and back fat in a ratio of 1 to 4:9 to 6.

[0014] In the step (1), the salting temperature is 3 to 8°C.

[0015] In step (1), the seasonings and auxiliary materials are added in the following mass percentages relative to the raw meat: salt 2.5%, glucose 0.7%, nitrite 0.01%, garlic powder 0.015%, fennel powder 0.05%, black pepper powder 0.05%, and sausage flavor 0.225%. Effect of the Invention

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Compared with traditional fermented sausages, the fermented sausages produced using the composite starter of the present invention can be inoculated with the composite starter of Lactiplantibacillus plantarum YR07, Lactibacillus sakei L.48, Staphylococcus xylosus S.14, and Staphylococcus schiuri S.18 of the present invention, which can significantly and quickly reduce the pH value of the sausage, inhibit the growth of spoilage bacteria, and ensure the safety of the product. (2) When sausages are fermented using the composite starter of Lactiplantibacillus plantarum YR07, Lactiplantibacillus sakei L.48, Staphylococcus xylosus S.14, and Staphylococcus schiuri S.18 of the present invention, the content of human essential amino acids in the fermented sausages is significantly increased compared with that of naturally fermented sausages, and the nutritional value is improved. (3) The sausages fermented by the composite starter of Lactiplantibacillus plantarum YR07, Lactiplantibacillus sakei L.48, Staphylococcus xylosus S.14, and Staphylococcus schiuri S.18 of the present invention are more popular among consumers after sensory evaluation. [Brief description of the drawings]

[0017] [Figure 1] Electropherograms of Lactiplantibacillus plantarum YR07, Lactiplantibacillus sakei L.48, Staphylococcus xylosus S.14, and Staphylococcus schiuri S.18. [Diagram 2] Phylogenetic tree of Lactiplantibacillus plantarum YR07, Lactiplantibacillus sakei L.48, Staphylococcus xylosus S.14, and Staphylococcus schiuri S.18. [Diagram 3] FIG. 1 shows a diagram of pH values ​​of various groups of fermented sausages during the fermentation process.

[0018] Description of biological deposit Lactiplantibacillus plantarum YR07 was deposited in the China Center for Type Culture Collection, the deposit address is Wuhan University, No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, the abbreviation of the depository institution is CCTCC, the date of deposit is August 18, 2022, and the biological deposit number is CCTCC NO: M20221303. Latilactobacillus sakei L.48 was deposited in the China Center for Type Culture Collection, the deposit address is Wuhan University, No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, the abbreviation of the depository institution is CCTCC, the date of deposit is August 18, 2022, and the biological deposit number is CCTCC NO:M20221306. Staphylococcus xylosus S.14 was deposited in the China Center for Type Culture Collection, the deposit address is Wuhan University, No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, China, the abbreviation of the depository institution is CCTCC, the date of deposit is August 18, 2022, and the biological deposit number is CCTCC NO:M20221305. Staphylococcus sciuri S.18 (Mammaliicoccus sciuri S.18) was deposited in the China Center for Type Culture Collection, the deposit address is Wuhan University, No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, China, the abbreviation of the depository institution is CCTCC, the date of deposit is August 18, 2022, and the biological deposit number is CCTCC NO:M20221304. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The technical solutions in the embodiments of the present invention will be described below clearly and completely with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and are not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts are included in the scope of protection of the present invention.

[0020] Unless otherwise specified, all reagents or materials described in the following examples are commercially available.

[0021] Example 1 Collection of traditional fermented meat products and isolation, purification and screening of lactic acid bacteria and coagulase-negative staphylococci 1. Isolation of lactic acid bacteria and coagulase-negative staphylococci Longxi bacon, Su-style sausage, Enshi ham, Dongzhi sour meat, Jian'ou salted duck, Guizhou bacon, etc. were collected from all over the country, and 10.0 g samples were weighed under sterile conditions, homogenized with 90 mL of sterile saline, and then diluted. 1.0 mL of the sample dilution was poured onto MRS solid medium containing 2% light calcium carbonate and cultured at 37°C for 48 hours. Colonies with dissolved calcium rings and different shapes were selected until pure colonies were obtained, and streaking culture on MRS solid medium was repeated 3 to 4 times. 0.1 mL of the sample dilution was taken, spread on MSA solid medium, and cultured at 37°C for 24 hours. Colonies with different shapes were selected until pure colonies were obtained, and streaking culture on MSA solid medium was repeated 3 to 4 times. 2. Screening for lactic acid bacteria and coagulase-negative staphylococci Gram stain microscopy and catalase tests were performed on the purified strains to screen for Gram stain positive and catalase negative strains. The obtained strains were subjected to mucus production test, hemolysis test, glucose gas production test, H2S production test, arginine ammonia production test, and amino acid decarboxylase test, and the antibacterial properties of the screened lactic acid bacteria were measured by the Oxford cup diffusion plate method. Two strains of lactic acid bacteria, YR07 (Lactiplantibacillus plantarum) and L.48 (Lactiplantibacillus sakei), which were safe and had excellent fermentation performance, were screened.

[0022] [Table 1] JPEG2025027465000003.jpg157170

[0023] Gram staining microscopy and catalase tests were performed on the purified strains to screen for Gram staining positive and catalase positive strains. The obtained strains were subjected to proteolytic and lipolytic enzyme tests, nitrite reductase tests, mucus production and hemolysis tests, glucose gas production tests, H2S production tests, arginine ammonia production tests, and amino acid decarboxylase tests. Staphylococcus aureus S.14 (Staphylococcus xylosus) and S.18 (Staphylococcus schiuri) with safety, good fermentation performance, and color-developing function were screened.

[0024] [Table 2]

[0025] Example 2 Identification of Lactic Acid Bacteria and Coagulase-Negative Staphylococci The lactic acid bacteria genes were extracted using a bacterial genomic DNA extraction kit, and the extracted 16S rDNA sequence was PCR amplified using 27F (5'-AGAGTTTGATCCTGGCTCAG-3') and 1492R (5'-TACGGYTACCTT-GTTACGACTT-3') upper and lower primers (shown in SEQ ID NO: 1-2). The PCR reaction conditions were 34 cycles at 95°C (95°C 30 seconds, 56°C 30 seconds, 70°C 65 seconds) for 20 minutes of initial denaturation and 72°C for 10 minutes of final chain extension. The obtained PCR products were subjected to agarose gel electrophoresis, and the electrophoretic results were observed using a gel imaging system, as shown in Figure 1. The sequencing results were compared and searched using the basic local alignment search tool (BLAST) in the GenBank data of the National Center for Biotechnology Information (NCBI) to select the 16S rDNA sequences of the model strains with high homology. A phylogenetic tree was constructed, and the results are shown in Figure 2. Strain YR07 was identified as Lactiplantibacillus plantarum, strain L.48 was identified as Latilactobacillus sakei, strain S.14 was identified as Staphylococcus xylosus, and strain S.18 was identified as Mammaliicoccus sciuri.

[0026] Example 3 Production of fermented sausage 1. Manufacturing of composite starter After activation, Lactobacillus casei YR07 and L.48 were harvested at 1% inoculum, inoculated into MRS liquid medium, cultivated for 12 hours, centrifuged at 8000×g and 4℃ for 5 minutes, the precipitate was collected, and washed three times with saline. After activation, Staphylococcus aureus S.14 and S.18 were inoculated into MSA liquid medium at 1% inoculation, cultivated for 12 hours, centrifuged at 8000×g and 4℃ for 5 minutes, the precipitate was collected, and washed three times with saline. The final concentration of the bacteria was 1×10 in a ratio of 1:1:2:2. 7 Adjust to CFU / g and prepare for use with a volume of 1 ml. 2. Production of fermented sausages Pork thigh meat was ground and mixed to a fat to lean ratio of 3:7, and the proportions of supplementary materials added were 2.5% salt, 0.7% glucose, 0.01% nitrite, 0.015% garlic powder, 0.05% fennel powder, 0.05% black pepper powder, 0.225% sausage flavor, and 1mL bacterial suspension. During stuffing, the sausage body was ensured to be plump and bubble-free. Then, it was hung in a constant temperature and humidity box and fermented at 30℃ and 85% relative humidity for 24 hours, and then air-dried at 15℃ and 45% relative humidity for 15 days to obtain the finished product. The test groups were a blank control group (CK group), a commercial fermentation group (CS group) and a composite starter inoculation group (CH group).

[0027] Example 4 Measurement of fermented sausage indicators 1. Measurement of pH value of fermented sausage The sausages of the CK, CS and CH groups in Example 3 were stuffed, fermented for 1 day, air-dried for 1 day, air-dried for 5 days, air-dried for 10 days and air-dried for 15 days, and then the pH value was measured. 10.0 g of sample was accurately weighed, cut into thin strips, added with 100 mL of distilled water, thoroughly and uniformly mixed with the sample, homogenized at 8000×g for 30 seconds, filtered, and the supernatant was taken and measured with a pH meter, and the average was calculated by repeating three times. The results are shown in Figure 3. The pH of the three groups before fermentation was similar. After fermentation for one day, the pH of the CS and CH groups dropped to below 5.0. After air drying for one day, the value dropped to a minimum of 4.6-4.7 and then slowly increased. The pH of the CK group was always above 5.0, but the pH of the CK group with the addition of commercial starter and compound starter dropped faster. It was found that the addition of starter can quickly produce acid, shorten the fermentation time of sausages, and inhibit the growth of miscellaneous bacteria. 2. Measurement of amino acid content in fermented sausages The measurement was performed according to the method of the national standard "GB5009.124-2016-Determination of Amino Acids" with some modifications. The fermented sausage was weighed out appropriately, cut into small pieces, and then freeze-dried. 0.1 g of the freeze-dried sample was accurately weighed, and 4 mL of 4% sulfosalicylic acid solution was added, and the sample was subjected to ultrasonic extraction for 30 minutes and then allowed to stand for 10 minutes. After separation, 1.5 mL of the supernatant was taken and centrifuged at 12000 x g and 4 ° C for 30 minutes. 1 mL of the supernatant was collected and filtered through a 0.22 μm aqueous phase filtration membrane, and the free amino acids were measured using a fully automated amino acid analyzer.

[0028] From Table 3, it can be seen that the total amino acid content of the sausage fermented with the composite starter prepared in Example 3 of the present invention is the highest, and the content of the eight essential amino acids for humans is also higher than that of the natural fermentation group and the commercial fermentation group.

[0029] [Table 3] JPEG2025027465000006.jpg248170JPEG2025027465000007.jpg248170JPEG2025027465000008.jpg16170Note: ND indicates that the corresponding compound was not detected. 3. Determination of the content of volatile compounds in fermented sausages The content of volatile compounds in the finished sausages of the CK, CS, and CH groups in Example 3 was measured. The volatile flavor substances in the fermented sausages were analyzed using headspace solid-phase microextraction-gas chromatography mass spectrometry. Thinly cut sausage samples (2.0 g) were placed in 20 mL headspace sample vials, and 10 μL of 2,4,6 trimethylpyridine (concentration: 0.1 g / L) was added as an internal standard. The headspace sample vial was equilibrated at a temperature of 60°C for 5 minutes, after which an aged 75 μm composite CAR / PDMS extraction needle was inserted and adsorbed for 30 minutes, and then the extraction head was immediately inserted into the gas chromatography mass spectrometry sample inlet and analyzed for 5 minutes. Volatile compounds were measured using a gas chromatography-mass spectrometry (GC-MS) system (5977B, Agilent), gas chromatography conditions: DB-WAX (30 m × 0.25 mm × 0.25 μm), sample inlet temperature was 250 °C, samples were injected in splitless mode, helium was used as carrier, flow rate was 1 mL / min, programmed temperature rise: column initial temperature was 40 °C and maintained for 5 min, then ramped to 90 °C at 2 °C / min and no hold, ramped to 180 °C at 5 °C / min and no hold, ramped to 230 °C at 10 °C / min and held for 8 min. Mass spectrometry conditions: ion source temperature was 230 °C, mass scan range was 30-550 m / z. The identification of volatile compounds was performed by comparing the NIST 20 mass spectral library, and a similarity of more than 80% was adopted as the identification result. Volatile compounds were quantified by the internal standard method using 2,4,6-trimethylpyridine solution dissolved in n-hexane as an internal standard substance, and the quantitative results were expressed in μg / kg. References on the evaluation method of important volatile substances: (Liu Tengyong, Zhou Guanghong, Xu Xinglian, A new method to identify important flavor compounds in food: "ROAV" method [J]. Food Science, 2008, 344 (7): 370-374.), Relative Odor Activity Value (ROAV) analysis method is used to identify important volatile substances in the sample. The results are shown in Table 4. A total of 25 important volatile substances in the sausages were identified by the relative odor activity values, among which the CH group contained a large amount of important volatile substances, with a content of 216.28 μg / kg, and 3-hydroxy-2-butanone, a special flavor compound with a pleasant creamy taste, was the most abundant in the CH group. Compared with the control group and the commercial fermentation group, the inoculation of the composite starter can significantly increase the content of characteristic flavor substances in the fermented sausages, so the inoculation of the composite starter can improve the flavor of the fermented sausages.

[0030] [Table 4] JPEG2025027465000010.jpg249170JPEG2025027465000011.jpg167170

[0031] 4. Sensory evaluation of fermented sausages The evaluation committee consisted of 10 selected graduate students majoring in food, half male and half female. The sausages were boiled for 20 min and cut into 20 mm thick pieces. The sensory evaluation was performed using a double-blind method, where the evaluators could not communicate with each other and had to rinse their mouths with clean water before evaluating the different samples. Scoring was based on a 10-point scale, assessing five aspects of the samples: appearance, texture, color, flavor, and overall acceptability, and the evaluation criteria are shown in Table 5.

[0032] From Table 6, it can be seen that inoculation with the composite starter in the present invention improves the appearance integrity of the sausage, enhances the flavor of the fermented sausage, improves the texture of the fermented sausage, and improves the overall acceptability of the fermented sausage.

[0033] [Table 5] JPEG2025027465000013.jpg169170

[0034] [Table 6] JPEG2025027465000015.jpg85170

[0035] 5. Determination of biogenic amine content in fermented sausages a. Sample preparation The content of biogenic amines in the finished sausage products of the CK, CS and CH groups in Example 3 was measured. 2.5g of sausage sample was weighed, cut into small pieces, added with 125L of internal standard solution (100mg / L), mixed thoroughly and uniformly, then added with 10mL of 0.6mol / L perchloric acid solution for extraction, homogenized at 8000rpm for 30 seconds, repeated twice, centrifuged at 4℃ and 8000×g for 10 minutes, took the supernatant, and repeated the above extraction process for the precipitated part, and quantified with the supernatant to 25mL. b. Preparation of standard solutions Appropriate amounts of histamine, tyramine, putrescine, cadaverine, tryptamine, spermine, and aniline standards were weighed and prepared into 1.0 g / L standard stock solutions with 0.1 mol / L hydrochloric acid. 1 mL of each standard stock solution was taken and 100 mg / L standard mixed solutions were prepared with 0.1 mol / L hydrochloric acid, and serial dilutions were performed to obtain mixed standard working solutions with final concentrations of 1.0, 5.0, 10.0, 20.0, and 100.0 mg / mL. c. Pre-column derivatization of samples and standards Derivation of sample: 0.2mL of sample solution was transferred, 40μL of 2mol / L NaOH solution was added to adjust the pH, then 60μL of saturated NaHCO3 solution and 400μL of derivatization agent (10mg / mL acetone) were added, and vortexed to mix uniformly. In the dark, it was immersed in a 40℃ water bath for 45 minutes, 20μL of ammonia water was added, and after uniform mixing, it was left in the dark for 30 minutes to stop the reaction. Acetonitrile was added to make the final volume 1mL, and it was filtered through a 0.22μm filter membrane, and the sample was loaded and detected. Derivation of standard: 0.2mL of biogenic amine standard series solution was transferred respectively, and 50μL of internal standard solution (100mg / L) was added sequentially, and the following operations are the same as the derivation step of the sample solution. d. Chromatography conditions The chromatography column was Waters-symmetry C18 (4.6 mm × 250 mm, 5 μm), the column temperature was 35 °C, the UV detection wavelength was 254 nm, the sample injection volume was 10 μL, the flow rate was 0.8 mL / min, the mobile phase A was acetonitrile, B was water, gradient elution was used, and the elution procedure is shown in Table 7.

[0036] [Table 7]

[0037] The results are shown in Table 8. The contents of cadaverine, tyramine and spermine in the sausages inoculated with the composite starter were lower than those in the control group and the commercially fermented group, no aniline or histamine was detected, and the total amount of biogenic amines in the composite starter group was significantly reduced (P<0.05) compared with the control group and the commercially fermented group. Therefore, the inoculation of the composite starter can effectively reduce the formation of biogenic amines in fermented sausages.

[0038] [Table 8] JPEG2025027465000018.jpg48170

[0039] While embodiments of the present invention have been illustrated and described, those skilled in the art will appreciate that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention.

Claims

1. A complex starter for improving the fermentation quality of sausage, comprising Lactiplantibacillus plantarum YR07, Lactibacillus sakei L. 48, Staphylococcus xylosus S. 14, and Staphylococcus schiuri S. 18; The Lactiplantibacillus plantarum YR07 was deposited at the China Center for Type Culture Collection (CCTCC) on August 18, 2022, and the strain has a deposit number of CCTCC NO: M20221303; The Latilactobacillus sakei L. 48 was deposited at the China Center for Type Culture Collection (CCTCC) on August 18, 2022, and the deposit number is CCTCC NO: M20221306; The Staphylococcus xylosus S. 14 was deposited at the China Center for Type Culture Collection (CCTCC) on August 18, 2022, with the deposit number CCTCC NO: M 20221305; The Staphylococcus schiuri S. 18 is deposited at the China Center for Type Culture Collection (CCTCC) on August 18, 2022, and has the deposit number CCTCC NO: M20221304.

2. The complex starter according to claim 1, characterized in that the complex starter is a liquid bacterial agent, and the ratio of effective viable bacteria counts of Lactiplantibacillus plantarum YR07, Lactibacillus sakei L.48, Staphylococcus xylosus S.14, and Staphylococcus schiuri S.18 is 1:1:2-4:2-4.

3. Application of the complex starter according to claim 1 or 2 in the production of fermented meat products.

4. The application of the composite starter in producing fermented meat products according to claim 3, characterized in that the fermented meat product is fermented sausage.

5. The method for producing the fermented sausage comprises: Step (1) of adding seasonings and auxiliary materials to raw meat and salting it to obtain pre-fermented meat; (2) inoculating the fermented meat with the composite starter according to claim 1 or 2, mixing it uniformly, and stuffing it into sausages; A fermentation step (3) of fermenting the mixture under conditions of 25 to 35° C. and 80 to 90% RH for 20 to 40 hours; The application of the composite starter in the production of fermented meat products according to claim 4, further comprising: (4) fermenting the mixture under conditions of 10-20°C and 40-50% RH for 10-20 days in air drying.

6. The application of the composite starter in the manufacture of fermented meat products according to claim 5, characterized in that the composite starter is a liquid bacterial agent, in which the ratio of effective viable bacteria count of Lactiplantibacillus plantarum YR07, Lactibacillus sakei L.48, Staphylococcus xylosus S.14, and Staphylococcus schiuri S.18 is 1:1:2~4:2~4.

7. The application of the composite starter in the manufacture of fermented meat products according to claim 6, characterized in that in step (1), the raw meat is obtained by removing and washing the fascia and tendon parts on the surface of fresh pork leg lean meat and back fat, grinding the meat, and then mixing the pork leg lean meat and back fat in a ratio of 1-4:9-6.

8. The application of the composite starter in the production of fermented meat products according to claim 7, characterized in that in step (1), the salting temperature is 3-8°C.

9. The application of the composite starter in the preparation of fermented meat products according to claim 8, characterized in that in step (1), seasonings and auxiliary materials are added according to the following mass percentages based on the raw meat: salt 2.5%, glucose 0.7%, nitrite 0.01%, garlic powder 0.015%, fennel powder 0.05%, black pepper powder 0.05%, and sausage flavor 0.225%.

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