Food-borne pathogenic bacterium selective co-enrichment culture medium and preparation method thereof

Abstract

The invention discloses a selective co-enrichment culture medium for food-borne pathogenic bacteria and a preparation method of the selective co-enrichment culture medium, and relates to the technical field of pre-enrichment culture of pathogenic bacteria. According to the food-borne pathogenic bacterium selective co-enrichment culture medium, carbon and nitrogen sources are optimized, and growth factors are supplemented, so that interference and inhibition of toxic products generated in the culture process on resuscitation of damaged thalli of target microorganisms are reduced, the enrichment efficiency is improved, and false negative misinformation in subsequent detection is reduced. The invention also discloses a preparation method of the food-borne pathogenic bacterium selective co-enrichment culture medium. The food-borne pathogenic bacterium selective co-enrichment culture medium and the preparation method thereof are suitable for pre-enrichment culture of low-abundance samples with salmonella, staphylococcus aureus, shigella and listeria monocytogenes as detection targets.

Description

Technical Field

[0001] The present invention relates to the technical field of pre-enrichment culture of pathogenic bacteria, and more particularly to a selective co-enrichment culture medium for foodborne pathogenic bacteria and a preparation method thereof. Background Art

[0002] Foodborne pathogens are the leading cause of foodborne illness; they primarily cause disease by releasing biotoxins and invading host cells, leading to complications and even death. Their severity far outweighs chemical contamination (such as pesticide residues and illegal additives) and physical contamination. With the rapid development of the food industry and the increasing complexity of related supply chains, foodborne pathogen contamination has emerged across multiple links and regions within the food supply chain, exacerbating the current challenges of foodborne pathogen prevention and control. Salmonella, Staphylococcus aureus, Shigella, and Listeria monocytogenes are all highly pathogenic foodborne pathogens with similar contamination pathways: primarily through contaminated food. These high-risk foods also include meat, eggs, milk, meat, egg, and dairy products, and ready-to-eat foods, which are key sources of human food. Therefore, Salmonella, Staphylococcus aureus, Shigella, and Listeria monocytogenes are considered priority foodborne pathogens for testing in these foods in food safety testing practices.

[0003] However, the detection of foodborne pathogens such as Salmonella, Staphylococcus aureus, Shigella, and Listeria monocytogenes is limited by the abundance of target pathogens in collected food samples. Both traditional microbiological detection methods and advanced molecular biology detection technologies require pre-enrichment culture of the collected initial samples. Considering that each pathogen has different nutritional requirements and culture conditions for its proliferation and culture, the usual practice is to prepare special enrichment culture media for different pathogens to achieve selective culture and directed proliferation of target pathogens. This not only increases the workload of related detection exponentially, but also greatly limits the advantages of advanced molecular biology detection technology. Therefore, proposing a method that can co-enrich foodborne pathogens such as Salmonella, Staphylococcus aureus, Shigella, and Listeria monocytogenes is the key to improving detection efficiency. In existing research, there are many reports on co-cultivation technologies for several pathogenic bacteria; some of them introduced carbon and nitrogen sources that can be quickly utilized in order to pursue the efficiency of bacterial growth, but ignored the fact that the new components introduced produced toxic products during the cultivation process, which interfered with and inhibited the recovery of damaged target microorganisms, affecting the efficiency of bacterial growth and making it more likely to cause "false negative" false alarms in subsequent detection processes. Summary of the Invention

[0004] In view of the above-mentioned problems existing in the prior art, the present invention provides a foodborne pathogen selective co-enrichment culture medium for the pre-enrichment culture of low-abundance samples with Salmonella, Staphylococcus aureus, Shigella, and Listeria monocytogenes as detection targets, and also provides a preparation method of the foodborne pathogen selective co-enrichment culture medium.

[0005] A first aspect of the present invention provides a culture medium for selective co-enrichment of foodborne pathogens.

[0006] The foodborne pathogen selective co-enrichment culture medium provided in the embodiment of the present aspect mainly comprises, by mass, the following: (a) 25-35 parts of TSB dry powder / granules; (b) 2-6 parts of yeast extract powder; (c) 2-5 parts of glucose; (d) 0.45-0.85 parts of alanyl-glutamine; (e) 4-10 parts of sodium pyruvate; (f) 0.3-0.8 parts of ammonium ferric citrate; (g) 0.5-0.75 parts of lithium chloride; (h) 0.0001-0.0002 parts of potassium tellurite; (i) 0.1-0.2 parts of sodium deoxycholate; (j) 1000 parts of distilled water; and the pH value is 7.2-7.4.

[0007] In a further aspect, preferably, the foodborne pathogen selective co-enrichment medium provided in the embodiment of the current aspect mainly comprises, by mass: (a) 28-32 parts of TSB dry powder / granules; (b) 4.5-5.5 parts of yeast extract powder; (c) 2.5-3.5 parts of glucose; (d) 0.65-0.75 parts of alanyl-glutamine; (e) 5-8 parts of sodium pyruvate; (f) 0.4-0.6 parts of ammonium ferric citrate; (g) 0.5-0.6 parts of lithium chloride; (h) 0.0001-0.00015 parts of potassium tellurite; (i) 0.1-0.15 parts of sodium deoxycholate; (j) 1000 parts of distilled water; and the pH value is 7.4.

[0008] In a further aspect, in order to more effectively utilize the alanyl-glutamine therein, the foodborne pathogenic bacteria selective co-enrichment culture medium provided in the embodiment of the current aspect further comprises, by weight: (k) 0.0001 to 0.0008 parts of a peptidase for hydrolyzing the alanyl-glutamine; wherein the peptidase refers to an aminopeptidase (such as an aminopeptidase, a leucine aminopeptidase), a specific dipeptidase (such as an enzyme secreted by Bacillus or Lactobacillus that can directly and efficiently hydrolyze dipeptide bonds).

[0009] In a further aspect, preferably, in the selective co-enrichment medium for foodborne pathogens provided in the embodiment of the current aspect, the peptidase used to hydrolyze the alanyl-glutamine refers to aminopeptidase N; the amount added is 0.0001~0.0002 parts by mass. In other words, the selective co-enrichment medium for foodborne pathogens further contains: (k) 0.0001~0.0002 parts of aminopeptidase N.

[0010] In a further aspect, aminopeptidase N is a zinc ion-dependent metalloprotease whose activity is highly dependent on the binding and regulation of zinc ions; therefore, the foodborne pathogenic bacteria selective co-enrichment culture medium provided in the embodiment of the current aspect further comprises, by mass: (l) 0.00001 to 0.00002 parts of zinc sulfate.

[0011] In a further aspect, in order to replenish the growth factor substances in yeast extract powder during its preparation process, the foodborne pathogen selective co-enrichment culture medium provided in the embodiment of the present aspect further comprises, by weight: (m) 0.001-0.002 parts of pyridoxal phosphate, and / or (n) vitamin B 12 0.001~0.003 parts.

[0012] A second aspect of the present invention provides a method for preparing a culture medium for selective co-enrichment of foodborne pathogens.

[0013] The method for preparing the selective co-enrichment culture medium for foodborne pathogens provided in the embodiments of the present aspect mainly comprises: adding 25-35 parts by weight of TSB dry powder / granules, 2-6 parts of yeast extract powder, and 0.5-0.75 parts of lithium chloride to 1000 parts of distilled water, heating and boiling until completely dissolved, cooling to room temperature, adjusting the pH to 7.2-7.4; sterilizing by high pressure at 121°C for 15-20 minutes; and cooling and using as a basal culture medium for later use.

[0014] Adding 0.45-0.85 parts by weight of alanyl-glutamine and other components of the basal medium to 1000 parts of distilled water, heating to dissolve, adjusting the pH to 7.2-7.4, sterilizing by autoclaving at 121° C. for 15-20 minutes, and cooling to prepare the basal medium for later use, or preparing a solution of 0.45-0.85 parts by weight of alanyl-glutamine, filtering through a 0.22 μm filter membrane, and then adding the solution to the basal medium;

[0015] Add 0.3-0.8 parts by weight of ammonium ferric citrate and other components of the basal medium to 1000 parts of distilled water, heat to dissolve, adjust the pH to 7.2-7.4, sterilize under high pressure at 121° C. for 15-20 minutes, cool and shake well to prepare as the basal medium for later use, or prepare a solution of 0.3-0.8 parts by weight of ammonium ferric citrate in the dark, filter through a 0.22 μm filter membrane, and then add to the basal medium;

[0016] 2-5 parts by weight of glucose are prepared into a solution, filtered through a 0.22 μm filter membrane, and then added to the basal medium; 4-10 parts by weight of sodium pyruvate are prepared into a solution, filtered through a 0.22 μm filter membrane, and then added to the basal medium; 0.1-0.2 parts by weight of sodium deoxycholate are prepared into a solution, filtered through a 0.22 μm filter membrane, and then added to the basal medium;

[0017] Furthermore, 0.0001 to 0.0002 parts by mass of potassium tellurite is prepared into a solution in the dark, filtered through a 0.22 μm filter membrane, and then added to the basal culture medium.

[0018] In a further aspect, preferably, the preparation method of the foodborne pathogen selective co-enrichment culture medium provided in the embodiment of the present aspect mainly comprises: adding 28 to 32 parts by mass of TSB dry powder / granules, 4.5 to 5.5 parts of yeast extract powder, and 0.5 to 0.6 parts of lithium chloride to 1000 parts of distilled water, heating and boiling until completely dissolved, cooling to room temperature, adjusting the pH value to 7.4; autoclaving at 121°C for 15 to 20 minutes; and using the cooled solution as a base. The culture medium is prepared for standby use; and 0.65 to 0.75 parts by weight of alanyl-glutamine and other components of the basic culture medium are added to 1000 parts of distilled water, heated to dissolve, adjusted to pH 7.4, sterilized by high pressure at 121°C for 15 to 20 minutes, and cooled as the basic culture medium for standby use, or 0.65 to 0.75 parts by weight of alanyl-glutamine are made into a solution, filtered through a 0.22 μm filter membrane, and then added to the basic culture medium; 0.4-0.6 parts of ammonium ferric citrate and other components of the basic culture medium are added to 1000 parts of distilled water, heated to dissolve, adjusted to pH 7.4, sterilized at 121 ° C. for 15-20 minutes, cooled and shaken to prepare a basic culture medium for standby use, or 0.4-0.6 parts of ammonium ferric citrate by weight is prepared into a solution in the dark, filtered through a 0.22 μm filter membrane and then added to the basic culture medium; 2.5-3.5 parts of glucose by weight is prepared into a solution, filtered through a 0.22 μm filter membrane, and then added to the basic culture medium; 0.22 μm filter membrane and then added to the basal medium; 5 to 8 parts by weight of sodium pyruvate are made into a solution, filtered through a 0.22 μm filter membrane and then added to the basal medium; 0.1 to 0.15 parts by weight of sodium deoxycholate are made into a solution, filtered through a 0.22 μm filter membrane and then added to the basal medium; 0.0001 to 0.00015 parts by weight of potassium tellurite are made into a solution in the dark, filtered through a 0.22 μm filter membrane and then added to the basal medium.

[0019] In a further aspect, the method for preparing the selective co-enrichment culture medium for foodborne pathogens provided in the embodiment of the current aspect further includes: preparing a solution of 0.0001 to 0.0008 parts by mass of a peptidase for hydrolyzing the alanyl-glutamine, filtering it through a 0.22 μm filter membrane, and then adding it to the basal culture medium.

[0020] In a further aspect, preferably, aminopeptidase N is used as the peptidase for hydrolyzing the alanyl-glutamine. In some embodiments of the present aspect, the method for preparing the selective co-enrichment culture medium for foodborne pathogens further comprises: preparing a solution of 0.0001-0.0002 parts by weight of aminopeptidase N, filtering the solution through a 0.22 μm filter membrane, and then adding the solution to the basal culture medium. In other embodiments of the present aspect, the method for preparing the selective co-enrichment culture medium for foodborne pathogens further comprises: preparing a solution of 0.0001-0.0002 parts by weight of aminopeptidase N and 0.00001-0.00002 parts by weight of zinc sulfate, respectively, filtering the solution through a 0.22 μm filter membrane, and then adding the solution to the basal culture medium.

[0021] In a further aspect, in order to compensate for the failure and loss of growth factor substances in yeast extract powder due to high pressure during the preparation of the selective co-enrichment culture medium for foodborne pathogens, the preparation method of the selective co-enrichment culture medium for foodborne pathogens provided in some embodiments of the current aspect further includes: preparing a solution of 0.001-0.002 parts by mass of pyridoxal phosphate in the dark, filtering it through a 0.22μm filter membrane, and then adding it to the basal culture medium. The preparation method of the selective co-enrichment culture medium for foodborne pathogens provided in some embodiments of the current aspect further includes: adding 0.001-0.003 parts by mass of vitamin B 12 The solution is prepared in the dark, filtered through a 0.22 μm filter membrane, and then added to the basal culture medium. It should be noted that there may be overlaps between the above embodiments, namely, pyridoxal phosphate and vitamin B 12 They can be prepared into solutions separately in the dark, filtered through a 0.22 μm filter membrane and then added to the basal culture medium. Alternatively, only one of them can be added as needed.

[0022] In a further aspect, in the method for preparing the foodborne pathogen selective co-enrichment culture medium provided in the embodiments of the present aspect, the added alanyl-glutamine refers to L-alanyl-L-glutamine.

[0023] The present invention provides a selective co-enrichment culture medium for foodborne pathogens. By optimizing carbon and nitrogen sources and supplementing growth factors, it reduces the interference and inhibition of toxic products produced during the culture process on the recovery of damaged target microorganisms, thereby improving the efficiency of the culture. Furthermore, a method for preparing the selective co-enrichment culture medium for foodborne pathogens is provided to ensure its quality and maximize its performance. Compared to the existing technology, the selective co-enrichment culture medium for foodborne pathogens provided by the present invention and its preparation method, when applied to the initial enrichment culture of low-abundance samples targeting Salmonella, Staphylococcus aureus, Shigella, and Listeria monocytogenes, reduces interference with the recovery of the target microorganisms, ensures the efficiency of the culture, and reduces false negatives in subsequent testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The co-enrichment effect of the target bacteria in SSSL medium (case A) with an inoculum size of 100 cfu / mL;

[0025] Figure 2 The co-enrichment effect of the target bacteria in SSSL medium (case B) with an inoculum size of 100 cfu / mL;

[0026] Figure 3 The co-enrichment effect of the target bacteria in SSSL medium (Case C) with an inoculum size of 100 cfu / mL;

[0027] Figure 4 This is the co-enrichment effect of the target bacteria with an inoculum size of 100 cfu / mL in SSSL medium (Case D). DETAILED DESCRIPTION

[0028] The present invention will be described below by way of specific examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the present invention. The methods and materials used in the examples are, unless otherwise stated, conventional materials and methods in the art.

[0029] The strains and main reagents involved in the following examples.

[0030] Bacteria:

[0031] Salmonella enterica (CICC22956), Staphylococcus aureus (CICC21600), Shigella flexneri (CICC21678), Listeria monocytogenes (CICC21633), Escherichia coli (ATCC25922), and Bacillus cereus (FSCC115001).

[0032] Main reagents:

[0033] TSB dry powder / granules (Guangdong Huankai Microbiology), yeast extract powder (Shanghai Kanglang Biotechnology), glucose (Shanghai Aladdin), L-alanyl-L-glutamine (Shanghai Aladdin), sodium pyruvate (Shanghai Aladdin), ammonium ferric citrate (Shanghai Aladdin), lithium chloride (Shanghai Aladdin), potassium tellurite (Shanghai Aladdin), sodium deoxycholate (Shanghai Aladdin), aminopeptidase N (Shanghai Qincheng Biotechnology), zinc sulfate (Shanghai Aladdin), pyridoxal phosphate (Shanghai Aladdin), vitamin B 12 (Shanghai Aladdin).

[0034] Example

[0035] I. Example 1: Evaluation of the Enrichment Effect of a Selective Co-enrichment Medium for Foodborne Pathogens

[0036] The present invention provides a culture medium for selective co-enrichment of foodborne pathogens, which is primarily used for pre-enrichment culture of low-abundance samples with Salmonella, Staphylococcus aureus, Shigella, and Listeria monocytogenes as detection targets. The culture medium is intended for selective co-enrichment of Salmonella, Staphylococcus aureus, Shigella, and Listeria monocytogenes. For ease of description, the culture medium for selective co-enrichment of Salmonella, Staphylococcus aureus, Shigella, and Listeria monocytogenes will be referred to as SSSL culture medium hereinafter, in conjunction with the initials of the target foodborne pathogens.

[0037] The present invention provides a basic formula for SSSL culture medium, as well as several optimized formulas. The following describes the bacterial enrichment efficacy of several SSSL culture media prepared with varying component ratios according to the formula provided by the present invention.

[0038] In parts by mass, according to the following formula,

[0039] Example A of SSSL medium: (a) TSB dry powder / granules 25 parts; (b) yeast extract powder 2 parts; (c) glucose 2 parts; (d) L-alanyl-L-glutamine 0.45 parts; (e) sodium pyruvate 4 parts; (f) ammonium ferric citrate 0.3 parts; (g) lithium chloride 0.5 parts; (h) potassium tellurite 0.0001 parts; (i) sodium deoxycholate 0.1 parts; (j) distilled water 1000 parts; pH 7.2;

[0040] Example of SSSL medium B: (a) TSB dry powder / granules 28 parts; (b) yeast extract powder 4.5 parts; (c) glucose 2.5 parts; (d) L-alanyl-L-glutamine 0.65 parts; (e) sodium pyruvate 5 parts; (f) ammonium ferric citrate 0.4 parts; (g) lithium chloride 0.5 parts; (h) potassium tellurite 0.0001 parts; (i) sodium deoxycholate 0.1 parts; (j) distilled water 1000 parts; pH 7.4;

[0041] Example C of SSSL medium: (a) TSB dry powder / granules 32 parts; (b) yeast extract powder 5.5 parts; (c) glucose 3.5 parts; (d) L-alanyl-L-glutamine 0.75 parts; (e) sodium pyruvate 8 parts; (f) ammonium ferric citrate 0.6 parts; (g) lithium chloride 0.6 parts; (h) potassium tellurite 0.00015 parts; (i) sodium deoxycholate 0.15 parts; (j) distilled water 1000 parts; pH 7.4;

[0042] Example D of SSSL medium: (a) TSB dry powder / granules 35 parts; (b) yeast extract powder 6 parts; (c) glucose 5 parts; (d) L-alanyl-L-glutamine 0.85 parts; (e) sodium pyruvate 10 parts; (f) ammonium ferric citrate 0.8 parts; (g) lithium chloride 0.75 parts; (h) potassium tellurite 0.0002 parts; (i) sodium deoxycholate 0.2 parts; (j) distilled water 1000 parts; pH 7.4;

[0043] Four SSSL culture media with different component ratios were prepared to identify the bacterial enrichment effect.

[0044] According to the above SSSL medium formula, add the corresponding parts by weight of TSB dry powder / granules, yeast extract powder, and lithium chloride to distilled water, boil until completely dissolved, cool to room temperature, and adjust the pH to the corresponding value. Sterilize by autoclave at 121°C for 15-20 minutes. After cooling, use as the basal medium.

[0045] L-alanyl-L-glutamine, glucose, sodium pyruvate, and sodium deoxycholate in corresponding mass fractions are prepared into solutions, filtered through a 0.22 μm filter membrane, and then added to the basal culture medium;

[0046] Ammonium ferric citrate and potassium tellurite in corresponding mass fractions are prepared into solutions in the dark, filtered through a 0.22 μm filter membrane, and then added to the basal culture medium; wherein, anti-toxic treatment should be carried out when preparing the potassium tellurite solution and adding the potassium tellurite solution to the basal culture medium.

[0047] Corresponding aliquots of 100 cfu / mL of Salmonella, Staphylococcus aureus, Shigella, and Listeria monocytogenes were added to the above-mentioned SSSL media for co-cultivation. After inoculation, the culture was shaken at 37°C, 80 rpm, and protected from light. Colony counts were performed on plate count agar after 4, 8, 12, 16, 20, and 24 h of culture.

[0048] The growth curves of Salmonella, Staphylococcus aureus, Shigella, and Listeria monocytogenes in each SSSL culture medium were drawn based on the colony count results at each time point. Figure 1 (Example A), Figure 2 (Case B), Figure 3 (C example), Figure 4 (Case D) shows that Salmonella, Staphylococcus aureus, Shigella, and Listeria monocytogenes all grow well in SSSL medium. After 16 hours of culture, each target strain has increased by six orders of magnitude, demonstrating sufficient co-enrichment efficiency for these target strains. While the recovery period (i.e., lag phase) and logarithmic growth phase may vary depending on the target strain type and the composition of each SSSL medium, they generally fall within empirical ranges. Analysis of the recovery period (i.e., lag phase) and logarithmic growth phase of each target strain using growth data from 0 to 4 hours and from 4 hours to 12 hours / 4 hours to 16 hours reveals that the target strains recovered well in all SSSL media (especially Case C) and, furthermore, proliferated significantly during the logarithmic growth phase, meeting the initial enrichment requirements of the target strains.

[0049] Example 2: Impact Assessment of Optimization of Medium for Selective Co-enrichment of Foodborne Pathogens

[0050] According to the results of Example 1, the formula of SSSL medium C was optimized. By weight, 0.0001 parts of aminopeptidase N were added to form SSSL medium C1; 0.0002 parts of aminopeptidase N and 0.00002 parts of zinc sulfate were added to form SSSL medium C2; 0.001 parts of pyridoxal phosphate and 0.001 parts of vitamin B were added to form SSSL medium C3. 12, as SSSL medium C3. When preparing the above-mentioned SSSL medium, aminopeptidase N and zinc sulfate were prepared into solutions, filtered through a 0.22 μm filter membrane, and then added to the basal medium; pyridoxal phosphate and vitamin B 12 All solutions were prepared separately in the dark, filtered through a 0.22 μm filter membrane, and then added to the basal culture medium.

[0051] 100 cfu / mL of Listeria monocytogenes and Shigella were inoculated into SSSL culture medium C, C1, C2, and C3, respectively. After inoculation, the culture was shaken at 37°C and 80 rpm, and the OD values ​​of the culture were measured after 4, 8, 12, and 16 hours. 600nm The results are as follows.

[0052] Table 1 OD values ​​of Listeria monocytogenes and Shigella at different times when cultured in various SSSL media 600nm value

[0053]

[0054] As shown in Table 1, the optimized SSSL culture media C1, C2, and C3 based on SSSL culture media C promoted the recovery of Listeria monocytogenes, which was the most difficult to culture, and Shigella spp., which was the most fragile, to a certain extent, with no negative effects overall.

[0055] III. Example 3: Identification of the inhibitory effect of selective co-enrichment culture medium for foodborne pathogens

[0056] 100 cfu / mL of Escherichia coli and Bacillus cereus were inoculated into SSSL medium C. After inoculation, the culture was shaken at 37°C and 80 rpm. The OD values ​​of the culture were measured after 4, 8, 12, and 16 hours. 600nm The results are as follows.

[0057] Table 2 OD values ​​of non-target bacteria at different times when cultured in SSSL medium (C) 600nm value

[0058]

[0059] As shown in Table 2, the non-target bacteria Escherichia coli and Bacillus cereus were strongly inhibited in SSSL medium (Case C) during the critical pre-growth stages of the target bacteria, namely the recovery and logarithmic growth phases. Escherichia coli was suppressed at 4, 8, 12, and 16 hours compared to its normal growth curve. The levels at 4 and 8 hours were particularly insufficient to interfere with the recovery of damaged Shigella and Listeria monocytogenes, the most vulnerable bacteria. Furthermore, Bacillus cereus was not detected, indicating that SSSL medium has a significant inhibitory effect on it.

[0060] The preferred embodiments of the present invention are described in detail above with reference to the accompanying drawings; however, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0061] It should be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0062] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A selective co-enrichment culture medium for foodborne pathogens, characterized in that: In parts by mass, it comprises: (a) 25-35 parts of TSB dry powder / granules; (b) 2-6 parts yeast extract powder; (c) 2-5 parts of glucose; (d) 0.45-0.85 parts of alanyl-glutamine; (e) 4-10 parts of sodium pyruvate; (f) 0.3-0.8 parts of ammonium ferric citrate; (g) 0.5-0.75 parts of lithium chloride; (h) 0.0001 to 0.0002 parts of potassium tellurite; (i) 0.1-0.2 parts of sodium deoxycholate; (j) 1000 parts of distilled water; The pH value is 7.2~7.

4.

2. The selective co-enrichment medium for foodborne pathogens according to claim 1, wherein In parts by mass, it comprises: (a) 28-32 parts of TSB dry powder / granules; (b) 4.5-5.5 parts yeast extract powder; (c) 2.5-3.5 parts of glucose; (d) 0.65-0.75 parts of alanyl-glutamine; (e) 5-8 parts of sodium pyruvate; (f) 0.4-0.6 parts of ammonium ferric citrate; (g) 0.5-0.6 parts of lithium chloride; (h) 0.0001 to 0.00015 parts of potassium tellurite; (i) 0.1-0.15 parts of sodium deoxycholate; (j) 1000 parts of distilled water; The pH value is 7.

4.

3. The selective co-enrichment medium for foodborne pathogens according to claim 1, wherein In parts by mass, it also comprises: (k) 0.0001 to 0.0008 parts of peptidase for hydrolyzing the alanyl-glutamine.

4. The selective co-enrichment medium for foodborne pathogens according to claim 3, wherein The peptidase refers to aminopeptidase N; The foodborne pathogenic bacteria selective co-enrichment culture medium further comprises, by weight: (k) Aminopeptidase N 0.0001 to 0.0002 parts.

5. The selective co-enrichment medium for foodborne pathogens according to claim 4, wherein In parts by mass, it also comprises: (l) 0.00001~0.00002 parts of zinc sulfate.

6. The selective co-enrichment medium for foodborne pathogens according to claim 1, wherein The alanyl-glutamine mentioned above refers to L-alanyl-L-glutamine.

7. The selective co-enrichment medium for foodborne pathogens according to claim 1, wherein In parts by mass, it also comprises: (m) 0.001-0.002 parts of pyridoxal phosphate; and / or, (n) Vitamin B 12 0.001~0.003 parts.

8. A method for preparing a selective co-enrichment culture medium for foodborne pathogens, characterized in that: The preparation method comprises: Add 25-35 parts by weight of TSB dry powder / granules, 2-6 parts of yeast extract powder, and 0.5-0.75 parts of lithium chloride to 1000 parts of distilled water, heat and boil until completely dissolved, cool to room temperature, adjust the pH to 7.2-7.4, sterilize by autoclave at 121°C for 15-20 minutes, and cool to use as basal culture medium. Adding 0.45-0.85 parts by weight of alanyl-glutamine and other components of the basal medium to 1000 parts of distilled water, heating to dissolve, adjusting the pH to 7.2-7.4, sterilizing by autoclaving at 121° C. for 15-20 minutes, and cooling to prepare the basal medium for later use, or preparing a solution of 0.45-0.85 parts by weight of alanyl-glutamine, filtering through a 0.22 μm filter membrane, and then adding the solution to the basal medium; Add 0.3-0.8 parts by weight of ammonium ferric citrate and other components of the basal medium to 1000 parts of distilled water, heat to dissolve, adjust the pH to 7.2-7.4, sterilize under high pressure at 121° C. for 15-20 minutes, cool and shake well to prepare as the basal medium for later use, or prepare a solution of 0.3-0.8 parts by weight of ammonium ferric citrate in the dark, filter through a 0.22 μm filter membrane, and then add to the basal medium; 2 to 5 parts by weight of glucose are prepared into a solution, filtered through a 0.22 μm filter membrane, and then added to the basal culture medium; 4 to 10 parts by weight of sodium pyruvate are prepared into a solution, filtered through a 0.22 μm filter membrane, and then added to the basal culture medium; 0.1-0.2 parts by weight of sodium deoxycholate was prepared into a solution, filtered through a 0.22 μm filter membrane, and then added to the basal culture medium; 0.0001-0.0002 parts by mass of potassium tellurite is prepared into a solution in the dark, filtered through a 0.22 μm filter membrane, and then added to the basal culture medium.

9. The method for preparing a selective co-enrichment culture medium for foodborne pathogens according to claim 8, wherein: The preparation method of the selective co-enrichment culture medium for foodborne pathogens comprises: adding 28 to 32 parts by weight of TSB dry powder / granules, 4.5 to 5.5 parts of yeast extract powder, and 0.5 to 0.6 parts of lithium chloride to 1000 parts of distilled water, heating and boiling until completely dissolved, cooling to room temperature, adjusting the pH value to 7.4; sterilizing by high pressure at 121°C for 15 to 20 minutes; cooling and using as a basal culture medium for standby use; and adding 0.65 to 0.65 parts by weight of TSB dry powder / granules, 4.5 to 5.5 parts of yeast extract powder, and 0.5 to 0.6 parts of lithium chloride to 1000 parts of distilled water, heating and boiling until completely dissolved, cooling to room temperature, adjusting the pH value to 7.4; sterilizing by high pressure at 121°C for 15 to 20 minutes; cooling and using as a basal culture medium for standby use; and 0.75 parts of alanyl-glutamine and other components of the basal culture medium are added to 1000 parts of distilled water, heated to dissolve, adjusted to pH 7.4, autoclaved at 121°C for 15-20 minutes, cooled and used as the basal culture medium for later use, or 0.65-0.75 parts of alanyl-glutamine are made into a solution, filtered through a 0.22μm filter membrane and added to the basal culture medium; 0.4-0.6 parts of ammonium ferric citrate and other components of the basal culture medium are added to 1000 parts of distilled water, heated to dissolve, adjusted to pH 7.4, autoclaved at 121°C for 15-20 minutes, cooled and shaken for later use as the basal culture medium for later use, or 0.4-0.6 parts of ammonium ferric citrate are made into a solution in the dark, filtered through a 0.22μm filter membrane and added to the basal culture medium; 2.5-3.5 parts of glucose are made into a solution, filtered through a 0.22μm filter membrane After filtering, add to the basal medium; prepare a solution of 5 to 8 parts by weight of sodium pyruvate, filter through a 0.22 μm filter membrane, and then add to the basal medium; prepare a solution of 0.1 to 0.15 parts by weight of sodium deoxycholate, filter through a 0.22 μm filter membrane, and then add to the basal medium; prepare a solution of 0.0001 to 0.00015 parts by weight of potassium tellurite in the dark, filter through a 0.22 μm filter membrane, and then add to the basal medium; and / or, The method for preparing the selective co-enrichment culture medium for foodborne pathogens further comprises: preparing a solution of 0.0001 to 0.0008 parts by mass of a peptidase for hydrolyzing alanyl-glutamine, filtering the solution through a 0.22 μm filter membrane, and then adding the solution to the basal culture medium; and / or, The method for preparing the selective co-enrichment culture medium for foodborne pathogens further comprises: preparing a solution of 0.001 to 0.002 parts by mass of pyridoxal phosphate in the dark, filtering the solution through a 0.22 μm filter membrane, and then adding the solution to the basal culture medium; and / or, The method for preparing the selective co-enrichment culture medium for foodborne pathogens further comprises: adding 0.001 to 0.003 parts by mass of vitamin B 12 The solution was prepared in the dark, filtered through a 0.22 μm filter membrane, and then added to the basal culture medium; and / or, The alanyl-glutamine mentioned above refers to L-alanyl-L-glutamine.

10. The method for preparing a selective co-enrichment culture medium for foodborne pathogens according to claim 9, wherein: The peptidase refers to aminopeptidase N; The preparation method of the selective co-enrichment culture medium for foodborne pathogens further includes: preparing a solution of 0.0001 to 0.0002 parts by mass of aminopeptidase N, filtering the solution through a 0.22 μm filter membrane, and then adding the solution to the basal culture medium; or preparing solutions of 0.0001 to 0.0002 parts by mass of aminopeptidase N and 0.00001 to 0.00002 parts by mass of zinc sulfate, respectively, filtering the solution through a 0.22 μm filter membrane, and then adding the solution to the basal culture medium.

Images