Culture medium for inhibiting growth of rhizopus and application of culture medium in sunflower seed mold separation

Abstract

The invention relates to a culture medium for inhibiting growth of rhizopus and application of the culture medium in sunflower seed mold separation. The selective culture medium is prepared by adjusting the combined synergistic inhibition effect of the water activity and the NaCl concentration; the water activity of the culture medium is 0.93, and the NaCl concentration is 2%, or the water activity of the culture medium is 0.96, and the NaCl concentration is 4%. The culture medium can be used for inhibiting rapid growth of rhizopus and effectively improving the separation efficiency of aspergillus flavus and penicillium in sunflower seeds. When the culture medium is used for carrying out mold separation on different sunflower seed samples, the culture medium has a remarkable effect of inhibiting rapid growth of rhizopus in the sunflower seed samples polluted by rhizopus, and rapid and effective separation of culturable mold florae in the samples is realized. And the culture medium does not have serious inhibition on various florae in sunflower seed samples without rhizopus pollution, so that the phenomenon that culturable florae are reduced is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of microbiological technology, and particularly to a culture medium for inhibiting the growth of Rhizopus and its application in the separation of mold from sunflower seeds. BACKGROUND

[0002] Mold is a small filamentous fungus widely distributed in nature. In the fields of medicine, food, etc., mold contamination may cause the failure of fermented food production, the decline of agricultural product safety, and even the occurrence of diseases; in addition, many mold strains are indispensable production strains in the food industry, such as saccharifying bacteria in brewing, mold in the production of fermented bean curd, and mold in the brewing of soy sauce and vinegar. Therefore, screening of production strains in the medical and food industries, separation of pathogenic bacteria and spoilage bacteria, and research on the physiological and biochemical characteristics of the separated and identified mold are of great significance for the utilization of microbial resources, the prevention and control of harmful microorganisms, and the control of food safety.

[0003] At present, the common mold separation methods mainly include the plate streaking method and the dilution plate coating method, and the commonly used culture media include the Bengal red agar medium, the potato dextrose agar (PDA) medium, the modified Martin agar medium, and the high-salt Czapek agar medium, etc. These culture media can be used for fungal separation and identification, but the composition of each medium is different, resulting in a large difference in the separated mold flora, and the mold flora cultured from a specific sample on different culture media also has a large difference. Deng et al. used the Bengal red agar medium and the modified Martin medium to separate and identify mold from moldy sunflower seeds of different sources, and found that 17 kinds of mold (194 strains in total) were separated on the Bengal red agar medium, while 8 kinds of mold (99 strains in total) were separated on the Martin medium. The number and species of mold separated on the Bengal red agar medium were higher than those on the Martin medium, which may be related to the fact that the nutrients of the Bengal red agar medium are more suitable for the growth of mold in sunflower seeds. Wang et al. used the Bengal red medium, the PDA medium, and the high-salt Czapek agar medium to separate mold from moldy corn and count mold colonies, and found that although the Bengal red agar medium and the high-salt Czapek agar medium can limit the rapid spread of most mold mycelium, mold such as Mucor and Rhizopus still grows vigorously and can cover the entire plate in a short time, greatly affecting the separation of other mold strains and the counting of mold colonies. It has been found that the Bengal red agar medium and the PDA medium are prone to be covered by Rhizopus in the separation of mold from sunflower seeds, especially in the separation of mold from moldy and diseased sunflower seeds, which affects the separation of other mold strains.

[0004] Rhizopus belongs to Zygomycota, has developed mycelium and structure that can form rhizoids, "cotton candy" colony grows densely, and grows fast. In the strain isolation culture experiment, Rhizopus can grow rapidly and cover the entire plate, which seriously affects the isolation of other filamentous fungi. Rhizopus is widely distributed in nature and has a wide range of uses. It is a common saccharifying bacteria in the brewing industry, and can also cause food spoilage or laboratory contamination.

[0005] The existing Rhizopus growth inhibiting substance is complex to prepare and has high preparation cost: the prior art uses a mixture of various chemicals to inhibit Rhizopus, such as preparing salicylaldehyde complex slow-release antibacterial gel to inhibit Rhizopus stolonifer in sweet potato storage; using volatile organic compounds of rice root bacteria to non-contact inhibit Rhizopus; using cinnamon-clove essential oil to inhibit postharvest Rhizopus and Penicillium and other pathogenic fungi pollution; using aldehyde volatile substances as fumigant to inhibit the growth of Rhizopus stolonifer. However, the preparation of essential oils and volatile components is complex, and the chemical composition of some mixed volatile substances is not clear. The preparation cost is high, it is difficult to configure a stable selective medium, and it is more difficult to use in sunflower seed fungal population isolation. In addition, the organic solvents such as methanol and acetonitrile used in the process of preparing essential oils and extracting volatile components have certain toxicity. If the organic solvents are not completely treated, they may cause environmental pollution. Although good results have been achieved in the use of chloramine for mold separation, chloramine is a low-toxicity bactericide that can irritate the eyes, skin and mucous membranes, and is flammable at high temperatures. It will pollute the water body when it enters the environment.

[0006] At present, the substances that inhibit the rapid growth of Rhizopus generally have broad-spectrum antibacterial activity, which is not suitable for the isolation of other fungal populations in sunflower seeds: neither cinnamon essential oil nor other volatile substances can inhibit the growth of Rhizopus, and they can also inhibit the growth of other molds. Ineffective inhibition of the rapid growth of Rhizopus in sunflower seeds, even complete inhibition of the growth of Rhizopus, also efficiently inhibits other fungal populations. In this way, other mold populations in sunflower seeds cannot be isolated, which is a big problem in the field. The inventors found in the previous sunflower seed mold population experiment that the commonly used mold culture medium has poor mold isolation effect on samples containing Rhizopus. Rhizopus grows too fast and quickly covers the entire plate, which significantly affects the isolation and culture of other molds.

[0007] In summary, there is still no selective medium that can effectively inhibit the rapid growth of Rhizopus and improve the isolation efficiency of other cultivable mold populations in sunflower seed samples. There is also no related research on a selective medium that can selectively inhibit Rhizopus by adjusting the water activity and NaCl concentration without affecting the isolation of other molds (e.g., Aspergillus flavus, Penicillium, etc.). Therefore, the isolation effect of the selective medium needs to be evaluated through experiments. SUMMARY

[0008] To solve the above technical problems, the application provides a culture medium for inhibiting growth of Rhizopus and application thereof in separation of sunflower seed molds.

[0009] The application is achieved by the following technical solutions:

[0010] The first object of the application is to provide a culture medium for inhibiting growth of Rhizopus, which is obtained by adding a water activity regulator and a salt inhibitor into a basic nutrient component; the water activity of the culture medium is 0.93, and the mass-volume percentage of the salt concentration is 2%;

[0011] Alternatively, the water activity of the culture medium is 0.96, and the mass-volume percentage of the salt concentration of the culture medium is 4%.

[0012] Further, the water activity regulator is one or more of glycerol, glucose or sucrose.

[0013] Further, the salt inhibitor is sodium salt and / or potassium salt; preferably, NaCl or KCl is added for adjustment.

[0014] Further, the basic nutrient component includes one or more of potato infusion powder, glucose, agar, proteose peptone, potassium dihydrogen phosphate, magnesium sulfate, Bengal red and chloramphenicol.

[0015] Further, the basic nutrient component includes 10-20 g / L of potato infusion powder, 10-20 g / L of glucose, 13-19 g / L of agar and 0.1-0.3 g / L of chloramphenicol.

[0016] Further, the basic nutrient component includes 5-10 g / L of proteose peptone, 10-20 g / L of glucose, 1-3 g / L of potassium dihydrogen phosphate, 0.5-2 g / L of magnesium sulfate, 13-19 g / L of agar, 0.033-0.1 g / L of Bengal red and 0.1-0.3 g / L of chloramphenicol.

[0017] Further, the culture medium further includes 121℃ high-pressure sterilization for 15-30 min.

[0018] The second object of the present application is to provide the use of the culture medium in the isolation of molds from products.

[0019] Further, the product is a product contaminated by Rhizopus; the culture medium can complete the isolation of molds; the molds include Rhizopus, Penicillium and Aspergillus, but are not limited to the three molds.

[0020] The third object of the present application is to provide the use of the culture medium in the isolation of molds from sunflower seeds.

[0021] Further, the sunflower seeds are sunflower seeds contaminated by Rhizopus; the culture medium can complete the isolation of molds; the molds include Rhizopus, Penicillium and Aspergillus, but are not limited to the three molds.

[0022] The present application adopts the flat confrontation method, inoculates Rhizopus, Penicillium oxalicum and Aspergillus flavus commonly found in sunflower seeds on the improved culture medium, evaluates the influence of different water activity and salt concentration on the growth of different molds, and selects a selective culture medium which has good inhibitory effect on Rhizopus and does not affect the growth of Aspergillus flavus and Penicillium oxalicum. The two selective culture media selected by the present application show the best Rhizopus inhibition and other mold isolation and selection effect. The selected culture medium is used for mold isolation of different sunflower seed samples, and the improved culture medium is used to verify the feasibility of inhibiting the growth of Rhizopus and not affecting the isolation of other molds.

[0023] (1) The culture medium A and the culture medium B are prepared according to the water activity and salt ion content of the culture medium in the proportion of 0.96-4% and 0.93-2%. The obtained culture medium A and culture medium B have good effect of inhibiting the overfast growth of Rhizopus, and do not excessively affect the growth of Aspergillus flavus and Penicillium.

[0024] (2) The culture medium of the present application has a significant inhibitory effect on Rhizopus in Rhizopus-contaminated sunflower seed samples, and realizes the rapid and effective isolation of cultivable mold flora in such samples.

[0025] (3) The culture medium of the present application does not cause serious inhibition of various flora in Rhizopus-uncontaminated sunflower seed samples, thereby reducing the cultivable flora.

[0026] The above technical solutions of the present application have the following advantages compared with the prior art:

[0027] (1) The antibiotics and biological dyes used in the prior art have broad-spectrum antibacterial activity, and are not limited to the growth of mold flora. The use of such substances can not allow many mold species to grow, and still cannot achieve the separation effect. The method for regulating water activity and salt concentration of the present application has biological safety, can effectively inhibit the rapid growth of Rhizopus, and can effectively separate the sunflower seed samples affected by Rhizopus coverage and make it difficult for other molds to separate; the selective separation medium is not prepared by broad-spectrum antibacterial drugs, and has limited inhibitory effect on most other mold flora, and still can grow colonies to achieve the separation effect.

[0028] (2) In practical application, most of the selective media related to mold separation at present have the disadvantages of complex preparation process, high cost or broad-spectrum inhibition of most molds, and are not suitable for the separation of mold flora in sunflower seeds; in view of the problem that the sunflower seed samples contain more Rhizopus contamination and cannot be separated from other molds, the present application provides an effective means for the separation and identification of microbial flora of special samples. The preparation of the selective medium in the embodiment of the present application only needs to mix glycerol and sodium chloride in a specific proportion in the basic PDA medium, which is simple in operation, low in cost, and simple in recovery and treatment, and can be sterilized by using a high-pressure steam sterilizer after use.

[0029] (3) The present application selects Penicillium and Aspergillus flavus, which are abundant in sunflower seed samples and have greater harmfulness, as indicator bacteria, and the selective medium has a good inhibitory effect on the rapid growth of Rhizopus. Although Penicillium and Aspergillus flavus grow more slowly in this medium, the inhibitory effect on the two indicator bacteria is obviously weaker than that on Rhizopus.

[0030] (4) The two selective media are applied to the separation and verification of sunflower seed samples, and it is found that the two selective media have good separation effect on sunflower seed samples affected by Rhizopus and making it difficult for other molds to separate; at the same time, the two selective media do not affect the separation of other molds when the basic PDA medium and the two selective media are used for mold separation of sunflower seed samples not affected by Rhizopus. The mold species that can grow in the basic PDA medium can also grow in the two improved selective media.

[0031] In summary, the medium of the present application has the advantages of low production cost, easy operability, biological safety, and effective delay of Rhizopus growth, and has a significant advantage in improving the separation effect of mold flora in sunflower seeds. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to make the content of the present application more easily understood, the present application will be further described in detail below according to specific embodiments of the present application and in conjunction with the drawings, in which:

[0033] Figure 1The figure is the influence of different proportion selective medium on the colony morphology of Rhizopus arrhizus, Aspergillus flavus and Penicillium oxalicum in the application; wherein, 1: Rhizopus arrhizus; 2: Aspergillus flavus; 3: Penicillium oxalicum (the mold positions of other mediums are similar);

[0034] Figure 2 The figure is the influence of different NaCl concentration on the diameter of Rhizopus arrhizus, Aspergillus flavus and Penicillium oxalicum under two water activity in the application; wherein, A is three NaCl concentrations under 0.96aw; B is three NaCl concentrations under 0.96aw;

[0035] Figure 3 The figure is the influence of different water activity (aw) medium on the colony morphology of Rhizopus arrhizus, Aspergillus flavus and Penicillium oxalicum in the application; wherein, 1: Rhizopus arrhizus; 2: Aspergillus flavus; 3: Penicillium oxalicum (the mold positions of other mediums are similar);

[0036] Figure 4 The figure is the influence of different water activity (aw) medium on the diameter of Rhizopus arrhizus, Aspergillus flavus and Penicillium oxalicum in the application;

[0037] Figure 5 The figure is the influence of different NaCl concentration medium on the colony morphology of Rhizopus arrhizus, Aspergillus flavus and Penicillium oxalicum in the application; wherein, 1: Rhizopus arrhizus; 2: Aspergillus flavus; 3: Penicillium oxalicum (the mold positions of other mediums are similar);

[0038] Figure 6 The figure is the influence of different NaCl concentration medium on the diameter of Rhizopus arrhizus, Aspergillus flavus and Penicillium oxalicum in the application;

[0039] Figure 7 The figure is the mold separation of sunflower seed sample I, II, III and IV in PDA medium, medium A and medium B in the application. DETAILED DESCRIPTION

[0040] The application will be further described below in conjunction with the drawings and specific examples, so that those skilled in the art can better understand the application and implement it, but the examples are not limiting to the application.

[0041] In the following examples, the experimental methods are conventional methods unless otherwise specified, and the materials, reagents, etc. can be obtained from commercial channels unless otherwise specified.

[0042] The composition of PDA medium is as follows: potato infusion powder 10 g / L, glucose 20 g / L, agar 13 g / L, chloramphenicol 0.1 g / L;

[0043] Glycerol is purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.; NaCl is purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0044] Rhizopus arrhizus is Rhizopus arrhizus CICC 40284 from China General Microbiological Culture Collection Center;

[0045] Penicillium oxalicum is Penicillium oxalicum CICC 41687 from China General Microbiological Culture Collection Center;

[0046] Aspergillus flavus is Aspergillus flavus ATCC 28539 from China General Microbiological Culture Collection Center.

[0047] Example 1

[0048] This example provides a mold isolation medium for selectively inhibiting Rhizopus from growing too fast

[0049] (0.96-4% combination), and the specific preparation method is as follows:

[0050] (1) Preparation of the medium: accurately weigh 4.3 g of PDA medium, add 12 mL of glycerol (glycerin) to control the water activity (a w ) of the medium to 0.96, and add 4 g of NaCl to control the NaCl concentration of the medium to 4%. Make up to 100 mL with purified water, stir until the medium is completely dissolved, and after dispensing, sterilize at 121°C for 20 min, and reserve.

[0051] (2) Plate confrontation co-culture experiment: pour the medium obtained in step (1) into a 90 mm culture dish, inoculate 5 μL of spore suspension of Rhizopus arrhizus, Penicillium oxalicum and Aspergillus flavus with a spore concentration of about 10 6 / mL at a distance of about 2 cm from the edge of the culture dish, evenly distributed, and cultivate in a 28°C constant temperature incubator for 3 days, and observe the colony growth and take photos.

[0052] Example 2

[0053] This example provides a mold isolation medium for selectively inhibiting Rhizopus from growing too fast

[0054] (0.93-2% combination), and the specific preparation method is as follows:

[0055] (1) Preparation of the medium: accurately weigh 4.3 g of PDA medium, add 18.2 mL of glycerol (glycerin) to control the water activity (a w ) of the medium to 0.93, and add 2 g of NaCl to control the NaCl concentration of the medium to 2%. Make up to 100 mL with purified water, stir until the medium is completely dissolved, and after dispensing, sterilize at 121°C for 20 min, and reserve.

[0056] (2) Flat plate confrontation co-culture experiment: pour the medium obtained in step (1) into a 90 mm culture dish, inoculate 5 μL of spore suspension of Rhizopus oligosporus, Penicillium oxalicum and Aspergillus flavus with a spore concentration of about 10 6

[0057] Comparative Example 1

[0058] This comparative example provides a mold isolation medium (0.96-2% combination), the specific preparation method is similar to that of Example 1, the only difference is that:

[0059] In step (1), 2 g of NaCl is added to control the NaCl concentration of the medium to be 2%. The remaining steps are consistent with Example 1.

[0060] Comparative Example 2

[0061] This comparative example provides a mold isolation medium (0.93-4% combination), the specific preparation method is similar to that of Example 2, the only difference is that:

[0062] In step (1), 4 g of NaCl is added to control the NaCl concentration of the medium to be 4%. The remaining steps are consistent with Example 2.

[0063] Comparative Example 3

[0064] This comparative example provides a mold isolation medium (0.93-4% combination), the specific preparation method is similar to that of Example 2, the only difference is that:

[0065] In step (1), 4 g of NaCl is added to control the NaCl concentration of the medium to be 4%. The remaining steps are consistent with Example 2.

[0066] Comparative Example 4

[0067] This comparative example provides a mold isolation medium (0.93-6% combination), the specific preparation method is similar to that of Example 2, the only difference is that:

[0068] In step (1), 6 g of NaCl is added to control the NaCl concentration of the medium to be 6%. The remaining steps are consistent with Example 2.

[0069] Comparative Example 5

[0070] This comparative example provides a mold isolation medium, the specific preparation method is similar to that of Example 1, the only difference is that:

[0071] ​In step (1), no NaCl was added, and the water activity (a w ) of the medium was controlled by adding 0 mL, 12 mL, 18.2 mL, 25 mL of glycerol, respectively. The remaining steps were consistent with Example 1, and four different water activity media were obtained.

[0072] Comparative Example 6

[0073] This comparative example provides a mold isolation medium, and the specific preparation method is similar to that of Example 1, and the only difference is that:

[0074] In step (1), no glycerol was added, and the NaCl concentration of the medium was controlled by adding 0 g, 2 g, 4 g, 6 g of NaCl, respectively, to obtain a medium with a NaCl concentration of 0%, 2%, 4%, and 6%. The remaining steps were consistent with Example 1, and four different NaCl concentration gradient media were obtained.

[0075] After the plate confrontation co-culture experiment, the effects of the selective media obtained in Example 1, Example 2, and Comparative Examples 1-4 on the growth of molds are shown in Figure 1 and Figure 2 It can be seen that the growth states of Rhizopus arrhizus, Aspergillus flavus, and Penicillium oxalicum on the six different selective media are quite different. On the selective medium with a combination of water activity and NaCl concentration of 0.96-2%, the growth rate of Rhizopus arrhizus is significantly faster than that of Aspergillus flavus and Penicillium oxalicum. On the selective medium with a combination of water activity and NaCl concentration of 0.96-4%, the colony size of Rhizopus arrhizus is basically the same as that of Aspergillus flavus, and the three molds are separated. On the selective medium with a combination of water activity and NaCl concentration of 0.96-6%, the colony size of Rhizopus arrhizus is smaller than that of Aspergillus flavus and Penicillium oxalicum, but the high concentration of NaCl inhibits the growth of Rhizopus arrhizus and also limits the growth of Aspergillus flavus and Penicillium oxalicum. On the selective medium with a combination of water activity and NaCl concentration of 0.93-2%, the effect on the growth of the three molds is basically the same as that of the selective medium with a combination of water activity and NaCl concentration of 0.96-4%, and the growth of Rhizopus arrhizus is inhibited while Aspergillus flavus and Penicillium oxalicum can grow normally. On the selective medium with a combination of water activity and NaCl concentration of 0.93-4% and 0.93-6%, the growth of Rhizopus arrhizus basically stops, and the growth of Aspergillus flavus and Penicillium oxalicum is also significantly inhibited.

[0076] Through the above experiments, it is found that when the water activity and NaCl concentration are 0.96-4% and 0.93-2% in the examples of the present application, Rhizopus arrhizus can be inhibited well, and the growth of Aspergillus flavus and Penicillium oxalicum is not affected too much, which can be used as a subsequent mold isolation medium for Rhizopus-contaminated sunflower seed samples.

[0077] The effects of different water activity media on the colony morphology and growth diameter of Rhizopus arrhizus, Aspergillus flavus and Penicillium oxalicum in Comparative Example 5 are shown in Figure 3 and Figure 4 At different water activity media, Rhizopus arrhizus grew vigorously at water activity of 0.99, completely covering the colonies of Aspergillus flavus and Penicillium oxalicum, so that the two indicator bacteria could not be separated to obtain pure culture; with the decrease of water activity, the mycelium spread of Rhizopus arrhizus was significantly inhibited; the spore number of Aspergillus flavus did not decrease, but the colony diameter did not decrease at water activity of 0.99, 0.96 and 0.93, and the colony diameter of Aspergillus flavus decreased significantly at water activity of 0.90; the colony of Penicillium oxalicum also gradually decreased with the decrease of water activity, but the decrease was very limited compared with Rhizopus arrhizus.

[0078] The effects of different NaCl concentration gradient media on the colony morphology and growth diameter of Rhizopus arrhizus, Aspergillus flavus and Penicillium oxalicum in Comparative Example 6 are shown in Figure 5 and Figure 6 At different NaCl concentration media, Rhizopus arrhizus covered the entire plate at NaCl concentration of 0% and 2%, but with the increase of NaCl concentration, the mycelium and colony size of Rhizopus arrhizus were inhibited; however, the colony size and spore number of Aspergillus flavus and Penicillium oxalicum were not significantly inhibited at NaCl concentration of 0%-4%, and only when the NaCl concentration was 6%, the colony morphology and diameter of Penicillium oxalicum were significantly inhibited, but Penicillium oxalicum could still grow.

[0079] Application Example: Application of Selective Medium in Mold Isolation Experiment of Different Sunflower Seed Samples

[0080] In order to facilitate the description below, the selective medium prepared in Example 1 is named as Medium A, and the selective medium prepared in Example 2 is named as Medium B.

[0081] Mold Isolation of Sunflower Seeds: Two groups of sunflower seed samples I and II containing Rhizopus were selected, which were difficult to perform mold isolation on PDA medium due to Rhizopus contamination; two groups of sunflower seed samples III and IV without Rhizopus were selected, which could normally perform mold isolation on PDA medium. The four groups of sunflower seed samples were subjected to mold isolation by dilution plate coating method using Medium A and Medium B, to verify the feasibility of Medium A and Medium B in mold isolation of sunflower seeds.

[0082] The isolation results are shown in Figure 7As shown, other molds can be observed when the sunflower seed samples I and II are subjected to mold separation using PDA medium, but are covered by Rhizopus hyphae and cannot be screened. When sample I is subjected to mold separation using medium A and medium B, it is observed that the rapid growth of Rhizopus is effectively inhibited, other molds can grow normally and be separated, and the separation effects of the two selective media are basically consistent; when sample II is subjected to mold separation using medium A and medium B, the growth of Rhizopus is also inhibited, and is obviously separated from other molds, which is more conducive to screening; sunflower seed samples III and IV are not affected by Rhizopus, and can be subjected to mold separation using PDA medium. In addition, the number of molds separated from samples III and IV using medium A and medium B is basically consistent with that using PDA medium.

[0083] From the above results, it is found that medium A and medium B have good effects on mold separation of sunflower seed samples I and II, which not only inhibit the growth of Rhizopus, but also do not affect the separation of other molds. For sunflower seed samples III and IV that can normally perform mold separation, medium A and medium B can increase the number of separated molds, and more comprehensively supplement the mold diversity of sunflower seed samples, which indicates that the selective medium for sunflower seed samples in the present application can not only effectively inhibit the rapid growth of Rhizopus, so that other molds cannot be separated, but also will not affect the diversity of cultivable molds of sunflower seed samples.

[0084] Obviously, the above examples are merely examples for clarity, and are not limiting of the embodiments. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description. Here, it is not necessary and impossible to exhaust all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A medium for inhibiting the growth of Rhizopus, characterized in that, The culture medium is obtained by adding a water activity regulator and a salt inhibitor into a basic nutrient component; the water activity of the culture medium is 0.93, and the salt concentration is 2%; Or, the water activity of the culture medium is 0.96, and the salt concentration is 4%.

2. The medium of claim 1, wherein, The water activity regulator is one or more of glycerol, glucose or sucrose.

3. The medium of claim 1, wherein, The salt inhibitor is sodium salt and / or potassium salt.

4. The medium of claim 1, wherein, The basic nutrient component comprises one or more of potato infusion powder, glucose, agar, peptone, potassium dihydrogen phosphate, magnesium sulfate, Bengal red and chloramphenicol.

5. The medium of claim 4, characterized in that, The basic nutrient component comprises 10-20 g / L of potato infusion powder, 10-20 g / L of glucose, 13-19 g / L of agar, 0.1-0.3 g / L of chloramphenicol; And / or, the basic nutrient component comprises 5-10 g / L of peptone, 10-20 g / L of glucose, 1-3 g / L of potassium dihydrogen phosphate, 0.5-2 g / L of magnesium sulfate, 13-19 g / L of agar, 0.033-0.1 g / L of Bengal red and 0.1-0.3 g / L of chloramphenicol.

6. The medium of claim 1, wherein, The culture medium further comprises 121℃ high-pressure sterilization for 15-30 minutes.

7. Use of the culture medium according to any one of claims 1-6 in product mold isolation.

8. Use according to claim 7, characterized in that, The product is a product contaminated by Rhizopus.

9. Use of the culture medium according to any one of claims 1-6 in sunflower seed mold isolation.

10. Use according to claim 9, characterized in that, The sunflower seed is a sunflower seed contaminated by Rhizopus.

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