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Freeze-drying protective agent for listeria monocytogenes standard substance, freeze-drying preserving method and application

A technology of Listeria monocytogenes and freeze-drying protective agent, which is applied in the direction of microorganism-based methods, biochemical equipment and methods, bacteria, etc., to achieve a high rate of viable bacteria, a simple and feasible freeze-drying preservation method, and a high rate of viable bacteria Effect

Inactive Publication Date: 2019-08-09
SHANGHAI INST OF MEASUREMENT & TESTING TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In the prior art, there is no special lyoprotectant for Listeria monocytogenes standard material with excellent protective properties, therefore, a kind of lyoprotectant with excellent protective properties for Listeria monocytogenes standard material has been developed. Special lyoprotectant is very necessary

Method used

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  • Freeze-drying protective agent for listeria monocytogenes standard substance, freeze-drying preserving method and application
  • Freeze-drying protective agent for listeria monocytogenes standard substance, freeze-drying preserving method and application

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Embodiment 1

[0038] In this embodiment, the resurrection, identification and cultivation of strains are carried out, and the specific operations are as follows:

[0039] The cryopreserved standard Listeria monocytogenes strain was revived by streaking on nutrient agar, and cultured at 37°C for 18h-24h. Pick a single colony of Listeria monocytogenes from the plate and inoculate it into the nutrient broth, culture at 37°C for 18h-24h, take the bacterial liquid and inoculate it on the TSA-YE medium, and perform Gram test at 37°C until the colony grows. Observed under the microscope after staining, the bacteria are arranged in the shape of short rods, with a size of about (0.4μm-0.5μm)×(0.5μm-2.0μm). Randomly pick colonies and use VITEK automatic biochemical analyzer for identification, pick pure culture A single colony was punctured in the SIM power medium, cultured at 30°C for 48 hours, and grew in an umbrella shape above the SIM medium, picked a purely cultured single colony and punctured i...

Embodiment 2

[0041] This embodiment provides a lyoprotectant for reference materials of Listeria monocytogenes. The lyoprotectant includes the following components in terms of mass percentage: 50% skimmed milk, 0.5% polyvinylpyrrolidone, sucrose 4%, tyrosine 0.5%, and the solvent is sterile distilled water.

[0042] Using this lyoprotectant to lyophilize the Listeria monocytogenes reference material comprises the following steps:

[0043] The protective agent was subjected to high-pressure steam sterilization, and then the cell density was 1×10 8 The CFU / mL Listeria monocytogenes suspension and the protective agent were mixed at a volume ratio of 1:100 to obtain a mixture, and then the mixture was distributed into brown vials with a sterile pipette, each bottle 1mL, in- Pre-freezing at 80° C. for 8 hours, freeze-drying at a vacuum degree of 0.015 mbar for 36 hours to obtain a freeze-dried product, and vacuum-capping the freeze-dried standard substance.

Embodiment 3

[0045] This embodiment provides a lyoprotectant for reference material of Listeria monocytogenes, the lyoprotectant comprises the following components in terms of mass percentage: 40% skimmed milk, 0.2% polyvinylpyrrolidone, sucrose 6%, tyrosine 0.8%, and the solvent is sterile distilled water.

[0046] The standard material of Listeria monocytogenes was freeze-dried by using the lyoprotectant, and the operation steps were consistent with those in Example 2.

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Abstract

The invention relates to a freeze-drying protective agent for a listeria monocytogenes standard substance, a freeze-drying preserving method and application. The freeze-drying protective agent is a special freeze-drying protective agent for the listeria monocytogenes standard substance. Through the cooperation of the four specific components (skim milk, polyvinylpyrrolidone, cane sugar and tyrosine) according to the specific mass percentage contents, the synergistic interaction can be realized, the freeze-dried listeria monocytogenes standard substance reaches the high living bacterium rate, and the living bacterium rate of the standard substance can still be kept at a high level after the standard substance is stored for a long time.

Description

technical field [0001] The invention belongs to the technical field of microbial auxiliaries, and in particular relates to a freeze-drying protectant for Listeria monocytogenes reference material, a freeze-drying preservation method and application. Background technique [0002] With the development of biotechnology, microbial reference materials, microbial detection methods, effective analysis and measurement methods, and quantitative traceability technology related to biosafety and food safety are still an important issue we face. Since the microbial detection process is affected by individual differences and is particularly sensitive to environmental pollution, most of the time the same sample cannot be re-inspected, so it is urgent to strengthen the ability to develop microbial reference materials. Body standard material, realize the quality control of microbiological test results, and ensure the accuracy and fairness of the test results. [0003] Listeria monocytogenes...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C12N1/20C12N1/04C12R1/01
CPCC12N1/04C12N1/20
Inventor 李妍罗超刘刚李智玮赵珂珂
Owner SHANGHAI INST OF MEASUREMENT & TESTING TECH
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