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Quantitative detection method of salmonella in soil and assay kit thereof

A technology for quantitative detection of Salmonella, applied in the direction of microbial-based methods, microbial measurement/inspection, biochemical equipment and methods, etc., can solve problems such as difficult operation, insufficient quantitative detection, time-consuming and labor-intensive troubles, etc., and achieve good economy Benefits and social benefits, improve detection efficiency, reduce the effect of cumbersome steps

Inactive Publication Date: 2012-02-01
NANJING AGRICULTURAL UNIVERSITY +1
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AI Technical Summary

Problems solved by technology

Among them, the traditional detection method is highly authoritative, but it has the disadvantages of time-consuming, labor-intensive and troublesome operations, and the quantitative detection of pathogenic microorganisms in soil has certain complexity and operational difficulty; with the modern molecular biology With the development of scientific methods, PCR technology is widely used in the qualitative detection of pathogenic microorganisms in food because of its rapidity and accuracy, but the PCR method cannot distinguish dead bacteria from live bacteria well, and it is also insufficient in quantitative detection. lead to inaccurate results

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  • Quantitative detection method of salmonella in soil and assay kit thereof
  • Quantitative detection method of salmonella in soil and assay kit thereof
  • Quantitative detection method of salmonella in soil and assay kit thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0033] Using representative Salmonella as the experimental strain, prepare a series of Salmonella with gradient concentration and add them to the sterilized soil for correlation analysis between plate colony counting method and MPN counting method. First, scrape purely cultured Salmonella colonies from the plate and inoculate to 100ml In the selenite enrichment culture medium, culture at 30°C and shake at 200r / min for 8h. Then serial dilutions of different concentrations were prepared by ten-fold dilution and added to the sterilized soil, and the number of Salmonella was counted by plate colony counting method and MPN counting method, respectively.

[0034] Plate colony count method refers to the literature [Shen Ping, Fan Xiurong, Li Guangwu. Microbiology Experiments [M]. Beijing: Higher Education Press, 1999, 92-94. ], firstly carry out gradient dilution on the soil bacterial suspension prepared above, take 0.1ml of the bacterial suspension with appropriate dilution and sp...

Embodiment 2

[0048] The specificity of the PCR detection method mainly depends on the specificity of the primers, so the selection of the target gene should have species or genus specificity in order to avoid the occurrence of false positives. According to the invA gene sequence of Salmonella, reference [Rahn K, De Grandis S A, Clarke R C, et al. Amplification of an invA gene sequence of Salmonella Typhimurium by polymerase chain reaction as a specific method of detection of Salmonella[J]. Mol Cell Probes, 1992, 6(4):271-279. 】Primer design software Primer 5.0 was used to design primers, and specific primers invA-1 and invA-2 for the detection of Salmonella were designed. The amplified fragment of the primers was 284bp; the above two pairs of primers were synthesized by Shanghai Yingjun Company. The specific sequence is as follows:

[0049] invA-1: 5'-GAAATTATCGCCACGTTCGGGCA-3',

[0050] invA-2: 5'-TCATCGCACCGTCAAAGGA-3'.

[0051] Use the invA specific primers of Salmonella to target 1...

Embodiment 3

[0053] There are a lot of humic acid and metal ions in the soil, and their existence will seriously affect the activity of Taq enzyme in the PCR reaction, which may lead to the failure of the PCR reaction. In order to improve the efficiency of PCR detection and obtain a clean DNA template that can amplify the target band, usually the DNA template is obtained by phenol / chloroform extraction. It is toxic and is not suitable for DNA preparation of a large number of samples. According to past experience, even if DNA can be extracted, the target band must be amplified after recovery and purification of DNA samples due to the large amount of impurities in the soil. In order to simplify the procedure of template preparation, this method was compared with other commonly used simple methods.

[0054] Salmonella multiplication method, PCR system, condition and electrophoresis method are all the same as embodiment 4.

[0055] Method 1: Direct amplification of the enrichment solution: Ta...

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Abstract

The invention discloses a quantiative detection method of salmonella in soil and an assay kit thereof. On the basis of taking related researches as reference, the method performs quantitative detection on pathogenic microorganism in the soil by adopting a method of combining MPN (most probable number) with PCR (polymerase chain reaction). By utilizing advantages of quickness and accuracy of the PCR method, biochemical identification, serological identification and other steps of positive results in the traditional MPN method are substituted, so that complex steps in a national standard methodare reduced, the detection efficiency is improved, and a pre-enrichment step in the national standard method is adopted at the same time to improve the accuracy of detection targeting pathogenic bacteria; and due to the complexity of soil, the soil contains massive microorganisms, as well as various pathogenic microorganisms of different items, so that the targeting pathogenic bacteria is selectively cultured to improve the detection efficiency in order to quantitatively detect the targeting pathogenic bacteria better and more accurately. By virtue of creative effort of the inventor and scientific test verification, the sensitivity of the salmonella quantitative detection method in an experiment of adding pure bacteria in the soil is 250 per gram of soil.

Description

technical field [0001] The invention belongs to the technical field of microbial quantitative detection, and in particular relates to a method for quantitative detection of Salmonella in soil and a detection kit thereof. Background technique [0002] With the acceleration of urbanization in our country, cities migrate and expand to the edge. The urban-rural fringe is at the junction of urban development and rural construction areas. Soil health and quality issues in the urban-rural fringe are too important to ignore. At present, experts and scholars mainly focus on the indicators of pesticide residues, heavy metal pollution and organic pollution in the research of soil quality, and pay little attention to the biological indicators of pathogenic microorganisms in soil. Pathogenic microorganisms from poultry manure and sewage irrigation soil can remain latent in the soil for a long period of time, and can enter vegetables, eventually affecting human health. In particular, fo...

Claims

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Application Information

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IPC IPC(8): C12Q1/68C12Q1/06C12R1/42
Inventor 曹慧李德成董丽宁崔中利
Owner NANJING AGRICULTURAL UNIVERSITY
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