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    Home > Biochemistry News > Microbiology News > Two methods of bacterial counting

    Two methods of bacterial counting

    • Last Update: 2021-01-24
    • Source: Internet
    • Author: User
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    suncg gives a standard count of bacteria:
    standard practice is to add quantitative bacterial suspension (1 ml, 0.5 or 0.1 ml) to
    melted to 50-55 degrees agar
    culture
    base (generally do bacterial fall count with nutritional agar plate, and do
    fill
    fill count with sass flat) after mixing in the incubator observation.
    Comrade-in-arms Sky Blue Star gives bacterial plate counting:
    First of all, we add 900 microliters of sterile N.S. or buffer to the N-tube to make a dilution, take 100 microliters from the specimen and add to the first EP Within, the concentration of bacteria in the first EP tube is 1/10 of the specimen, and in the same way, 100 microliters are taken from the first EP and added to the second EP, the concentration of bacteria in the second EP tube is 1/100 of the specimen. And so on, the Nth tube is 1/10n of the concentration of the original specimen, and then take a suitable gradient of 100 microliths. After culture, such as flat dishes on the number of bacterios on 10-200 is more correct, easy to count, then you choose the concentration gradient is better, the count is more reliable! Count it out and you can roll out the concentration of your specimen upside down.
    if the unknown concentration of a specimen has a count of 18 for its third gradient, then the bacterial concentration of the specimen per milliliter is 18×10 (because you only use the third tube 1/10) ×100×10
    A certain amount of bacteria inoculated on the surface of the plate this is a simplified counting method, the difference between the two in the operation of a trouble, a simple, in the judgment results of inoculation of the surface of the plate, the amount of bacteria is not diluted at many times easy to produce the fall of the fungus fusion together not easy to separate the phenomenon, resulting in difficult reading and not allowed. Mixing together then the distribution of bacterial cells is more uniform, the results are easy to observe, of course, both methods should be well-made bacteria liquid for a series of dilution, different dilution of the bacterial suspension for the bacteriosligia count, and then multiplied by the dilution of the number of actual bacteria cells, generally to grow 100-300 bacteria flat plate as good.
    editor's note: tablet counting is faster and more convenient, and, when counting bacteria more convenient, if you use mixed counting ... You can see your eyes when you count bacteria! In general, we believe that the number of bacteria between 30-300 is more accurate, in more than 300 easy to spread the bacteria mixed together, 30 or less dilution error is too large.
    experience of the editor: when coating do not be tired, more than one will not have any harm, otherwise, bacteria coating is not equal on....
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