Table of Contents
- 1 What is the advantage of spread plate method?
- 2 Why We Do dilution in plate count method?
- 3 What is the difference between pour plate and spread plate technique?
- 4 What are the advantages and disadvantages of pour plate method?
- 5 What is the purpose of dilution?
- 6 How do dilution factors work?
- 7 When to use the serial dilution plate technique?
- 8 What are the advantages and disadvantages of serial dilution?
What is the advantage of spread plate method?
Heat sensitive microbes are not affected. No subsurface colonies appear in spread plate so isolation of the organism is easy.
Why We Do dilution in plate count method?
By diluting the sample, it is possible to plate different concentrations of the sample and obtain an incubate plate with an easily countable number of colonies and calculate the number of microbes present in the sample.
Why is dilution important in microbe number?
Each dilution will reduce the concentration of bacteria by a specific amount. So, by calculating the total dilution over the entire series, it is possible to know how many bacteria you started with.
What is the importance of dilution method in bacteria culture and identification?
The Dilution method is used to determine the minimal inhibitory concentration of an antimicrobial to inhibit or kill the bacteria/fungi and is the reference for antimicrobial susceptibility testing.
What is the difference between pour plate and spread plate technique?
The key difference between Pour plate and Spread plate is that a known volume of the sample is spread on the surface of the agar medium in spread plate, while, in pour plate, a known volume of the sample is mixed with agar and then poured into a plate.
What are the advantages and disadvantages of pour plate method?
Advantages of Pour Plate Technique
- Easy to undertake.
- Will detect lower concentrations than surface spread method because of the larger sample volume.
- It requires no pre-drying of the agar surface.
- The most common method for determining the total viable count is the pour-plate method.
What is the importance of dilution?
A dilution can be performed not only to lower the concentration of the analyte that is being tested, so that it is in range, but also to help eliminate interferences from other substances that may be present in the sample that can artificially alter the analysis.
How is dilution factor calculated?
For example, a 1:5 dilution (verbalize as “1 to 5” dilution) entails combining 1 unit volume of solute (the material to be diluted) + 4 unit volumes of the solvent medium (hence, 1 + 4 = 5 = dilution factor).
What is the purpose of dilution?
How do dilution factors work?
The dilution factor may also be expressed as the ratio of the volume of the final diluted solution to the initial volume removed from the stock solution. For example, if 100 mL of a stock solution is diluted with solvent/diluent to a total, final volume of 1000 mL, the resulting dilution factor is 10.
How do you calculate the number of bacteria in original culture?
- To find out the number of CFU/ ml in the original sample, the number of colony forming units on the countable plate is multiplied by 1/FDF. This takes into account all of the dilution of the original sample.
- 200 CFU x 1/1/4000 = 200 CFU x 4000 = 800000 CFU/ml = 8 x 10.
- CFU/ml in the original sample.
Why dilution method is important?
Dilutions can be important when dealing with an unknown substance. By performing a dilution on a sample it may reduce the interfering substance to a point where it no longer interferes with the test. When performing a dilution there is a equation that can be used to determine the final concentration.
When to use the serial dilution plate technique?
If this happens, you should perform the process over again using the aseptic technique until your results yield a pure culture. The serial dilution agar plate technique is when you dilute a sample several times to achieve several different dilutions.
What are the advantages and disadvantages of serial dilution?
What Are Some Advantages And Disadvantages Of The Serial Dilution Agar Plate Technique It is not a method of sterilization because sterilization is the process used to remove all life forms, including bacteria spores. It is important to disinfect your work area before and after working.
What are the advantages of the pour plate method?
Pour plate Method: Principle, Procedure, Uses, and (Dis) Advantages. Pour plate method is usually the method of choice for counting the number of colony-forming bacteria present in a liquid specimen. In this method, fixed amount of inoculum (generally 1 ml) from a broth/sample is placed in the center of sterile Petri dish using a sterile pipette.
How is the pour plate technique used in microbiology?
At times also the determination of viable cells is very crucial in many microbiological procedures. To accomplish this, the serial dilution–agar plate technique is used. Briefly, this method involves serial dilution of a bacterial suspension in sterile water blanks, which serve as a diluent of known volume.