Why We Do dilution in plate count method?

We use serial dilutions to create decreasing concentrations of the original sample that are then plated so that a plate will be created with a low enough number of bacteria that we can count individual colonies. From that number, we can calculate the original cell density in the broth.

Which dilution method is used in standard plate count method?

The standard plate count method consists of diluting a sample with sterile saline or phosphate buffer diluent until the bacteria are dilute enough to count accurately. That is, the final plates in the series should have between 30 and 300 colonies.

What is serial dilution and plate count method?

Serial dilutions are used to calculate the concentration of microorganisms. As it would usually be impossible to actually count the number of microorganisms in a sample, the sample is diluted and plated to get a reasonable number of colonies to count. The countable plate has between 30 and 300 colonies.

What are the factors that may affect the results obtained by standard plate count?

The plate count method is generally affected by agar media, the state of bacterial cells, the presence of preservatives, and the optimization of growth conditions.

What is the spread plate method used for?

The spread plate method is a technique to plate a liquid sample containing bacteria so that the bacteria are easy to count and isolate. A successful spread plate will have a countable number of isolated bacterial colonies evenly distributed on the plate.

What is the difference between total plate count and standard plate count?

The APC term stands for aerobic plate count, but again is interchangeable with the others. Other terms used more historically are Standard Plate Count, Mesophilic Count or Total Plate Count these too generally refer to aerobic bacteria able to grow at average temperatures (e.g. 30 to 40°C).

How would you inoculate a plate to get 1/10 dilution A 1 100 dilution?

How would you inoculate a plate to get a 1:10 dilution? AND a 1:100 dilution? Just plate 0.1ml for a 1:10. To do a 1:100 do a 1:10 dilution then plate 0.1 dilution then plate 0.1 ml.

What does 5% dilution mean?

“The dilution factor is 5″ “It was a 5 fold dilution” “It was diluted 1/5″ These all mean the same thing, that there is 1 volume part of sample and 4 volume parts of whatever liquid is being used to dilute the sample for a total of 5 volume parts.

What is the difference between aerobic plate count and total plate count?

What are the disadvantages of plate count assays?

among these disadvantages are: (1) the length of time required for incubation, 48 hours being the shortest; (2) large amount of glassware and culture medium required, as well as other expensive equipment, and (3) the paucity of details regarding the kinds of organisms present.

What is a 1 to 2 dilution?

A 1 to 2 dilution should be written as ½. It means to dilute something in half. One is a dilution and the other is a ratio. In the scientific literature, if you see “1:2”, it means to add 1part to 2 parts. That will be 1 mL added to 2 mL, for a total of 3 mL, or a 1/3 dilution.

How to calculate the total dilution of a plate?

One way to solve this, is to factor it into the total dilution. In this problem 0.1 ml was added to the plate, or 1/10th of a ml. So multiply the total dilution by 1/10 for the amount added to the plate. This leaves the total dilution as one-one millionth. The next step is to work out the dilution factor.

How to count the number of viable plates?

Microbiology: Viable Plate Counts or……. how to count a million. 1 Look at the dilution scheme to determine the total dilution. 2 Look at the plate and multiply the number of colonies by the dilution factor (the inverse of the total dilution) to determine the total CFUs per mL in

How to calculate bacterial count for pour plate technique?

For pour plate technique, bacterial count is No.X 10 c /gm, where c = dilution factor. For spread plate technique, bacterial count is No. X10 c+1 /gm, where c = dilution factor. The number is converted to two decimal places in the form of (x.yz X 10 m). For example, 288 X 10 4 is expressed as 2.88 X 10 6.

How is the plate count of a sample calculated?

That is why, instead of expressing the counts of bacteria as ‘No. of bacteria/gm or ml of sample’, it is very often expressed as number of colony forming units per gm or ml (CFU/gm or ml). The total plate count (TPC) in the original sample is calculated by multiplying the number of CPUs with the respective dilution factors.