Explain the serial dilution process - plate counts, Biology

Assignment Help:

Explain the Serial Dilution Process - Plate Counts?

Dilution factor is the reciprocal of the dilution used. As number of microorganisms in original sample is not known, the original sample is diluted several times in sterile water blanks to ensure that separate colonies are developed and some colony counts will be in the specified range. The process is called serial dilution. The procedure is shown in Figure. Usually a ten-fold serial dilution is used in the process where 1 ml of the sample is transferred to a 9 ml of the diluent to get 1:10 dilution. 1 ml of this is transferred to another tube of 9 ml of diluent to get 1:100 dilution and so on till the required dilutions are obtained.

105_Serial dilution process.png

Figure: Serial dilution process

It is important that the dilution used should produce a limited number of colonies on plate. When many cells are present, overcrowding of cells may not allow many colonies to develop and may also result in many colonies to fuse. This leads to inaccuracies in count. Similarly, too less colonies are not statistically significant. According to Food and Drug Administration, only those plates having 25-250 colonies should be considered for calculation; but most microbiologists use plates with 30-300 colonies to get the microbial numbers in the sample. Plates getting colonies less than 30 are marked too less to count (TLTC) and getting more than 300 are marked as too numerous to count (TNTC) and are discarded.


Related Discussions:- Explain the serial dilution process - plate counts

Cell biology, what is the role of cholesterol in membrane fluidity?

what is the role of cholesterol in membrane fluidity?

What is forebrain, Q. What is Forebrain? Forebrain: Found in the area o...

Q. What is Forebrain? Forebrain: Found in the area of the forehead, this part of the brain is concerned with all the emotions, planning, organising, reasoning, memory, movement

Explain foscarnet, Foscarnet  (Foscavir)  Foscarnet is an alternative t...

Foscarnet  (Foscavir)  Foscarnet is an alternative to ganciclovir and valganciclovir for treatment of CMV infection. It is approved for use in CMV retinitis, including progress

What is the clitellum of earthtworms and where it is located, What is the c...

What is the clitellum of earthtworms and where it is located? The clitellum is a special region of the annelid constituted by rings (metameres) with reproductive function. It c

Methods of curing meat, M e t h ods of curing Curing ingredients ar...

M e t h ods of curing Curing ingredients are applied in dry form or as a solution of curing ingredients in water (pickle or brine). The combination cure is applied in the i

Different from all the other cellular microbes, How are the bacteria and th...

How are the bacteria and the archaea different from all the other cellular microbes? -They have cell walls? -They can move? -They reproduce asexually? -They have no nucleus?

Determine the separation of homologous chromosomes, During mitotic anaphase...

During mitotic anaphase is there separation of homologous chromosomes or separation of identical chromatids? In the anaphase of mitosis the identical chromatids separate and co

Explain about the torbed dryer, Explain about the Torbed Dryer? On the ...

Explain about the Torbed Dryer? On the other hand, is a variation of the fluidized bed dryer. This is designed for use with particulate foods. Torbed dryers are used to dry haz

Exstrophy of the bladder, Exstrophy of the Bladder This is the most c...

Exstrophy of the Bladder This is the most common major congenital defect of lower urinary and genital tract. This is found more frequently in males than in females. Exstr

Tooth associated with persistent apical periodontitis, Tooth associated wit...

Tooth associated with Persistent apical periodontitis Functional retention of the tooth : persistent lesion while remain asymptomatic function for an extended period of time .

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd