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

Cost due to damage to equipment, Cost due to Damage to Equipment Cost ...

Cost due to Damage to Equipment Cost due to Damage to Equipment, Property etc. Tooling may have to be redesigned, adding cost. Cost due to reduced output and delay

Limerick, how do we write a limerick spell?

how do we write a limerick spell?

What are the benefits of soil testing, What are the benefits of Soil testin...

What are the benefits of Soil testing Soil testing is done to assess the nutrient supplying capacity of the soil. The data obtained as a result of  testing is useful for recom

Pathogenesis, Even though association between GAS pharyngitis and the ARF i...

Even though association between GAS pharyngitis and the ARF is fairly well established, the exact pathogenic mechanisms are not clearly understood. However, two mechanisms are post

What is viscosity?, Q. What is viscosity? Viscosity is resistance to fl...

Q. What is viscosity? Viscosity is resistance to flow of a liquid. It is a measure of the resistance of a fluid to deformation under shear stress. It is commonly perceived as "

Cell-cycle controls, • Cancer cells do not respond normally to the body's c...

• Cancer cells do not respond normally to the body's control mechanism. o They divide excessively and invade other tissues. o If left unchecked, they can kill the organism. •

What is kingdom plantae or how organism included in plantae, What is Kingdo...

What is Kingdom Plantae and what organism included in Plantae? Kingdom Plantae :  includes organisms that are eukaryotic, multicellular, photosynthetic. Their cells also cont

Explain purpose of therapeutic dietary adaptations, Purpose  of  Therapeuti...

Purpose  of  Therapeutic Dietary Adaptations A therapeutic diet is a quantitative/ qualitative modified version of a basic nutritious diet which has been tailored to suit the c

What is cryopreservation, Name the location and function of Meibomian gland...

Name the location and function of Meibomian glands in the human eye. a) What is cryopreservation? Give its single use. b) Commercial importance of cryopreservation is relate

Endosperm of gymnosperms and the endosperm of angiosperms, How dissimilar a...

How dissimilar are the endosperm of gymnosperms and the endosperm of angiosperms? In the gymnosperms the endosperm is haploid (n), it is called as primary endosperm. In the ang

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