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Why are plates with 25 to 250 colonies used for calculations?
To write:
The reason for the use of plates with 25 to 250 colonies for the calculations.
Introduction:
A culture plate:
In biology, it is a low and flat-bottomed laboratory container. It is useful to grow a layer of organisms on a thin nutrient medium layer. These include the molds, bacterias, and other cells. The most ordinary types of culture plates are the multiwell plate and the Petri dish.
Explanation of Solution
A colony can be defined as a visible mass of microbes that all originate from a single mother cell. Thus, a colony is formed of a clone of bacteria which are all genetically similar.
Plates with 25 to 250 colonies:
The FDA Bacterial Analytical Manual (BAM) recommends 25-250 CFU/plate as a countable range. If there are less than 25 colonies then it is too little count that it is not a statistically significant number of colonies.
While if there are more than 250 colonies then it is too many to count as it is impossible to recognize whether the colonies are parted.
Plates having 25-250 colonies should be used for calculations as they provide most precise results.
Plates having 25-250 colonies should be used for calculations as they provide most precise results.
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Chapter 54 Solutions
Laboratory Experiments in Microbiology (12th Edition) (What's New in Microbiology)
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- How would I figure out how many dilutions to make given cell density ? And volume to plate ? For example, I want to plate 0.1 ml and want 200 colonies how many dilutions would i need to make, given 7.5 x10^5 cells/ mlarrow_forwardWhat types of compounds make up the gels used in electrophoresis?arrow_forwardHow do we reconcile the number of colonies in the plates to the actual number of bacteria in the original sample? Count Plate Methodarrow_forward
- Why sometimes specimen may show organisms under the microscope but not appear in the culture media?arrow_forwardYou have performed an experiment and your aim is to obtain pure colonies. However, you observe some colony variations and you need to verify that this is not due to contamination, name and describe the staining method would you use to achieve this goal?arrow_forwardWhy is it important to first determine whether growth occurred in a different medium, such as starch agar before examining the plates?arrow_forward
