Chapter 54, Problem 1Q

Why are plates with 25 to 250 colonies used for calculations?

Summary Introduction

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.

Conclusion

Plates having 25-250 colonies should be used for calculations as they provide most precise results.