Asked by: Rafayel Spek
medical health infectious diseases

How do you count bacterial growth in a Petri dish?

Last Updated: 5th March, 2020

Use the formula: [Number of colonies counted]× 10 × [how many times the sample must be multiplied toget to the original concentration: for example, 105] =Number of colony forming units (CFU) per milliliter of startingculture. This is the bacterial growth in yourpetri dishes.

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Keeping this in consideration, how do you measure bacterial growth in a Petri dish?

The easiest way to measure bacterial growth is toput your sample on a clear glass plate under a microscope and counthow many bacteria cells there are. Alternatively, you canmeasure turbidity, which is the amount of bacteria inyour sample.

Furthermore, how long does it take for bacteria to grow in a petri dish? 4-6 days

how do you count bacterial growth?

The bottom sample is a mixed culture. There are avariety of ways to enumerate the number of bacteria in asample. A viable cell count allows one to identify thenumber of actively growing/dividing cells in a sample. The platecount method or spread plate relies on bacteriagrowing a colony on a nutrient medium.

How do you identify a bacterial colony?

Bacteria. Each distinct circular colonyshould represent an individual bacterial cell or group thathas divided repeatedly. Being kept in one place, the resultingcells have accumulated to form a visible patch. Most bacterialcolonies appear white, cream, or yellow in color, and fairlycircular in shape.

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