How can you count bacteria?

Question

I am doing a science fair project and i grew bacteria from water that was frozen, in the refrigerator and in room temperature. Now that the bacteria has grown i dont know how to record my data. Does anyone know how to count the bacteria grown on agar. is there a simple way?

Answer 1

You can do serial dilutions in sterile broth.
Pipette a known volume of the diluted culture on an agar plate, for each dilution.
When you have the right dilution, the plate will grow individual colonies. Each colony can be assumed to have a single founder.

So: (# colonies/ volume of innoculum) * dilution factor = original concentration.


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Answer 2

Typically, bacteria grown on agar are not counted individually. Instead, you count the number of colonies (small circles) formed on the agar. When you smear the bacteria onto the plate, each individual bacterium should eventually multiply, forming a circular colony. In other words, each colony on your agar represents one "founder" bacterium from your water sample.

Answer 3

How to Count Bacteria, check the link below for the step by step on several methods...

Answer 4

there are three ways to calculate the bacterial colonies number :
1- the microscopic count: by taking a part of the growth and make it on a slide then you can count it under he microscope

2- the plate count : by your sight u can count the number of colonies by direct counting and if the number is very high u can divide the plate to four quarters the count the number of colonies in one quarter then multiply in four to have the total number

3- counting by using the spectroscopy( if u use a liquid medium) this is a device which use a ray of light to calculate te total turbidity of the medium this turbidity is the total number of colonies and u must record the turbidity of one colony on this device before making the count then the device can calculate the total number of colonies

Answer 5

You try this by technique of understanding how super the viewing element of your microscope is in comparison to the size of your specimen. If at 1000X magnification you're seeing a million/10 of a millimeter^2 of your specimen, and the specimen is a hundred mm^2 total, then once you concentration on a given section you're observing a million/one thousand of the finished floor section. So, for this occasion, in case you have been to count variety 50 person bacterium you will possibly multiply that by technique of one thousand and you will possibly get the finished bacterial count variety. (it is for rather even distribution of micro organism) in the journey that your micro organism is separated into small colonies, you employ the comparable hardship-unfastened concept. start up by technique of understanding how huge your viewing section is, degree the width of an elementary colony, then count variety the variety of micro organism you will discover. Multiply by technique of the exterior section ratio you have established and you have the variety of microorganisms in a colony. Multiply that my the variety of seen colonies and you have an estimate of total inhabitants. in case you're counting different varieties of micro organism, do the comparable element for everybody interior of your pattern.

Answer 6

To count individual bacteria you are going to have to get ahold of spectroscopy equipment. I have used serial dilutions for eukaryotic cells, but im not too optimistic about it working for bacteria...

Answer 7

you can take a random spot of your experiment say a square inch.

count the bacteria in that spot, then multiply it by how much times that spot fits into the area... its sampling