Last to update on June 11th, 2021Pour plate method is commonly the an approach of choice for count the number of colony-forming bacteria current in a liquid specimen. Since the sample is combined with the molten agar medium, a larger volume can be used than v the spread out plate. In this method, a addressed amount that inoculum (generally 1 ml) native a broth/sample is put in the center of a sterile Petri dish utilizing a sterile pipette. Molten cooled agar (approx. 15mL) is then poured into the Petri food containing the inoculum and also mixed well. After the solidification that the agar, the bowl is inverted and incubated in ~ 37°C for 24-48 hours.Microorganisms will flourish both ~ above the surface and also within the medium. Nests that prosper within the medium generally are little in size and also maybe confluent; the couple of that flourish on the agar surface space of the same size and also appear prefer those ~ above a streak plate. Every (both huge and small) swarm is closely counted (using magnifying swarm counter if needed). Each colony represents a “colony-forming unit” (CFU).The number of microorganisms existing in the details test sample is figured out using the formula:CFU/mL= CFU * dilution variable * 1/aliquot
Pouring the molten agar medium

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Collect one bottle of sterile molten agar (containing 15 mL that melted Plate count Agar or any type of other standard culture media) from the water bathtub (45°C).Hold the party in the right hand; eliminate the cap with the small finger that the left hand.Flame the neck of the bottle.Lift the lid of the Petri dish slightly with the left hand and pour the sterile molten agar right into the Petri dish and also replace the lid.Flame the neck the the bottle and also replace the cap.Gently swirl the bowl on the benchtop to mix the society and the tool thoroughly. Ensure that the medium covers the key evenly and also do no slip the agar end the leaf of the Petri dish.Allow the agar to completely gel without disturbing it, it will take about 10 minutes.Seal and also incubate the key in one inverted position at 37°C because that 24-48 hours.
Overview of pour plate an approach and spread plate method

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After 24-48 hours, count all the nests (again: keep in mind that the embedded nests will be much smaller 보다 those which happen to type on the surface). A magnifying swarm counter can aid in counting tiny embedded colonies.Calculate CFU/mL utilizing the formula: CFU/mL= CFU * dilution factor * 1/aliquot(the volume that diluted specimen (aliquot) is either 0.1 or 1.0 mL)

Disadvantages of to water plate method

Preparation for the pour plate method is time-consuming contrasted with the streak plate/and or spread plate technique.Loss the viability of heat-sensitive organisms coming into call with warm agar.Embedded colonies are lot smaller than those which take place to it is in on the surface. Thus, one need to be mindful to counting these so that none space overlooked.Reduced expansion rate that obligate aerobes in the depth of the agar.References and also further readingsBasic handy Microbiology A hand-operated by culture for general Microbiology (SGM)