Streak Plate Method: Principle, Purpose, Procedure, And Results
- Introduction. In microbiology, streaking is a technique used to isolate a pure strain from a single species of microorganism, often bacteria.
- Principle. Streak Plate Method is done by diluting a comparatively large concentration of bacteria to a smaller concentration.
- Experiment
- Procedure. ...
- Results Interpretation. ...
- Precautions Of Streak Plate Method. ...
How to streak a plate?
What to keep in mind when doing a streak plate method?
- Make sure you use only a small amount of inoculum.
- Make sure you streak lightly so as not to gouge the agar.
- See to it that the plate’s surface is free of droplets of condensed moisture.
- After streaking each quadrant, do not forget to flame the loop.
How to streak microbiology plates?
- Area of initial inoculation and the first streak yields heavy growth.
- Area of the second streak from the area 1 yields gives dense growth.
- Area of the third streak from the area2 yields weak growth.
- Area of the fourth streak from the area3 yields single colonies.
What is a quadrant streak plate technique?
Terms in this set (5)
- Open the agar plate, streak the loop across the surface of the agar in a back and forth motion covering about 1/5 of the plate. ...
- Sterilize loop, open plate, cool loop in the portion of the plate with no streaks. ...
- Continue this process for 3 and 4.
- Sterilize loop, incubate plate UPSIDE DOWN in incubator.
How many types of streaking methods are there in microbiology?
how many types of streaking methods are there in microbiology? The streaking process will dilutes out the sample that was placed in the initial region of the agar surface. There are two most commonly used streak patterns, a three sector "T streak " and a four quadrant streak methods.
What is the purpose of the streak plate method quizlet?
What is the purpose of streak plating? To obtain isolated, pure colonies. Bacteria is transferred to the edge of an agar plate with an inoculating loop and then treated out over the surface in one of several patterns.
What is the purpose of streaking in microbiology?
As you might guess, the purpose of streaking for isolation is to produce isolated colonies of an organism on an agar plate. This is useful when you need to separate organisms in a mixed culture or when you need to study the colony morphology of an organism.
What is the purpose of spread plating and streak plating in isolation cultures?
Colony streaking leads to to the isolation of individual colonies, which are a group of microbes that came from one single progenitor mircrobe. Spread plates allow for the even spreading of bacteria onto a petri dish; allowing for the isolation of individual colonies, for counting or further experiments.
What is the purpose of streak plate method?
Likewise, people ask, what are the advantages of streak plate method? Advantages. The streak plate method enables you to select and work with individual colonies. It is the ideal method if you are doing general work with a certain type of microorganism.
What is streak plate?
A streak plate involves the progressive dilution of an inoculum of bacteria or yeast over the surface of solidified agar medium in a Petri dish. The result is that some of the colonies on the plate grow well separated from each other. The aim of the procedure is to obtain single isolated pure colonies. Likewise, people ask, what are the advantages ...
What is the purpose of streaking?
What is the purpose of streak plate method? As you might guess, the purpose of streaking for isolation is to produce isolated colonies of an organism on an agar plate. This is useful when you need to separate organisms in a mixed culture or when you need to study the colony morphology of an organism. Click to see full answer.
How to tell if streak plate is contaminated?
How would you know if the streak plate is contaminated? Checking for Contamination Look for signs of fungal contamination. Fungal contamination will appear as fuzzy, filamentous, or hair-like growths, and should be visible to the unaided eye. Fungal contamination often occurs right along the edge of an agar plate.
What is the purpose of streak plate method?
The purpose of the streak plate method is to produce an isolated colony of an organism on the agar plate. Isolation of the organism is a must in a mixed culture, especially if you need to thoroughly study the colony morphology of a particular organism. (4, 7)
What is a streak plate?
What is Streak Plate Method ? Streaking is a method that isolates a pure strain from a species of bacteria. A sample is taken from a colony and a microbiological culture is grown on the new plate in order for the organism to be identified properly. It was Loeffler and Gaffky who first developed this method in Koch’s laboratory.
What is the procedure for dilution of agar plate?
The procedure includes a dilution technique which requires spreading a loopful of culture over the agar plate surface. This is to make sure that the individual cells fall apart on the agar medium surface so as separation of the different species takes place.
How long should streaked plates be incubated?
The streaked plate should be incubated for a total of 24 hours at a temperature of 37 degree Celsius. Carefully examine the colonies grown on the petri plate. The expected result is that all colonies must have the same general appearance.
Can a streak plate ruin a plate?
A wrong streaking method can ruin your plate. The streak plate method can be time-consuming, especially if you are going to prepare a large sample size. It requires strict maintenance. The streak plate method will require constant use of the streaking loop.
Who developed the method of agar diluting?
It was Loeffler and Gaffky who first developed this method in Koch’s laboratory. The procedure involves diluting bacteria by streaking the bacteria over the surface of the agar in the Petri dish. That way, an isolated colony can be obtained and grow into a number of cells.
Does streak plate work?
The streak plate method does not work with high volumes of organisms. It will not enable you to get a concentration count. It requires huge storage space and there is a possibility that your incubator cannot accommodate a large volume o f pet ri plate. You will be required to prepare the agar ahead of time.
What is the purpose of streaking?
In microbiology, streaking is a technique used to isolate a pure strain from a single species of microorganism, often bacteria. The dilution or isolation by streaking method was first developed by Loeffler and Gaffky in Koch’s laboratory, which involves the dilution of bacteria by systematically streaking them over the exterior ...
How is streaking done?
The streaking is done using a sterile tool, such as a cotton swab or commonly an inoculation loop. The inoculation loop is first sterilized by passing it through a flame. When the loop is cool, it is dipped into an inoculum such as a broth or patient specimen containing many species of bacteria.
How many sections are streaked in a quadrant?
In the quadrant method, four equally sized sections are streaked. The continuous streaking method typically involves inoculating the top half of the plate, rotating it 180 degrees, and inoculating the other half of the plate without sterilizing the loop or dragging bacteria from the previous section.
What is the technique used to isolate discrete colonies?
It is essentially a dilution technique that involves spreading a loopful of culture over the surface of an agar plate.
What are the limitations of streak plating?
Firstly, users will not be able to grow obligate anaerobes using this method. Secondly, only organisms that were viable in the original sample are able to be grown.
What is the most common method for isolating specific bacteria from a sample containing a mixture of micro
The streak plate technique is the most popular method for isolating specific bacteria from a sample containing a mixture of microorganisms. Streak plate technique is used to grow bacteria on a growth media surface so that individual bacterial colonies are isolated and sampled.
What is the process of picking colonies?
The process is called “picking colonies” when it is done from an agar plate with isolated colonies and is transferred to a new agar or gelatin plate using a sterile loop or needle. The inoculating loop or needle is then streaked over an agar surface.
How to do streak plate method?
Streak Plate Method is done by diluting a comparatively large concentration of bacteria to a smaller concentration. The decrease of bacteria should show that colonies are sufficiently spread apart to affect the separation of the different types of microbes.
How is streaking done?
The streaking is done using a sterile tool, such as a cotton swab or commonly an inoculation loop. The inoculation loop is first sterilized by passing it through a flame. When the loop is cool, it is dipped into an inoculum such as a broth or patient specimen containing many species of bacteria.
How to make a loop in a sterile agar plate?
Cool the loop by touching it on the edge of the sterile agar plate. Dip the loop into the broth culture containing the mixture of bacteria. Lift the lid of the plate just enough to insert the loop. Drag the loop over the surface of the top one-third of the plate back and forth in a “zig-zag” formation.
What is streaking in microbiology?
Introduction. In microbiology, streaking is a technique used to isolate a pure strain from a single species of microorganism, often bacteria. Samples can then be taken from the resulting colonies and a microbiological culture can be grown on a new plate so that the organism can be identified, studied, or tested.The Aim of this method is ...
What is aseptic technique?
Aseptic techniques are used to maintain microbiological cultures and to prevent contamination of the growth medium. There are many different types of methods used to streak a plate. Picking a technique is a matter of individual preference and can also depend on how large the number of microbes the sample contains.
Which section of a plate should show the heaviest growth?
The plate should show the heaviest growth in the first section . The second section will have less growth and a few isolated colonies, while the final section will have the least amount of growth and many isolated colonies.
How long to incubate a plate?
Incubate the plate for 24 hours.
What is the process of streaking?
In the streaking procedure, a sterile loop or swab is used to obtain an uncontaminated microbial culture. The process is called “picking colonies” when it is done from an agar plate with isolated colonies and is transferred to a new agar or gelatin plate using a sterile loop or needle.
How many times to repeat a streak?
Intersect the first streak only two or three times . Sterilize the loop, then repeat with a third streak beginning in the second streak. Sterilize the loop, then perform a fourth streak beginning in the third streak and extending into the middle of the plate. Be careful not to enter any streaks but the third.
How to spread organisms in a plate?
Starting at the edge of the plate (Area A) with a loopful of organisms, spread the organisms in a single continuous movement to the center of the plate. Use light pressure and avoid gouging the medium. Rotate the plate 180 degrees so that the uninoculated portion of the plate is away from you.
How to sterilize wire loops?
Sterilize the wire loop or inoculating loop by holding it in the light blue area of a Bunsen burner just above the tip of inner flame of the flame until it is red-hot. Then allow to cool it. While holding the loop between the thumb and forefinger, grasp the mixed bacterial culture in the other hand.
What is streak plate method?
The streak plate method is a rapid qualitative isolation method. The techniques commonly used for isolation of discrete colonies initially require that the number of organisms in the inoculums be reduced. It is essentially a dilution technique that involves spreading a loopful of culture over the surface of an agar plate. The resulting diminution of the population size ensures that, following inoculation, individual cells will be sufficiently far apart on the surface of the agar medium to effect a separation of the different species present. Although many type of procedures are performed, the four ways or quadrant streak is mostly done.
Who developed the streak plate method?
The dilution or isolation by streaking procedure was originally developed by Loeffler and Gaffky in Koch's laboratory, which involves the dilution of bacteria by systematically streaking ...
How to pour agar into a petri plate?
Pouring the Agar Plate: The agar is immediately poured into a sterile, dry petri plate while holding the top carefully above the petri plate bottom in order to avoid contamination. Replace the top, allow the agar to cool and harden, and store the petri plates in an inverted position.
How high should you stack petri plates?
When storing petri plates, do not stack them more than three high, or use a special petri plate storage holder. The agar is then poured into the plates using aseptic technique, preferably in a sterile cabinet (laminar air flow cabinet).
What is the process of picking colonies?
The process is called "picking colonies" when it is done from an agar plate with isolated colonies and is transferred to a new agar or gelatin plate using a sterile loop or needle. The inoculating loop or needle is then streaked over an agar surface. On the initial region of the streak, many microorganisms are deposited resulting in confluent ...
Introduction
Principle
- Streak Plate Method is done by diluting a comparatively large concentration of bacteria to a smaller concentration. The decrease of bacteria should show that colonies are sufficiently spread apart to affect the separation of the different types of microbes. Streaking is done using a sterile tool, such as a cotton swab or commonly an inoculation loo...
Experiment
- Reagents And Material Required
1. 24 hours old nutrient broth culture of two or more bacteria (Mixed Culture) or Sample/Specimen. 2. Nutrient Agar Medium 3. Six 9 ml Sterile Water Blanks 4. Sterile Petri plates 5. Graduated pipette (1ml or 1000 ml) 6. Bunsen burner or Spirit lamp 7. Marker
Procedure
- Serial Dilutions of the Specimen / Sample
1. Label the 6 Sterile Water blanks (9ml sterile water in each tube) as number 1 to 6 with the help of Marker. Also, label the Sterile Petri plates as number 1 to 6. Pour the Agar media in the plates and Kept aside to Solidify. 2. Place the labeled tubes in the test tube rack. Mix well the 24 hours … - Three Sector Streak
1. Sterilize the wire loop. 2. Cool the loop by touching it on the edge of the sterile agar plate. 3. Dip the loop into the broth culture containing the mixture of bacteria. 4. Lift the lid of the plate just enough to insert the loop. Drag the loop over the surface of the top one-third of the plate back a…
Results Interpretation
- Typically, a confluent growth will be observed where the initial streak was made, the growth is less dense away from the streak, and discrete colonies will be there in the last area and tail streak. If the diluted specimen was used to inoculate the media plates, the colonies in the cultures media plates will shows the lesser and lesser no. of the colonies with the increase in dilution factor tha…
Precautions of Streak Plate Method
- While flaming the inoculation loop be sure that each segment of metal glows orange/red-hot before you move the next segment into the flame.
- Always handle open tubes at an angle near to the flame of the burner; never let them point directly up, since airborne or other environmental organisms could fall into the tube and cause contaminat...
- While flaming the inoculation loop be sure that each segment of metal glows orange/red-hot before you move the next segment into the flame.
- Always handle open tubes at an angle near to the flame of the burner; never let them point directly up, since airborne or other environmental organisms could fall into the tube and cause contaminat...
- As soon as the inoculation is completed, flame your loop or needle. Never place a contaminated tool on your workbench.
- Rotate the plate counter clockwise 90 degrees and cross the prior streaks to pick up some bacteria and spread them into the next quadrant (Repeat in all the four quadrants).
