What is Streak Plate an approach ?

Streaking is a method that isolates a pure stress, overload from a species of bacteria. A sample is taken from a colony and a microbiological culture is grown on the brand-new plate in order because that the biology to be identified properly.

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It to be Loeffler and Gaffky who first developed this method in Koch’s laboratory.

The procedure entails diluting bacteria through streaking the bacteria over the surface ar of the agar in the Petri dish. The way, one isolated colony can it is in obtained and also grow right into a number of cells. The culture is dubbed a microbiological culture if the organism grows in the agar surface. (1, 2, and 3)


Picture 5: The actual result of a streak bowl technique.

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What is the tools needed for the streak key method?

Inoculation loop (6)Bacteria sourceBunsen burnerStriker/lighterAgar key (5)LysolPaper towel

What to save in mind when doing a streak key method?

Make sure you use only a little amount the inoculum.Make certain you streak easy so as no to gouge the agar.See come it the the plate’s surface is complimentary of droplets the condensed moisture.After streaking every quadrant, carry out not forget to fire the loop.The inoculum source can it is in a broth or heavy culture, an eco-friendly swab, a clinical specimen, or sedimented urine.The petri food to be used need to be a hundreds millimeter in diameter. (3, 6, 7, and also 8)

What is the objective of the streak key technique?

The objective of the streak plate method is to develop an isolated swarm of an organism on the agar plate. Isolation that the organism is a have to in a combined culture, especially if you should thoroughly research the swarm morphology the a details organism. (4, 7)

How is the streak plate method done?

The inoculating loop must be sterilized in the Bunsen burner by merely putting the loop into the flame. Wait because that the loop to turn red indicating the it is already hot. Let it cool under for a few minutes.Using the inoculating loop, choose an isolated nest from the agar plate and also spread on the first quadrant that the petri plate. (4, 5)Gently streak the inoculating loop making use of a back and soon motion.Put the loop in the flame and also let that cool. Prolong the streaks right into the second quarter the the petri plate.Repeat action four and this time expand the streak into the petri plate’s 3rd quadrant.Repeat step four and go back to the area friend streaked in the 3rd quadrant that the petri plate and also this time expand the streak into the fourth quadrant of the petri plate.Flame the loop. (8, 9, and also 10)

Interpreting results

The streaked plate should be incubated because that a full of 24 hours at a temperature that 37 level Celsius. Carefully examine the nests grown on the petri plate. The expected result is the all colonies must have actually the same general appearance.

If you notification that there is much more than one kind of colony, climate you should start come streak again however this time on a different plate so as to obtain a pure culture. (4, 5, and also 6)

Streak plate method advantages and disadvantages


The streak plate method enables you come select and work with individual colonies.It is the ideal method if you space doing general work v a certain type of microorganism.Through the streak key method, you will end up with a genetically identical individual colony, which makes it simple for you to grab and transfer colonies for a microscope examination.The streak plate method is convenient and hassle-free together you will have the ability to get clearly shows individual nests in a solitary petri plate for as long as you have a an excellent streaking skill. (2, 6, 9, and 10)


The streak plate technique does not work-related with high volumes of organisms. It will certainly not allow you to obtain a concentration count.It requires vast storage space and there is a possibility that her incubator cannot accommodate a large volume of petri plate.You will be compelled to prepare the agar ahead of time. The procedure have the right to be a tedious process, especially if you don’t recognize the sample size prior to the laboratory work.Training and technique are compelled as various growth media have various densities to the agar. If you are not expert enough, then you would finish up tearing with the agar, specifically if you use too lot pressure top top the agar. A dorn streaking technique can damage your plate.The streak plate technique can it is in time-consuming, specifically if you space going come prepare a huge sample size.

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It requires strict maintenance. The streak plate method will require constant use of the streaking loop. Eventually, it will certainly wear out and you require to change it every as soon as in a while. (2, 5, 7, and also 10)