Streak Plate Technique for The Isolation of Pure Culture_A Complete Procedure (Microbiology)

0:00 street plate technique is used for the isolation of the bacteria into a pure culture from a mixed population so it is a very important method for a microbiologist welcome to the channel microchem's experiments be with us be a laboratory expert to perform this technique we need a biological safety cabinet incubator bunsen burner inoculating loop colony counter and prepared a gar culture media plate so let's begin with the culture media preparation take weight of agar media and mix with distilled water following the label on the media container sterile the media according to the manufacturer's instructions for sterilization some media need to just boil at 100 degrees celsius some need autoclaving at 121 degrees celsius and 15 pounds for 15 minutes others need to

0:46 boil in microwave oven for two minutes pour the hot media in sterile petri dishes aseptically and cool to solidify the agar media now incubate the newly prepared culture media for checking the contamination and choose the fresh plates for testing now we are going to main test for inoculation clean your workstation inside the biological safety cabinet bring a bacterial culture into it from which you want to get pure bacterial colonies and bring also a previously prepared fresh agar culture media in this test we will use trypton soya gar which is a universal growth medium for almost all bacteria

1:31 burn a burner with firebox carefully now burn an inoculating loop until it becomes red hot as shown in this video [Music] use inoculating loop made up by nichrome wire if available [Applause] [Music] [Applause] [Music] [Applause] [Music] [Applause] after burning bring the sterile loop inside the cabinet immediately to avoid contamination

2:16 now wait to cool the loop at room temperature label the fresh media plate by the detail information like media name test name date etc [Music] after cooling the inoculating loop pick up one loop full of bacterial culture from the culture plate [Music] make a smear with the culture of a corner of the fresh plate

3:08 [Music] burn the loop again as done previously and take it inside of the cabinet immediately [Music] wait to cool the loop at room temperature [Music]

3:56 after five minutes of cooling take the loop and start streaking in zigzag style on the first quarter of the plate starting from the bacterial smear as shown in this video close the plate and burn the loop again as done previously after burning bring the loop inside the cabinet and cool to room temperature

4:42 [Music] streak again on the second quarter of the plate touching the streaking lines of the first quarter once it is done start streaking on the third and fourth quarter in the same way without burning the loop this pattern of streaking is called four-quadrant streaking method finish the streaking by covering the newly inoculated tsa plate with its lid [Music] [Applause] [Music] invert the plate and incubate at 37 degrees centigrade for 24 hours

5:30 after incubation take out the plate from the incubator [Music] now we are in the last step which is result observation [Music] place the newly bacterial cultured plate on the stage of a colony counter you can see the colony density is higher in the first quarter of this plate 10 lower in the fourth quarter so the colony density is decreasing from the first quarter to the fourth quarter there are many isolated bacterial colony in the third and fourth quarter of the plate we can get a pure bacterial culture by taking a single isolated colony from this plate and streaking onto another fresh tsa culture plate

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