In this video you will learn how to perform streak plate technique. The streak plate method allows isolation of a single colony from a bacterial culture by splitting the plate into quadrants and diluting the bacteria repeatedly as the loop is streaked through each quadrant. To light a Bunsen burner, start by closing the valve at the base by rotating the collar so that the vents are covered. Then slowly turn on the gas.
Once you hear the gas, ignite the burner and set the height of the flame by adjusting the amount of gas. The temperature of the flame can be adjusted by rotating the collar to control the flow of oxygen. The coolest flame is yellow and orange.
A medium flame is blue, and the hottest flame is a roaring blue flame characterized by a clear blue cone in the middle. The tip of the cone is the hottest part of the flame. Flame an inoculating loop to sterilize and allow it to cool. You can lightly touch the loop on an empty spot on the bacterial plate to make certain the loop is cool. Gently scrape a colony from the surface of the plate so that it collects on the loop.
Transfer the bacteria to your LB auger plate and gently rub the loop back and forth across the top left corner of the plate about 10 times. Stain the top left quadrant of the plate and do not break the surface of the auger. When finished, flame the loop.
Rotate the plate 45 degrees or a quarter turn. and draw the loop through one end of the first streak and rub back and forth in the second quadrant about 10 times. Flame the loop again to sterilize. Rotate the plate 45 degrees and draw the loop through one end of the second streak.
and rub the loop back and forth in the third quadrant about 10 times. When finished, flame the loop again. Repeat the process one final time in the fourth quadrant.
Flame the loop after completing the streak plating. Invert the plate and place it in an incubator at 37 degrees Celsius for 24 to 48 hours. After 24 to 48 hours the colonies will have grown and can be examined.