Carolina Bottled Media - Manual (Page 4)

4
Pouring the Plates
1. Place the agar plates on the prepared work surface.
2. Remove the cap of the bottle you are going to use. Sterilize the mouth
of the medium bottle by passing it through the flame of a bunsen burner
or by wiping with an alcohol prep.
3. Lift the cover of a plate just enough to pour in the medium.
4. Pour a small amount of agar medium into the plate. Use just enough to
cover the bottom of the dish. Each bottle will pour approximately five
100-mm plates.
Note: Pour only one plate at a time to minimize contamination. Hold the
agar bottle tilted at close to a 45° angle until all the medium in the bottle
has been used to pour plates. Never set the bottle down or hold it
upright during the pouring process because this increases the potential
for contamination.
5. Immediately close the plate cover. Remember: Do not set the bottle
down or hold it upright.
6. Follow the same steps to pour the remaining plates.
7. Allow at least 30 minutes for the plates to set up.
8. Dispose of the empty bottles (See Disposal section.)
Inoculating the Streak Plates
Prior to inoculating the streak plates, it is important that the agar surface be
smooth and moist; however, excessive moisture is undesirable since it can
cause the bacterial colonies cultured on the plate to merge. Be sure the agar
is allowed to set for at least 30 minutes before establishing cultures on the
plates.
Note: For a standard inoculation, streak in the simple zigzag pattern shown in
Figure 1, using either a sterile swab or wire loop. If you are trying to isolate
types of bacteria on a plate, use an isolation streaking pattern, such as the
one shown in Figure 2. Isolation streaking requires a wire loop, which must
be flamed between each of the streaks on a plate. In isolating bacteria, each
successive streak creates a more “diluted” population on its section of the
plate.
1. Place the plates on the clean work surface.
2. Use either a fresh, sterile, cotton swab, just removed from its package,