Microbial isolation procedures

Microbial isolation procedures

Plate Scribing Separation

The plate streaking method is a method in which the inoculation loop is streaked on the surface of the plate medium to achieve the separation of microorganisms. The principle is to dilute the microbial samples on the surface of the solid medium for multiple times “from point to line” to achieve the purpose of separation.
(1) Pour the melted beef extract peptone agar medium into the plate, and let it stand horizontally for coagulation.
(2) Burn the inoculation ring on the flame of an alcohol lamp, and after cooling, take an inoculation ring mixed with Staphylococcus aureus and Escherichia coli.
(3) Hold the agar plate with the left hand and slightly lift the lid of the dish, while it is close to the flame, and the inoculation loop with the right hand extends into the dish, and draw a line on an area on the plate. -40° angle lightly touch, make a brisk sliding on the surface with wrist force, do not scratch the surface of the tablet or embed it in the base.
(4) Burn the inoculation cup to kill the remaining bacterial liquid on the inoculation loop. After cooling, extend the inoculation loop into the dish, touch it slightly at the place where the line is drawn in the first area, and turn 90° , continue to draw lines in the second area.
(5) After drawing, burn the inoculation cup, and use the same method to draw lines in other areas after cooling.
(6) After all the lines are completed, use a special crayon at the bottom of the plate to indicate the strain, date, group and name. Put the whole dish upside down into the incubator for incubation.
(7) Take out and observe after 24-48 hours of incubation at 37°C. Note the colony’s on/off, size, color, edge, surface structure, transparency, and other traits.