1. Clean the Petri dish, wrap it with kraft paper or gauze, and sterilize it in the autoclave 12 1℃ for 30 minutes.

2. Dissolve the sample with sterile physiological saline, inject the diluent 1ml into the Petri dish, and pour it into the sterilized culture medium for solidification.

3. Place the Petri dish in a biochemical incubator at 36℃ for 2-3 days, and observe the colonies growing in the culture medium.

Petri dish is a kind of laboratory vessel used for microorganism or cell culture, which consists of a flat disc-shaped bottom and a cover, usually made of glass or plastic. Petri dish materials are basically divided into two categories, mainly plastic and glass. Glass can be used for plant materials, microbial culture and animal cells, and can also be used for monolayer culture. Plastic may be made of polyethylene and can be used once or more. It is suitable for laboratory inoculation, labeling and bacterial separation, and can be used for the cultivation of plant materials.