(1) Liquid culture media is mainly used for bacteria enrichment. The growth of bacteria in liquid medium can be manifested as turbid liquid, forming bacterial membrane on the surface, and collecting and sorting the sediment at the bottom of the tube.
(2) The semisolid culture media contains 0.3% - 0.5% agar of low concentration, which can be used to observe the bacterial motility. Bacteria with flagella can overcome the barrier of low concentration agar, spread beyond the puncture line, and the puncture line becomes turbid; bacteria without flagella can only grow on the puncture line, and the puncture line is clear.
(3) The solid culture media contains 2% - 3% agar, the plate solid culture media is used for bacteria separation, and the tube solid culture media is used for bacteria preservation. Colony is a group of bacteria that can be seen by naked eyes after a single bacteria grows and propagates on solid culture media. The bacterial colonies are divided into three types: smooth type, rough type and mucous type.
Bacteria in semi-solid culture media are mainly used for bacterial dynamic test. In addition to the growth of flagella bacteria along the puncture line, feather like or fog like turbid growth can also be seen on both sides of the puncture line. Bacteria without flagella can only grow along the puncture line in an obvious state, culture media for bacterial growth is still clear and transparent, which is negative for dynamic test.