1. The hyphae are white, like fine wool and wool. The hairs are short and tidy, dense and stout, and they extend to the bottom of the bottle and grow evenly. They are uniform from top to bottom and dug out into pieces. They are not loose. 2. When the mycelium grows over the bottle, brown beads are generally secreted on the surface of the bacteria. Later on the surface and surface of the bottle appeared light yellow transparent colloidal ear buds. 3. The strain column is closely attached to the wall of the bottle, and a small amount of white water droplets attached to the inner wall of the bottle are fresh strains. If there is a slight yellowish water at the bottom of the bottle, the bacterial column will shrink from the wall and become an aging strain, so it cannot be used. 4. The normal strains have the characteristic aromatic odor of black fungus. If there is odor and musty smell, or the phenomenon of plaque and globular no bacteria, it is bacterial contamination. If there are other red, green, yellow, black, etc. Color indicates that it has been contaminated with bacteria and cannot be used. 5. If there is a light black colloidal substance (ear base) between the medium and the bottle wall, it indicates that the strain is precocious or has too many expansion times. After cultivation, the ear piece is small, the quantity is large, and it is not easy to grow up. The quality is poor. The output is low and should be eliminated. 6, if the bottle can see the wooden particles and the mycelium is small, indicating that the culture time is too short, should continue to cultivate. If there is no significant change after a period of culture, it means that the nutrient in the medium is insufficient and should be supplemented. 7, if the bacteria grow to about half or a corner no longer continue to grow, it may be too dry or too wet. If the mycelium grows neatly and densely, it appears sparsely and there is a clear demarcation, indicating that the upper material is moderate and the lower part is too dense. 2019-Ncov Saliva Antigen Rapid Test Kit,2019-Ncov Antigen Test Kit (Colloidal Gold Method),2019 Ncov S-Rbd Neutralizing Antibody,Influenza A,B Virus Guangdong Hecin Scientific, Inc. , https://www.hecinscientific.com