Production of Shiitake Mushroom Spawn

Spawn production generally begins about 80 days before inoculation of the fruiting bags. Each mother spawn can be used to propagate 5 spawn bottles, with a cultivation time of about 30 days. The spawn production process is as follows: ingredient preparation → bottling and sterilization → cooling and inoculation → cultivation.

(1) Main Culture Medium Formulas

① Sawdust Culture Medium: Broadleaf sawdust 7-8%, wheat bran 2-0%, sugar 1%, gypsum 1%, pH 6.5-7.

② Cottonseed Hull Culture Medium: Cottonseed hulls 7-8%, wheat bran 2-0%, sugar 1%, gypsum 1%, pH 6.5-7.

(2) Selection of Spawn Bottles: 500mL standard spawn bottles are commonly used.

(3) Mixing, Boiling (Bagning), Sterilization, and Cooling

① Mixing: Mix the material and water evenly using conventional methods. ② Bottling: After washing and drying the culture bottles, fill them with culture medium up to the shoulder. Wipe the inside and outside of the bottles clean and cover them with a cap with ventilation holes.

③ Sterilization and Cooling: Temperature control is crucial during sterilization. High-pressure sterilization tanks must be used for centralized sterilization of the culture medium. Maintaining a steam pressure of 0.15 MPa for 2 hours will achieve thorough sterilization. When cooling the sterilized culture bottles, slowly vent the gas to lower the temperature. Once the temperature inside the sterilization tank drops to 60℃, move them to a cooling room for complete cooling.

(4) Inoculation: Inoculate in an inoculation box or inoculation room. Inoculation steps: First, place the cooled culture bottles into the box according to its capacity, leaving sufficient space for bottle transfer. Place the mother culture tubes and necessary inoculation equipment together for pre-inoculation disinfection. After igniting the gas mist disinfectant, promptly seal and disinfect the box (room). During inoculation, under aseptic conditions, cut the mother culture slant culture medium into 5 pieces. The first piece should be cut longer because the culture medium is thin and easily dries out, affecting mycelial growth. Then, transfer it along with the culture medium to the original culture bottle, inoculating one piece per bottle, and making sure it is close to the inoculation hole to facilitate the germination of the mother culture piece . After germination, the mother culture piece should be planted as soon as possible.

(5) Cultivation The original culture room should be clean, dry, and cool. The indoor temperature should be maintained at 23-25℃, the indoor air relative humidity at 40%-50%, and the indoor air should be kept fresh. The windows of the original culture room should be covered with black cloth to prevent the mycelium from being affected by light, causing the moisture in the substrate to evaporate, resulting in premature appearance and aging of the primordia. During the cultivation of the original culture, the culture bottles should be checked frequently for contamination by other bacteria. Once contamination is found, the bottles should be discarded in time. The original culture can generally be fully grown in 30 days.