Detailed Explanation of the Production and Application Technology of Shiitake Mushroom Capsule Spawn

At the end of the last century, Japan invented capsule spawn and applied it on a large scale to log-cultivated shiitake mushrooms. In 1999, this technology was introduced to our country. After years of research, the Qingyuan County Edible Fungi Research Center overcame the technical difficulties of applying capsule spawn to substitute-material-cultivated shiitake mushrooms and achieved domestic production. Because capsule spawn has the advantages of saving labor, saving effort and a high survival rate, it is very suitable for large-scale production. In the past two years, the amount used has doubled and redoubled, and tens of millions of bags have been promoted and applied so far. It is estimated that in a few years this technology will become commonly used in our country. To help people in the industry better understand this technology, the author introduces the main characteristics, production technology and methods of use of capsule spawn as follows.

1 Main characteristics of capsule spawn

Conventional spawn is bagged or bottled, inconvenient to take out, and exposed to the air for a long time during use, so there is a great chance of contamination by foreign fungi and the inoculation survival rate is relatively low; on the other hand, when conventional spawn is used for inoculation, the holes vary in size, and since the amount of spawn taken is not easy to control, the gaps at the inoculation openings are often relatively large. During the handling and operation of the mushroom logs, artificial squeezing causes air to move in and out through the gaps, carrying foreign fungus spores into the logs and causing infection.

Shiitake mushroom capsule spawn, just like capsules, is pressed one grain at a time onto a plastic honeycomb board. Each grain of spawn is cone-shaped, and its tail end is attached to a breathable foam cover. The design is scientific, the standard is standardized, and it is convenient to take out; during the inoculation operation, the time of contact with air is short, so there are few chances of contamination; after inoculation, the foam cover seals and allows air through, which can both prevent infection by foreign fungi and pests and diseases and maintain the moisture of the spawn, promoting good development of the mycelium. Therefore, the finished-product rate can be greatly increased compared with traditional spawn. Capsule spawn inoculation is quick, with work efficiency increased by 1-2 times compared with conventional methods, and the consumption of raw materials for producing spawn reduced by more than 80%. Because capsule spawn is made by crushing conventional spawn and pressing it onto a plastic honeycomb board, its strain characteristics have not changed, and the quality and yield of the mushrooms produced are no different from those of traditional spawn.

2 Capsule spawn and its production technology

2.1 Preparation of special culture material The formula of the culture material differs somewhat from that of conventional spawn. First, fine material is required, because material that is too coarse easily causes damage to the cavity trays; second, it is required to have both a good water-retention effect and good permeability.

2.2 Bagging and sterilization Same as conventional.

2.3 Inoculation Same as conventional.

2.4 Incubation The culture is required to be carried out under completely dark conditions, with the degree being that the mycelium matures and no mycelial skin forms.

2.5 Aseptic crushing and aseptic filling This step must be carried out in a sterile room. If foreign fungus spores are mixed into the culture material, after inoculation the foreign fungus spores will germinate under certain conditions and outgrow the shiitake mycelium, causing infection at the inoculation openings. The filling is required to be moderately firm; too firm easily crushes the cavity trays, while too loose causes the grains to be not plump and affects quality.

2.6 Pressing spawn into cavity trays and capping This step is also carried out in a sterile room, and skilled operation is required to reduce the exposure time during capping.

2.7 Incubation Within 3-5 d after the spawn is crushed and press-molded, respiration is vigorous and the spawn is very prone to overheating. Therefore, the incubation of capsule spawn should maintain a relatively low temperature and maintain ventilation, and the stacking height should preferably not exceed 10 layers.

3 Key points for using capsule spawn

3.1 Mushroom logs should be bagged tightly to facilitate the establishment of the capsule spawn.

3.2 The inoculation process, like that of conventional spawn, requires strict operation. Before inoculation, the operator's hands and instruments must be wiped and disinfected with 75% medicinal alcohol or Jiezhongling. The punch bar disinfected with alcohol cotton must be passed through the flame of an alcohol lamp to avoid residual alcohol droplets on the bar. The spawn must not be aerosol-disinfected at the same time as the mushroom logs, to prevent killing the spawn mycelium. The surface of the foam cover of the capsule spawn may be wiped with alcohol, but do not let alcohol flow into the spawn.

3.3 Punch one hole and inoculate one capsule of spawn, and keep the exposure time of the spawn in space as short as possible. The punch bar should not leave the hand and must not be placed anywhere.

3.4 For convenience in taking the spawn, you may first use a single-edge blade to cut the capsule spawn from the reverse side into small pieces. When taking the spawn, gently press the breathable cover of the spawn with the right index finger, support it from the bottom and lift upward with the left index finger, then gently pinch the cover with the right thumb and index finger to take out the spawn, quickly insert it into the punched hole, and gently press the cover so that it seals with the surface of the bag. Note that you must not touch the part of the spawn below the cover with your hands.

3.5 Because capsule spawn has good sealing performance, when the mycelium has grown to more than 4 cm, the inoculation opening is prone to oxygen deficiency, so holes should be pricked in time to increase oxygen and facilitate mycelial growth.

3.6 Shiitake mushroom logs after sterilization must be thoroughly cooled; otherwise, with internal heat and external cold, moisture will condense at the inoculation openings and drown the spawn.

4 Preservation and transportation of capsule spawn

4.1 Preservation of capsule spawn Capsule spawn is required to be preserved in a clean, light-proof environment. At 18°C, the preservation period is about 12 d; if preserved at low temperature in a cold storage (4-10°C), it can be stored for 30-40 d. For low-temperature preservation in cold storage, the spawn must be tightly tied and wrapped in plastic bags. When using it, it must be taken out 1 d in advance and placed at room temperature for activation before it can be used for inoculation. Capsule spawn is prone to dehydration and is not suitable for long-term preservation.

4.2 Transportation of capsule spawn Before the spawn has fully grown through, respiration is excessive and it is not suitable for transportation; it can be shipped only after at least 4 d. Transportation requires an air-conditioned vehicle or refrigerated vehicle. In winter, ordinary freight may be used, and the time in transit should preferably not exceed 1 week.