Detailed Explanation of Edible Mushroom Spawn Production Methods and Key Technical Points

Right now is the peak season for edible mushroom spawn production. As a technology-intensive and labor-intensive product, edible mushrooms, with their short, smooth and quick production advantages, are being favored by more and more farmer friends. "Good seed gives good seedlings" is a phrase familiar to everyone in ordinary agricultural production, but it is easily overlooked in edible mushroom production. Therefore, especially under the current situation, it is very necessary to train and standardize spawn production technology and to determine the direction of technological research and development. Adaptive selection of spawn 1. Selecting and introducing spawn (strains) adapted to local climatic conditions is the basic condition for the smooth progress of edible mushroom production. The reason is that, on the one hand, because of the particularity of the spawn itself, even professional workers find it difficult to distinguish good mycelium from bad under ordinary conditions, and mushroom farmers, restricted by their knowledge and experience, are even less able to tell the difference. Therefore, a considerable number of mushroom farmers can only use brand names, spawn names and prices as the criteria for judging whether to introduce spawn, which further promotes the spread of inferior and counterfeit spawn. On the other hand, hearing by word of mouth that spawn from a certain place is good, and then blindly introducing it and expanding cultivation on a large scale regardless of regional differences, climatic differences and market differences, will lead to predictable consequences. The correct method of spawn introduction should be: first, choose a formal spawn production unit and examine its technical strength, facilities and equipment, and testing level; second, carefully inquire about the biological characteristics of its spawn, including suitable substrate, suitable formula, suitable temperature, fruiting body occurrence and morphological characteristics, commercial traits, flush turnover speed and growth cycle, and compare these with local conditions before determining whether trial cultivation is possible. 2. Scientific research and development units and specialized spawn production enterprises should make the domestication, selection and breeding of spawn one of their main work contents. Although each spawn production unit can list dozens or even hundreds of spawn names, when it comes to a specific variety, taking oyster mushroom (Pleurotus) as an example, the so-called dozens of "varieties" are, from a professional point of view, merely different code names for various strains; yet once they are labeled as "new varieties," mushroom farmers feel a sense of novelty and develop a desire to buy. From a long-term perspective, this kind of phenomenon is only a short-term effect and provides no substantial promotion or help to actual production. As a spawn production unit, broad introduction of spawn is necessary, but it is even more necessary, even urgent, to screen and domesticate varieties or strains adapted to local conditions from different spawn sources in various regions. 3. Capable units or individuals should carry out cross-breeding and domestication of wild mushrooms as soon as possible. Most spawn is introduced, either renamed or given a different code, but it is still not "one's own thing." Therefore, using high-tech means to carry out cross-breeding and domestication of wild resources as soon as possible can both truly give one one's own spawn source and increase competitiveness. Spawn production technical standards 1. Production of first-level spawn (mother culture) -- Corresponding spawn source conditions: Whether the spawn source is obtained through introduction, gift, preservation, isolation or other channels, the primary condition must be that it is adapted to local climatic conditions and has corresponding fruiting tests, variety comparison tests, and market recognition of that variety or strain. And the spawn age should be conventionally produced within 60 days. -- Corresponding facilities and equipment: including an operation (ingredient preparation) room, sterilization room, hand sterilizer (portable steam sterilizer), inoculation box, etc.; for large-scale production, a refrigerator, microscope, etc. are also needed. -- Corresponding tools and materials: including ingredient preparation tools, dispensing tools, cotton, kraft paper, and disinfection and sterilization drugs such as alcohol, formaldehyde, potassium permanganate, etc. -- Corresponding operating techniques: including the operating techniques and experience for spawn production and inspection and testing. The standard for culture medium sterilization treatment is: high pressure 0.11 MPa x 0.5 hour (specific operations omitted). -- Corresponding culture conditions: for general varieties, about 25 degrees C is suitable; individual varieties may be lower or higher, and should be "suited to the spawn." Key technical points: ensure the quality of the spawn source; strictly perform aseptic operations; check and remove contaminants in a timely manner; preserve at suitable temperature and timely manner (specific operations omitted, the same below). 2. Production of second-level spawn (stock culture): Under the condition that the quality of the first-level spawn is guaranteed, the spawn source is no longer discussed as a problem. -- High-pressure steam sterilization equipment, or normal-pressure sterilization stove; small spawn production units can use normal-pressure stove sterilization, while medium and large units should be equipped with high-pressure sterilization equipment of corresponding volume. -- Necessary operation rooms, sites, and a clean, ventilated and well-sealed culture room; if conditions permit, room temperature should be regulated and controlled. -- Corresponding materials, including raw materials, spawn bottles (bags), sealing film (stoppers), etc. -- Corresponding disinfection and killing drugs, including alcohol, formaldehyde, potassium permanganate and DDV, etc. -- Necessary tools, including common tools for ingredient preparation, material mixing, bottling (bagging), transportation, inoculation, inspection, etc. -- Sterilization treatment standards: high pressure 0.15 MPa x 2 hours; normal pressure 100 degrees C x about 8 hours. -- Corresponding operators: including workers for each production link, among whom inoculation personnel are especially important and must meet the requirements of proficiency and responsibility. -- Corresponding culture conditions: the same as first-level spawn. Key technical points: except for some varieties, the pH of the ingredients is generally required to be between 7 and 9; during normal-pressure sterilization, the time gap between bottling (bagging) and sterilization should be shortened as much as possible; 3. Production of third-level spawn (cultivation spawn, production spawn): The production of third-level spawn is basically the same as that of second-level spawn, except that the production quantity is expanded by more than ten times or even more, and labor intensity is also somewhat increased. Due to limited space, it will not be described in detail. Cultivation, Inspection, Removal of Contaminants The culture temperature range for spawn is generally 5 degrees C to 35 degrees C, with 25 degrees C being the most suitable, but it should be specifically determined according to the characteristics of the variety; in actual production, it can be controlled at 20 degrees C to 30 degrees C. As far as the climatic conditions of Shandong are concerned, the relative air humidity of the culture room is generally between 50% and 75%. However, in spring, water should be sprinkled appropriately to increase humidity, and in summer and autumn, ventilation should be maintained. Inspection of spawn. Counting from inoculation, the initial inspection of first-level to third-level spawn should be on the 2nd day, 3rd day and 3rd day respectively; thereafter, the intervals between inspections are 1 day, 2 days and 3 days respectively. The focus of inspection: whether the spawn germination situation and mycelial growth trend conform to the characteristics of its spawn source; for first-level spawn with any transparent, semi-transparent or paste-like contaminated patches (bacteria) on the slant, as well as contamination by orange, black, gray, green, yellow (fungi), etc., they should be promptly removed; especially attention should be paid to the timeliness of inspection, because some bacterial contamination spots can be covered by edible mushroom mycelium after 1 to 2 days; for second-level to third-level spawn, the main focus is inspection for contamination by foreign (true) fungi. Points to note: when producing in summer and autumn, especially strictly prevent and control contamination by orange mold (Neurospora), remove contaminants promptly, and bury them deeply in a timely manner; otherwise, once contamination breaks out, it will lead to "total annihilation." Research and development trends in spawn production At present, first-level spawn containers are mostly small test tubes of (18 x 180) mm specifications. Long-term research and development practice has told us that even under the same culture medium conditions, first-level spawn made in test tubes of (20 x 200) mm specifications, due to reasons such as thicker blocks, larger amount of culture medium, richer nutrition and larger inoculation amount, clearly gives the transferred second-level spawn production advantages such as earlier germination and earlier colonization. Therefore, first-level spawn production should shift to large test tube culture as soon as possible. Traditional second-level spawn production mostly uses waste cans as containers, and their disadvantages such as being heavy, fragile, inconvenient to transport and polluting the environment are obvious. Our developed "second-level spawn production technology with automatic oxygen-increasing lightweight containers" completely solves the above disadvantages. Under the premise of the same weight, the amount of spawn increases by about 50% compared with traditional spawn, and production cost decreases by about 40%, making it the development direction of second-level spawn production in the future. Liquid spawn is the future development direction. Liquid spawn clearly has the production and application advantages of large-scale production, automated control, aseptic growth and high-speed mycelial growth, and is favored by people in the industry. At present, the unit where the author works undertakes the provincial research project "Edible Mushroom Liquid Spawn," has carried out a large number of experimental studies, and spawn production units and cultivation production units from various places have come to visit and consult. In general spawn production, from inoculation to completion of mycelial growth takes only 3 days, and individual high-grade varieties such as Armillaria mellea also require only 5 to 7 days, which is 1/5 to 1/10 of conventional production time. Moreover, because after sowing the mycelial pellets are uniform in individual size and relatively evenly distributed in the substrate, once they germinate, they "bloom everywhere" in the substrate and rapidly occupy the substrate, leaving no opportunity for contaminating fungi. This provides good spawn source conditions for the development of edible mushroom industrialization and is an inevitable direction for the development of edible mushroom industrialization.