A Detailed Guide to Simple Storage Methods for Edible Mushroom Spawn

Ensuring the storage quality of edible mushroom spawn can effectively preserve its superior strain characteristics and extend the number of years a good variety can be used. Therefore, it is just as important as breeding new varieties and is an indispensable and important part of edible mushroom production. However, formal and strict storage methods require some equipment and also place high demands on operating technique; for many mushroom growers, some simple traditional methods are more feasible and more worth promoting.

1. Low-temperature storage at the bottom of a well. This is a method of storing spawn by using the principle that the bottom of a well has a constant and low temperature, and it is suitable for mushroom growers who do not have a preservation refrigerator. Dip a sterile rubber stopper in paraffin and use it to seal the mouth of the test-tube mother culture to be preserved, place it in a sealed wide-mouth bottle or plastic bag and tie it tightly, then sink it to the bottom of the well for storage; it can be stored for 2-5 months.

2. Paraffin sealing storage. Cut wax paper into 6-8 cm squares and soak them in 75% alcohol for 1 minute. After the mouth of the well-cultured test-tube spawn has been sterilized by rotating it above the flame of an alcohol lamp, take out the wax paper with tweezers and tie it tightly over the tube mouth. Then dip the tube mouth wrapped with wax paper into melted paraffin until the wax paper is completely immersed, so that the wax paper is tightly sealed onto the tube wall with absolutely no air leakage. After the paraffin cools and solidifies, store it in a refrigerator or at room temperature.

Spawn sealed with paraffin can effectively maintain the moisture of the culture medium, increase the carbon dioxide concentration inside the tube, avoid contamination by foreign microorganisms, and the mycelium recovers and grows quickly after transfer. When stored at room temperature for 6 months, the culture medium has not yet shown shrinkage, and the mycelium still has fairly strong vitality; after storage at 0-4°C for 12 months, the mycelium appears normal with no signs of aging, and the transfer survival rate is high.

3. Cellophane sealing storage. Dissolve 15 g gelatin (adhesive), 2 g copper sulfate, and 1-2 drops of methylene blue (indicator) in 100 ml hot water to prepare a sealing agent. Remove the cotton plug from freshly fully grown mother culture, turn the tube mouth downward, dip it in the sealing agent, apply cellophane (celluloid) that has been soaked in 95% alcohol, and then seal it with melted paraffin. At room temperature, the spawn can be stored for at least 8 months, and infection by molds or mites can be prevented. Injecting sterile mineral oil (liquid paraffin) onto the slant can greatly extend the storage time.

4. Manure storage. This method is suitable for storing straw-rotting fungi such as Agaricus bisporus. Sun-dry and crush compost such as decomposed cow manure, take 300 g of dry compost, sieve it through a 5 mm mesh sieve, add 1000 ml water to adjust the moisture, put it into test tubes to occupy 1/3-1/2 of the tube depth, and sterilize at 0.15 MPa for 2 hours. After confirming it is sterile, inoculate it; after the mycelium grows fully, store it in a 3°C refrigerator and transfer it once every 2 years. During long-term storage, if the culture medium loses water, the stored spawn should be promptly inoculated onto agar slants for activation and then stored again. After 4 years of continuous storage by this method, its production traits showed no obvious changes.

5. Wheat bran storage method. Weigh out a certain amount of wheat bran, add water or nutrient solution, and mix well before use. Put the water and wheat bran into test tubes, sterilize under high pressure, then inoculate with spawn and culture at a suitable temperature. After the mycelium has developed well, place the test tubes in a drying room and dry them at room temperature. After drying, store them in a dry place below 20°C; they can be stored for 3-5 years.

6. Physiological saline storage method. Inoculate the spawn into potato culture liquid, with 60 ml culture liquid per 250 ml Erlenmeyer flask, culture with shaking or shake 5-10 times a day for 5-7 days, then transfer the formed mycelial pellets into test tubes containing 5 ml sterile physiological saline, with about 4-5 mycelial pellets per tube, plug with cotton plugs, seal the mouths well with wax, and place at low temperature; they can be stored for 1 year.

7. Wheat grain storage method. Take high-quality @#@245@#@, wash it, soak it in 20°C water for 5 hours, dry it slightly, put it into tubes, with the amount filling 1/4 to 1/3 of the tube length being appropriate, sterilize, spread it while hot, and after cooling inoculate with mycelium and culture at a suitable temperature until sparse mycelium appears on most wheat grains, then stop culturing. Place in a dry place below 25°C; it can be stored for 1-2 years.