How to Identify the Quality of Edible Mushroom Spawn? Practical Tips Shared

Edible mushroom spawn, like the seeds of crop vegetables, is the internal factor and foundation for achieving high and stable yields. The quality of the spawn directly affects the yield of edible mushrooms and even determines the success or failure of cultivation. Therefore, identifying and assessing the quality of spawn is very important.

1. Look

1. Check whether there are abnormal spots or patches of red, yellow, black, green, etc. around or on the surface of the substrate in the spawn bottle (bag). If any of the above phenomena exist, it indicates that the spawn has been contaminated by foreign molds (except for varieties that produce pigments, such as shiitake and nameko), and the spawn should not be used further.

2. Check whether the spawn bottle (bag) has been opened and whether the exterior of the bottle (bag) is damaged. Any spawn that has been opened or is damaged may have been contaminated by foreign molds, so such spawn should no longer be used as spawn and can only be used for fruiting.

3. Check whether the date on the label of the spawn bottle (bag) is too old. Mycelium that is too old will transition from vegetative growth to reproductive growth. If used again as spawn and inoculated into culture medium, the mycelium will germinate slowly, the mycelium quality will be poor, and the ability to resist foreign molds will be weakened. If some bottles (bags) are fully colonized while others are not (under the premise of the same spawn production batch), this is caused by differences in the order of spawn production and the tightness of substrate filling. This is acceptable, and it indicates that the spawn age is not too long yet. You can select the bottles (bags) whose mycelium colonized earliest and use them first. If all spawn bottles are fully colonized and some mycelium has grown out of the bottle (bag) opening, or some substrate has lost water and pulled away from the bottle (bag) wall, or a large number of small fruiting bodies have appeared, it indicates that the spawn age is too old and it should no longer be used as spawn. Spawn in which the substrate in the bottle (bag) has not yet been fully colonized by mycelium but has already produced mushrooms should also not be used as spawn. This kind of spawn is mostly caused by unlimited transfer of mother cultures, or by using stock cultures as mother cultures and production cultures as stock cultures when transferring to bottles (or bags). In this situation, the spawn has weak mycelial vitality, colonizes substrate slowly, and has a long cycle. If continued to be used as spawn, it will seriously affect the yield and quality of the finished mushrooms.

4. Check whether the mycelium of the spawn is white and thick. Thick, white, dense mycelium, with the substrate color changing from dark to light, indicates superior spawn; sparse mycelium, or mycelium that is sparse on top and dense below or dense on top and sparse below, are all abnormal conditions, and such spawn should no longer be used as spawn. One point that needs special explanation: different types of edible mushroom spawn also differ in appearance and each has its own characteristics. For example: shiitake mycelium often produces brown pigment and has fewer aerial hyphae; oyster mushroom aerial hyphae are extremely luxuriant and can often fill the container; nameko mycelium has poor whiteness and often has yellow-brown pigment. Therefore, when selecting spawn, different situations should be treated differently.

2. Smell

When purchasing spawn, you can open a few bottles and smell them. Normal spawn should have the special fragrance of that spawn (strain). If the spawn has a musty smell, sour smell, foul smell, or other off-odors, it is abnormal, indicating that the spawn has been infected by other foreign molds and can no longer be used as spawn.

3. Test

1. For bagged spawn, you can pinch it from outside the bag. Good spawn is packed with moderate tightness; if it is relatively soft, loose, and easily broken, it is inferior spawn.

2. For glass bottle spawn, you can open any bottle at random, use tweezers or another hard stick to break up the substrate blocks, and stir the substrate blocks appropriately. If it breaks easily, it is inferior spawn; if it is relatively hard and produces few fragments, it is superior spawn.

3. Whether bagged or bottled spawn, you can also use your hands directly to judge the quality of the spawn. When pressing the spawn block with your fingers, superior spawn is elastic; when breaking it into small pieces by hand, few fragments fall off, and mycelium is clearly visible on the cross-section of the culture block. Conversely, if the spawn block has no elasticity, the dug-out spawn does not form blocks, is loose, and has many fragments, it is inferior spawn and cannot be used for production.