What are the precautions for buying mushroom mother cultures?
Through surveys in Pulandian and the surrounding areas, it was found that in actual production most mushroom growers do not buy spawn for direct cultivation, but instead buy mother cultures and propagate the spawn themselves. Although this can save costs, the following points should be noted when purchasing to avoid unnecessary losses.
1. Ask about culture age. When buying mother cultures, first ask about the culture age, which directly affects the quality and finished-product rate of the spawn.
2. Ask about the substrate. Mother cultures grown on different substrates look different; for example, grain-based cultures have denser and whiter mycelium than straw-based cultures, and straw-based cultures with more wheat bran, soybean powder, cornmeal, etc. grow more vigorously than those with less of these supplements. Do not let the nutritional richness or poverty of the medium affect your judgment of culture quality. Judge culture quality according to the different substrates. In addition, relatively nutrient-rich substrates age quickly after the culture finishes growing and should not be stored too long.
3. Visual observation includes observation of outward appearance, form, growth vigor, color and other aspects.
Outward appearance observation: carefully check whether the mycelium is plump and whether the culture body is plump and fresh. If the mycelium is shriveled, the variety may be poor, or the culture age may be too old; if the culture body is shrunken, it indicates that the culture age is too old and the culture has aged.
Form observation: carefully observe whether the mycelium is uniform and neat. If the mycelium is scattered and disordered, it may be an inferior culture.
Color observation: the color should be pure and consistent from top to bottom; otherwise it must not be used. Color observation can be used to judge whether the culture is young or old and whether contamination has occurred. Aged mother cultures often show old skin, yellow liquid, patches and shrunken culture bodies. In cultures contaminated by mold, the contaminated colonies can be seen on the surface; even if these colonies have been covered by the mushroom mycelium, their traces can still be seen if observed carefully. If the contaminated colonies are on the surface, the original color of the contaminant can be seen beneath the mushroom mycelium, or the surface aerial mycelium of the mushroom appears uneven; if the contaminated colonies form around the culture body, an obvious yellow antagonistic line between the contaminated colonies and the mushroom mycelium can be seen. Some mushrooms can continue to grow after contamination by Mucor, such as oyster mushrooms, and can even cover the Mucor mycelium and sporangia; once the culture is fully grown, inexperienced people often regard such a culture as normal. In this case, careful observation reveals that the mycelium is rather disordered in distribution and darker or slightly yellow in color, lacking the neat, bright and plump appearance of a normal culture.
Take-out inspection: when buying mother cultures, it is best to take out a representative culture, open the container and dig it out. First, smell it to see whether it has a rich mushroom aroma; second, see whether the mycelium is tightly connected. If the mushroom aroma is faint or the mycelium is not tightly connected (it feels very loose when dug out, and the culture can be broken up and removed without effort), it is not an excellent mother culture.
Some mushroom growers also often mail-order mother cultures from reputable research institutes or colleges and universities in other places, or even from specialized institutions for culture collection management. Mail-ordered mother cultures should be carefully checked for damage; for bottled mother cultures, focus on checking the bottle mouth, cap and stopper; for bagged mother cultures, in addition to the bag opening, carefully check the entire body, with special attention to whether the plastic bag has worn-through pinholes. Before inoculation, wipe and disinfect the entire outer surface of test tubes and bottles; after opening, burn and wipe them over an alcohol lamp flame with a 75% alcohol cotton ball. This double disinfection and sterilization treatment must be strictly carried out whether or not the culture has mold visible to the naked eye.