Several New Methods for Reducing the Contamination Rate of Edible Mushroom Spawn

I. Bottled fermented substrate (1cm)

The improved method is: above the culture medium, about 4cm from the bottle mouth, fill in 1-2cm of fermented substrate, then sterilize. Because the fermented substrate itself is sterile, after inoculating the spawn, the mycelium quickly covers the upper part of the whole bottle, and the mycelium feeds on the substrate at the same time. The advantage of this method is that contaminant microorganisms can hardly infect the culture medium, and the spawn age is uniform. The contamination rate can be reduced to below 3%.

II. Wheat grain germination method

The improved method is: let the wheat grains germinate before bottling and sterilizing. The storage substances of wheat grains are mainly starch, fat and protein. When the seeds imbibe water and their cellular physiological activity is reactivated, the activity of various enzymes increases, and these substances are decomposed during germination into simple-structured substances such as maltose, sucrose and amino acids, which are easily utilized by the mycelium, so the mycelium grows fast. The specific procedure is: let the wheat grains used for making spawn germinate all at once, with the sprout length being 1-2 times the length of the wheat grain, then dry them thoroughly in the sun and store them. On the day before making the spawn, soak the wheat grains for 12h and directly bottle and sterilize them. The advantage of this method is that it saves the process of boiling the wheat grains, saves manpower and money, and the spawn grows fast with few contaminant microorganisms, with a contamination rate of only 2%-3%.

III. Use liquid spawn

The improved method is: use liquid spawn. Liquid spawn overcomes the shortcomings of solid spawn, and liquid spawn can be directly used as cultivation spawn for cultivation. The use of liquid spawn not only has a low probability of contaminant microorganism infection, with the contamination rate reducible to about 2%, but also, from a long-term perspective, because its production does not use plastic bags, it causes no pollution to the environment and reduces the production cost of spawn.

IV. Inoculate from the lower part of the stock spawn bottle

The improved method is: start inoculation from the bottom of the stock spawn bottle. We know that the spawn in the lower part of the stock spawn bottle has a short spawn age and vigorous vitality, and has few contaminant microorganisms. After inoculation, the mycelium feeds on the substrate quickly and the contamination rate is low, so the contamination rate can be reduced to about 3%. In order to further reduce the contamination rate of cultivation spawn, it is recommended to discard the upper 1/5 of the stock spawn at the mouth of a normal stock spawn bottle, to prevent contaminant microorganisms invisible to the naked eye from contaminating the cultivation spawn.

V. In hot seasons, advance or delay the inoculation time

The improved method is: inoculate during the periods of lower temperature in July-August, such as in the morning or at night. Of course, if inoculation is carried out indoors with air conditioning, the effect is even better, and the contamination rate can be reduced to below 5%.