Pollution Prevention and Rehydration Precautions for Mushroom Inoculation Boxes

Various contaminant organisms (such as molds and bacteria) are almost without exception competitive; they live on the same culture medium as the edible fungi, competing for nutrients and living space, and affecting the growth of the edible fungi. Many contaminants also inhibit the growth of edible fungus mycelium by producing toxic substances.

In a sense, the central task of edible fungus spawn production and cultivation is how to prevent and control contamination by various contaminant organisms in order to obtain pure cultures of mycelium or cultivated material. In production, one important link in preventing and controlling contaminant contamination is the inoculation work. The contamination caused by inoculation and preventive measures are analyzed below for reference.

1. Contamination caused by mold growth in the inoculation box

The direct cause of contamination caused by the inoculation box occurs when the inoculation box is used during the production season. When using the inoculation box, non-standard operation or improper use by the producer can make the inoculation box too humid, for example, letting culture medium or mushroom material spill into the box without timely cleaning, or because the temperature difference between the inside and outside of the inoculation box is large, causing the hot air inside the box to condense into water droplets when it meets cold surfaces, etc. After the inoculation box becomes damp, if ventilation and dehumidification are not carried out in time, then when the inoculation box is idle and not in use, it is very easy for mold to grow.

In view of the above causes of contamination in the inoculation box, to prevent contamination, in actual work, first, when the inoculation box is in use, the humidity inside the inoculation box should be reduced as much as possible. Avoid culture medium, mushroom material, or alcohol cotton balls, etc. directly falling into the box; if they accidentally fall in, they should be cleaned up as soon as possible. Avoid moisture caused by temperature differences between the inside and outside of the inoculation box. Specifically, the following should be done:

(1) After sterilization, material bags or material bottles should be fully cooled before entering the inoculation box for disinfection treatment, so as to avoid causing excessively high temperature inside the inoculation box.

(2) The amount of disinfectant used must strictly follow the regulations. Currently common disinfectants such as aerosol disinfectants and formalin, when used, rely on oxidation reactions of these substances to produce smoke or steam, thereby achieving the purpose of disinfecting the air. As we know, oxidation reactions often generate a large amount of heat; therefore, on the premise of ensuring the disinfection effect, the use of disinfectants should not be excessive.

(3) Increase inoculation speed and control inoculation time well. Slow inoculation speed and long time not only mean low work efficiency and a long production cycle, but also the long-term burning of the alcohol lamp will generate a large amount of heat, making the temperature inside the box too high. In addition, long inoculation time will also prolong the exposure time of culture medium, spawn, etc. in the air, thus increasing the chance of contamination by foreign microorganisms. Second, when the inoculation box is left idle for a long time, the box cover and sleeve openings should be opened in time to facilitate ventilation and dehumidification. In fact, in production it is often very difficult to completely avoid the inoculation box becoming damp, but the key to the problem is that after the production season ends, ventilation and dehumidification should be carried out in time, and the inoculation box should be placed in a ventilated and dry place.

If mold contamination has already appeared in the inoculation box, then how should it be handled? In actual work, some producers often do not pay enough attention to this problem, or simply are not aware of it at all, and still carry out disinfection treatment according to conventional methods when using the inoculation box (unaware that, without extending the concentration of the disinfectant used and the disinfection time, the disinfection effect of the disinfectant is closely related to the number of contaminant organisms in the air), and as a result there is often large-scale contamination for "unknown" reasons. After mold contamination appears in the inoculation box, first wipe the visible mold with alcohol cotton balls or cotton balls dipped in formalin, then fumigate with formalin or disinfect with an aerosol disinfectant; only after continuous treatment 2 to 3 times can it be used.

2. Contamination caused by inoculation operations

Inoculation is a very important step in edible fungus spawn production and cultivation, and is crucial for controlling contamination by foreign microorganisms. During inoculation, producers are required to strictly master microbial aseptic operating procedures. In summary, the main points are as follows:

(1) Various inoculation tools and supplies should be disinfected together with material bags, material bottles, spawn, etc., and passing items into the box during operation should be avoided as much as possible.

(2) Before entering the box for operation, wash both hands thoroughly with clean water outside the box; after entering the box, wipe both hands and inoculation tools with alcohol cotton balls, and sterilize the inoculation tools by flaming them; during the inoculation process, flame sterilization should also be carried out regularly.

(3) For the expansion culture of test-tube spawn, the test tube should be held horizontally; the mouth of the test tube must not face upward, and at the same time the mouth of the test tube should not leave the flame of the alcohol lamp, so as to achieve the purpose of "sealing the mouth" with flame.

(4) Inoculation operations should achieve "light, fast, accurate." "Light" means the movement amplitude during inoculation should not be too large, to reduce air disturbance; "fast" means the operation should be fast, to avoid too long exposure of spawn and culture medium in the air; "accurate" means the inoculation action should be accurate and in place, and inoculation tools, spawn blocks, etc. should not be bumped or placed randomly.

(5) After inoculation operations are completed, remove the items in time and clean up the inside of the box.

3. Contamination caused by the air in the inoculation box

The number of contaminant spores or microbial cells in the air inside the inoculation box directly affects the pure culture rate of the culture after inoculation. The causes of air contamination inside the box are many-sided, such as incomplete disinfection and poor sealing performance of the inoculation box. Among them, incomplete disinfection is the most common cause of air contamination inside the box. Incomplete disinfection may be caused by the disinfectant itself, for example, poor disinfectant effect, insufficient dosage, etc., or it may also be caused by long-term use of the same disinfectant (if the quality problem of the disinfectant itself can be ruled out, from a biological perspective, the poor disinfection effect caused by long-term use of the same disinfectant is often due to the directional selection effect of the disinfectant on variation in contaminant resistance, so that contaminant-resistant populations continuously increase. In view of this, different disinfectants should be used in rotation in production). In addition, poor sealing performance of the inoculation box is also one of the causes of incomplete air disinfection.