Know the prevention and control methods of edible fungi diseases, and strictly prevent pollution of edible fungi culture strains

The contamination of edible fungi such as green mold, Penicillium, Aspergillus, Rhizopus, Mucor and bacteria will occur in the process of culture, especially in the high temperature season. In the process of production, due to the invasion of miscellaneous bacteria, it will often lead to a reduction in production or even no harvest. Therefore, to find the causes of miscellaneous bacteria pollution is of great significance to improve the success rate of cultivation and economic benefits. Under normal circumstances, the pollution rate of secondary and tertiary bacteria is less than 5%. If it goes beyond this range, we need to find out the cause. The causes of strain pollution are as follows:

1. Incomplete sterilization: incomplete sterilization of culture materials will cause miscellaneous bacteria pollution, which can occur in 3-5 days. The incomplete sterilization is also caused by the following reasons:

Improper operation of ① mold: the mycelium and spores of general miscellaneous bacteria can be killed after 100 ℃, 6-8 hours or 121 ℃, 0.5-2 hours at atmospheric pressure. At present, the culture materials of edible fungi often use atmospheric pressure sterilization or high pressure sterilization. Atmospheric pressure sterilization is difficult to sterilize grain, dung grass and other materials, and it is not easy to fully achieve the effect of sterilization, while the effect of high pressure sterilization is much better.

The influence of the properties of ② culture materials: the type of materials needed for seed production, the bacterial content, water content and pH of the culture materials can affect the sterilization effect. When sterilizing, the corresponding sterilization time should be selected according to the different formula of the culture material.

Improper stacking of ③ strain bottle (bag): the stacking form of strain bottle (bag) in the sterilization pot can affect the effect of sterilization. There should be a certain gap in the discharge to facilitate the flow and heating of steam. When sterilizing the culture material in the strain bag, because the plastic bag is easy to deform and soften after being heated, if the loading is not tight, the gap between the bacteria bag will be reduced when stacked, which will affect the effect of sterilization.

The influence of ④ strain bottle or seed bag: generally choose strain bottle or seed bag when producing seeds. The heat transfer rate of plastic bag is fast, while that of glass bottle is slow. when the same culture material and the same sterilization method are used, the sterilization time of bottle filling is slightly longer than that of bag filling. In addition, individual containers are not tightly sealed or small and damaged, which can also lead to contamination of miscellaneous bacteria.

two。 Non-standard inoculation operation: the inoculation process of edible fungi requires strict aseptic operation, such as non-standard operation, it is very easy to cause miscellaneous bacteria pollution of culture materials. The contaminated miscellaneous bacteria are generally miscellaneous bacteria in the air of the inoculation room, miscellaneous bacteria on the surface of bacterial bags, and miscellaneous bacteria on the body surface of vaccinators. The characteristic of the pollution of the culture material caused by the non-standard operation is that the miscellaneous bacteria grow on the surface of the culture material, which usually occurs at the opening of the bacterial bag and the inoculation place. Therefore, the aseptic operation rules must be strictly observed, and the inoculation room should be strictly disinfected with the special disinfection king of the bacteria room.

3. Strain with miscellaneous bacteria: the original species used for expanded culture must be pure bacteria in order to ensure the oneness of the strain. If the strain itself is not pure, it can cause batch pollution, in a batch of bacteria in production, the bacteria concentrated together all appear pollution, and the contaminated part is in the strain block, the pollution appears earlier, it can appear in 3-5 days after inoculation. Therefore, we should try our best to use the original strain with strong vitality, suitable bacterial age and strong stress resistance in seed production.

4. The culture room is not clean: the culture material is not clean, the air is not ventilated, the room is damp, and it can also be infected with miscellaneous bacteria. In this case, the pollution rate is relatively low, but with the extension of culture time, the pollution rate will gradually increase. A large amount of pollution appeared relatively late, usually 10 days after inoculation.