JP2006325513A - Method for sterilizing mushroom culture medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for effectively sterilizing a mushroom culture medium so as to harvest high-quality mushroom at high yield. <P>SOLUTION: This method for sterilizing a mushroom culture medium comprise making chlorine dioxide act on the mushroom culture medium to sterilize the culture medium. Alternatively, the method comprises using chlorine dioxide aqueous solution as water to be added when adjusting water content while mixing the raw material of the culture medium. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for sterilizing a culture medium used for artificial cultivation of mushrooms.

Mushroom cultivation methods are widely used, in which mushrooms are inoculated into a culture medium prepared by mixing sawdust with nutrients such as rice bran, inoculated with mushroom inoculum, and grown. This method has an advantage that mushrooms can be efficiently harvested.
The culture medium made of a mixture of sawdust, rice bran, etc. used in this mushroom cultivation method is easy to propagate molds and bacteria. Thus, it is important to cultivate purely mushrooms.
Conventional sterilization is performed by filling culture media into individual containers, storing the culture media together with the containers in a sterilization pot, and heating them at normal pressure or high pressure for a certain period of time.

By the way, after mixing raw materials such as sawdust and adjusting the water content of the culture medium, it takes several hours to reach the temperature at which the culture medium stored in the sterilization pot is sterilized. This is because sterilization pots sterilize a large number of containers at a time, so it takes time to finish filling the culture medium in the container, the culture medium contains air and is difficult to heat, and is further packed in the container This is because it is difficult to sufficiently heat the core of the culture medium. There is no problem in the low temperature period, but in summer when the temperature is relatively high, bacteria may propagate and the culture medium may ferment during these hours. Once fermented and oxidized, the mushrooms inoculated into the culture medium cause delays in generation, deterioration in quality, and reduction in yield.
Therefore, in order to suppress the growth of bacteria, after filling the culture medium in the container and storing it in the sterilization pot, the container is stored in a cool box, or lime is mixed with the culture medium to prevent oxidation and the pH is adjusted. The method to do is adopted. However, according to the method using a cold storage, there is a problem that equipment costs are required. Moreover, the method which mixes lime did not obtain a remarkable effect. This is considered to be an effect of harmful gas generated during fermentation.

  Therefore, the present invention has been made to solve the above-mentioned problems, and the object of the present invention is to enable the culture medium to be sterilized effectively and in a simple manner, thereby harvesting high-quality mushrooms. The present invention provides a method for sterilizing a mushroom culture medium that makes it possible.

In order to achieve the above object, the present invention comprises the following arrangement.
That is, the present invention is characterized in that chlorine dioxide is allowed to act on a mushroom culture medium to sterilize the culture medium. According to this, the culture medium can be effectively sterilized.
In addition, a chlorine dioxide aqueous solution is used as water to be added when adjusting the water content while mixing the raw materials of the culture medium. According to this, the culture medium can be sterilized without unevenness.
In addition, the culture medium sterilized by the mushroom culture medium sterilization method is filled in a container, and then the container filled with the culture medium is heat sterilized together with the container. According to this, it can sterilize reliably also including a container.
Moreover, what dissolved the tablet in which the chlorine dioxide was compression-stored in water as a chlorine dioxide aqueous solution is used, It is characterized by the above-mentioned. According to this, a chlorine dioxide aqueous solution can be obtained easily.

  According to the present invention, the culture medium can be effectively sterilized, and high-quality mushrooms can be highly harvested.

Hereinafter, preferred embodiments of the present invention will be described in detail.
In producing the culture medium, first, while stirring the sawdust as a raw material, water is added to adjust the water content to a predetermined water content.
After that, add raw materials as nutrients such as bran, okara, rice bran, corn cob, etc. to the moisture-adjusted sawdust, add water while stirring and mixing, adjust the water to a predetermined amount of water and To do. A mixer or the like may be used for stirring the raw materials.
In the present embodiment, a chlorine dioxide aqueous solution is used as water for water adjustment when adding moisture to sawdust to adjust water. The chlorine dioxide concentration in the aqueous chlorine dioxide solution is preferably 0.6 to 50 ppm.
Stirring may be continued for a predetermined time after the addition of a predetermined amount of chlorine dioxide aqueous solution necessary for moisture adjustment to the raw material. This makes it possible to produce a culture medium in which raw materials are uniformly mixed, and to allow chlorine dioxide to act uniformly on the raw materials.

Chlorine dioxide is represented by ClO ₂ and is in a gaseous state at room temperature, and has excellent bactericidal and deodorizing effects. Chlorine dioxide is excellent in sterilizing molds, bacteria, viruses, spore bacteria, and the like, and is also effective in sterilizing molds such as blue mold, Aspergillus or the like, and Bacillus subtilis that are easy to propagate in the culture medium.
Chlorine dioxide has less sterilization power pH dependency than chlorine sterilization, has a sterilization (oxidation) power 2.6 times that of chlorine sterilization, and does not generate harmful substances such as trihalomethanes. There is an advantage such that it can be made harmless when the reaction with germs or the like is completed.

  As a method for generating chlorine dioxide, a method using a commercially available agent that generates chlorine dioxide by dissolving in water is simple. As this medicine, for example, there is a pure chlorine dioxide generator “Smell Fungus Buster (trade name)” manufactured by Saber Oxidation Technology, USA. This pure chlorine dioxide generator is a tablet in which chlorine dioxide is compressed and stored, and when one tablet is put into 1 liter of purified water, a pure chlorine dioxide aqueous solution of 24 ppm is formed in about 10 minutes.

Alternatively, a chlorine dioxide generator may be used as a method for generating chlorine dioxide. The chlorine dioxide generator includes a two-component reaction type and a three-component reaction type.
As the two-component reaction type, there is an apparatus that generates chlorine dioxide by a reaction between two chemical solutions of sodium chlorite and an acid. As the acid, an organic acid or an inorganic acid can be used. More specifically, citric acid, hydrochloric acid or the like can be used.
As the three-component reaction type, there is an apparatus that generates chlorine dioxide by a three-component chemical reaction of sodium chlorite, sodium hypochlorite, and hydrochloric acid.
Chlorine dioxide is produced by a chemical reaction of a chlorine dioxide generator and diluted with water to obtain a chlorine dioxide aqueous solution having a predetermined concentration.

By using a chlorine dioxide aqueous solution as water for adjusting moisture and mixing with the raw material of the culture medium while stirring, the culture medium can be prepared while the raw material is sterilized uniformly with chlorine dioxide.
Then, the produced culture medium is filled in individual containers such as bottle-shaped cultivation containers and plastic cultivation bags, and the whole container is heated and sterilized. As a method for heat sterilization, a conventional method can be used in which the culture medium is housed in a sterilization pot and the container is heated for a predetermined time by high pressure sterilization or normal pressure sterilization. At this time, the container filled with the culture medium seals the opening or covers the opening so that the inside and outside of the container can be ventilated only through the filter. The filter prevents fungi and bacteria from entering the container.

When the heat sterilization is completed, the culture medium is inoculated with mushroom inoculum through the opening of the container, and the opening is sealed or covered again so that the inside and outside of the container can be ventilated only through the filter. In this state, the container is accommodated in the culture chamber and the mushrooms are cultured. When inoculating the inoculum, it is the same as before that the inoculation chamber is sterilized so that no germs enter the container.
When the culture period is over and the mycelium is sufficiently propagated and spreads in the culture medium, the container is moved to the growth chamber to generate fruit bodies and grown outward through the opening of the container. When the fruiting body has grown to a sufficient size, it is harvested.

In this embodiment, the following effects can be obtained.
Since the culture medium is sterilized by chlorine dioxide at the time of preparation, bacteria and molds do not propagate during filling of the culture medium in the container and heat sterilization.
Further, by sterilizing the culture medium together with the container, the container can be sterilized and the culture medium can be reliably sterilized. Furthermore, sawdust and other nutrients are also decomposed by steam for heat sterilization, and nutrients are more easily absorbed by the mycelium.
In addition, conventionally, since the culture medium filled in the container is in a block shape, when heated in the sterilization pot, the culture medium core portion is not sufficiently heated and sterilization becomes insufficient and remains in the core portion. Bacteria and molds could inhibit mushroom growth. On the other hand, according to the above method, the culture medium is stirred and mixed with the aqueous chlorine dioxide solution, so that it can be sterilized evenly to kill bacteria and molds and the growth of mushrooms is not hindered. .
In addition, the sterilizing power of chlorine dioxide is attenuated within a few hours and becomes harmless, so that it does not adversely affect mushrooms and is advantageous in terms of food safety compared to the use of fungicides and the like.
Moreover, if the chemical | medical agent which generate | occur | produces chlorine dioxide by making it melt | dissolve in water is used as a generation source of chlorine dioxide, a chlorine dioxide aqueous solution can be obtained easily and effective and effective culture medium disinfection can be performed.
Thus, according to the above method, the culture medium can be effectively sterilized, so that the growth of mushrooms is not hindered by bacteria, molds, etc., and high quality mushrooms can be harvested at a high yield.

Claims (4)

  A method for sterilizing a mushroom culture medium, wherein chlorine dioxide is allowed to act on the mushroom culture medium to sterilize the culture medium.   The method for sterilizing a mushroom culture medium according to claim 1, wherein an aqueous chlorine dioxide solution is used as water to be added when adjusting the amount of water while mixing the raw materials of the culture medium.   A method for sterilizing a mushroom culture medium, comprising filling a container with the culture medium sterilized by the method for sterilizing a mushroom culture medium according to claim 1, and then sterilizing the container filled with the culture medium together with the container.   The method for sterilizing a mushroom culture medium according to claim 2, wherein the aqueous solution of chlorine dioxide is a tablet in which chlorine dioxide is compressed and stored in water.