Edible mushroom sterilization treatment method

Abstract

The invention relates to an edible mushroom sterilization treatment method. The method comprises the following steps: S1, putting edible mushrooms into a sterilization cabinet for sterilization; s2, after sterilization is finished, negative pressure is continuously applied into the sterilization cabinet, residual hot steam in the sterilization cabinet is discharged, and the central negative pressure temperature of the edible mushrooms in the sterilization cabinet is reduced to be not higher than 35 DEG C; and S3, after cooling is finished, the negative pressure in the sterilization cabinet is relieved, so that the sterilization cabinet and the interior of the edible mushroom sticks recover to the normal atmospheric pressure state. Through combination of positive pressure sterilization and negative pressure cooling, the sterilization treatment efficiency and effect are remarkably improved, energy consumption is remarkably reduced, and energy conservation, emission reduction, cost reduction, efficiency increase and yield increase are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of edible fungus cultivation, and in particular to a cultivation method for sterilizing edible fungus sticks and rapidly cooling and oxygenating the inside of the sterilized fungus sticks to save energy and increase production. Background Art

[0002] At present, the sterilization of edible mushroom bags or sticks is to kill the microorganisms in the culture medium. It is a necessary condition for the cultivation of bacteria. Moist heat sterilization is usually used. Because hot steam has strong penetrating power and the coagulation point of protein decreases with the increase of water content, moist heat sterilization uses high temperature to inactivate the protein of microorganisms, thereby achieving the purpose of sterilizing the culture medium.

[0003] Taking the commonly used high-temperature sterilization method of edible fungi as an example, the sterilization of edible fungi bags (sticks) is usually carried out of the sterilization cabinet at 100-124℃ positive pressure. The sterilization time often takes 4-12 hours, and the most suitable inoculation temperature should be between 20-35℃; the bag is cooled from about 100℃ to 30℃ just after it comes out of the pot. The commonly used method is refrigeration and air conditioning. Long-term use needs to consider the depreciation and wear costs of the machine, and according to different temperatures, each bag must also require electricity costs between 0.01 cents and 0.05 cents. According to the scale of 200,000 bags of bags (sticks) per day, the electricity cost for cooling the bags is 2,000-4,000 yuan per day. The existing commonly used edible fungi sterilization methods still have problems such as large machine wear, large energy consumption, and excessive temperature difference (above 8-10℃) between the inside and outside of the bag and the upper and lower ends of the rack, resulting in uneven cooling of the bag (stick).

[0004] In summary, with the country's requirements for energy conservation and emission reduction and the needs of enterprises to reduce costs and increase efficiency, there is an urgent need for a method for rapid cooling, rapid oxygenation, energy conservation and increased production in edible fungus bags (mushroom sticks). Summary of the invention

[0005] In order to solve the above problems, the present invention provides a method for sterilizing edible fungi. After sterilization, the method adopts a method of creating a negative pressure environment and cooling down, which greatly improves the cooling efficiency and cooling uniformity, and well achieves energy saving and increased production, cost reduction and efficiency improvement.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A method for sterilizing edible fungi comprises the following steps:

[0008] S1. Place edible fungi in a sterilization cabinet for sterilization;

[0009] S2. After the sterilization is completed, negative pressure is continuously applied in the sterilizer to discharge the residual hot steam in the sterilizer and reduce the negative pressure temperature of the center of the edible fungi in the sterilizer to no higher than 35°C;

[0010] S3. After the temperature is lowered, the negative pressure in the sterilizer is released, so that the sterilizer and the edible fungi return to normal atmospheric pressure.

[0011] The technical solution of the present invention uses negative pressure in S2 to quickly and evenly discharge the residual steam and heat in the sterilization cabinet and remove the heat source. On the other hand, according to the physical properties of water, under certain conditions, as the environmental pressure decreases, the boiling point of water also decreases, but the heat consumed by evaporating a unit mass of water increases. This step in the technical solution of the present application relies on artificially achieving a low-pressure vacuum state, so that the water in the edible fungi in the sterilization cabinet evaporates rapidly under low-pressure conditions, and while a large amount of water molecules migrate, a large amount of heat in the mushroom stick is absorbed and taken away, thereby achieving the purpose of rapid and uniform cooling of the edible fungi material.

[0012] In S3 of the technical solution of the present invention, the process of releasing the negative pressure and restoring the normal atmospheric pressure state is also the process of accelerating the edible fungi in the cabinet to fully absorb oxygen. Specifically: after negative pressure cooling, the environment inside the sterilization cabinet and the interior of the edible fungi are in a sufficient negative pressure vacuum state. After cooling to a suitable temperature, the negative pressure is released. The pressure difference between the sterilization cabinet and the edible fungi will cause the external gas to accelerate into the sterilization cabinet and the edible fungi. In the process of restoring the normal atmospheric pressure from negative pressure, the edible fungi will also accelerate the absorption of oxygen, so that the edible fungi are more fully activated, greatly accelerating the germination speed of the edible fungi, making the mycelium vigorous, with strong vitality and strong anti-infection ability.

[0013] In one possible implementation,

[0014] In S1, during sterilization, the temperature in the sterilization cabinet is maintained at a positive pressure of 100 to 124°C.

[0015] In one possible implementation,

[0016] In S2, the duration of applying negative pressure in the sterilization cabinet is 20 to 30 minutes.

[0017] In one possible implementation,

[0018] In S2, the residual hot steam in the sterilization cabinet is discharged and introduced into other sterilization cabinets to be sterilized.

[0019] In one possible implementation,

[0020] In S3, after the temperature is lowered, clean oxygen is introduced into the sterilization cabinet so that the sterilization cabinet and the edible fungi are restored to normal atmospheric pressure.

[0021] In this preferred technical solution, by directly introducing oxygen into the sterilization cabinet, on the one hand, it can further avoid the contamination of edible fungi due to the inhalation of external impurity gases into the sterilization cabinet during the process of releasing the negative pressure; on the other hand, high-concentration oxygen is fully introduced into the sterilization cabinet under the action of the internal and external pressure difference and is absorbed by the edible fungi at an accelerated rate, which can further enhance the effect of oxygen absorption and activation of the edible fungi.

[0022] The above technical solution provided by this application has at least the following technical effects or advantages:

[0023] (1) The present application can greatly accelerate the cooling efficiency of edible fungi in the sterilization cabinet, improve the uniformity of cooling, reduce costs and increase efficiency.

[0024] (2) The present application can effectively recycle waste heat after positive pressure sterilization in the sterilization cabinet, thereby saving energy and increasing production.

[0025] (3) The present application can promote the absorption of oxygen by edible fungi in the sterilization cabinet, so that they can be more fully activated, greatly accelerate the germination speed of edible fungi, make the mycelium vigorous, have strong vitality and strong anti-infection ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments of the present application or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 This is a comparison of the inside of the mycelium in the experimental group and the control group after 10 days of growth in Example 1 of the present application; in the figure, A is the experimental group mycelium stick, and B is the control group mycelium stick; the actual sizes of A and B are the same, Figure 1 In the example of A, a square is used to compare and show its size;

[0028] Figure 2 This is a comparison of the external appearance of the mycelium in the experimental group and the control group after 16 days of growth in the mushroom sticks treated in Example 1 of the present application; in the figure, A is the mushroom stick of the experimental group, and B is the mushroom stick of the control group;

[0029] Figure 3 This is a comparison chart of the output of mushroom sticks after treatment of experimental groups 1-2 and control groups 1-2 in Example 2 of the present application; in the figure, A is the mushroom bag of experimental group 1, B is the mushroom bag of experimental group 2, C is the mushroom bag of control group 1, and D is the mushroom bag of control group 2. DETAILED DESCRIPTION

[0030] The specific implementation of the embodiment of the present invention is described below in conjunction with the accompanying drawings.

[0031] Example 1

[0032] This embodiment includes an experimental group and a control group, wherein:

[0033] The edible mushroom sticks of the control group were sterilized in a positive pressure sterilizer at 100-124℃ for 4-12 hours, and then placed in a refrigerated air-conditioned room to cool down to a central temperature of 35℃ for 6-12 hours.

[0034] The experimental group provides a method for sterilizing edible mushrooms, which is specifically used for processing edible mushroom sticks, and includes the following steps:

[0035] S1. The edible mushroom bags (or mushroom sticks, hereinafter referred to as mushroom sticks) are sterilized in a sterilizer at a positive pressure of 100-124°C; at this temperature, the sterilization effect and the effect on the activity of the strain can be better balanced;

[0036] S2, negative pressure cooling: When the positive pressure sterilization of the bacteria sticks in the sterilizer at 100-124℃ is completed, the vacuum pump unit is started to extract the steam and heat in the sterilizer, and the negative pressure is continuously extracted for 20-30 minutes, so that the temperature of the bacteria sticks in the sterilizer reaches 35℃ within 20-30 minutes, and the negative pressure temperature in the center of the bacteria sticks reaches 35℃, and the sterilizer and the bacteria sticks are both in a negative pressure state; the extracted steam and heat are pumped into another sterilizer ready for bacteria stick sterilization through the vacuum pump unit;

[0037] It should be noted that, first, according to the physical properties of water (under a standard atmospheric pressure, i.e. 101325Pa, the boiling point of water is 100°C, and the latent heat of evaporation of water is 538.8Kcal / Kg; when water is at 6626Pa, the boiling point of water is 38°C, and the latent heat of evaporation of water is 575Kcal / Kg; when water is at 610Pa, the boiling point of water is 0°C, and the latent heat of evaporation of water is 597Kcal / Kg), it can be seen that under certain conditions, as the environmental pressure decreases, the boiling point of water is also decreasing, but the heat consumed to evaporate a unit mass of water is increasing. In this embodiment, negative pressure is applied to the sterilization cabinet and the bacteria sticks after positive pressure sterilization, which is to artificially achieve a low-pressure vacuum state, so that the moisture of the bacteria sticks in the sterilization box evaporates rapidly under the low-pressure state, and a large number of water molecules migrate and quickly absorb and take away the heat inside the bacteria sticks, thereby achieving the purpose of rapid and uniform cooling of the bacteria stick materials; secondly, regarding the heat and steam after high-temperature sterilization, the current common practice in the industry is to discharge all the steam and heat in the sterilization cabinet as waste heat after sterilization. The effective sterilization volume of the sterilization cabinet used in this embodiment is 60m 3 About, removing the effective volume of the sterilization sticks in this embodiment, there is still 55% of the effective sterilization volume left. By calculation, 33m 3About, according to the fuel price before the application date, the cost of steam per ton is about 160-170 yuan, each time saving 33 cubic meters * 160 yuan / cubic meter = 5280 yuan / cabinet / time, according to the daily output of 200,000 bags, 5280 yuan / cabinet / time * 19 times = 100320 yuan; it can be seen that this embodiment has a huge improvement in energy saving, emission reduction, cost reduction, efficiency improvement and production increase compared with the existing common technology;

[0038] S3, negative pressure oxygenation: after the negative pressure cooling is completed, the sterilization cabinet and the bacteria stick are both in a negative pressure state, and then clean oxygen is directly charged into the sterilization cabinet through the pipeline valve control, so that the sterilization cabinet and the bacteria stick all reach the normal atmospheric pressure state, so that the bacteria sticks absorb enough oxygen, and after opening the cabinet door and taking it out of the cabinet, the bacteria sticks can be directly inoculated with bacteria, without being placed in an air-conditioned room for 6-12 hours of cooling and cooling like the control group, thereby greatly achieving energy saving effect. According to measurement, in this embodiment, the temperature of the bacteria sticks in the experimental group and the control group is cooled to the same temperature, and the electricity cost required for cooling in the experimental group is 1 / 5 of the electricity cost used for cooling in the control group, and the time used is only 20-30 minutes, which is far from the time used for cooling in the control group of 6-12 hours, greatly improving production efficiency and saving 2 / 3 of the bacteria racks. Due to the negative pressure cooling, the temperature of the bacteria sticks is uniform, and this embodiment further uses the method of direct clean oxygen to make the oxygen concentration in the sterilization cabinet higher, the environment is cleaner, and there is sufficient oxygen in the bacteria sticks. Therefore, the germination speed of the bacteria sticks in the experimental group is more than doubled than that of the control group. The mycelium is vigorous, has strong vitality and strong anti-infection ability. The growth time is shortened by 5-7 days from the original 30 days (depending on the variety, it can be shortened by 25% and the mycelium is fully grown), and the yield can be increased at the same time. Figure 1 , Figure 2 It can be seen that in different growth periods of mycelium in the mushroom sticks, there are significant differences in the growth of mycelium between the experimental group and the control group, and the mycelium in the experimental group grows more rapidly and fuller.

[0039] The vacuum pump units used in the experimental group of this embodiment are all conventional vacuum pumping equipment such as Roots pumps commonly found on the market. Specifically, the negative pressure cooling unit is composed of a water ring pump, a first-stage Roots pump, a second-stage Roots pump, a cold trap and other components. It is a special mechanical device with three effective functions, namely, vacuuming, condensing and draining. The pump unit is connected to the circulating water pipe, and a steam-water separator is provided at the outlet of the vacuum water ring pump. It can be flexibly selected as needed in actual application, and no further elaboration is made here.

[0040] Next, the mechanism of action of the negative pressure cooling method used in the experimental group S2 of this embodiment is further described:

[0041] The amount of heat absorbed by 1 kg of water when its temperature rises by 1°C while its phase remains unchanged

[0042] Q1=c·m·Δt=4.186×1×1=4.186Kj=1Kcal

[0043] The water in the negative pressure cooling bacteria bag material changes phase, and the water turns into water vapor. At this time, the water absorbs latent heat of evaporation. The latent heat of evaporation of water at different temperatures is shown in Table 1 below:

[0044] Table 1 - Latent heat of evaporation of water at different temperatures

[0045]

[0046] When water is in phase, the heat absorbed by 1kg of water at 38℃ is as shown in the table above: Q2 = m·r = 1 × 575.7Kcal / Kg = 575.7Kcal

[0047] Compare Q2 to Q1:

[0048] Q2 / Q1=575.7Kcal / 1Kcal=575.7

[0049] The example proves that the heat absorbed by water when it vaporizes is nearly 600 times the heat absorbed by water when it rises 1°C in liquid state. For this reason, the experimental group in this embodiment can achieve rapid and uniform cooling in a short period of time by using negative pressure cooling method compared with the conventional cooling method of the control group.

[0050] The method used in the experimental group of this embodiment has at least the following advantages:

[0051] The cooling time is short. It only takes about 30 minutes to cool the mushroom sticks from 100-124℃ to 35℃, which greatly improves the production efficiency.

[0052] Completely sterile, cooling is completed under a sealed negative pressure state, and the survival rate of bacteria is almost 0;

[0053] Negative pressure cooling has uniform temperature, and the temperature of each part of the sterilizer and the bacteria stick is always kept uniform;

[0054] Improve the quality of the mushroom sticks and effectively control the biological fermentation of the mushroom sticks at 60℃~30℃, that is, inhibit the germination and growth rate of the residual bacteria spores in the culture medium in the mushroom sticks;

[0055] Filled with clean fresh oxygen, after the mushroom stick is inoculated, the mycelium and fungus fruiting bodies grow, which can better absorb the nutrients in the mushroom stick material. The mushroom stick germination speed is more than doubled than the conventional one, the mycelium is vigorous, the vitality is strong, and the anti-infection ability is strong. The growth time is shortened from the original 30 days to 5-7 days (25% earlier according to different varieties, the mycelium is fully grown), that is to say, the yield of mushrooms (fruiting bodies) is increased, and the mushroom picking (mushroom growth) cycle is shortened, increasing production and efficiency;

[0056] After the mushroom sticks are sterilized in the high-temperature sterilizer, they are cooled directly in the pot, avoiding the risk of workers' operation and reducing cross contamination;

[0057] Adopting negative pressure cooling in sterilizing cabinet can greatly save electricity cost and site cost of conventional cooling, reduce sterilizing racks and sterilization time, etc. Through calculation, in this embodiment, each sterilizing cabinet extracts about 33 cubic meters of steam and heat. According to the fuel price before the application date, the cost of steam per ton is about 160-170 yuan, and each time saves 33 cubic meters * 160 yuan / cubic meter = 5280 yuan / cabinet / time. According to the daily production of 200,000 bags, it can save 5280 yuan / cabinet / time * 19 times = 100320 yuan of steam and heat costs.

[0058] In summary, it can be seen that the method used in the experimental group of this embodiment can reduce a large amount of investment whether it is for building a new factory or renovating an old factory, thereby achieving the purpose of reducing costs and increasing efficiency.

[0059] Example 2

[0060] In this embodiment, there are two experimental groups and control groups, namely, experimental group 1-control group 1, both of which use the same bacterial species; experimental group 2-control group 2, both of which use the same bacterial species; experimental groups 1 and 2 both adopt the method used by the experimental group in embodiment 1, and control groups 1 and 2 both adopt the method used by the control group in embodiment 1. The mushroom sticks of experimental group 1-control group 1 and experimental group 2-control group 2 were treated respectively, and then cultured until the ears were picked, and the ear-picking effects were compared. The comparison of the output of the mushroom sticks of experimental group 1-control group 1 and experimental group 2-control group 2 after treatment is shown in the figure below. Figure 2 shown.

[0061] according to Figure 2 By comparison, it can be further found that the method used in the experimental group of Example 1 has significant progress compared with the existing commonly used technologies in terms of sterilization and cooling of mushroom sticks, as well as subsequent growth and harvest of mushrooms, and has fully achieved energy conservation and emission reduction, cost reduction, efficiency improvement and production increase.

[0062] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can refer to each other, and each embodiment focuses on the differences from other embodiments. The above embodiments are only used to illustrate the technical solutions of this application, rather than to limit this application; although the application is described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of this application.

Claims

1. A method for sterilizing edible fungi, characterized in that: The following steps are involved: S1. Place edible fungi in a sterilization cabinet for sterilization; S2. After the sterilization is completed, negative pressure is continuously applied in the sterilization cabinet to discharge the residual hot steam in the sterilization cabinet, and the negative pressure temperature of the center of the edible fungi in the sterilization cabinet is reduced to no more than 35° C.; S3. After the temperature is lowered, the negative pressure in the sterilization cabinet is released, so that the sterilization cabinet and the edible fungi return to normal atmospheric pressure.

2. A method for sterilizing edible fungi according to claim 1, characterized in that: In S1, during sterilization, the temperature in the sterilization cabinet is maintained at a positive pressure of 100 to 124°C.

3. The method for sterilizing edible fungi according to claim 1, characterized in that: In S2, the duration of applying negative pressure in the sterilization cabinet is 20 to 30 minutes.

4. The method for sterilizing edible fungi according to claim 1, characterized in that: In S2, the residual hot steam in the sterilization cabinet is discharged and introduced into other sterilization cabinets to be used for edible fungi sterilization.

5. The method for sterilizing edible fungi according to claim 1, characterized in that: In S3, after the temperature is lowered, clean oxygen with a concentration of more than 80% is introduced into the sterilization cabinet, so that the sterilization cabinet and the edible fungi are restored to a normal atmospheric pressure state.

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