Preparation and use of Chemical Disinfection agents commonly used in Edible Fungi production
In the seed production and production of edible fungi, sterilization and disinfection is an important link, and the use of chemicals to sterilize and disinfect is an important means. The use of chemical disinfection and sterilization agents can achieve the purpose of sterilization and disinfection by soaking, flushing, wiping, spraying, fumigation and powder according to the object of sterilization, drug performance, equipment, machinery and environmental conditions. The preparation and use techniques of commonly used disinfectants are introduced as follows:
1. Formalin: formalin is a formaldehyde solution containing 36-38%. Because it can coagulate protein and has germicidal effect, it is an important disinfectant. 5% formalin can kill bacterial spores and fungal spores. It is often used to disinfect inoculation box (room) and culture room. Generally use 5-10 ml per cubic meter of space. When it is stored for a long time at evaporation or low temperature, it is often polymerized into a white flocculent precipitation, which can disappear when heated.
2. Alcohol: the killing ability of alcohol is mainly dehydration, which can cause bacterial protein dehydration and denaturation and lead to death, dissolve ester secretions, and also have the effect of mechanical sterilization. 70-75% alcohol is commonly used to disinfect skin and various utensils. The concentration is not ideal when the concentration is too low or too high, and the dehydration ability is poor when it is too low. When it is too high, the protein on the surface of the bacteria is dehydrated and solidified, which hinders the penetration of alcohol into the deep layer. The internal structure is not destroyed, but the germicidal effect is reduced. Alcohol is flammable and volatile, so it should be sealed and kept away from the source of fire. 75% alcohol was prepared with 75 ml of 95% alcohol and 20 ml of water.
3. Phenol: phenol, also known as carbolic acid, can denature and precipitate unexplained proteins, destroy the cell membrane and kill most bacteria. But it has little effect on fungal spores. Pure phenol is a colorless needle hexagonal crystal with a special smell. It is common to spray 3-5% phenol solution to disinfect the inoculation room (box) or disinfect utensils. Phenol is toxic, the harm degree of the poison is Ⅲ (moderate hazard), it is corrosive to the skin, and can be washed with clean water when touching the skin. When preparing, 50 grams of phenol can be added to 1000 ml of distilled water to form a 5% aqueous solution of phenol, which is a commonly used disinfectant.
4. Lysol: Lysol is a mixture of three isomers of cresol, also known as cresol soap solution. It contains 50% cresol and soap solution, which is a good disinfectant and its germicidal ability is four times stronger than that of phenol. 1-3% Lysol aqueous solution is commonly used to disinfect the skin and various instruments. Soak the utensils and dirt with 3-5% aqueous solution for about 1 hour. It can also be sprayed to disinfect the inoculation box (room). When preparing, 30 ml of 50% Lysol and 470 ml of water can get 3% Lysol solution.
5. Potassium permanganate. Potassium permanganate is a strong oxidant. 0.1% of the solution has disinfection effect, 2-5% of the solution is effective on spores and can also kill anaerobes. 0.1% potassium permanganate is commonly used to disinfect the surface of utensils, or 1 part of crystalline potassium permanganate can be poured into two parts of formaldehyde solution to fumigate the inoculation room (box). Use 5 grams of potassium permanganate per cubic meter.
6. Bleach. Bleach is a kind of white powder with irritating smell, and its effective ingredient is calcium hypochlorite. It dissolves in water and decomposes into hypochlorite. When it seeps into the bacteria, it can denature the protein and thus play a bactericidal role. 2-5% bleach solution is commonly used to wash inoculation room, culture room wall, bed wall and so on. Because it is easy to absorb water and carbon dioxide in the air to form hypochlorite and fail, it should be kept in an airtight container and stored in a dry and cold place.
7. Xinjie Min. Bromogeramine, also known as dodecyl dimethyl phenylmethyl ammonium bromide, is a yellowish colloid with aromatic flavor. The concentration of the original solution is 5% and can be diluted to 0.25% when used. It is often used for surface disinfection of inoculation boxes and glassware, and has a good ability to kill bacteria and viruses. Mild irritation to the skin and mucous membrane, and rash may occur in severe cases.
8. Lime. It is an alkaline substance that can increase the pH value of the culture material or environment, thereby inhibiting the growth and reproduction of most yeasts and molds and achieving the purpose of disinfection. When in use, quicklime can be used to cover the mold contaminated area. It can also be prepared to spray with 5-10% aqueous solution, or soak culture materials such as rice straw and wheat straw with 0.5-2% aqueous solution.
9. Liter of mercury. Liter mercury, also known as mercuric chloride, is highly toxic, and the degree of poison harm is Ⅰ (extremely harmful). The germicidal effect is strong. 0.1% mercury solution can kill the vegetative cells of bacteria in a few minutes. 0.1-0.2% solution is commonly used to disinfect the surfaces of mushrooms, water, glassware and non-metallic instruments. A 0.1% liter of mercury solution can be obtained by adding 1 g of mercury to 1000 ml of distilled water during preparation. If mercury comes into contact with the skin, rinse with a large amount of water and wet apply 3-5% sodium thiosulfate solution. The mercury solution should be stored in a brown glass bottle.