Technical Regulations for Sterilization in Bagged Edible Mushroom Production

Whether sterilization in bagged edible mushroom production is thorough or not determines the success or failure of production. Sterilization means holding the production substrate at a certain temperature and pressure for a certain period of time to kill the spores of contaminating bacteria in the substrate, promote the growth of microorganisms (such as enoki mushroom and shiitake mushroom mycelium), increase yield and quality, and improve the grower's returns. Regardless of what type of sterilization stove is used, the principles of sterilization fall roughly into two categories: one is high-pressure sterilization, and the other is atmospheric-pressure sterilization. Atmospheric-pressure sterilization requires low investment, simple facilities, convenient operation, and is safe and economically practical. The technical regulations for atmospheric-pressure sterilization of edible mushroom production substrate are introduced as follows:

1. Bags already filled with substrate should be placed into the stove promptly;

2. When stacking in the stove, gaps should be left between the bags to facilitate steam circulation;

3. The seal must be tight to prevent steam leakage; at the same time, a thermometer should be inserted below the stove door to observe the temperature;

4. The quantity sterilized each time must not be too large, generally about 4000 bags is appropriate;

5. The principle of sterilization is "strong start, sustained end, controlled middle," that is, in the early stage the fire should be fierce and the temperature should rise quickly, and near the end of the insulation period a certain temperature must be maintained; during the insulation period the temperature must be kept at 100 degrees, and must never fluctuate up and down;

6. Insulation requirements: generally, from ignition to 100 degrees should be controlled at 6-8 hours, 100 degrees should be maintained for 20-22 hours, and after the fire is stopped, the stove should remain sealed for 6 hours.

Based on the several types of sterilization stoves commonly used at production bases in our county, the following points should be given special attention during use:

1. Steam-type sterilization stove;

1. Before use, check whether the steam pipe is unobstructed or has any cracks.

2. The quantity sterilized each time must never be too large; for model 1.2, about 4000 bags per sterilization is appropriate, and for model 0.8, about 3000 bags per sterilization is appropriate.

3. Because the insulation time is relatively long, during the insulation period prevent the temperature from falling below 100 degrees.

2. Iron drum (steel plate, oil drum converted) type sterilization stove

1. Before use, strictly check whether the welds are normal; those that have been used for 3 years should be scrapped.

2. When sealing the door, intentionally leave a small vent hole to facilitate steam circulation.

3. The insulation temperature must never exceed 102 degrees.

3. Three-oil-drum type sterilization stove

1. Those that have been used for 2 years can no longer be used.

2. Control valves must not be installed on the connecting steam pipes.

3. The quantity sterilized each time should preferably not exceed 4000 bags.