What should be paid attention to in the production process of edible fungi? How to prevent edible fungus Aspergillus?

Edible fungus is a kind of natural food with rich color, fresh crisp and tender, delicious, balanced nutrition and therapeutic value, which is very popular. However, Aspergillus contamination will occur in the process of edible fungus cultivation, and loose particles of different colors such as yellow, black, grayish green and so on can be seen after damage. Aspergillus is widely distributed in nature, and the conidia float and spread with the air. So what should be paid attention to in the production process of edible fungi? How to prevent edible fungus Aspergillus?

What should be paid attention to in the production process of edible fungi?

1. The ambient temperature of cultured bacteria should not exceed 28 ℃. In addition, the cultured bacteria should not be stored for more than half a month at room temperature.

2. Grasp the time and temperature of the culture medium to prevent the destruction of nutrients, and the pH should be suitable.

3. The medium should be changed frequently, and the raw materials such as peptone, wheat bran and potato should be used alternately.

4. The original seed should not be used up at once, but should be used in stages, and the rest should be preserved at low temperature to prevent excessive passage.

5. The fruiting bodies with large individuals, normal growth and strong disease-free insects should be selected for tissue separation once a year, and the good and bad should be selected to expand the inoculation growth.

Second, how to prevent edible fungus Aspergillus?

1. Harmful symptoms

After being contaminated by Aspergillus, the meat limit can be seen loose, showing yellow, gray-green, black and other different colors of particles, depending on different types. Aspergillus can also cause mildew of grain and mildew and deterioration of industrial materials such as leather, textile and optical glass.

2. Morphological characteristics.

The hyphae are septate, colorless, pale or agglutinated with colored substances on the surface, the conidiophores grow erect and unbranched, and the tip of the pedicel expands into a spherical or club-shaped apical sac, its surface is covered with radiating peduncles, and conidia are serially at the tip of the peduncle. The conidia are unicellular, spherical, oval or oval, the spores are yellow, green, brown, black and other colors, and the colony color varies with different species.

3. Occurrence regularity

Aspergillus is widely distributed in nature and can survive on all organic materials such as soil, grain and plant materials. Conidia float and spread with the air. The optimum temperature for the growth of Aspergillus flavus is 25: 30 ℃, and the air relative humidity is about 80%. The suitable temperature for Aspergillus Niger is 20: 30 ℃, and the air relative humidity is more than 85%. Aspergillus gray-green Aspergillus has strong dry resistance, temperature 20: 35 ℃, air relative humidity 65% 80% is the most suitable for its growth. In the cultivation of edible fungi, the environment such as high water content of culture materials, excessive air relative humidity and poor ventilation is conducive to the growth of Aspergillus and pollution harms edible fungi.

4. Prevention and control methods

Pay attention to environmental hygiene, keep the surrounding of the culture room and the cultivation land clean, and dispose of the waste in time. Inoculation rooms and mushroom rooms should be cleaned and disinfected in accordance with the regulations; operators must ensure thorough sterilization during seed production; bagged bacteria should be handled gently in the process of handling and strictly prevent plastic bags from breaking; they should be regularly checked and found to be contaminated and should be removed in time. Never sow diseased bacteria. If Aspergillus occurs on the mushroom bed culture material, it can be ventilated and dried in time, and the room temperature can be controlled at 20: 22 ℃. After the miscellaneous bacteria are restrained, the routine management can be resumed. Adjust pH, increase pH appropriately, add 1%-3% quicklime or spray 2% lime water to inhibit the growth of miscellaneous bacteria. Medicament mixing material, with 0.1% weight of dry material methyl topiramate mixing material, the prevention and control effect is better. In addition, the strain bottle should not be too full to avoid contamination with the cotton stopper. Wash the bottle mouth after the bottle is finished and keep the cotton plug clean.