Prevent bacterial contamination during fermentation.

In order to prevent bacterial pollution during fermentation, the main measures include:

1. Keep the environment clean: Yeast uses the surrounding nutrients for reproduction and fermentation. If there are other bacteria and viruses in the surrounding environment, they will seize nutrients and cause abnormal growth of yeast. Therefore, it is necessary to keep a clean environment in the fermentation process to avoid pollution by other bacteria and impurities.

2. Select suitable materials: the materials used in the fermentation process should be kept fresh and clean, free from germs and other bacterial pollution, so as to avoid producing miscellaneous bacteria and miscellaneous bacteria.

3. Control temperature and humidity: Yeast needs proper temperature and humidity during fermentation. Too high or too low temperature and too high or too low humidity are not conducive to the propagation and fermentation of yeast.

4. Use appropriate starter: Appropriate starter can promote the propagation and fermentation of yeast and reduce the influence of miscellaneous bacteria and heterogeneous bacteria.

5. Strictly control the fermentation process: In the fermentation process, we should strictly control the time and fermentation conditions to avoid the interference of external factors on the fermentation process and affect the normal growth of yeast.