Preparation method of lactic acid bacteria freeze-dried powder suitable for storage at room temperature

The invention discloses a preparation method of lactic acid bacteria freeze-dried powder suitable for storage at room temperature, comprising the following steps: carrying out fermentation culture on lactic acid bacteria strain liquid to obtain fermentation liquid, carrying out concentrating treatment on the fermentation liquid to obtain mycelium concentrated liquid and fermentation waste liquid, adding a freeze-drying protecting agent into the mycelium concentrated liquid, uniformly mixing, carrying out freeze drying, grinding under a vacuum and nitrogen charged condition and packaging. According to the preparation method disclosed by the invention, lactobacillus casei strain liquid, lactobacillus acidophilus strain liquid or a mixed strain liquid of lactobacillus casei and lactobacillus acidophilus in proportion of 1:1 is used as a strain, the freeze-drying protecting agent containing special contents of polydextrose, maltose, trehalose and the like which are compounded is adopted, water remaining in the fr