Abstract: Enterococcus faecium is one part of normal microflora of human and animal intestinal tract, the bacteria colony has the regulative function to the intestines. The application effect of Enterococcus faecium used in probiotics is largely influenced by the number of vial bacteria and storage stability. In this study, the optimal cryoprotectant formula for Enterococcus faecium was determined using orthogonal array design and storage stability test at 4℃ and 37℃ to be composed of 5% skim milk,1% sucrose and 5% maltodextrin. The survival rate of Enterococcus faecium was 97.90% after 4 weeks, which was protected in sealed aluminum foil bag, under the condition of 37℃ and relative humidity 75%.

Key words: Enterococcus faecium, freeze-drying, croprotectant, probiotic