Abstract: The survival rate and storage period of lactic acid bacteria (LAB) are affected by numerous factors in the vacuum freeze-drying process. Hence, optimizing the freeze-drying process and storage conditions is an effective method to improve the survival rate and prolong the storage period of LAB. This paper reviews the factors that influence the survival rate of LAB during the vacuum freeze-drying process and explores how to optimize the freeze-drying process and storage conditions to improve the survival rate and extend the storage period of LAB. We expect that this review will provide a basis and reference for the preparation of lyophilized LAB formulations with high activity and good storage stability.

Key words: lactic acid bacteria; vacuum freeze-drying; freeze-drying protective agents; encapsulation materials; survival rate