Death of Lactobacillus bulgaricus Resulting from Liquid Nitrogen Freezing1

摘要: Concentrated cell suspensions of Lactobacillus bulgaricus prepared from cells grown in semisynthetic media were frozen liquid nitrogen. After storage for 24 hr, the found to have decreased colony counts and acid-producing capacity milk. The amount loss varied among different strains tested. addition known cryoprotective agents most labile strain before freezing provided little or no protection cells. However, stability all investigated was improved by supplementing growth medium with Tween 80 (polyoxyethylene sorbitan monooleate). concentration necessary maximal strains.