Properties of Stock Cultures of Lactic Acid Bacteria during Long-Term Storage

Abstract

The study featured the viability of lactic acid bacteria during long-term storage at 2-4 C. The stock cultures were preserved by vacuum drying with no freezing or lyophilization. In general, the lactococci demonstrated a high survival rate after 3-54 years of storage: the residual viable cell count was 0.98-43 million CFU per ampoule. However, 8.3 % out of 3,552 lactococcal strains demonstrated a significant decrease in acid-inducing activity. Thirty strains, which had been used to produce bacterial starters for the past 25 year, lost their viability. Only 12.9 % of the lactobacilli that had been sublimated 62 years ago could not be revived.