SURVIVAL RATE AND ENZYME-ACTIVITIES OF LACTOBACILLUS-ACIDOPHILUS FOLLOWING FROZEN STORAGE

The ability of two strains of Lactobacillus acidophilus, CRL 640 and C RL 800, to survive and retain their biological activities under frozen storage was determined. Freezing and thawing, as well as frozen stora ge, damaged the cell membrane, rendering the microorganisms sensitive to sodium chloride and bile salts. Both lactic acid production and pro teolytic activity were depressed after 21 days at - 20 degrees C, wher eas beta-galactosidase activity per cell unit was increased. Cell inju ry was partially overcome after repair in a salt-rich medium. (C) 1998 Academic Press.