Optimization of the freeze-drying media and survival throughout storageof freeze-dried Lactobacillus gasseri and Lactobacillus delbrueckiisubsp. delbrueckii for veterinarian probiotic applications

The use of lactic acid bacteria (LAB) as vaginal probiotic culturesdepends on the preservation technologies employed by the related industries.A full two-factor analysis of variance (ANOVA), considering medium andstrain, of the decrease in bacterial viability during freeze-drying wasapplied. Lactobacillus gasseri CRL1421 was significantly more resistantthan L. gasseri CRL1412 to the process. L. gasseri CRL1412 suspendedin skim milk showed a significantly higher resistance than when it wassuspended in water, but lactose or sucrose did not significantly increase itsviability after lyophilization. Lactobacillus delbrueckii subsp.delbrueckii CRL1461, an autoaggregative strain, was significantly moresensitive to freeze-drying under the assessed conditions. The dried cultureswere included in two pharmaceutical forms and viability was monitored during270 days of storage. Although the microorganisms studied belonged to the samespecies, the optimal storage conditions were different for each of them. Ourresults can be applied to the design of a veterinarian probiotic to preventmetritis in diary postpartum cows.