Comparative studies on the activity of freeze-dried mesophilic lactic acid cultures for direct application

Freeze-drying as a storage method guarantees the preservation of the initial morphological and biochemical properties of lactic acid bacteria. The aim of the present work was to study the conditions for improving the activity of mesophilic lactic acid concentrates by freeze-drying in different protective media. Different survival rates of single-strain and multi-strain concentrates of mesophilic lactic acid bacterial after freeze-drying were found in the course of the study. The results suggest satisfactory acidification capacity of the culture during the processing of the cheese mass, the cell concentration per one gram culture being 25 x 10(11). Comparative studies have demonstrated preservation of the activity of mesophilic lactic acid cultures, freeze-dried in protecting medium 2 for butter and in protecting medium 6 of mesophilic lactic acid cultures for cheese, applied directly.