Characterization of the commercial starter preparation
Characterization of the commercial starter culture for water kefir production was at species level. Freeze-dried preparation (1 g) was diluted and analysed for LAB and yeasts, as reported above. Four colonies of yeasts and Gram-positive (determined by KOH method) and catalase negative (determined by transferring fresh colonies from a Petri dish to a glass slide and adding 5%, w/v, H2O2) bacteria for each morphology observed were isolated from the agar media inoculated with the highest dilutions of cell suspension. Purification of the cultures to homogeneity was by successive sub-culturing in the same agar media and then propagating in the corresponding broth media.