PROPORTION OF THE MICROFLORA OF LACTOBACILLUS AND STREPTOCOCCUS GENERA IN YOGHURTS OF DIFFERENT DEGREES OF CONDENSATION

Abstract

Investigations were carried out on yoghurts of different content of dry matter, which were manufactured applying Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus at 1:1 ratio and then subjected to storage at refrigerated conditions for 21 d. Lactobacillus and Streptococcus bacterial counts as well as their mutual proportions were determined in these yoghurts. It was found, that the higher degree of condensation of the processed milk, the more thermophilic yoghurt bacteria were determined in the final product. Significant changes in the number and mutual ratio of the microflora of both species took place during yoghurt storage. The above-mentioned proportions were most uniform in the yoghurt obtained from milk condensed with 3% addition of powdered skim milk, whereas the highest discrepancies – in the yoghurt manufactured from noncondensed milk.