Compositional characteristics of commercial yoghurt based on quantitative determination of viable lactic acid bacteria

Abstract

Yoghurt quality is particularly difficult to standardize because of the many forms, varieties, manufacturing methods, ingredients and consumer preferences that exist. Since these factors will always play an important role, it is unlikely that a uniform yoghurt quality concept will ever emerge, such as has been developed for other dairy products. There are a number of common denominators, however that have bearing on yoghurt quality. Since a number of producers are recognized within the broad category entitled yoghurt. This situation makes yoghurt an interesting, challenging, but also a confusing area to work in. The present investigation was undertaken to isolate from commercial yoghurt the strains involved in its manufacture and determine the characteristics of Streptococcus thermophilus and Lactobacillus delbrueckii subsp.bulgaricus. This study is concerned with the lactic acid bacteria (L.delbrueckii subsp. bulgaricus and S. thermophilus) growth in yoghurt from involving different procedures and with the determination of the number of lactic acid bacteria in dependence of the temperature and acidity in the period of storage. Predominant samples of yoghurt were with 11-107/ml lactic acid lactococci (44.28%).