Streptococcus thermophilus Isolation Agar is recommended for determining the ratio of Streptococcus thermophilus and Lactobacillus bulgaricus in yoghurt. Streptococcus Thermophilus Isolation Agar, recommended by APHA. Symboitic activity and equal population of Streptococcus thermophilus and Lactobacillus bulgaricus is essential for optimum consistency, flavour and odour generation during yoghurt production. Increase in the numbers of either species can lead to defects in the yoghurt characteristics.
1. Downes F. P. and Ito K., (Eds.), 2001, Compendium of Methods for the Microbiological Examination of Foods, 4th Ed.,APHA, Washington, D.C.2.Lee S. Y., Vedamuthu E. R., Washam C. J. and Reinbold G. W., 1974, J. Milk Food Technol., 37:272.3.Driessen F. M., Ubbels J. and Stadhouders J., 1977, Biotechnol. Bioeng., 19:821.