The commercial process of yoghurt making uses a defined mixture of lactic acid bacteria, for example thermophilus and L delbrueckii subsp. bulgaricus, but other require different blend. For example, Bulgarian buttermilk is products may a L delbrueckii subsp. bulgaricus alone, whilst dahi in India is produced duced using using a mixed starter culture containing S thermophilus, Lactococcus lactis biovar diacetylactis and Lactococcus lactis subsp, cremoris (amime and Marshall, 1997).