Two microorganisms (S. thermophilus and L. delbrueckii subsp.
bulgaricus) of the yoghurt starter culture have “associate growth” in
yogurt . Microbial growth continues during
storage and the number of viable microorganisms is a critical factor in
the final product in terms of acidification and also nutritional health
benefits attributed to yogurt starters as probiotics. It is generally
recommended that yogurt or fermented milk should contain at least
108 CFU/serving , which represents approximately one
million viable cells per gram at the time of consumption. To maintain
these numbers, it is important to follow viability during cold storage