What Are Live and Active Cultures?

Milk contamination with bacteria

The FDA mandates that live and active cultures be put in yogurt. We have all seen the labels on the yogurt cups. That little symbol meaning they contain…what? Microbes? How the heck do they help with digestion as often shown on Activia commercials?

There are plenty of microbes in yogurt, but I’m just going to name a few. Two big microbe names in yogurt are Lactobacillus bulgaricus and Streptococcus thermophilus. Say What?
Well, lets look at each name to find the meaning of each microbe and figure out what it does..


Lactobacillus bulgaricus
Lacto means milk, and bacillus means its a rod shape. This microbe is actually a rod shaped bacteria that helps you convert lactose into lactic acid. This aids in digestion, especially with lactose intolerant people. it also helps promote other healthy bacteria that keep your immune system up to grow.

Streptococcus thermophilus
Strepto means it is found in small lines or strips, coccus means it is a small

round shape, thermophilus means it can withstand really hot temperatures!  This is good because when milk and other dairy products are pasteruized, they are put in extremely hot temperatures to kill “bad bacteria.” Since Streptococcus can handle the heat, this process wont kill it, but your stomach might. The picture on the right is what this little guy looks like under a light microscope. S. thermophilus actually does not stay active in the gut of healthy humans. It’s main purpose is to help culture and form yogurt.