starter cultures

Starter cultures are microorganisms—typically bacteria, yeasts, or molds—introduced to begin fermentation in food production.

They convert sugars into acids, alcohol, or gases, transforming raw ingredients into yogurt, cheese, sourdough, beer, or kimchi.

She added starter culture to the warm milk to make yogurt.

Commercial starter cultures ensure consistency, while wild or heirloom cultures produce more variable, complex flavors.