What is a pure culture and how is it obtained?

A pure culture contains only one type of microorganism, descended from a single cell (clonal population). Obtaining pure cultures involves: streak plate method (diluting organisms across agar surface to get isolated colonies), pour plate method (mixing diluted sample with molten agar), spread plate method (spreading diluted sample on agar surface), serial dilution to extinction, and micromanipulation or cell sorting. Verification involves examining colony morphology, microscopy, and biochemical or molecular testing. Pure cultures are essential for characterization, consistent fermentation, and regulatory compliance. Working cell banks are established from verified pure cultures.