Sources and preservation of microorganisms
Start with the big picture
The lesson follows microorganisms from source and collection through transport, initial subculture, and preservation. Aseptic collection and suitable transport media help maintain organisms during transit; appropriate subculture supports purity before storage. Preservation approaches range from refrigerated agar cultures for short-term use and mineral-oil overlay for medium-term storage to deep-freezing, liquid nitrogen, and lyophilization for longer-term preservation. Cryoprotectants help protect cells during freezing. Storage alone is not enough: viability and identity checks, limited serial passage, clear vial labeling, and biosafety practices contribute to strain integrity and traceability. Together, these practices support reproducible work and the timely retrieval of cultures for clinical, research, or industrial purposes.
What you'll learn
- Identify common clinical, environmental, food, host-associated, and collection-based sources of microorganisms.
- Explain how aseptic collection, transport media, and initial subculture support culture integrity.
- Compare short-, medium-, and long-term preservation approaches.
- Describe quality checks and labeling practices that support strain identity and traceability.
- Recognize biosafety considerations for handling and storing pathogenic or resistant strains.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
