kulturmedier

Culture media, or kulturmedier in Scandinavian usage, are prepared substrates used to grow and observe microorganisms in laboratory settings. They provide a controlled nutritional environment that supports microbial growth, helps isolate species, and allows assessment of physiological properties. Culture media can be liquid (broth) or solid (agar-based), often with a base of water and carbon and energy sources, nitrogen, minerals, and sometimes growth factors, vitamins, or blood components. Solid media use a gelling agent such as agar to create a surface or columns for colony formation.

Culture media are categorized by purpose: general-purpose media support a wide range of organisms (for example nutrient broth); selective media contain components that inhibit some organisms to favour others; differential media allow visual differentiation of organisms by color or colony morphology; enriched media include added nutrients to support fastidious organisms. Common examples include nutrient agar or broth, blood agar, MacConkey agar.

Applications include diagnostic microbiology, where media are used to isolate pathogens from specimens, and research or industrial microbiology, where they are used to culture model organisms, study metabolism, or produce biomass. Quality control and validation, including sterility checks and performance testing, are essential. Preparation and use are subject to biosafety and regulatory oversight. Media are designed with known properties, but results depend on correct technique, sample quality, and environmental conditions. The concept dates to the 19th century with pioneers like Koch, and has evolved toward standardized, well-characterized formulations and quality-assured supply chains.