What are the principles of transport media?

The underlying principle of transport media is to maintain the viability of the microorganisms in a clinical sample without allowing them to multiply. 

Transport media is formulated with specific energy sources such as carbohydrates and peptone. These components provide just enough energy to maintain the viability of microorganisms potentially present in a specimen during transportation from the collection point to the laboratory. The media are also well buffered and pH maintained to prevent the organisms from experiencing any chemical stress. 

What transport media does not contain is just as important as what it does contain. Transport media do not contain additional nitrogen, carbon, or any organic or inorganic growth factors, so they are unable to multiply while being transferred. This helps in preserving the microbiome of the specimens in their original condition until such time that they are processed in a lab.