<P> Dependent on the strain, the plate may then be incubated, usually for 24 to 36 hours, to allow the bacteria to reproduce . At the end of incubation there should be enough bacteria to form visible colonies in the areas touched by the inoculation loop . From these mixed colonies, single bacterial or fungal species can be identified based on their morphological (size / shape / colour) differences, and then sub-cultured to a new media plate to yield a pure culture for further analysis . </P> <P> Automated equipment is used at industrial level for streak plating the solid media in order to achieve better sterilization and consistency of streaking and for reliably faster work . While streaking manually it is important to avoid scratching the solid medium as subsequent streak lines will be damaged and non-uniform deposition of inoculum at damaged sites on the medium yield clustered growth of microbes which may extend into nearby streak lines . </P> <P> Bacteria exist in water, soil and food, on skin, and intestinal tract normal flora . The assortment of microbes that exist in the environment and on human bodies is enormous . The human body has billions of bacteria which creates the normal flora fighting against the invading pathogens . Bacteria frequently occur in mixed populations . It is very rare to find a single occurring species of bacteria . To be able to study the cultural, morphological, and physiological characteristics of an individual species, it is vital that the bacteria be divided from the other species that generally originate in the environment . This is important in determining a bacterium in a clinical sample . When the bacteria is streaked and isolated, the causative agent of a bacterial disease can be identified . </P>

Plating is a commonly used technique for isolating individual species in the microbiology lab