文档介绍：Chapter3MicrobialGrowth?Growthis definedasanincreaseinthenumber,sizeor anismisverysmall,tomeasurethegrowthofasinglemicrobialcell is difficult. Somicrobialgrowthis generally pure culture?ursasonly ponentofa large acertainkind,thatstrainmustbeseparatedfromallthe others.?anism,whichis usuallyderivedfroma singlecellorsporeis The pourplate and spreadplate method?Asampletobetestedusuallycontainsbillions is notpossibletogetwell-separatedcoloniesina plate if thesampleis not stepofisolatingpurecultureis a waythat1mlof sampleis addedto9ml ofsteriledistilledwaterorsaline solution.?Thepour plateandspreadplatemethodsdiffer onlyin the way thedilatedsampleis addedto the method,the dilutedsampleis addedto a petri dish(plate),thenmeltedagarmediumis pouredandmixed.?Inthe spreadplate method,the dilutedsampleis placedontothe surface ofanalreadysolidifiedagar medium plateandspreadevenlyover thesurface bymeansof a sterile,bent glass incubatedat a optimaltemperatureuntil The streakplate method?Bymeansofasteriletransferloop, aloopofsampleis diluted by movingtheloopbackandforthonthe surfaceofsolidified theloop is streakedbackandforth,fewerand fewermicrobialcellsaredepositedonthe agarsurfacesothat :C3:C4:C1:firstsetofstreaks