What is the lowest magnification needed to at least recognize a bacteria such as E. Coli in water?
You can use a lower magnification, about 100X, to clearly see gram stained bacteria. At this magnification, you can see the bacteria’s shape (round, long,etc) and colony formation (ie: do the bacteria form a chain or simply separate after dividing). However, if you need more information to identify a bacterium, in college we used a 1000X magnification. At this magnification, we used the oil immersion technique. As xprofessor stated above, this magnification allows you to have a clearer view of the individual bacterium on your slide. Hope this helps.
