How many bacterial cells are found in one standard loop?

Question

How many bacterial cells are found in one standard loop?

Answer 1

A typical fully grown 1-liter culture of Escherichia coli (at an optical density of 1.0, corresponding to ca. 10^9 cells/ml) yields ca. 1 g wet cell mass. So one gram of bacteria equals 10^12 cells. If one loopful equals one drop (1/20 ml), the number of bacteria will be

10^12 cells /20 = 5 x 10^10 cells.

Answer 2

the standard loop is based on a volume not concentration.It will "deliver" the same volume but the broth culture or plate growth densities may be widely diffeernt depending on frowth characteristics, etc.  

Answer 3

You can't tell--it depends on the concentration of bacteria in the solution that you've picked up with the loop.