Question

How is microbial growth measured directly?

Answer 1

The microbial growth can be calculated directly by a number of methods including the most microscopic counts, membrane filtration, viable cell count, most probable number methods And electonic counts.

1. Microscopic count: in this method the non viable microbes like the large sized eukaryotes and the prokaryotic microbes are generally counted by viewing them under the microscope. The mean is taken by using a grid.

2. Membrane filtration: in this method a large sample of the microbial colony of the coliforms are poured and are passed down through the membrane filters. Then followed by incubation depending upon the type of the microbes further the viable count of the bacteria colony is done.

3. Viable cell count: viable bacterial colony is counted by hands by undergoing a series of dilutions and the number of cells are counted on the plate followed by the reciprocal of dilutions.

4 electronic count: number of the microbial cells in a colony ar re calculated by passing them through an electric current.

5. MPN: this method is used for the counting of the microbes that usually don't grow on the solid media statistically.

In this 5 test tubes are used do three dilutions and then entered into an MPN table for counting the microbial cells per 100 ml of the liquid.