Question

MPN index is measure of one of the following:

• A. $BO{D}_5$
• B. Coliform bacteria
• C. Dissolved Oxygen content
• D. Hardness

Answer 1

The correct option is B Coliform bacteria

MPN (Most Probable Number) index is measure of coliform bacteria.
Pathogenic bacteria are tested and counted in laboratory with great difficulty. Hence, coliform bacteria are tested and counted which themselves are harmless aerobic lactose fermenters but their presence or absence indicates the presence or absence of pathogenic bacteria.