In analyzing water for coliform, it can be Stretchy Escherichia coli that is being tested for. Except when coliform are many, only a few bacteria will ferment the lactose with simultaneous productions of acid gas. The aim is to limit the identification of coliform to E. coli.
This technique can be divided into there groups which are;
A. Presumptive test
B. Confirmed test
C. Completed test
Presumptive Test For coliform Bacteria
In this method lactose broth is used, to ferment the test medium lactose broth is used. Durham tuber are being inserted into the fermentation tuber, then the tested water is added to the tube as described by most probably number technique. All the fermentation tuber are then incubated at 37 degrees C. Each tuber must be checked after 24hrs and where there is no gas fermentation, incubation period should be extended to 48hrs.
Confirmed Test For Coliform Bacteria
Eosin Methylene Blue Agar plate should be use here by taking some loops from the positive presumptive Test and should then incubate at 37 degree Celsius for 24hrs.
Two inoculate should be picked From Eosin Methylene Blue Agar plates and should be transfer into nutrients agar slant and lactose broth fermentation tube with inserted Durham tube.
He result; the lactose production in the lactose broth culture complete the test for coliform