Total Coliform Bacteria

You are looking at a petri dish showing the "golden-green sheen" colonies typical of total coliform colonies. These colonies were grown on m-endo agar containing lactose, protein digest, vitamins, selective chemicals and Schiff’s Reagent. Coliform bacteria produce an acid aldehyde (among other by products) that combines with the Schiff’s Reagent to form an irridescent green coating over the growing colonies thus giving the "golden-green sheen " appearance.

A 100ml sample of water is drawn through a membrane filter (45m pore size) with the help of a vacuum pump. The plate is placed in an incubator inverted in a moist container for 24 hours at 35° C.

*Illustration utilized from Water Microbiolgy Laboratory and Field Procedures, Millipore Corportation, 1992.

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