HETEROTROPHIC PLATE COUNT AGAR

Heterotrophs are organisms including bacteria, yeasts and moulds that require an external source of organic carbon for growth. Heterotrophic Plate Count Method has been applied in many variants and is widely used to measure the heterotrophic microorganism population in drinking water systems (potable water), swimming pool and other waters. Three different methods are described for determining the heterotrophic plate count i.e. pour plate method, spread plate method and membrane filter method. The concentration of heterotrophic bacteria in the distribution system can be influenced by the bacteriological quality of the finished water entering the system, as well as water temperature, residence time, levels of disinfectant residual, pipe materials, surface area-to-volume ratio, flow conditions, and the availability of nutrients for growth.

for heterotrophic plate count of bacteria in water