Heterotrophic plate count (HPC)

Definition

A culture-based test that counts culturable planktonic bacteria in the bulk water over 48 to 72 hours.

HPC measures planktonic populations in the water column and takes 48 to 72 hours to develop. It misses viable-but-nonculturable organisms and does not indicate biofilm activity on surfaces. A clean HPC can coexist with a mature biofilm, so it must be supplemented with trend analysis and physical inspection.

Related concepts

Reconnaissance and monitoring · Planktonic cells · Viable-but-nonculturable organisms

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Part of The Blueprint of Water · 📏 measurement