Biofilm

A community of micro-organisms attached to a surface and embedded in a slimy matrix they produce themselves. Biofilms form readily in water systems, drains and wet equipment. They protect bacteria from disinfectants and heat, are very hard to remove once established, and shed bacteria and endotoxin into the water intermittently. Good design with continuous turbulent flow, no dead legs and regular sanitisation is the best way to prevent them.