Surface and suspension testing: Conflict or complementary

The suspension and surface disinfectant test methods available are discussed and results of such tests using impedance and traditional techniques are presented. Surface attached organisms were generally found to be less susceptible to disinfectants than suspended organisms. In practice, however, many factors are present in the factory environment that may affect the resistance of bacteria prior to disinfection. Consequently surface or suspension tests do not necessarily reflect disinfectant activity in practice, and should therefore be confirmed by trials in the factory environment.