Eight individual and blended chemical disinfectants were screened for preliminary evaluation of efficacy against duct organisms. Viable counts of surviving bacteria were determined after 30 min contact with each disinfectant. The single and blended disinfectants with high microcidal activity included glutaraldehyde/formaldehyde-based, glutaraldehyde/formaldehyde-based, cresol-based, organic acid-based and potassium peroxymonosulphate-based products. Iodophors of disinfectants showed an inconsistent and low anti-microbial effect.