Comparison of sodium hypochlorite and sodium dichloroisocyanurate disinfectants: neutralization by serum

A comparison has been made of the activity against Pseudomonas aeruginosa of sodium hypochlorite (NaOCl) and sodium dichloroisocyanurate (NaDCC) solutions containing 0-40% and 0-70% horse serum respectively. The degree of inactivation of NaOCl and of NaDCC solutions by different concentrations of horse serum is expressed in terms of a neutralization coefficient, which demonstrates that NaDCC solutions are less prone to inactivation by serum than are NaOCl solutions, the disparity diverging as serum concentration is increased. In 30% serum an NaDCC solution containing 4000 ppm of available chlorine exhibited similar bactericidal activity to an NaOCl solution containing 17,000 ppm available chlorine.