Sporicidal activity of sodium dichloroisocyanurate, peroxygen and glutaraldehyde disinfectants against Bacillus subtilis

The activity of sodium dichloroisocyanurate (NaDCC), peroxygen and glutaraldehyde disinfectants against spores of Bacillus subtilis NCTC 10073 was evaluated using suspension tests. The activity of aqueous solutions of NaDCC disinfectants increased with the level of available chlorine (av.Cl) but was considerably reduced by low levels of blood. Five percent Titan Sanitizer (1200 ppm av.Cl) achieved a > 10⁵-fold reduction in spore count (kill) in 3 h in the absence of blood but no kill in 3 h with 2% blood present. One percent Presept (3180 ppm av.Cl) achieved a > 10⁵-fold kill in 1 h in the absence of blood and in 2 h with 2% blood present. One percent Haz-Tab (5750 ppm av.Cl) achieved a >10⁵-fold kill in 5 min in the absence of blood and in 30 min with 2% blood present. One percent Virkon (peroxygen) achieved a 10⁵-fold kill in 2–3 h in the absence of blood but little kill in 3 h with 2% blood present. Nu-Cidex (peracetic acid) was rapid in action and tolerant of organic matter. A 24 h old solution achieved a > 10⁵-fold kill in 5 min with 10% serum present. Cidex Long-Life (glutaraldehyde) worked much slower; a 28-day-old solution achieved a >10⁵-fold kill in 2 h with 4% blood present. Neat sporicidin (glutaraldehyde-phenate) was slightly superior to Cidex Long-Life but in a 1 in 8 dilution exhibited markedly reduced activity; a 30-day-old solution achieved a 10⁴-fold kill in 10 h in the absence of blood but only a 10²-fold kill in 10 h with 2% blood present.