A comparison of the bactericidal activity of 'Phoraid 6000' and 'Clearsol' disinfectants

The bactericidal activity of 'Phoraid 6000' and 'Clearsol' disinfectants was evaluated using suspension and surface tests. In suspension tests, 2% 'Phoraid' achieved a > 5 log10 reduction of Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus in 1 min in the absence of blood, but negligible activity in 10 min in the presence of 1% blood; 10% 'Phoraid' exhibited no useful activity in the presence of 5% blood and 20% Phoraid no useful activity in the presence of 10% blood. In contrast, 'Clearsol' was very resistant to neutralization by blood: 1% 'Clearsol' achieved a > 5 log10 reduction of P. aeruginosa, E. coli and S. aureus in 5 min in the presence of > or = 70% blood. In surface tests, undiluted 'Phoraid 6000' failed to disinfect wet blood contaminated with either P. aeruginosa, E. coli or Proteus vulgaris in the 2-min exposure period. 'Clearsol' gave mixed results: 2% 'Clearsol' was very effective but the standard use-dilution of 1% proved inadequate.