347. The disinfection of contaminated metal surfaces with hypochlorite solutions

Abstract

Tinned trays were artificially infected with Staphylococcus aureus in diluted milk and the dried surfaces disinfected by rinsing with sodium hypochlorite solutions. Under the conditions described, which we believe approximate those on many dairy utensils which have been imperfectly cleaned, the p H of hypochlorite solutions was found not to be a very important factor in determining their germicidal efficiency. At p H 10 and 11, the solutions were equal to or slightly more efficient germicides than solutions at p H 7. In the destruction of 99% of the organisms on the metal trays, a solution at p H 10, containing 200 p.p.m. available chlorine was about 7 times as rapid as one with 25 p.p.m. available chlorine.