The Combined Effect of Hydrogen Peroxide and Ultraviolet Irradiation on Bacterial Spores

Abstract

Ultra‐violet (u.v.) light irradiation of spores of Bacillus subtilis in the presence of hydrogen peroxide produced a rapid kill which was up to 2000‐fold greater than that produced by irradiation alone. A kill of 99–99% was produced by 30s u.v. irradiation of spores of 6 strains of Bacillus and Clostridium in the presence of hydrogen peroxide 1.0 g/100 ml but with the more resistant spores of 9 further strains, irradiation in the presence of hydrogen peroxide 2–5 g/100 ml followed by mild heating was required.