The relative resistance of f2 bacteriophage to inactivation by disinfectants.

f2 bacteriophage in the presence of fetal calf serum (at a final concentration of 10%) was exposed to six commonly used disinfectants for times of 10, 20 and 30 sec. At the end of exposure times skim milk neutralized the disinfectant activity and residual virus was assayed using the plaque technique. The 6 disinfectants considered were Javex, sodium hydroxide, ethanol, Wescodyne, One Stroke Ves-Phene and Sonacide. A 0.25% (w/v) solution of sodium hydroxide and 1/50 Javex (1200 parts/10(6) chlorine) were the most effective of the six disinfectants considered since 10(5) f2 bacteriophage were inactivated in 30 seconds in each instance. Since a 0.25% (w/v) solution of sodium hydroxide had a pH of 12.5 this made it too caustic to use as a disinfectant in many practical situations. It was concluded therefore that Javex at some dilution less than 1/50 (greater than 1200 parts/10(6) chlorine) was the most practical of the six disinfectants to use. Ethanol (95%, v/v) inactivated 10(3) f2 bacteriophage in 30 seconds while 1/20 Wescodyne and undiluted Sonacide inactivated 10(1)-virus particles. Ves-Phene at a dilution of 1/50 was a completely ineffective virucide during the 30 sec exposure. The resistance of f2 bacteriophage to inactivation by these six disinfectants was compared with that of echovirus 11 and coxsackievirus B5. In all instances except exposure to undiluted Sonacide, f2 was comparable in resistance to inactivation and in many cases had greater resistance.