Comparative Destruction of Lactic Streptococcus Bacteriophages on Various Surfaces by Germicidal Aerosols1,2

Abstract

Summary A comparison was made of destruction by various germicidal aerosols of lactic streptococcus bacteriophages on a number of different types of representative building surfaces and stainless steel. With the exception of the stainless steel the surfaces were coated either with enamel or epoxy resin. Surfaces were contaminated by fogging with a phage suspension in a test chamber. After 15 min, germicide was fogged into the chamber and phage recovered from surfaces by scrubbing with inactivator solution. Chlorine compounds as represented by dichloroisocyanuric acid (DCCA) and sodium hypochlorite (NaOCl) were markedly superior to quaternary ammonium compound (QAC) and phosphoric acid wetting agent (PAWA). Porosity of surface greatly influenced rate of phage inactivation. Aerosols appeared to be most effective on surfaces in the horizontal as compared to the vertical position. Complete inactivation of phage was not realized with either QAC or PAWA at all concentrations tested. However, fogging levels of 2000 ppm DCCA and NaOCl attained 100% of destruction of bacteriophage on horizontal building surfaces and 500 to 1000 ppm accomplished this on stainless steel.

Cheese starters

“…Since most phages survived for up to 10 min at 75 °C in liquid suspension (408,(429)(430)(431)(432)(433), phages present in raw milk (434) would survive pasteurization. While much attention has been paid to phagicide by H 2 O 2 , iodophor or hypochlorite (435)(436)(437)(438), no reports concerning the effect of drying have appeared. Since phages consist of nucleic acid wrapped in a protective protein coat they can be expected to show the same sensitivity to denaturing agents as do other structural proteins.…”