Bacteriostatic, germicidal, and sanitizing action of quaternary ammonium compounds on textiles: II. Sanitization of cotton fabrics

Abstract

Summary Five typical quaternaries have been studied in an attempt to ascertain the conditions necessary for disinfection of cloth inoculated with bacterial population of E. coli comparable to the numbers of organisms found in the final rinse water of heavily contaminated laundry. One product tested did not disinfect fabric under any conditions in these tests and another failed to provide for disinfection at 20°C. With those which did disinfect, it has been found that dilutions ranging from 1:50 to 1:1,000 are necessary. The quaternary—dry cloth ratio of this range of dilutions is from 1 oz. quaternary for 0.094 to 1.8 lb. of dry cloth. In general, the five quaternaries were more efficient at 45° than at 20°C. Quaternary A, para diisobutyl phenoxy ethoxy ethyl dimethyl benzyl ammonium chloride, disinfected fabric in a dilution of 1:50 at 20°C. but only 1:500 was required at 45°C. These provide ratios of 1 oz. quaternary to 0.094 and 0.94 lb. of fabric, respectively. With quaternary B, alkyl (C 8 –C 18 ) dimethyl benzyl ammonium chloride, a dilution of 1:1,000, 1 oz. quaternary to 1.8 lb. cloth, was effective at both 20° and 45°C. Disinfection was secured with quaternary C, alkyl (C 6 –C 12 ) naphthyl methyl pyridinium chloride, at 1:100, 1 oz. quaternary to 0.18 lb. fabric, at 20°C, and at 1:500 at 45°C. Quaternary D, dodecyl acetamido dimethyl benzyl ammonium chloride, failed to disinfect at 20°C, in any dilution, but at 45°C. disinfection was accomplished at 1:50. No disinfecting dilution was obtained for fabrics with quaternary E, cetyl trimethyl ammonium bromide, due, in part, to its low solubility. It was found that quaternary B disinfected more efficiently as the numbers of organisms in the inocula decreased. The dilution necessary to disinfect fabric contaminated with numbers of cells comparable to conditions found in rinse waters of commercial laundries was 1:4,000 or 1 oz. quaternary to 7.5 lb. of dry cloth. When the contamination was in the order that might be expected to represent rinse waters in home conditions, the effective dilution was 1:1,000 or 1 oz. quaternary for 1.8 lb. of dry fabric.