The chlorine-releasing compounds were highly effective in destroying air-borne lactic streptococcus bacteriophages 144F and 18–16. At a concentration of .048 ppm available chlorine in the chamber, which was attained with 1000 ppm available chlorine in the solution applied, the inactivation was 99.999% or better. Of the various germicides tested, the quaternary ammonium compound and phosphoric acid wetting agent were found to be least effective as virucidal aerosols. Incorporation of chelating agents (EDTA) with quaternary ammonium compounds, to enhance their virucidal activity, was unsuccessful. The effectiveness of iodophor applied as an aerosol, was progressively greater with increasing concentration; however, undesirable side effects such as a heavy brown residue on all surfaces contacted and undesirable odors were noted.

The study of corrosive effects by germicides on various metals indicated that of the chlorine-containing compounds, dichloroisocyanuric acid was least corrosive. Phosphoric acid wetting agents were the least corrosive of all compounds tested.

Results of this study suggested that the chlorine-containing compounds, when applied as an aerosol at sufficiently high concentration, should provide the most effective agents for sanitizing procedures for the control of bacteriophages in the air and on building and equipment surfaces. The results further indicated that a concentration of .048 ppm available chlorine or more in the air provided most effective phage destruction under experimental conditions. This concentration was provided by the equivalent of 1 to 1.5 liters of 1000 ppm applied as an aerosol per 1000 ft3 of space.

Present state of knowledge would indicate that dichloroisocyanuric acid should be an effective and practical compound for control of bacteriophage in dairy plants. In addition to being highly virucidal, dichloroisocyanuric acid also has a low rate of corrosion.

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Author notes

1Technical paper No. 1745 Oregon Agricultural Eperiment Station.

2This work was supported in part by a grant from Klenzade Products, Incorporated.