The use of bacteriophage MS2 for the development and application of a virucide decontamination test method for porous and heavily soiled surfaces.

AIMS: (i) To develop an analytical method for recovery and quantification of bacteriophage MS2-as a surrogate for foot-and-mouth disease virus-from complex porous surfaces, with and without the presence of laboratory-developed agricultural grime; (ii) to evaluate, with a 4-log dynamic range, the virucidal activity of common biocides for their ability to decontaminate surfaces and hence remediate facilities, following a foreign animal disease contamination incident. METHODS AND
RESULTS: An analytical method was developed and optimized for MS2 recovery from simulated agricultural surfaces. The addition of Dey-Engley neutralizing broth to an extraction buffer improved MS2 viability in liquid extracts, with optimal analytical holding times determined as <8 to ≤24 h, depending on matrix. The recovery of MS2 from surface materials decreased in the order: nonporous reference material >grimed porous materials >nongrimed porous materials. In disinfectant testing, two spray applications of pAB were effective against MS2 (≥4-log reduction) on all operational-scale materials. Two per cent citric acid had limited effectiveness, with a ≥4-log reduction observed on a selected subset of grimed concrete samples.
CONCLUSIONS: Decontamination efficacy test results can be affected by surface characteristics, extraction buffer composition, analytical holding time and surface-specific organism survivability. Efficacy should be evaluated using a test method that reflects the environmental characteristics of the intended application. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this study demonstrate the importance of analytical method verification tests for disinfectant testing prior to application in complex environments.