The Effects of Decontaminant Residue on the Viability of Bacillus Spores during Wipe Sample Storage

Special Issue Article

M. Worth Calfee

Abstract

Clearance sampling following a biological terror incident potentially necessitates samples being collected from surfaces recently treated with decontaminant. The impact of residual decontaminant co-collected with surviving biologicals is currently unknown. The purpose of this study was to assess whether residues remaining on non-porous surfaces following decontamination impact estimates of surface contamination. Two experimental approaches were used to determine if agent viability within wetted wipe samples (post-collection) is affected by the presence of pH-adjusted bleach residues, and therefore impacts the quantitative determination of Bacillus spore recovery. Results indicated that following sample storage (22°C, overnight) that determined number of colony forming units (CFU) were not statistically different for positive controls and samples containing dry decontaminant residue. These data are necessary for interpretation of post-bioterror or other contamination incident sampling results, and support current use of wetted wipes in non-porous surface sampling protocols for clearance following liquid decontamination activities.

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