Q-269. Surface Sampling Based Decontamination Assessment of Military-Relevant Materials with Vaporous Hydrogen Peroxide (VHP®) and Liquid Disinfectants

L. Wallace1, V. K. Rastogi1, L. S. Smith1, J. W. Pfarr1, L. S. Sobota2, B. Davis3, A. Prugh4, J. S. Sabol5;
1US Army, Aberdeen Proving Ground, MD, 2Naval Surface Warfare Ctr., Dahlgren, VA, 3US Army, Dugway Proving Ground, UT, 4Science & Technology Corp., Edgewood, MD, 5SAIC Corp., Abingdon, MD.

A major consequence of biological terrorism is a wide degree of contamination of not only complex structural surfaces within and around a building, but also of communication/combat or protective equipment used by war-fighters. Appropriate selection of a decon technology, and re-occupation/re-use of building and assets rely principally on extensive pre- and post-decontamination sampling. One of the challenges related to the demonstration of decon products has been poor recovery of biological contaminants from complex surfaces. Two federal laboratories, Edgewood Chemical & Biological Center and Naval Surface Warfare Center Dahlgren Laboratory, collaborated for the optimization of surface sampling for quantifying biological contaminants. Bacillus subtilis, ATCC 19659 and B. anthracis, ΔSterne spores were inoculated on large-size panels (12x12 in) prepared from four military-relevant materials, i.e. glass, butyl rubber, polycarbonate, and CARC-coated steel. The inoculated surfaces were sampled by a combination of one polyester wipe followed by three successive cotton swabs. The results show that for recovery, while sterile water is an adequate extractant for B. subtilis spores, the buffered peptone water containing surfactant is the best extractant for B. anthracis spores. Based on a sampling data from a replication of four panels, each inoculated with 16 sectors, the spore recoveries ranged between 50-100%. For evaluation of gaseous decontaminants, the panels were exposed to a dose of 1100 - 1350 (ppmv.hr) of VHP®. Based on a set of six panels, each inoculated with 16 sectors, i.e. 96 data sets in all, >6-log spore kill was observed on each of the four material types. Similar log reductions were observed for the two spore types, B. subtilis and B. anthracis ΔSterne. NSWCDL has been evaluating the decontamination efficacy of HTH, bleach, DF200, and Spor-Klenz® on a set of six panels. The relative effectiveness of the disinfectant for spore kill was found to be dependent on the test chemical and the material type. These results comprise the first ever demonstration of sampling-based assessment of decontamination effectiveness of gaseous fumigants and liquid disinfectants.