Bacillus anthracis Spore Decontamination in Food Grease

Abstract

Bacillus anthracis Sterne strain spores were analyzed for their resistance against five disinfectants: commercial sodium hypochlorite, Spor-Klenz Ready-to-Use Cold Sterilant, accelerated hydrogen peroxide (AHP), Virkon, and surface decontamination foam (SDF). The aim of this study was to find an effective disinfectant that would reduce the viability of B. anthracis Sterne spores at ≥6 log in the presence of variables such as animal grease and fat, stainless steel, and temperature (room temperature and 4 °C). SDF and 10% sodium hypochlorite consistently reduced the growth of viable B. anthracis Sterne spores after 5 min in the presence of stainless steel at room temperature. It took at least 10 min of contact time for AHP to consistently reduce spore growth by ≥6 log, while it took at least 20 min for 5% bleach and Spor-Klenz to consistently inactivate ≥6 log spores in the presence of stainless steel at room temperature. AHP was the only disinfectant that reduced the viability of B. anthracis Sterne spores at ≥6 log in the presence of stainless steel and animal grease, both at room temperature and 4 °C after 24 h of contact time.

Review of Decontamination Techniques for the Inactivation of Bacillus anthracis and Other Spore-Forming Bacteria Associated with Building or Outdoor Materials

“…These solutions were effective against B. anthracis (Ames and other strains such as Vollum and Albia) on nonporous surfaces immersed in the liquid (3000–5000 ppm FAC), , but efficacy was reduced or required substantially higher concentrations in the presence of organic burden. − Several spray-applied commercial off-the-shelf cleaning products containing bleach (≥20 000 ppm FAC or 2% hypochlorite) and surfactants, with pH of approximately 12.5, were effective against spores of B. atrophaeus on porous and nonporous building surfaces The use of carbon nanotubes improved efficacy of hypochlorite solutions as well . Diluted bleach and consumer products may be less hazardous to work with (compared to pAB) because less chlorine gas is released from the liquid at higher pH, potentially reducing the level of respiratory protection needed.…”

Decontamination of Bacillus anthracis Spores at Subzero Temperatures by Complete Submersion

“…anthracis Sterne spores were prepared as previously described. 24 Aliquots of 1 mL containing *1.08 • 10 9 spores from this preparation were stored at À20°C until needed.…”

“…in the absence of interfering substances such as food grease. 24 The efficacy of NaOCl increases as a function of temperature; for example, a 100 • increase in efficacy between 20°C and 45°C against Enterococcus feacalis, 25 and a 6-log reduction in the number of B. anthracis spores in milk in <60 s at 80°C. 26 It is, therefore, heartening to see that the efficacy of NaOCl is not reduced until temperatures below À20°C when used in the presence of the freezing point depression agent CaCl 2 .…”

“…We have previously examined the effectiveness of disinfectants in food grease containing anthrax spores. 24 In this study we examined the decontamination efficacy of the ECCC decontamination solution formulations on B. anthracis strain Sterne spores through immersion at subzero temperatures. Results of this study could be used for the rapid decontamination of materials and equipment after a bioterrorism event, or by those needing routine decontamination at subzero temperatures of wastes or materials amenable to submersion.…”