Disinfection of Bacillus spores with acidified nitrite

• Acidified nitrite can be an effective disinfectant against spores.
• High ionic strength may inhibit the acidified nitrite disinfection.
• Disinfection is inhibited by lower temperature and higher pH.

Disinfecting water generated from a bioterrorism contamination event will require large amounts of disinfectant since the volume of water flushed from a drinking water distribution system or wash water collected from a contaminated outdoor area can accumulate quickly. Commonly used disinfectants may be unavailable in the necessary amounts, so evaluation of alternative disinfectants is needed. This study focuses on disinfection of Bacillus spores in water using acidified nitrite. The effect of varying pH (2 or 3), temperature (5 °C or 24 °C), nitrite concentration (0.01 or 0.1 M), buffer (Butterfields or Phosphate Buffered Saline, PBS) and Bacillus species (B. globigii and B. anthracis Sterne) was evaluated. B. globigii was more resistant to disinfection under all water quality conditions. Disinfection was more effective for B. globigii and B. anthracis Sterne at 0.1 M nitrite, pH 2, and 24 °C. Disinfection of B. anthracis Sterne was enhanced in low ionic strength Butterfields buffer compared to PBS.