Hot, humid air decontamination of a C‐130 aircraft contaminated with spores of two acrystalliferous Bacillus thuringiensis strains, surrogates for Bacillus anthracis

Aim To develop test methods and evaluate survival of Bacillus thuringiensis kurstaki cry − HD ‐1 and B. thuringiensis Al Hakam spores after exposure to hot, humid air inside of a C‐130 aircraft. Methods and Results Bacillus thuringiensis spores were either pre‐inoculated on 1 × 2 or 2 × 2 cm substrates or aerosolized inside the cargo hold of a C‐130 and allowed to dry. Dirty, complex surfaces (10 × 10 cm) swabbed after spore dispersal showed a deposition of 8–10 log 10  m −2 through the entire cargo hold. After hot, humid air decontamination at 75–80°C, 70–90% relative humidity for 7 days, 87 of 98 test swabs covering 0·98 m 2 , showed complete spore inactivation. There was a total of 1·67 log 10 live CFU detected in 11 of the test swabs. Spore inactivation in the 98 test swabs was measured at 7·06 log 10  m −2 . Conclusions Laboratory test methods for hot, humid air decontamination were scaled for a large‐scale aircraft field test. The C‐130 field test demonstrated that hot, humid air can be successfully used to decontaminate an aircraft. Significance and Impact of the Study Transition of a new technology from research and development to acquisition at a Technology Readiness Level 7 is unprecedented.