Non-pathogenic aerobic Gram-positive spore-bearing organism with an unusually high incubation temperature (45 – 60tl)—i.e., a thermophile. The spores are killed when subject to a temperature of 121°C for 12 minutes, and sporing cultures may be used for tests of autoclave efficiency. Bacillus stearothermophilus is responsible for ‘flat – sour’ spoilage of canned foods.
A spore forming bacillus that may survive disinfection or sterilization. Its presence on a clinical instrument or surface is used as an indicator of inadequate sterility.