Influence of Various Pretreatments (Carriers, Desiccation, and Relative Cleanliness) on the Destruction of Bacillus subtilis var. niger Spores with Gaseous Ethylene oxide

The ethylene oxide resistance of Bacillus subtilis var. niger spores inoculated on a variety of carriers was determined. After initial experiments indicated that cleanliness of the spores was important, desiccated and undesiccated spores of varying degrees of cleanliness on aluminum foil and chromatography paper were studied. Under the experimental conditions, desiccation of the spore population had no influence on susceptibility to ethylene oxide. The degree of cleanliness of the spore preparation was the significant factor in excessive resistance. The bacteriological controls used for testing ethylene oxide sterilization processes should be adequately cleaned so that they may accurately monitor the process.