Efficacy of Nanostructures as Preservation Carriers of Bacillus atrophaeus in the Preparation of Sterilization Bioindicators

Abstract

The spores of Bacillus atrophaeus are used to monitor the efficacy of disinfection and sterilization processes, particularly in dry heat and ethylene oxide sterilization processes. The production process of biological sterilization indicators of this bacterium includes bacterial sporulation, which leads to a dormant structure with extreme resistance to heat stresses. In this study, the efficacy of the application of nanomaterials as alternative carriers instead of regular paper strips in the recovery of spores and the stability of the prepared bioindicator was investigated. For this purpose, the structural types of nanomaterials applied as carriers on D values and spore absorption were evaluated and compared. The results suggest the nanomaterial’s potential to be used as the supports of bioindicators. Among the evaluated nanomaterials adsorbents, including nanocellulose, lignocellulose, chitin, gamma alumina and silica, silica and gamma alumina illustrated the highest spore absorption potency (107 CFU/mL) and highest spore resistance by the D value of 6.5 min. The results of this study suggest that nanomaterials can be a suitable replacement for conventional strips due to their higher perdurability.