Reducing microbial contamination on historical leather artifacts at the Auschwitz-Birkenau State Museum using ethanol in the form of mist

Purpose: The aim of the study was to evaluate the biocidal efficacy and determine the influence of 90% ethyl alcohol applied in the form of a mist on the surface of model and historical leather. Materials and methods: The main object of the study were historical leather shoes from the collections of the Auschwitz-Birkenau State Museum (A-BSM) in Oświęcim (Poland). Microorganisms found before on historical leather objects in A-BSM were inoculated onto samples of model and historical leather. Ethanol mist was applied with an airbrush with optimized parameters for 15 s at a concentration of 90%. To increase the biocidal effectiveness, the samples were sealed in a tight package and stored for 22 hours. The effect of disinfection was assessed using culture-dependent methods. Changes on the surfaces was assessed using SEM, FTIR, and XPS techniques. Results: CFU fungi, a reduction of 99.51% to 99.99% was observed. Ethanol disinfection had no negative effect on the surface morphology and collagen structure. Conclusions: Disinfection with ethanol applied in the form of mist can be effectively used to eliminate microbiological contamination of historical objects made of leather in A-BSM.