Optimization of the Process of Eliminating Microorganisms Harmful to Human Health and Threatening Objects Isolated from Historical Materials from the Auschwitz-Birkenau State Museum in Poland (A-BSM) Collection with the Use of Ethanol in the Form of Mist

Abstract

The aim of the study was to assess the biocidal effectiveness and the effect of 80% and 90% ethanol applied in the form of mist on the surface of textile materials from historical A-BSM objects. The microorganisms used for the tests, namely, Cladosporium cladosporioides, Aspergillus niger and Penicillium chrysogenum, were isolated from the surface of textile objects in the A-BSM. Bacillus subtilis, Staphylococcus aureus, Aspergillus flavus and Aspergillus niger were also used from the American Type Culture Collection (ATCC). Fabric samples were inoculated with microorganisms at a concentration of 105–106 CFU/ml. Ethanol in the form of mist was applied in concentrations of 80% and 90%. Airbrushes VL 0819 and VE 0707 were used for this purpose, where the pressure was 0.2 MPa and the PA HEAD VLH-5 nozzle with a tip of 1.05 mm in diameter was used. In order to achieve more effective disinfection after applying the ethanol mist, samples were stored in PE foil in the conditions of 21 °C ± 1 °C for 22 ± 1 h. After applying the ethanol mist, changes in the properties of the materials were assessed using scanning electron microscopy (SEM). The reduction in the number of microorganisms on modern cotton fabric after the use of ethanol in the form of mist at concentrations of 80% and 90% ranged from 93.27% to 99.91% for fungi and from 94.96% to 100% for bacteria, except for 74.24% for B. subtillis. On the historical fabric, after the time of application of 90% ethanol was shortened to 4 s, the microorganisms were reduced by over 99.93% and S. aureus was completely eliminated. After applying the tested disinfection technique, no changes in fiber morphology were observed on the surface of the model and historical cotton.

Analysis of the Surface of Historic Fabric from the Auschwitz-Birkenau State Museum after Treatment with Ethanol Mist Used to Eliminate Microorganisms Harmful to Human Health

“…In A-BSM, using the 90% ethanol mist decontamination technique, a reduction level was achieved at concentrations of 80% and 90%, ranging from 93.27% to 99.91% for fungi and from 94.96% to 100% for bacteria, with 74.24% for B. subtillis [19].…”

“…In previous studies in A-BSM, SEM was utilized, demonstrating no changes in fiber morphology after the application of ethanol mist on historical fabric [19].…”

“…Wawrzyk et al, presented the results of microbiological studies, confirming the biocidal effectiveness of the method. The reduction of most microorganisms was over 99% [19].…”

“…To confirm that ethanol mist does not have a harmful effect on the fibers of historical fabric, the authors conducted scanning electron microscopy (SEM) tests, which did not show any significant, visible changes on the surface after the use of ethanol mist [19].…”

“…In the case of employing innovative techniques or using a biocidal agent different from the traditional one, the composition and structure of the disinfected material should not undergo adverse changes. The authors also presented results from Scanning Electron Microscopy (SEM), which did not reveal significant, visible changes on the surface after the application of ethanol mist [19].…”