Microbial Contamination of Photographic and Cinematographic Materials in Archival Funds in the Czech Republic

Bacterial Diversity on Historical Audio-Visual Materials and in the Atmosphere of Czech Depositories

Microbial contamination in cultural heritage storage facilities is undoubtedly still a huge problem and leads to the biodeterioration of historical objects and thus the loss of information for future generations. Most studies focus on fungi that colonize materials, which are the primary agents of biodeterioration. However, bacteria also play crucial roles in this process. Therefore, this study focuses on identifying bacteria that colonize audio-visual materials and those present in the air in the archives of the Czech Republic. For our purposes, the Illumina MiSeq amplicon sequencing method was used. Using this method, 18 bacterial genera with an abundance of higher than 1% were identified on audio-visual materials and in the air. We also evaluated some factors that were assumed to possibly influence the composition of bacterial communities on audio-visual materials, of which locality was shown to be significant. Locality also explained most of the variability in bacterial community structure. Furthermore, an association between genera colonizing materials and genera present in the air was demonstrated, and indicator genera were evaluated for each locality. IMPORTANCE The existing literature on microbial contamination of audio-visual materials has predominantly used culture-based methods to evaluate contamination and has overlooked the potential impact of environmental factors and material composition on microbial communities. Furthermore, previous studies have mainly focused on contamination by microscopic fungi, neglecting other potentially harmful microorganisms. To address these gaps in knowledge, our study is the first to provide a comprehensive analysis of bacterial communities present on historical audio-visual materials. Our statistical analyses demonstrate the critical importance of including air analysis in such studies, as airborne microorganisms can significantly contribute to the contamination of these materials. The insights gained from this study are not only valuable in developing effective preventive measures to mitigate contamination but also valuable in identifying targeted disinfection methods for specific types of microorganisms. Overall, our findings highlight the need for a more holistic approach to understanding microbial contamination in cultural heritage materials.

Influence of Disinfection Methods on Cinematographic Film

Microbiological contamination of cinematographic films can cause damage and loss of image information. A large part of the films is made with the base of cellulose triacetate, which has been used from the 1940s until today. Cellulose triacetate is relatively resistant to common organic solvents, but some types of microorganisms can contribute to its faster degradation. In this work, we tested four types of disinfectants suitable for mass disinfection and sufficiently effective against various types of microorganisms. Butanol vapours, a commercial mixture of alcohols (Bacillol^® AF), Septonex^® (an aqueous solution of [1-(ethoxycarbonyl)pentadecyl] trimethylammonium bromide) and ethylene oxide applied as a gas mixed with carbon dioxide were tested. Samples of a commercial film made of cellulose triacetate were disinfected. The samples were aged for 56 days at 70 °C and 55% RH. Changes in optical, mechanical and chemical properties were studied. None of the disinfectants affected the change in the degree of substitution. For samples disinfected with Bacillol^® AF (alcohol mixture), part of the plasticiser (triphenyl phosphate) was extracted and the intrinsic viscosity of the cellulose triacetate solution was reduced after ageing. A slight decrease in intrinsic viscosity also occurred after disinfection with ethylene oxide. Compared to the non-disinfected samples, butanol vapours and Septonex^® appear to be the most gentle disinfectants for the cellulose triacetate film base, within the studied parameters.

Monitoring the effects of fungi isolated from archival document on model albumen silver prints

Fungi are a common problem in the photographic collection, so the aim of this study focused on isolating and molecular identification of fungi from old albumen prints dating to an archive of Dr. Francis and belonging to the Al-Hagar Family and dating back to 1880-1890. The isolated fungi were identified according to their morphological traits and PCR sequencing. The ability of these isolates to cause deterioration was evaluated on model samples (2 × 2 cm) of albumen silver prints. The effect of these fungi on the morphology and structure of the tested samples were examined by SEM, ATR-FTIR, and chromatic alternations. Four fungal species Aspergillus sydowii, A. flavus, Talaromyces atroroseus, and Penicillium chrysogenum were identified. All isolates were able to grow on the surface of the model Albumen silver print and were capable of causing damage to the binder and able to extend their growth to the paper fibers. A. sydowii, A. flavus, and P. chrysogenum caused hydrolysis and oxidation to the albumen prints, while no significant chemical damage to the albumen was detected for the photographic sample infected with T. atroroseus. All the inoculated samples were significantly affected in terms of color change and the high-light areas have become darker. ATR-FTIR spectra showed the degradation of the protein content in Albumen silver prints inoculated with A. sydowii, A. flavus, and P. chrysogenum.