Original articleDisinfection of archival documents using thyme essential oil, silver nanoparticles misting and low temperature plasma
Graphical abstract
Section snippets
Research aim
Archival documents and library collections are of great cultural value. Due to their chemical composition, are rapidly undergo biodeterioration. To inhibit this process, reduce the spread of microbial contamination to other objects, and to protect personnel, archives should be disinfected before any other conservation treatment. Scientists are still looking for new, alternative methods for disinfecting archival materials with high efficiency while ensuring the safety of treated materials,
Books
For our study, two books with visible signs of biodeterioration such as fungal growth, discoloration, permanent staining (seen in book Nos. 1 and 2) and musty odour (observed only in book no. 2) were chosen. Book no. 1 was obtained from Jozef Pilsudski Regional and Municipal Public Library in Lodz, Poland and book no. 2 was obtained from National Archive in Prague, Czech Republic. The characteristic of the books studied is presented in Table 1.
Microbial contamination analysis
Samples for microbial analysis were taken from 4
Results
All disinfection methods were generally bacteriostatic and fungistatic. The microbial reduction level obtained was 12–100%, except in the fore edge and the inside page of book no. 1 (no fungal number reduction) (Table 3). The AgNPs misting was the most effective method, it reduced bacterial number by 0.5–4 log (reduction level 60–100%). Both methods, LTP and TEO, reduced bacterial number by 0.5–5 log (reduction 0–100%) (Fig. 1, Fig. 2; Table 3). All tested methods were less effective against
Discussion
The applied disinfection methods: AgNPs, TEO, LTP were microbiostatic, with better effectiveness for bacteria than fungi. The most effective antibacterial method was AgNPs (reduction level: 60–100%), followed by LTP (25–100%) and TEO (12–100%). The effectiveness against fungi was lower than for bacteria and at the same level for all three tested methods (0–99.8%). The decrease in the microorganism number reached up to 4–5 log for bacteria, and only up to 1.5 log for fungi.
Based on the
Conclusions
It was shown that silver nanoparticle misting, thyme essential oil microatmosphere and low temperature plasma can be used as microbiostatics, alternatively to methods currently available. These tested methods show better bacteriostatic than fungistatic activity. For higher effectiveness, the disinfection processes need to be optimized taking into account the type of microorganisms inhabiting the books. The disinfection methods slightly influenced the structural, mechanical and optical
Acknowledgments
These studies were carried out with a Small Grant “Modern approach for biodeterioration assessment and disinfection of historical book collections”, co-funded by the International Visegrad Fund (Grant No. 11530002) and VEGA project “Innovative disinfection strategies: the essential oils effect on microflora and materials of cultural heritage objects” (Project No. 2/0061/17).
Authors sincerely thank: Barbara Czajka, M.A. from the Jozef Pilsudski Regional and Municipal Public Library in Lodz,
References (51)
Foxing caused by fungi: twenty-five years of study
Int. Biodeterior. Biodegrad.
(2000)Observations on aesthetic and structural changes induced in Polish historic objects by microorganisms
Int. Biodeterior. Biodegrad.
(2004)The recovery of biodeteriorated books and archive documents through gamma radiation: some considerations on the results achieved
J. Cult. Herit.
(2004)- et al.
Antifungals on paper conservation: an overview
Int. Biodeterior. Biodegrad.
(2012) - et al.
Comparative study of antimicrobial and cytotoxic effects of selected essential oils by gaseous and solution contacts
Int. J. Aromather.
(2003) - et al.
Biological effects of essential oils – a review
Food Chem. Toxicol.
(2008) - et al.
Effective biocide to prevent microbiological contamination during PEG impregnation of wet archaeological iron-wood artefacts
J. Cult. Herit.
(2007) - et al.
Biofouling and biodetrioration in materials stored at the Historical Archive of the museum of La Plata, argentine and at the National Archive of the republic of Cuba
Colloids Surf B.
(2011) - et al.
Monitoring the effects of different conservation treatments on paper-infecting fungi
Int. Biodeterior. Biodegrad.
(2013) - et al.
Analysis of the sensitivity of microorganisms contaminating museums and archives to silver nanoparticles
Int. Biodeterior. Biodegrad.
(2012)