Microbial colonization of cultural heritage objects is inevitable. Microorganisms cause physical, chemical, and aesthetic alteration in valuable works of art, leading to the loss of both financial and cultural value. To prevent and control microbial colonization and their growths, physical, chemical, and biological methods are used. However, physicochemical methods are often ineffective on treated works of art, and can be dangerous for people involved in the conservation process. Due to inherent characteristics, chemical compounds and biocides, they are hazardous for humans, animals, and the environment. Given the significant weaknesses of these conventional methods, new approaches are continuously being developed to reduce the negative impact of deteriogenic microorganisms. These new approaches are environmentally friendly, safe, low-cost and low-risk. However, more research is needed to monitor the safety and effectiveness of these approaches. The lack of simple, reliable and standard measurements remains a limitation in the selection of
effective treatments. Field experiments are necessary and useful for evaluating the effectiveness of these methods: however, their design and implementation face several challenges. Therefore, researchers are seeking to develop methods to investigate how these new approaches work. Laboratory model systems are tools for testing the efficacy of antimicrobial compounds before field application on art works. In this study, we will first review the types of biological control methods, and then introduce the new and environmentally friendly approaches, that have been developed in this field. Finally, we will discuss methods of testing the effectiveness of new strategies using laboratory model systems.

Biological contamination of paper artifacts is a significant threat, causing not only damage to the paper itself but also posing health risks to conservators and restorers who are in close contact with them. Therefore, identifying the type of contamination is crucial for effective preservation and restoration. This article focuses on identifying biological contamination in a collection of paper artifacts from the Imamzadeh Mohammad in Tafresh, Iran. Preliminary examinations revealed evidence of biological contamination, including stains resulting from biological activity. These stains are a consequence of biodeterioration, leading to a reduction in the structural and artistic quality of the artifacts. To investigate the biological contamination, samples were taken from areas suspected of contamination and cultured on Sabouraud dextrose agar (for fungal contamination) and nutrient agar (for bacterial contamination). After incubation, the grown colonies were examined and identified. The results of the identification of isolated fungal and bacterial showed contamination with various fungi, including Penicillium, Aspergillus, Cladosporium, and yeasts, as well as bacteria belonging to the Actinomycetes and Bacillus genus.

Valuable cultural heritage is always exposed to the invasion of biological agents and the resulting destruction, especially when the physical and chemical conditions of the work and its surrounding environment are compatible with the characteristics of an organism or a microorganism. Therefore, preventing the occurrence of such conditions and limiting the invasion of biological agents should be among the main and primary goals of every center. Over the years, various methods such as the use of disinfectants have been used to control biological agents in various historical and cultural collections. With the passage of time and increasing awareness of the harmful effects of these substances on the treated works, the environment and the users, nowadays the use of non-toxic alternative methods is more recommended. Experience has shown that the method that causes the least damage to collections and employees is preventive methods and regular control, which is possible through monitoring and managing the environment. Integrated pest management with the ultimate goal of removing harmful biological agents from a place is one of the long-term preventives and non-toxic methods of controlling biological agents that is used in many museums, archives, and libraries. In this article, along with a brief overview of biological deterioration and its preventive and control strategies, microbiological monitoring of the air inside 4 storerooms in the world heritage complex of Golestan Palace Museum including: the anthropological clothing, the manuscripts, the carpets, and the Painting storerooms was carried out. For this purpose, air sampling was done by sedimentation method and isolated microbial colonies on the culture media were investigated and identified. The results of the microbiological monitoring of the air inside the storerooms in this study showed that except for the carpet storeroom, other studied storerooms, including the anthropological clothing, the manuscript and the painting storerooms, are acceptable in terms of the number of microorganisms in the air.