Comparative evaluation of antimicrobial activity of green biocides on infected substrata reproducing original materials of Italian tombs

The hypogeal cultural heritage due to their favourable environmental conditions can be subject to microbial attack usually controlled using biocides. Recently the number of products allowed in the restoration practice has been reduced because, in addition to their effectiveness, the biocidal product should not have effects on the treated surfaces, and it should be safe for the operator and environment. Following this field research, we propose a reconstruction experiment in which we tested 4 different natural products (Clove oil, Oregano Oil, Usnic Acid, IPA+ DMSO + Usnic Acid) on tiles, reproducing the substrate of Etruscan hypogeal tombs (Macco) of Monterozzi Necropolis, inoculated with a selection of fungal/bacterial strains. After one month from the biocide’s application, we evaluated their efficiency by image analysis and by culture analysis. The achieved results evidenced a clear gradient between the four tested biocides and gave suggestions for further improvements.