S7: Fungi Associated with commercial carpet: Aspects of preservation, sanitization, and recycling contaminants

Our laboratory studied development of fungal growth on commercial carpet tile.  The face construction had low height loop pile nylon fiber with a polyvinyl plastisol backing.   Fungal growth and the formation of fungal biofilms typically were associated with the polymer backing that typically rests on concrete subfloor.   A moisture event such as a flood or plumbing leak proved to be the trigger event which facilitated mold growth and subsequent odor.   In these events, the polymer backing supported genera which included Cladosporium, Aspergillus, and Penicillium.

Strategies to prevent mold colonization of carpet include control of relative humidity coupled with maintenance.   Other preemptive strategies include the incorporation of antimicrobial preservatives at the face fiber or backing layer. Here we report on the incorporation of a phosphated amine complex (Intersept^®) and its efficacy and durability in carpet backing.  New standard methods for rapid screening carpet with incorporated preservatives were used to determine (qualitatively) fungal inhibitory activity prior to and after sanitizing cleaning.  Carpet tile preserved with Intersept and used for eight years in a southwestern US hospital neo-natal ICU unit retained antifungal activity after multiple cleanings.

The path of reclaimed and recycled carpet tile was examined for viable fungal contaminants at each step in the recycling and remanufacturing process.   Our preliminary data indicate a stepwise reduction in viable fungal contaminants due both to filtration of dirt and particulates during the separation process and exposure to heat during polymer agglomeration and melt-fusion of polyvinyl crumb.