Samples of ceiling tiles with high levels of bacteria exhibited cytotoxic activities on a HEP-2 tissue culture assay. Ceiling tiles containing low levels of bacterial colonization did not show cytotoxic activities on the HEP-2 tissue culture assay. Using a spread plate procedure on blood agar plates, the levels of bacteria colonizing portions of cellulosic indoor ceiling tiles were easily identified. Levels of bacteria measured by this simple procedure may be a good indicator of microbial colonization of indoor building materials especially in the case of water damage. We suggest that bacterial levels above 150 CFU g−1 of ceiling tile material indicate colonization has occurred.
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Received 24 December 1998/ Accepted in revised form 26 March 1999
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DeMaria, L., Lye, D. Detection of bacterial cytotoxic activities from water-damaged ceiling tile material following incubation on blood agar. J Ind Microbiol Biotech 23, 653–655 (1999). https://doi.org/10.1038/sj.jim.2900670
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DOI: https://doi.org/10.1038/sj.jim.2900670