JOURNAL OF THE INSTITUTE OF WOOD SCIENCE ISSN 0020-3203

THE HYGIENE OF LAMINATED MEDIUM DENSITY FIBERBOARD (MDF) USED AS

FLOOR PARQUET.

ALMA, M. H. and DIĞRAK, M.

ABSTRACT

In this study, the hygiene of the medium density fibreboard (MDF) laminated with for different types of wood veneers used as floor parquet was investigated (Suchsland and Woodson, 1986). The evaluation of the MDF hygiene was done in agar-agar medium by using fifteen pathogenic microorganisms including 11 bacteria and 2 fungi and 2 yeasts, which are abundantly available in soil. The results indicated that the growths of all the microorganisms were significantly inhibited by the MDF laminated with four kinds of veneers, thus showing that the whole MDF used can easily be used as floor parquet, especially in hospital-like places where a lot of pathogenic microorganisms might be available.

More recently, the laminated MDF composite materials have extensively been used as floor parquet instead of solid wood. This shifting is due to the fact that the laminated MDF material has much higher dimensional stability and is rich in a variety of colours in comparison to solid wood. In order to use these kinds of products where a variety of microorganisms are most probably available, e.g., in hospitals and po.lyclinics, the hygiene of the products should be confirmed by conventional methods. As yet, there has not been found any study on the hygiene of wood-based composite materials such as fibreboard, particleboard or other types of composites used where people live. Therefore, the aim of this study was to determine the hygiene MDF laminated with four kinds of veneers by using disk diffusion method in comparison to solid wood.

Four kinds of dry method-based MDF samples laminated with dark beech and open European beech (Fagus sylvatica L.), white oak (Quercus a/ba L.) and black walnut (Jug/ans regia L.) veneers, 10 mm x 10 mm x 10 mm, were prepared from MDF floor parquet (196 mm x 8 mm x 1500 mm) produced by Kastamonu Entegre Timber Ltd. in Turkey. In addition, solid wood samples of Anatolian beech (Fagus orientalis Lipsky) were used as control.

Microorganisms tested in this study were

provided from culture collections of Microbiology Laboratory of Science & Art Faculty of the University of Kahramanmara~SutçU Imam, in Turkey. In the study, Yersinia enterocolitica, Corynebacterium xerosis UC 9165, Enterococcus faecalis ATCC 15753,Salmone/la typhimurium TA 100 hi,Mycobacterium smegmatis CCM 2067, Aeromonas hydrophila ATCC 7966, Serratia maecenscens NRLL 3284, Escherichia co/i DM, Pseudomonas aeruginosa ATCC 27853, Listeria monocytogenes SCOTT A and Micrococcus /uteus LA 2971 bacteria, Pen id/hum digitatum and Aspergib/us niger fungi, and Candida tropicabis and Candida a/bicans CCM 314 yeasts. The above-mentioned bacteria, fungi and yeasts were incubated at:37 d 0.1⁰C for 24 hours, 25 ~ 0.1⁰C for 7 days,and 25 ~ 0.l⁰C for 24 hours by injection into Nutrient Broth (Difco) and in Sabourand Dextrose Broth (Difco) for 24 h, respectively. MUeller Hinton Agar (MHA) (oxoid) and Sabourand Dextrose Agar (SDA) sterilised in a flask and cooled to 45⁰C to 50⁰C were placed to the sterilised petri dishes having a diameter of 9 cm in the amount of 15 ml after injecting cultures of bacteria and yeasts prepared as mentioned above. The sterilised laminated MDF and solid wood samples were located on the solid agar medium by pressing slightly. After the petri dishes so-obtained were held at 4⁰C for 2 hours, the plates were injected with bacteria, fungi and yeasts and were incubated at: 37 ~ 0.1 ⁰C for 24 hours,25 ± 0.1⁰C for 7 days, and 25 ± 0.1⁰C for 24 hours,respectively .

Table 1 demonstrates the inhibition zones of fifteen microorganisms in the presence of four kinds of laminated MDF largely used as floor parquet. As shown in Table 1, the inhibition zones of all the bacteria and fungi range between 9 mm and 50 mm. The. greater inhibition zone is, the slower growth of micro organisms are observed. Generally speaking, all the types of micro organisms can considerably be inhibited by the MDF floor parquet samples due to their inhibition zone sizes between 9 mm and 50 mm, which are amongst the acceptance limits of over 7 (see Table 1) (Dtgrak et al., 1999b). Aspergillus niger fungus depicts somewhat lower inhibition zone size varying between 9 mm and 19 mm in

VOLUME 16 NO 2 (ISSUE 92) WINTER 2002 110