EN
Bark is a waste material in the furniture industry. It is mainly used for mulching in gardens. To fulfil its task in that field, bark must be microbiologically clean. Ergosterol (ERG) is the main sterol of the fungal cell wall. The research aimed to assess the usefulness of ergosterol concentration analysis for its use in the wood industry in order to quickly assess the level of microscopic contamination of the bark after the drying process. We tested the bark of oak, beech, hornbeam, spruce and pine in terms of ERG concentration and endogenous sterols content. The highest concentration of ERG was obtained for bark of coniferous species (1483.0 and 227.6 mg/kg for spruce and pine respectively), while much lower was found for deciduous (27.4−127.7 mg/kg). No sterols were found in the bark of deciduous trees after the drying process, with the exception of campesterol which was detected only in bark of beech and hornbeam. However, they were found in samples of conifer bark at the level of 1.6−1.78 mg/kg. The bark of deciduous trees is safer in terms of microbiology, and thus can be used in various industries as a secondary raw material.