Qualitative structure of airborne bacteria and fungi in dairy barn and nearby environment

Abstract

The study was conducted in a dairy barn and nearby environment to determine the level of air bacterial and fungi contamination. Measurements were performed in morning, noon and evening sampling periods once a week during two autumn months inside the barn and in a 25 m distant barn environment. A Merck MAS-100 air sampler was employed with different medium and incubation combinations for the capture and identification of bacteria and fungi. The results of the study showed a statistically significant difference (<i>P</i> < 0.05) between the bacterial and fungi counts measured inside and outside the barn, whereby total outside bacterial count was by 97.4% to 98.0% lower, and total outside fungi count by 85.2% to 99.4% lower than the respective indoor counts in various sampling periods. In 125 analyzed colonies, gram-positive bacteria, especially those of the genus <i>Staphylococcus</i> and <i>Streptococcus</i>, were most commonly identified in the air samples from both inside and outside the barn. Gram-negative bacteria were present at a low rate, predominated by enterobacteria and by the genus <i>Moraxella</i> and <i>Pseudomonas</i>. Nine mould genera were identified in 325 fungi colonies, predominated by the genus <i>Aspergillus</i>, <i>Penicillium</i>, <i>Rhizopus</i> and yeasts, both in the barn and in the nearby environment.