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

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 (P < 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 Staphylococcus and Streptococcus, 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 Moraxella and Pseudomonas. Nine mould genera were identified in 325 fungi colonies, predominated by the genus Aspergillus, Penicillium, Rhizopus and yeasts, both in the barn and in the nearby environment.