Prevalence of microfungi in Finnish cow barns and some aspects of the occurrence of Wallemia sebi and Fusaria.

Abstract

The occurrence of microfungi in the air and in feeding and bedding materials was studied on 32 Finnish dairy farms. Air samples for determining viable and total spore concentrations were collected on membrane filters and with a cascade impactor. Genera of mesophilic, xerophilic, and thermophilic fungi were identified in four culture media. Total spore counts were done with the aid of an epifluorescence microscope. To identify fungal flora in agricultural materials, feeding and bedding material samples were also taken from the farms. The airborne spore concentrations varied for viable mesophilic, xerophilic, and thermophilic fungi from 10(1) to 10(7) colony-forming units per cubic meter, and for total spores from 10(5) to 10(7) spores per cubic meter. Aspergillus, Penicillium, Cladosporium, Absidia species, Wallemia sebi and yeasts were the predominant fungi in the air, as well as in the material samples. In general, the airborne spore concentrations were high although the variation in the concentrations of different fungal groups was large between the farms. Along with using new growth media, two fungi whose prevalence was earlier poorly known in Finland were detected. W sebi proved to be the most abundant xerophilic fungi in the air and hay samples, while Fusarium spp were very common in grain and straw but rare in air.