Spore exposure arising from stored hay, grain and straw

Authors

• Marjut Kotimaa Kuopio Regional Institute of Occupational Health, P.O.B. 93, SF-70701 Kuopio, Finland

DOI: https://doi.org/10.23986/afsci.72935

Abstract

The quantitative and qualitative differences in microbe exposure arising from hay, grain and straw during the end of the indoor feeding period were investigated by using a six-stage fractionating impactor (model 10—800, Andersen Inc.). Straw samples (n = 5) liberated significantly higher amounts of spores (3.7 x 106 cfu/m3 air) in comparison to hay samples (n = 33) and grain samples (n = 2), which liberated 0.6 x 106 cfu/m3 and 0.2 x 106 cfu/m3 , respectively. Thermotolerant and thermophilic microflora were typical of the exposure originating from straw. Hay liberated about 10 % and grain only 0.7 %, the level of spores of thermotolerant fungi liberated from straw. The corresponding percentages of spores of thermophilic actinomycetes were 5 % and 0.4 %. Thermoactinomyces vulgaris was the dominating microbe in the exposure caused by straw; Aspergillus umbrosus was the major species in the microflora liberated from hay and grain. Other Aspergillus (A.) species (A. fumigatus, A. ochraceus, A. flavus, A. repens, A. versicolor) and Penicillium (P.) species (P. expansum, P. piceum, P. citrinum, P. brevicompactum, P. echinulatum, P. verrucosum var. cyclopium) occurred frequently, and in great amounts, in all the analysed materials. Spores of Cladosporium (C.) species (mainly C. herbarum, C. cladosporioides, and C. macrocarpum) were found frequently, and abundantly, during the handling of hay. The present results suggest that not only the traditional causative agents of farmer’s lung disease but also other fungal and actinomycete species may be found in high concentrations during the handling of bedding and feeding stuffs, and that these fungal and actinomycete exposures may cause respiratory symptoms and other health problems in both man and animals. Special attention should be paid to decreasing the moisture content of hay and straw before storing in order to lower the risk of moulding during the indoor feeding period.