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Bioaerosol sampling in field studies: can samples be express mailed?

Thorne PS; Lange JL; Bloebaum P; Kullman GJ
Am Ind Hyg Assoc J 1994 Nov; 55(11):1072-1079
A study examining whether overnight express mailing of agricultural bioaerosol samples collected in the field would produce valid results was conducted. The study was part of a large epidemiological investigation of pulmonary risk factors in dairy farmers. The field performance of all glass impinger (AGI) and nucleopore filtration and elutriation (NFE) methods for sampling viable bioaerosols was also evaluated. Sampling for viable yeasts, molds, and mesophilic and thermophilic bacteria was performed in 25 dairy barns during the summer or winter. The AGI technique utilizing peptone or aqueous betaine collection media was used in the summer and winter. Parallel sampling was done using the NFE method. Sampling times varied from 2 to 6 hours and duplicate samples were obtained in each case. For each sample, one duplicate was analyzed for the bioaerosols, usually within 2 hours, by a laboratory located less than 50 kilometers from the sampling site. The other duplicate was placed on ice and mailed by overnight express to the authors' laboratory for analysis. All samples were analyzed for yeasts, molds, and mesophilic and thermophilic bacteria by standard microbiological techniques. Of the samples collected by the AGI/peptone method during the winter, mailing did not affect the results. Mesophilic bacteria counts were increased in samples mailed during the summer. Mailing samples collected by the AGI/betaine method affected only the results of the mold analyses, which were increased. Airborne yeast and mesophilic and thermophilic bacteria counts measured by all methods during the winter were similar. The AGI/betaine and NFE sampling methods yielded significantly higher mold counts than the AGI/peptone method. In the summer, only the AGI/peptone and NFE sampling methods were compared. The AGI/peptone method yielded significantly higher yeast and mesophilic bacteria counts than the NFE technique. The NFE method yielded significantly higher mold counts than the AGI/peptone method. The authors conclude that their data support the notion that bioaerosol samples can, under certain circumstances, be shipped on ice overnight to a distant laboratory for analysis. The NFE method is recommended for molds and thermophilic bacteria although the AGI/peptone method provides good data. The AGI techniques are better for sampling yeasts and mesophilic bacteria.
NIOSH-Publication; NIOSH-Cooperative-Agreement; Microorganisms; Air-sampling; Occupational-exposure; Agriculture; Work-environment; Statistical-analysis; Aerosols
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Journal Article
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Cooperative Agreement
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American Industrial Hygiene Association Journal
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University of Iowa, Iowa City, Iowa
Page last reviewed: October 5, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division