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Levels of bacteria, fungi, and endotoxin in bulk and aerosolized corn silage.

Authors
Dutkiewicz-J; Olenchock-SA; Sorenson-WG; Gerencser-VF; May-JJ; Pratt-DS; Robinson-VA
Source
Appl Environ Microbiol 1989 May; 55(5):1093-1099
NIOSHTIC No.
20040961
Abstract
Three samples of silage taken from the surface of a silo and from depths of 20 and 45 cm in the silo were studied for identification of the potential agents causing symptoms of organic dust toxic syndrome. The samples were examined by dilution plating before and after aerosolization in an acoustical dust generator. Aerosol samples were collected by liquid impinger and filter cassettes. The samples were examined for total aerobic bacteria, anaerobic bacteria, gram-negative bacteria, lactobacilli, listeriae, thermophilic actinomycetes, fungi, and endotoxin. Very high levels of total aerobic bacteria and fungi were found in the surface sample (up to 10(9) CFU/g in the bulk sample and up to 10(9) CFU/m3 after aerosolization), whereas the corresponding values from the deepest site were 100 to 50,000 times lower. Aspergillus fumigatus predominated among the fungi, whereas Bacillus and gram-negative organisms (Pseudomonas, Alcaligenes, Citrobacter, and Klebsiella species) prevailed among bacteria. Thermophilic actinomycetes occurred in numbers up to 10(7) CFU/g in the bulk samples, whereas anaerobic bacteria, lactobacilli, and listeriae were only few or absent. The concentration of endotoxin was high in the surface sample (up to 211.4 Endotoxin Units/mg) and about 200-fold lower in the sample from the deepest site. The results show that contact with dust from the surface of silage carries the risk of exposure to high concentrations of microorganisms, of which A. fumigatus and endotoxin-producing bacteria are the most probable disease agents.
Keywords
Endotoxins; Agricultural-products; Agricultural-workers; Agricultural-industry; Organic-dusts; Microorganisms; Aerosols; Aerosol-particles; Bacteria; Bacterial-dusts; Fungi
CODEN
AEMIDF
Publication Date
19890501
Document Type
Journal Article
Fiscal Year
1989
NTIS Accession No.
NTIS Price
Issue of Publication
5
ISSN
0099-2240
NIOSH Division
DRDS
Source Name
Applied and Environmental Microbiology
State
WV; NY
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