Viable fungi in corn dust.

Area of Science:

• Agricultural Science
• Environmental Microbiology
• Mycology

Background:

• Fungal contamination in agricultural settings is a significant concern.
• Understanding airborne fungal propagules in corn dust is crucial for occupational health.
• Previous studies have not fully characterized fungal populations in corn dust across different environmental conditions.

Purpose of the Study:

• To quantify viable fungal propagules in corn dust during farm and grain elevator operations.
• To identify dominant fungal species and assess their abundance variations.
• To evaluate the potential respiratory exposure risks associated with airborne fungi in corn dust.

Main Methods:

• Utilized a six-stage Andersen sampler to collect viable microbial particles from corn dust.
• Employed various agar media for culturing and identifying fungal species.
• Collected air samples during different years (1979, 1980, 1982) representing varied weather patterns.
• Compared airborne fungal counts with outdoor air samples and petri dish exposure methods.

Main Results:

• Corn dust contained high concentrations of fungi, ranging from 10(4) to 10(9) viable propagules per m³.
• Yeasts, Aspergillus, Penicillium, Cladosporium, Alternaria, Helminthosporium, and Fusarium were the most abundant fungi.
• Aspergillus flavus group incidence was higher in the hot, dry year of 1980.
• A. flavus propagules were predominantly deposited in Andersen sampler stages 3 and 4, corresponding to human respiratory tract regions.

Conclusions:

• Corn dust harbors substantial levels of viable fungal propagules, exceeding outdoor air concentrations.
• Environmental conditions significantly influence the relative abundance of specific fungi, notably Aspergillus flavus.
• The deposition pattern of A. flavus suggests a potential for respiratory tract exposure and associated health risks.