A. S. HALSTENSEN1,2*, K. C. NORDBY1,
I.M. WOUTERS3 andW. EDUARD1
Abstract
Objectives:Exposure
to organic dust containing high concentrations of
microorganisms is
common in grain farming, although the farmers have
practices to counteract microbial growth
to obtain optimal grain yields. We investigated the
influence of weather and production practices
on personal microbial exposure during grain work.
Methods: Airborne
dust was collected by personal sampling during threshing &
and storage
work on 92 Norwegian farms. The personal exposure
for bacteria, endotoxin, fungal spores
and hyphae, 
-(1
3)-glucans
and actinomycetes was quantified and compared with
climatic
data expressed as fungal forecasts from the grain
growth season and production practices as
reported by farmers.
Results: Farmers
were exposed to a geometrical mean of 4.4 mg m-3
inhalable dust [geometrical
standard deviation (GSD) = 4.0], 4 X 106
m-3 bacteria and fungal spores (GSD 5 5.2
and 5.9, respectively), 5.9 X 103 EU m-3
of endotoxins (GSD = 8.6), 2 X 105 m-3
actinomycetes
(GSD = 15.3), 120 
gm-3
-(13)-glucans
(GSD = 4.7) and 5 X 105 AUm-3
of hyphae
(GSD = 4.4). Univariate associations were found between
one or several of these microbial
factors and work operation, visible fungal damage,
grain species, lodging of grain, storage technology
or harvester type. As assessed by general linear models,
storage work was the main predictive
determinant for microbial exposure, although grain
species and visible fungal damage
also were also important.Wet and warm weather throughout
the grain growth season were associated
with elevated exposure for inhalable dust, -(13)-glucans,
endotoxins and hyphae
during threshing. The -(13)-glucan
exposure could biologically be explained by the fungal
spore and hyphal exposure, both variables contributing
equally. However, spores were most
important during storage work, whereas only hyphae
were predictive during threshing.
Conclusions: Farmers
were exposed to high levels of microorganisms and
their components
during dusty grain work. Dust prevention and protection
may reduce microbial exposure, and
may be particularly important in areas with frequent
fungal forecasts, when fungal damage has
been observed, during storage work or when handling
barley.
Keywords: -(13)-glucan;
endotoxin; fungal spores; grain work; hyphae; inhalable
dust; microbial exposure
determinants; personal exposure;
Organis farming.
