PoultryUSA - May 2018 - 14
14 ❙ WATTPoultryUSA
Broiler respiratory tracts:
A route for Salmonella?
Dust inside the growout house should be considered as a potential
Salmonella transmission route.
DR. DIANNA BOURASSA
Salmonella is a persistent food safety risk the poultry
industry is trying to control in every step from hatching to processing. One potential infection path worth
considering is the airborne route.
Salmonella in dust during growout
How Salmonella infects birds
through the trachea
Several studies demonstrated inoculating broilers
with Salmonella within the trachea leads to further
intestinal colonization. There is also evidence that the
During broiler harvest, there is often an increase in
the levels of dust in the air. | Dianna Bourassa
rate of colonization from birds inoculated in the trachea is greater than if birds are orally inoculated.
When comparing five inoculation routes - oral,
intra-tracheal, subcutaneous, ocular and cloacal - the
intra-tracheal inoculation route led to intestinal tract
colonization significantly more frequently than all other
routes. In turkeys exposed to Salmonella-contaminated
fecal dust, Salmonella was detected from respiratory
tract samples, lungs and small intestines.
The transfer of Salmonella from the litter or house
dust to the respiratory tract (specifically the trachea) may
influence the colonization of the bacteria within the birds
and the distribution of Salmonella through the flock.
Harvest dust and Salmonella
The presence of dust may also have further impact in
the processing plant on broiler product Salmonella status.
www.WATTAgNet.com ❙ May 2018
Tyrannosaurus | BigStockPhoto.com
Salmonella can be spread throughout the litter in
a broiler house by several mechanisms including insects, such as flies or darkling beetles, and broiler fecal
shedding. The bacteria is then transmitted to broilers
through physical contact and ingestion. An additional
route of contamination is the presence of Salmonella
on dust inhaled by the birds.
There's a high variability of the levels of dust present in a broiler house. A wide range of dust concentrations from 0.03 to 6.5 milligrams per cubic meter is
influenced by everything from the time of day to the
house ventilation differences based on outside temperatures to the levels of bird activity in the house.
Broiler house dust contains a mixture of dander, litter, feed, feces and microbes, with the vast majority of
dust containing microbial DNA. Broilers inhaling dust
contaminated with Salmonella are a potential route
of bird contamination and subsequent fecal shedding
once colonization occurs.