4. Discussion
Small ruminant farms are known reservoirs of foodborne
pathogens such as C. jejuni and Salmonella spp.
(Pao et al., 2005; Stanley and Jones, 2003). This current
study further shows that preventive measures such as
pasturing pre-screened animals, applying worker sanitation,
and/or using a protective feeding system failed to
exclude pathogen shedding by small ruminant herds.
Small ruminants can intermittently shed pathogens, as
shown in our data as well as in prior reports (Stanley and
Jones, 2003), thus by-passing initial screening. Furthermore,
pathogens may be transmitted to the herds on open
pastures via unavoidable vehicles such as wildlife and
rain water.
Small ruminant studies with concurrent pathogen detections
often found higher incidences of Campylobacter than
Salmonella. As examples, Adesiyun and Kaminjolo (1994)
isolated Campylobacter and Salmonella from fecal samples,
respectively, from 21.3% and 3.3% of 61 diarrheic sheep and
12.5% and 3.1% of 32 non-diarrheic sheep in Trinidad. Zweifel
et al. (2004) reported that the prevalence of Campylobacter by
testing cecum samples from 653 slaughtered sheep on 31
farms in Switzerland was 17.5% while Salmonella was found in
only 11.0% of the samples. Furthermore, Little et al. (2008)
found that approximately 12.6% of 905 raw lamb meat
collected at retail and food service premises in the U.K. were
contaminated with Campylobacter, but only 2.0% of them had
Salmonella. The current study conducted in the Mid-Atlantic
region of the U.S. further shows 9.3% for C. jejuni and 3.5%
for Salmonella among 689 small ruminants tested. Although
the exact reason for the observed difference is unclear, the
potential influence of wildlife as a contamination source
should be considered.