2. Materials and methods
2.1. Sample collection
This cross-sectional study was carried out between August 2013
and February 2014 in cooperation with a commercial poultry plant
in Northeast Georgia, USA. Spleen and MSC samples were collected
from 18 flocks at the processing plant. Two to three chicken flocks
were sampled every month over the study period. The flocks
included in this study were those processed during the night shift
(i.e., 11 p.m.e2 a.m.). Only one flock was processed during that shift
at the processing plant. This is to ensure that MSC and spleens
samples were from the same flock.
During each visit to the plant and at the start of processing a
flock, 10 composite spleen samples (approximately 30 g each) and
10 MSC samples (25 g each) were collected. The spleen composite
samples were gathered right after the USDA-FSIS inspection of
eviscerated carcasses. The sample collection was as follows: Ten
chicken viscera from 10 consecutive carcasses were removed off the
processing line. Thereafter, 10 spleens were harvested from the
viscera using a cutting scissors. The 10 spleens representing 10
carcasses were placed in one Whirl-Pak bag (NASCO, Fort Artkinson,
WI) forming one composite sample. Scissors were sanitized
with 70% ethanol between each composite sample. The 10 composite
spleen samples were collected over 100 min (i.e., one