Detection and isolation of salmonella in broiler chickens around the slaughter time
Crop contents may serve as important sources of Salmonella carcass contamination within processing plants. This study, evaluated the effect of feed withdrawal before the slaughtering time on Salmonella existence in the crops of broilers from ten commercial broiler flocks reared in
individual houses. Crops were collected aseptically from 50 randomly selected broilers in each flock before feed removal and at the end of the feed withdrawal period, immediately before capture and transport to the processing plant. Similarly, the ceca were collected before and after feed withdrawal in six of the ten broiler flocks. The presence of Salmonella in the crops and ceca was determined by enrichment culture in tetrathionate broth followed by culture on XLT4 and Brilliant green agar. The incidence of Salmonella in crop contents increased significantly (p< 0.05) in five of the ten flocks during feed withdrawal. The total number of Salmonella contaminated crops from all ten flocks increased significantly (p< 0.005) from 11/500 (2.2%) before feed removal to 55/499 (11.0%) at the end of feed withdrawal. The increased incidence of Salmonella in the crop contents was associated with an increased tendency of the broilers to consume contaminated rearing house litter during feed withdrawal. The incidence of Salmonella in the ceca increased none significantly from 19/300 (6.3%) before feed removal to 25/300 (8.3%) at the end of feed withdrawal. The
results indicate that the incidence of Salmonella crop contamination may increase as much as five fold during pre-slaughter feed withdrawal and represent a critical pre-harvest control point in reducing Salmonella entry into the processing plant.
Keyword: Broiler chickens Salmonella, pre-slaughter time, crop content, ceca