Effect of feed withdrawal on the incidence of Salmonella in the crops and ceca of market age broiler chickens

Previous research regarding Salmonella contamination in poultry has focused predominantly on cecal and intestinal contamination. Recently, the crop has been implicated as an important source of carcass contamination within the processing plant. In the present study, broiler chickens were orally challenged with 1 x 10(8) cfu S. enteritidis at 6 wk of age. At 7 wk of age, birds were randomly divided into two groups consisting of full access to feed, or total feed withdrawal, 18 h prior to sample collection. At the time of sample collection, crops and ceca were aseptically removed and cultured for the presence or absence of S. enteritidis by enrichment. The incidence of S. enteritidis-positive crops was consistently higher (range: 2.8- to 7.3-fold increases) following feed withdrawal than the incidence in samples collected from full-fed broilers in four experiments. Similarly, the incidence of S. enteritidis isolation was consistently higher (range: 1.4- to 2.1-fold increases) in ceca following feed withdrawal than in samples collected from full-fed broilers in these experiments. In a subsequent experiment, ceca and crops were aseptically collected and cultured for the presence of Salmonella immediately prior to or following 8 h feed withdrawal at a commercial broiler house. Similar to the laboratory experiments, the incidence of Salmonella isolation was significantly (P < 0.01) greater from crops following feed withdrawal (36/100) than from samples obtained immediately prior to withdrawal (19/100). However, the incidence of Salmonella in the ceca was not significantly higher following feed withdrawal (31/100) than in samples obtained immediately prior to withdrawal (25/ 100) in this field experiment. These studies indicate that feed withdrawal increases the incidence of Salmonella in broiler crops prior to slaughter and provide further evidence that the crop may be an important critical control point for reducing Salmonella contamination of broiler carcasses.