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Title: Partioning of external and internal bacteria carried by broiler chickens before processing

item Cason Jr, John
item Hinton, Jr, Arthur
item Northcutt, Julie
item Buhr, Richard - Jeff
item Ingram, Kimberly - Kim
item Smith, Douglas
item Cox, Nelson - Nac

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/18/2007
Publication Date: 9/5/2007
Citation: Cason Jr, J.A., Hinton Jr, A., Northcutt, J.K., Buhr, R.J., Ingram, K.D., Smith, D.P., Cox Jr, N.A. 2007. Partioning of external and internal bacteria carried by broiler chickens before processing. Journal of Food Protection. 70:2056-2062.

Interpretive Summary: Just before processing, broiler chickens were sampled to count pathogenic bacteria and bacteria that are thought of as indicating fecal contamination. Three external samples were taken (feathers, head/feet, and defeathered carcass rinse) and three internal samples (ceca and colon from the intestinal tract and the crop from the esophagus). Coliforms and E coli counts were highest in the ceca, but overall the total external and internal counts were equivalent. Campylobacter counts were highest in the intestinal tract, but were present at high levels in external samples. Salmonella incidence in external samples was more than double the incidence in internal samples. Numbers of Salmonella indicated contamination was spread relatively equally between different samples. Coliform and E. coli bacteria did not predict incidence or numbers of Campylobacter or Salmonella in any of the samples. The pattern of bacterial contamination is complex and variable.

Technical Abstract: Broiler chickens from the loading dock of a commercial processing plant were sampled to determine incidence and counts of index/indicator and pathogenic bacteria. Feathers were removed by hand from ten 6-week-old chickens from each of 7 different flocks and rinsed in 400 ml of 0.1% peptone water. Heads and feet were removed and rinsed and the picked carcass was also rinsed, each in 200 ml. The ceca, colon, and crop were aseptically removed and stomached separately in 100 ml of peptone water. Campylobacter was present in 6 of the 7 flocks. Salmonella was isolated from 50 of the 70 carcasses with at least two positive carcasses in each flock, with five-tube MPN assays performed on positive samples. Significantly more coliforms and Escherichia coli were found in the ceca compared to feathers, which in turn carried more than the other samples, but total external and internal counts were roughly equivalent. Counts of Campylobacter were higher in ceca and colon than in other samples. Salmonella was isolated in external samples from 46 of the 50 positive carcasses compared to 26 positive internal samples or 17 positives in the ceca alone. Total MPN of Salmonella was approximately equivalent in all samples, indicating that contamination was distributed through all external and internal sampling locations. Salmonella-positive samples did not carry higher counts of coliforms or E. coli, and there were no significant correlations between the indicators and pathogens in any sample. There were low but significant correlations for counts of coliforms (also E. coli and Campylobacter) in ceca:feathers and ceca:colon comparisons, but not for Salmonella. The pattern of bacterial contamination before processing is complex and highly variable.