DEVELOPMENT OF IMAGING TECHNOLOGY FOR FOOD SAFETY AND SECURITY
Location: Quality and Safety Assessment Research Unit
Title: Effect of External or Internal Fecal Contamination on Numbers of Bacteria on Pre-Chill Broiler Carcasses
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 18, 2007
Publication Date: July 25, 2007
Citation: Smith, D.P., Northcutt, J.K., Cason Jr, J.A., Hinton Jr, A., Buhr, R.J., Ingram, K.D. 2007. Effect of External or Internal Fecal Contamination on Numbers of Bacteria on Pre-Chill Broiler Carcasses. Poultry Science. 86:1241-1244.
Interpretive Summary: Chicken meat may come into contact with visible contaminants and bacteria during processing. The contamination and some bacteria are typically removed by thoroughly washing the chicken carcasses before chilling them. Since contamination may occur inside or outside the carcass, an experiment was conducted to determine whether the washing step was affected by the location of the contaminant. Visible contamination was removed and more bacteria were removed by the washer when the contamination was placed on the inside of the carcass than when contamination was on the outside the carcass. Although the interior of the carcass is more difficult to inspect visually, the washing step is sufficient to remove the contamination. Although more contamination remained on the exterior of the carcass after washing, those carcasses are more likely to be seen and removed for re-washing or trimming prior to chilling.
During processing, fecal material may contact broiler carcasses externally or internally. A study was conducted to determine the effect of external versus internal fecal contamination on numbers of bacteria on broiler carcasses. In each of three trials, 12 carcasses just prior to evisceration were obtained from a commercial processing plant, placed on a shackle line and eviscerated with commercial equipment in a pilot scale processing plant. Also, approximately 20 intestinal tracts were collected from the processing plant, then cecal contents were collected and pooled. One g of cecal content was placed on either the exterior breast skin (External), inside the carcass cavity (Internal), or not applied (Control). All carcasses were held 10 min, then placed on the shackle line and passed through a commercial inside-outside bird washer (IOBW) set at 80 PSI (552 kPa), 5 s dwell time, using approximately 189 L per min of tap water at ambient temperature. After a 1 min drip, whole carcass rinses (WCR) were conducted on each carcass and coliforms, Escherichia coli (E. coli), and Campylobacter counts were determined and reported as log cfu/mL rinse. External carcass contamination resulted in significantly higher (P<0.05) coliform, E. coli, and Campylobacter numbers than Internal contamination (5.0 vs. 4.5, 4.9 vs. 4.2, and 3.6 vs. 2.6, respectively). Control carcass counts were significantly lower than either External or Internal carcass contamination counts for coliforms (3.7), E. coli (3.6), and Campylobacter (2.2). External contamination resulted in higher numbers of bacteria after carcass washing, but carcasses with Internal contamination still have higher numbers of bacteria after washing than carcasses without applied contamination.