Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 27, 2004
Publication Date: September 1, 2004
Citation: Cason Jr, J.A., Berrang, M.E., Buhr, R.J., Cox Jr, N.A. 2004. Effect of pre-chill fecal contamination on numbers of bacteria recovered from broiler chicken carcasses before and after immersion chilling. Journal of Food Protection. 67(9):1829-1833.
Interpretive Summary: The possibility of fecal contamination during processing of broiler chickens is a matter of industry and regulatory concern. To test the ability to detect fecal contamination after processing, eviscerated chicken carcasses were cut into matching left and right halves and one half was randomly chosen to be contaminated. A small amount of feces (containing 1 to 10 million bacteria) was spread over a test area on one half and was left on the skin for 10 minutes. After a brief water spray to remove the visible feces, the matching halves were chilled in cold water for 45 minutes. After chilling, carcass halves were sampled again by rinsing and by taking pieces of skin. After chilling, counts of three kinds of bacteria that indicate fecal contamination were not different between the control and fecally contaminated carcass halves. Rinse and skin samples after chilling did not detect the amount of pre-chill fecal contamination that was applied in this experiment.
Paired carcass halves were used to test whether fecal contamination of the skin during processing of broiler chickens can be detected by increased bacterial counts in samples taken before and after immersion chilling. In each of 3 trials, 6 freshly defeathered and eviscerated carcasses were split in half and matching 3 × 5 cm rectangles were marked with dots of ink on the breast skin of each half. One half of each pair was randomly chosen and 0.1 g of freshly collected feces was spread over the rectangle with a spatula. After 10 min, both halves were sprayed with tap water for 10-15 s until feces could no longer be seen in the marked area. Both halves were sampled with a 1-min whole carcass rinse and were then put in a paddle chiller with other eviscerated carcasses for 45 min to simulate industrial immersion chilling. Immediately after chilling, each half carcass was subjected to another 1-min whole carcass rinse, after which the skin within the rectangle was aseptically removed from the half carcasses and stomached. Rinses of fecally contaminated halves had significantly higher Enterobacteriaceae immediately before chilling, but there were no differences in coliform and E. coli counts. After chilling, there were no differences in Enterobacteriaceae, coliform, and E. coli counts in rinse or skin samples from the paired carcass halves. Correlations were generally poor between counts in rinse and skin samples, but were significant between pre-chill and post-chill rinses for both control and fecally contaminated halves. Correlations were also significant between counts in rinses of control and contaminated halves of the same carcass after chilling. Bacterial counts in post-chill carcass rinses did not detect the levels of fecal contamination applied in this experiment.