Presence of bacterial pathogens and levels of indicator bacteria associated with duck carcasses in a commercial processing facility

Authors: Berrang, Mark; Meinersmann, Richard - Rick; Knapp, Steven - Steve

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/9/2019
Publication Date: 3/16/2020
Citation: Berrang, M.E., Meinersmann, R.J., Knapp, S.W. 2020. Presence of bacterial pathogens and levels of indicator bacteria associated with duck carcasses in a commercial processing facility. Journal of Food Protection. https://doi.org/10.4315/0362-028X.JFP-19-397.
DOI: https://doi.org/10.4315/0362-028X.JFP-19-397

Interpretive Summary: Duck meat, while not as commonly eaten in the U.S as chicken, is enjoyed by a substantial population. There is little information available regarding the microbiological safety of U.S. processed duck meat. In this study we examined duck samples collected once a month for one year in a large U.S. commercial duck slaughter and processing facility. Internal organ samples, ceca and crop, collected at evisceration represent what is carried into the slaughter plant with the live ducks. Campylobacter was detected in 80% of ceca samples. Results showed that Campylobacter and to a lesser degree Salmonella can be expected to accompany live animals into the plant. Campylobacter was detected on 67% of whole duck carcasses examined prior to carcass chilling. Pathogen prevalence was reduced significantly thanks to antimicrobial processes applied. Overall, 3% and 2% of final oven ready cut-up duck leg quarters yielded detectable numbers of Campylobacter and Salmonella respectively. Numbers of indicator bacteria on duck carcasses were similarly lessened due to the antimicrobial nature of commercial duck processing including immersion chilling and chlorinated spray treatment. Overall, current commercial duck processing techniques are effective to lessen bacterial prevalence and numbers on duck meat products.

Technical Abstract: Little is published on the microbiological aspects of U.S. commercial duck processing. The objective of this study was to measure prevalence and/or numbers of bacteria on duck samples representing the live bird, partially processed and fully processed oven ready duck meat. In each of 12 replications, five samples of each of the following type were collected in a commercial duck slaughter plant (N=60). Crop and ceca samples were collected at the point of evisceration. Whole carcass rinse samples were collected before and after application of carcass chill and antimicrobial spray. Leg quarters were collected from the cut-up line before and after application of an antimicrobial dip treatment. All samples were direct plated and/or enriched for Salmonella and Campylobacter. Carcass and leg quarter rinse samples were also used to enumerate total aerobic bacteria, E. coli and coliforms. Most ceca, crop and pre-chill carcass rinses were positive for Campylobacter (80%, 72% and 67% respectively). Carcass chilling and chlorinated spray significantly lowered Campylobacter prevalence (P<0.01) and even fewer leg quarters were positive (P<0.01). Passage through a chlorinated dip did not further reduce Campylobacter prevalence on leg quarters. Salmonella was infrequently found in any of the samples examined (= 10%). Total aerobic bacteria, coliform and E. coli numbers were lessened (P<0.01) on whole carcasses due to chilling but were not changed by cut-up or leg quarter dip treatment. Overall, current commercial duck processing techniques are effective to lessen bacterial numbers and prevalence of Campylobacter on duck meat products.