Submitted to: Journal of Food Protection
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/27/2003
Publication Date: 5/15/2003
Citation: PEARCE, R., WALLACE, F.M., CALL, J.E., DUDLEY, R.L., OSER, A., YODER, L., SHERIDAN, J.J., LUCHANSKY, J.B. PREVALENCE OF CAMPYLOBACTER WITHIN A SWINE SLAUGHTER AND PROCESSING FACILITY. JOURNAL OF FOOD PROTECTION. 2003. Vol. 66(9) p. 1550-1556. Interpretive Summary: Campylobacter are one of the leading causes of foodborne illness in the United States, causing an estimated two million cases per year. Although the pathogen is commonly found in swine, the involvement of this animal species in foodborne disease is not well understood. Accordingly, the present study was conducted to assess the prevalence of the pathogen on swine carcasses and equipment using the following four methods: direct plating onto CCA media, direct plating onto CLA media, enrichment followed by direct plating onto CCA media, and enrichment followed by direct plating onto CLA media. Swine carcasses were sampled at four places in the facility: after killing, after hair removal, after removal of the internal organs, and after overnight chilling. In addition, the prevalence of the pathogen was assessed in rectal and colon samples collected from corresponding swine carcasses. The prevalence of the pathogen on the carcasses at the four stages was 33%, 0%, 7%, and 0%, respectively, and the prevalence in corresponding rectal and colon samples was 100% and 80%, respectively. The prevalence of Campylobacter on equipment used in the slaughter and processing operations was 5% and 3%, respectively. Direct plating onto CLA media recovered the pathogen from more swine-associated samples when compared to the other three recovery methods. These results demonstrate that Campylobacter can be found in the intestinal tract of swine and on carcass surfaces. However, these data also show that this bacterium can be eliminated from the carcass as it progresses through the slaughtering process and that it is not found on carcasses after overnight chilling. In addition, this study shows that direct plating onto CLA media is an efficient method for recovering Campylobacter from swine samples.
Technical Abstract: The present study examined the prevalence and distribution of Campylobacter in a swine slaughter and processing facility. Samples obtained on three visits over a 30-day period in the summer of 2001 included composite carcass samples (30 total), representing 360 swine carcasses, taken at each of the following four stages in the slaughter and processing facility: (A) immediately after exsanguination (Post-kill); (B) immediately after polishing (Post-polish); (C) after the final washer (Pre-chill); (D) and after overnight chilling at 2°C (Post-chill). Matching composite rectal samples (30 total) were also taken immediately after exsanguination and non-matching individual colon samples (60 total) were collected from the same lot of swine during evisceration. In addition, a total of 72 environmental samples were collected from equipment used in the slaughter (42 total) and processing (30 total) operations. Campylobacter were isolated using the following four recovery methods: (1) direct plating onto Campy-Line agar (CLA); (2) direct plating onto Campy-Cefex agar (CCA); (3) Bolton broth enrichment and subsequent inoculation onto CLA; and (4) Bolton broth enrichment and subsequent inoculation onto CCA. When the results of all four recovery methods were combined, Campylobacter were detected on 33% (10/30) of carcasses immediately after exsanguination, 0% (0/30) after polishing, 7% (2/30) immediately before chilling, and 0% (0/30) after overnight chilling. The pathogen was recovered from 100% (30/30) of the composite rectal samples and 80% (48/60) of the individual colon samples. Campylobacter were detected in 4.8% (2/42) of the slaughter equipment samples and 3.3% (1/30) of the processing equipment samples. Method 1 displayed a higher recovery rate, 23% (66/282), when compared to the other three recovery methods. Of the total isolates recovered, C. coli was the predominant species (75%, 151 of 201 total isolates) followed by C. spp. (24%, 48 of 201 total isolates) and C. jejuni (1%, 2 of 201 total isolates). These results indicate that Campylobacter are highly prevalent in the intestinal tract of swine and on carcass surfaces arriving at the slaughter facility. However, these data also suggest that this organism does not progress through the slaughtering operation and is not detectable on carcasses after overnight chilling. In addition, this study indicates that direct plating onto Campy-Line agar is an efficient method for recovering Campylobacter from swine samples.