Submitted to: Journal of Food Protection
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/10/2010
Publication Date: 8/1/2010
Citation: Oscar, T.P., Rutto, G.K., Ludwig, J.B., Parveen, S. 2010. Qualitative map of Salmonella contamination on the chicken carcass. Journal of Food Protection. 73:1596-1603. Interpretive Summary: Maps are important tools that are used in everyday life. For example, maps are used to travel from one location to another. Maps are also used by military organizations to plan actions against adversaries. An important component of a military map is accurate knowledge of the precise location and strength of opposing forces. By analogy, maps of pathogen contamination on food would allow better detection and removal of these risks to public health. Salmonella contamination of poultry is a global health problem. In the current study, a map of the distribution of Salmonella contamination on the chicken carcass was developed for the purpose of improving poultry inspection (i.e. Salmonella detection) and food safety (i.e. removal of Salmonella). The results indicated that a diverse population of Salmonella was randomly distributed on individual carcass but at the population level the carcass contained ‘hot spots’ of contamination. Thus, poultry inspection could be improved by changing from a single whole carcass rinse for detection of Salmonella to whole carcass incubation followed by characterization of multiple isolates of Salmonella from each carcass to properly assess and manage this risk to public health. In addition, this study demonstrated the high value of carcass mapping for identification of critical control points where greater process control can be exercised to reduce the level of Salmonella on the chicken carcass. For example, changes in the way the intestines are removed from the carcass could reduce the incidence of Salmonella contamination on the right drumstick, which was identified as a ‘hot spot’ of contamination.
Technical Abstract: Salmonella contamination of poultry is a global public health problem. The objective of this study was to map the distribution of Salmonella on the chicken carcass for the purpose of improving poultry inspection and food safety. Young chickens (n = 70) in the Cornish game hen class were obtained at retail over a three-year period. Carcasses were aseptically sectioned into 12 parts and then Salmonella were isolated from whole part incubations by conventional culture methods. Isolates were characterized for serotype and antibiotic resistance and by pulsed field gel electrophoresis (PFGE). Salmonella incidence was 21.5% (181/840) for parts and 57.1% (40/70) for carcasses. The number of contaminated parts per carcass ranged from 0 to 12 with a mean of 4.5 among contaminated carcasses. Chi-square analysis indicated that Salmonella incidence differed (P less than 0.05) among parts with rib back (38.6%) and sacral back (34.3%) being the most contaminated. Among the 40 contaminated carcasses, there were 37 different patterns of contamination among parts. More than one serotype, antibiotic resistant profile and PFGE pattern were observed on 12.1%, 33.3% and 100% of carcasses (n = 33) with more than one contaminated part, respectively. The most common serotype was Typhimurium (94.5%) and most (97.2%) isolates were resistant to multiple antibiotics. These results indicated a diverse pattern of Salmonella contamination among carcasses and that multiple subtypes of Salmonella were often present on contaminated carcasses. Thus, whole carcass incubation followed by subtyping of multiple isolates per carcass is needed to properly assess and manage this risk to public health.