Purpose: This study was to detect the level of Campylobacter contamination during poultry processing and compare the sensitivity of traditional biochemical method with real-time PCR assay for Campylobacter confirmation.
Methods: A survey was conducted in 2012 to estimate Campylobacter prevalence on broiler carcasses and processing environment during two visits to a poultry plant. A total of 73 samples collected at different sites along the processing line were examined by direct plating onto modified Charcoal Cefoperazone Deoxycholate agar (mCCDA) and enrichment in Bolton broth followed by plating onto mCCDA. Isolates were confirmed as members of Campylobacter genus using oxidase biochemical method and a real-time PCR reaction based on 16S rRNA gene.
Results: Our results revealed that 54.8% (40/73) of the analyzed samples were positive for Campylobacter spp. by real-time PCR but all of them were negative when tested by oxidase phenotypic method. All except two samples positive for Campylobacter spp. were C. jejuni. There was a significant difference in Campylobacter contamination between sampling days A and B, with positive rates of 72.7% and 27.6%, respectively. Water and swab samples, pre-scald and pre-evisceration sites on day A, were 100% positive, whereas no campylobacters were isolated from machinery on sampling day B. Processing reduced (P < 0.05) the average concentration of C. jejunifor 1.5 ± 0.4 and <1.0 log CFU/ml on the broiler carcasses post-chilling for days A and B, respectively.
Significance: Our survey revealed the widespread of C. jejuni on poultry carcasses and in poultry processing environment and confirmed that the newly optimized real-time PCR assay was more sensitive than oxidase phenotypic method for Campylobacter isolate confirmation.