Purpose: The purpose of this internal AOAC Performance Tested MethodSM evaluation, conducted at Food Safety Net Services, was to compare the bioMérieux CampyFood Agar (CFA) assay to the USDA/FSIS MLG and ISO reference methods for the detection and the enumeration of Campylobacter in chicken carcass rinses, turkey carcass sponges, raw pork, raw chicken breast, and processed chicken nuggets.
Methods: The comparative food studies consisted of testing chicken carcass rinses, turkey carcass sponges, raw pork, raw chicken breast, and processed chicken nuggets. For the enumeration testing, five replicates of four inoculation levels (uninoculated, 50, 500 and 5,000 CFU/ml or g) for each method and matrix were evaluated for a total of 120 samples. The standard deviation was determined using log-transformed values and a T-test was performed.
For the detection testing, twenty replicates of one inoculation level and five uninoculated controls for each method and matrix were evaluated. Samples were enriched in the proprietary ready-to-use broth, the CFB broth, for 48 hours at 42 °C, before streaking onto the CFA agar. Microaerobic atmosphere was generated using a specific stomacher bag type, the combibag, including a microaerobic generator.
Results: Overall, the CFA method detected 66 positive samples versus 60 for the reference methods. The CFA test methods was equivalent to the USDA method for the detection of Campylobacter in chicken rinsates and turkey swabs and equivalent to the ISO method for the detection of Campylobacter in raw chicken, processed chicken and raw pork, using the chi-square test at 5% level.
Significance: In the PTM validation study the CFA method demonstrated reliability as a rapid method for the isolation, detection and enumeration of Campylobacter in selected foods.