Comparison between conventional and qPCR methods for enumerating Campylobacter jejuni in a poultry processing plant

Area of Science:

• Food Microbiology
• Molecular Biology
• Food Safety

Background:

• Campylobacter jejuni is a significant foodborne pathogen commonly found in poultry.
• Its presence in poultry meat preparations and processing environments is not well understood.
• The viable but non-culturable (VBNC) state of C. jejuni poses detection challenges for traditional methods.

Purpose of the Study:

• To compare the efficacy of two primer pairs (rpoB and hipO) for detecting and quantifying Campylobacter jejuni using quantitative PCR (qPCR).
• To assess the prevalence of C. jejuni in poultry processing environments and meat products.
• To evaluate the utility of qPCR as a rapid and sensitive detection method compared to standard culture techniques.

Main Methods:

• Development and validation of qPCR assays targeting the rpoB and hipO genes.
• Preparation of specific calibration curves for meat and environmental samples.
• Application of the Microbial Assessment Scheme (MAS) to identify Critical Sampling Locations (CSLs).
• Comparison of qPCR results with standard culture methods (ISO 10272-1:2006).

Main Results:

• The rpoB primers demonstrated higher sensitivity, with a quantification limit of 1 log cfu/g or ml.
• qPCR detected C. jejuni in 46 out of 48 samples after enrichment, significantly higher than the 6 samples positive by ISO 10272-1:2006.
• A high number of samples (43/48) tested positive by qPCR without enrichment, with 16 quantifiable.

Conclusions:

• Campylobacter jejuni is highly prevalent throughout the poultry industry.
• Quantitative PCR is a rapid, sensitive, and effective method for detecting and quantifying C. jejuni in both meat and environmental samples.
• qPCR is particularly valuable for detecting C. jejuni in its viable but non-culturable state.