Tuning the Bloodhound® VOC Analyzer to Detect Campylobacter during Broiler Poultry Production

Introduction: The broiler commensal Campylobacter is estimated to cause >280,000 human disease cases annually in the United Kingdom via consumption of undercooked contaminated meat or through cross-contamination during food preparation. Detecting the presence of Campylobacter in broiler flocks preslaughter is one of many approaches suggested to reduce its prevalence on processed broiler meat, but industry adoption of farm-level testing has been limited due to the absence of a real-time, on-site monitoring method.

Purpose: This study optimized the detection of Campylobacter spp. by the Bloodhound^®VOC Analyzer based on volatile organic compounds (VOCs) produced.

Methods: Thirteen Campylobacter (Campylobacter jejuni, Campylobacter coli, Campylobacter lari, and Campylobacter upsaliensis) and 12 nonCampylobacter isolates (including Salmonella spp., Listeria monocytogenes, Arcobacter spp. and Bacteriodes fragilis) were cultured on CBA at 37°C for 24 to 48 h under appropriate atmospheric gas conditions. Culture plates were heat sealed in polyethylene sachets inflated with clean air. Lids were removed allowing the VOCs to equilibrate in the headspace before sampling (n=12 per isolate). This was repeated following sensor tuning. Linear Discriminant Analysis was used to process the raw data.

Results: Tuning of the Bloodhound^® sensors improved the detection of Campylobacter spp. within a shorter time period. Prior to sensor tuning, all 48 h old Campylobacter spp. cultures were successfully detected and differentiated from control and nontarget culture plates with Mahalanobis distances ranging from 405 to 652. Sensor tuning increased the Mahalanobis distances to between 13,510 and 17,391. This improvement enabled differentiation of Campylobacter spp. Sensor tuning also effected earlier detection of C. jejuni by increasing the sensitivity of the sensors 21 times for the 24 h culture and 158 times for the 48 h culture.

Significance: Applying tuned sensors to an on-farm monitoring system will improve the speed and reliability of Campylobacter detection, which will promote better control via flock management.