Browsing by Author "Kingsbury JM"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Longitudinal survey investigating vectors and reservoirs for Campylobacter colonization of chickens on a New Zealand broiler poultry farm
    (American Society for Microbiology, 2025-09-17) Kingsbury JM; French N; Midwinter A; Lucas R; Callander M; Hird CP; Smith S; Mulqueen K; Biggs R; Biggs PJ; Ercolini D
    This longitudinal survey followed the life cycle of a New Zealand broiler flock to investigate sources of flock colonization by Campylobacter. Samples were collected at frequent intervals from potential Campylobacter reservoirs and sources, transmission routes for Campylobacter ingress into the broiler shed, and to monitor flock colonization. Of the 738 samples, 200 (27%) tested positive for Campylobacter. Campylobacter species from sample isolates included 316 Campylobacter jejuni, 39 Campylobacter coli, and 8 Campylobacter lari isolates; only C. jejuni was isolated from chickens. C. jejuni isolates (n = 199) were sequenced and consisted of seven sequence types (STs); the most abundant was ST6964 (105 isolates). Most flock isolates were ST6964 (44 isolates) or ST50 (27 isolates). ST6964 isolates closely matched those from the previous flock and another age-matched flock on the same farm, supporting a role for an on-farm reservoir contaminating flocks. There were six STs from catching crew and equipment isolates; the most prevalent were ST6964 (19 isolates) and ST50 (21 isolates). The close genetic match, high Campylobacter prevalence in catching samples (59/130, 45%), and the timing of flock colonization occurring closely following catcher presence in the shed support that catchers and equipment might also contaminate the shed and flock from prior flocks that they visited. There was no evidence for wildlife, feed, drinking water, breeder flock, or shed litter as sources of the Campylobacter genotypes colonizing the flock. Taken together, this study identified key areas where the poultry industry might focus on-farm risk management practices to reduce colonization of broiler flocks by Campylobacter.IMPORTANCECampylobacteriosis is the most frequently notified enteric disease in New Zealand, and New Zealand has one of the highest rates of campylobacteriosis among industrialized countries. Reducing Campylobacter colonization of poultry at the farm level would reduce reliance on processing interventions for reducing Campylobacter contamination of broiler meat. This study aimed to identify on-farm sources of Campylobacter contamination in New Zealand broiler chicken flocks. No evidence was found that wildlife, chicken feed, drinking water, or parent breeder flocks were contaminating sources. Instead, carryover of Campylobacter from the previous flock or other farm flocks, and/or contamination from chicken catching crews and their equipment, may have contributed Campylobacter strains that colonized the study flock. These are key areas where the poultry industry might focus on-farm risk management practices to reduce colonization of broiler flocks by Campylobacter.
  • Thumbnail Image
    Item
    The impact of primary and secondary processing steps on Campylobacter concentrations on chicken carcasses and portions
    (Elsevier Ltd, 2023-04) Kingsbury JM; Horn B; Armstrong B; Midwinter A; Biggs P; Callander M; Mulqueen K; Brooks M; van der Logt P; Biggs R
    Campylobacteriosis is the most commonly notified foodborne disease in New Zealand and poultry meat is the major source for human infection. Carcasses and portions were sampled from key points along primary and secondary processing chains of three New Zealand poultry processors to determine the impact of processing steps on Campylobacter concentrations. Primary processing reduced Campylobacter concentrations on carcasses by almost 6-log; the biggest reduction was achieved by the spinchill, followed by the scald step. Significant plant differences in the degree of Campylobacter reduction were also observed at these steps. The spinchill and final acidified sodium chlorite wash resulted in carcasses with low-to-no levels of Campylobacter regardless of concentrations at prior steps. A similar study was conducted at primary processing for one plant in 2013; significant improvements in Campylobacter mitigation since 2013 were noted. Campylobacter concentrations from final product from secondary processing were higher than concentrations at the end of primary processing. Drumsticks had lower Campylobacter concentrations than other portion types. Skin removal from product did not consistently result in product with lower Campylobacter concentrations. Results identify key areas to target for further reduction of Campylobacter on poultry meat, and provide a benchmark to compare the efficacy of future interventions.
  • Thumbnail Image
    Item
    Validation of a Relative Centrifugal Force method for the enumeration and detection of Campylobacter from chicken carcass rinsates
    (Elsevier B V, 2025-09-01) Kingsbury JM; Midwinter A; Mills J; Englefield M; Biggs R; Perchec Merien A-M; Dermer N; Soni A; Blakemore M
    Campylobacteriosis is the most frequently notified foodborne disease in New Zealand and poultry is the predominant infection source. New Zealand monitors Campylobacter present in poultry carcass rinsates under the National Microbiological Database (NMD) programme. To better monitor Campylobacter control improvements, a more sensitive method is required that can enumerate rinsates with lower Campylobacter numbers. This study developed a modification of the current NMD method involving adding a relative centrifugal force (RCF) step for concentrating Campylobacter from poultry carcass rinsates. Centrifugation for 30 min significantly improved Campylobacter recovery compared with 15 min (p < 0.001), but there were no differences between RCFs of 3500, 4000 and 4430 x g (p = 0.992). RCF and NMD method performances were compared in a single laboratory validation study that used different inoculation levels of twelve Campylobacter strains, including poultry isolates. Campylobacter was detected from more samples (p < 0.001) using the RCF method (93 of 126; 73.8 %) than the NMD method (65 of 126; 51.6 %). The RCF method had a seven-fold lower detection limit (28 colony forming units (CFU)/400 ml) than the NMD method (200 CFU/400 ml). The detection limit accounted for an observed 70.3 % of the inoculated CFU captured within the centrifuged pellet. Campylobacter was also detected from significantly more (p < 0.001) commercial chicken rinsate samples tested by poultry industry laboratories using the RCF method (257 of 863; 29.8 %) than the NMD method (114 of 863; 13.2 %). Taken together, results support the RCF method as a modification of the NMD method to enumerate lower numbers of Campylobacter in rinsates.