Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2017

Analysis of the microbial community structure on poultry carcasses within a processing line using 16s rRNA Illumina MiSeq sequencing (#213)

Stanley H. Chen 1 2 , Narelle Fegan 3 , Chawalit Kocharunchitt 2 , Lesley L. Duffy 1 , John P. Bowman 2
  1. Agriculture & Food, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Coopers Plains, Queensland, Australia
  2. Tasmanian Institute of Agriculture/School of Land and Food, University of Tasmania, Hobart, Tasmania, Australia
  3. Agriculture & Food, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Werribee, Victoria, Australia

    Poultry products are recognised as the main reservoir hosting Campylobacter, which is the leading cause of bacterial-mediated diarrhoea in humans. The population changes of Campylobacter along a poultry processing line by culture techniques are known, but not the changes of the non-culturable microbial community. The aim of the study was to investigate the Campylobacter incidence, overall population and the community structure on samples from before scalding, after air chiller and caecum along the processing line by targeting the V4 region of 16S rRNA and to find out the effect of the current industry pathogen control measures on the entire bacterial population.
    The three most dominant phyla across each sample set were Bacteriodetes, Firmicutes and Proteobacteria, which were 17.3%, 60.1% and 19.5% respectively before scalding; 9.1%, 15.6% and 72.2% after air chiller; 62.3%, 31.2% and 3.8% in the cecum samples. The population of Proteobacteria, which included Campylobacter, Escherichia, Serratia, Klebsiella, Janthinobacterium, and Pseudomonas, increased dramatically after processing, while the Total Viable Counts (TVC) dropped from 6.49 log CFU/ml to 2.94 log CFU/ml. The population of Campylobacter increased from 0.4% to 1.4% after processing, whereas the counts from selective Charcoal-Cefoperazone-Deoxycholate agar (CCDA) declined from 5.03 log CFU/ml to 1.74 log CFU/ml.
    The data showed that the current industry pathogen control measures worked effectively to reduce Bacteriodetes and Firmicutes, but not very well to reduce Proteobacteria, which dominated across all samples. One interesting finding was that the percentage of Pseudomonas increased significantly from 1.2% of samples before scalding to 36.9% after air chilling, which indicated that these bacteria were a primary downstream component of the spoilage community.
    The study offered a preliminary understanding of the microbial population changes on poultry carcasses within a modern processing line. Future investigation will look at a larger sample set with more intensive sampling.