Pathogen Influence on Microbiota of Antimicrobial Treated Chicken Thighs

In order to provide consumers with safe poultry producers, integrators are tasked with implementing further multi-hurdle technology during second processing such as poultry part dips. However, to utilize these interventions properly, it is important to understand the effect these antimicrobials have on key pathogens and the resulting microbiota of poultry parts. Therefore, the objective of this study was to determine the influence of two antimicrobials, peracetic acid (PAA) and acidified sodium chlorite (ASC), on the microbiota of chicken thighs inoculated with Salmonella and Campylobacter. In two independent trials, chicken thighs (N = 360, n = 5, k = 9, 2 time points, 2 inocula, 2 trials) were inoculated with either a cocktail of S. Enteritidis, Heidelberg, Infantis, Kentucky, Typhimurium or a cocktail containing C. jejuni and incubated at 4C for 90 min. Inoculated thighs were independently dipped for 10 s into sterile bags containing 400 mL of the following treatments: Tap water (TW), TW + 800 or 1100 ppm of ASC (pH 2.4 and 2.8), and TW + 200, 350, 500, or 650 ppm of PAA. After treatment, samples were immediately stored at 4C. At 0 and 24 h, thighs were rinsed in 150 mL of nBPW and rinsates were aliquoted for pathogen detection and microbiota analyses. Genomic DNA of rinsates was extracted, and the 16S rDNA was sequenced (Illumina MiSeq platform). Microbiota data was filtered and aligned using the QIIME 2-2020.2 pipeline, with data considered significant at P < 0.05 for main effects and Q < 0.05 for pairwise differences. Both ASC and PAA treatments were effective at reducing inoculated pathogens over both trials (P<0.05) with PAA potentially being more effective on Salmonella and ASC on Campylobacter. There were no differences among Alpha or Beta Diversity metrics during trial 1 and 2 when thighs were inoculated with either Salmonella or Campylobacter. In the Salmonella study, Enterobacteriaceae and Bacillus spp. were significantly different in treatments across time, regardless of trial. In the Campylobacter study, Campylobacter and Bacillus spp. were significantly different among treatments and time, regardless of trial. During Trial 2 of that study, there was a significant relative abundance of Pseudomonas and Proteus spp. Overall, both ASC and PAA were effective at altering the microbiota composition of chicken thighs when inoculated with Salmonella or Campylobacter with the microbiota varying across trials.