Purpose: The purpose of this study was to identify antimicrobial applications and parameters that best reduce microbial populations on poultry carcasses using in-plant generated data.
Methods: In six poultry processing facilities, antimicrobial solutions were applied during inside-outside bird washing (IOBW), online reprocessing (OLR), hydro-chilling (HC), and post-chiller antimicrobial wash (PCAW) and consisted of acidified sodium chlorite (ASC), buffered sulfuric acid (BSA), chlorine (C), or peroxyacids (PA) that were applied as a topical carcass spray or whole carcass immersion using a dip tank. Before and after each process, bacteria were rinsed from carcasses (1 min, 400 ml Butterfield’s phosphate solution). Rinsates (4 replicates, 7 samples/step/repetition) were neutralized via pH adjustment (6.5-8.0), and analyzed for total aerobic bacterial and Escherichia coli populations. Microbiological data were analyzed by plant using the general linear model of Minitab and means were separated (α=0.05) using Tukey’s honestly significant differences test.
Results: Recovered E. coli populations were numerically fewer than total aerobic bacteria; however, general trends in data were conserved. In all plants, multiple antimicrobial applications lowered (P < 0.05) E. coli population from 1.9-2.3 to <0.0-0.7 log CFU. E. coli populations after OLR tended to be fewer with a dip (ASC, 15 s) application than spray (ASC, BSA; 8 s) application (0.5-0.6 and 0.7-1.4 log CFU, respectively). After HC, results were inconsistent and no clear trends were observed based on antimicrobial agent (C, PA; 1.5 h) or concentration (17-54 ppm). Undetectable levels (< 0.0 log CFU) of E. coli were observed after the PCAW in plants that implemented an immersion style intervention (ASC, BSA; 15 s).
Significance: These data can be used as validation for in-plant application parameters and suggest the best performance of an antimicrobial agent is in a dip-style application for at least 15 s at OLR and PCAW.