Research note: Stage-associated differences in hygiene indicator bacteria from pre-chlorinated water immersion chilling (CWIC) carcasses through CWIC to packaged quail products

Abstract

Commercial processing of quails has been less studied than broiler processing, despite the food safety relevance of hygienic control in poultry slaughter operations. This study characterized hygiene indicator bacteria in quail carcasses pre- and post-chlorinated water immersion chilling (CWIC), in finished packaged products, and in selected processing-environment matrices across three independent trials in a commercial facility. In each trial, whole-carcass rinse samples were collected from pre-CWIC (n = 5) and post-CWIC (n = 5) carcasses, with technical triplicate plating for each carcass. The finished packaged products (n = 15 per trial) and environmental samples (gloves, precooling chamber floor, aspiration inlet opening, wash water, and CWIC water) were also evaluated. Aerobic plate counts (APC), coliforms, and Escherichia coli were enumerated and expressed as log colony forming units (CFU)/mL. Qualitative screening for Salmonella was performed using enrichment. Across trials, CWIC reduced APC; however, the magnitude varied (Trial 1: 2.75–2.28 log CFU/mL; Trial 2: 4.60–2.35 log CFU/mL; and Trial 3: 3.21–3.08 log CFU/mL). Coliforms and E. coli were not detected in Trial 1 carcass-stage samples. Trial 2 showed decreased coliforms post-CWIC, with E. coli not detected in the post-CWIC group. Trial 3 showed detectable coliforms and E. coli both pre- and post-CWIC. In all trials, packaged finished products exhibited higher indicator levels than post-CWIC carcasses, including higher APC (4.05–4.88 log CFU/mL across trials). Gloves consistently showed the highest indicator counts among the environmental matrices, whereas wash water and CWIC water were negative in Trial 1 but showed detectable APC in Trials 2 and 3, indicating variability in process hygiene. Salmonella was not detected in any of the carcass stages, packaged products, or environmental samples tested. Overall, the data identified post-wash handling points and water/disinfectant management as practical targets for verification to improve hygiene consistency during commercial quail processing.