https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/720 2026-07-03T18:41:30Z 2026-07-03T18:41:30Z Oh, Hyungsuk Kim, Hyunsook Seo, Kun-Ho https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/213338 2026-06-17T06:00:27Z 2026-09-01T00:00:00Z

Title: Same-day, culture-independent detection of Salmonella in chicken carcass rinsate and feed using immunomagnetic separation, whole-genome amplification, and loop-mediated isothermal amplification Authors: Oh, Hyungsuk; Kim, Hyunsook; Seo, Kun-Ho Abstract: Rapid detection of Salmonella in poultry supply chains is essential for timely risk management; however, culture-based detection methods are constrained by multi-day turnaround times for results. Therefore, we developed a culture-independent workflow combining immunomagnetic separation (IMS), whole-genome amplification (WGA), and loop-mediated isothermal amplification (LAMP) targeting the conserved invA locus to enable same-day detection of Salmonella in chicken carcass rinsate and poultry feed. Fluorescence-based real-time LAMP and phenol red–based colorimetric LAMP were integrated and benchmarked against existing workflows. The IMS–WGA–real-time LAMP detected 10 CFU g−1 of Salmonella enterica serovar Enteritidis ( S. enteritidis ) in spiked carcass rinsate with a 90% detection rate (9/10) and in spiked feed with an 80% detection rate (8/10). Inclusivity and exclusivity testing using 27 Salmonella enterica strains with 23 serotypes and six non- Salmonella strains showed 100% agreement with invA targeting. The entire process, from sample preparation to obtaining results, took approximately 5 h and required minimal equipment. Overall, IMS–WGA–LAMP offers a rapid and sensitive alternative for on-site Salmonella screening in poultry-related matrices.

2026-09-01T00:00:00Z Kwon, So-Yeon Lee, Soo-Ah Kim, Hyunsook Chon, Jungwhan Lee, Jong-Young Seo, Kun-Ho https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/212303 2026-04-22T02:00:10Z 2026-07-01T00:00:00Z

Title: Influence of housing system on antimicrobial resistance and population structure of extended-spectrum beta-lactamase–producing Escherichia coli in South Korean layer farms Authors: Kwon, So-Yeon; Lee, Soo-Ah; Kim, Hyunsook; Chon, Jungwhan; Lee, Jong-Young; Seo, Kun-Ho Abstract: Extended-spectrum β-lactamase (ESBL)–producing Escherichia coli are widespread in poultry production, posing serious public health risks. However, evidence from commercial layer farms—particularly environmental reservoirs—and direct comparisons between cage and floor housing systems remain limited. In this study, we aimed to investigate the prevalence, antimicrobial resistance (AMR) profiles, β-lactamase genotypes, and clonal diversity of ESBL-producing E. coli in floor- and cage-housed layer farms in South Korea to inform AMR risk assessment and control strategies. Eighty ESBL-producing E. coli isolates were recovered from 34 environmental samples collected across six farms (three floor-housed and three cage-housed layer farms). All isolates exhibited high resistance to ampicillin and third-generation cephalosporins, whereas susceptibility to imipenem and amikacin was retained. Resistance to tetracycline (45.2% vs. 15.8%; P = 0.005), chloramphenicol (64.3% vs. 31.6%; P = 0.005), and trimethoprim–sulfamethoxazole (54.8% vs. 18.4%; P = 0.001) was higher among floor-housed than cage-housed isolates, resulting in a higher prevalence of multidrug resistance in floor-housed isolates. Genotypic analysis identified blaCTX-M-14 (27.5%) and blaCTX-M-55 (21.3%) as the most prevalent ESBL genes. Among non-ESBL β-lactamase genes, blaTEM-30 and blaTEM-116 were more frequent in floor-housed isolates, whereas blaTEM-163 predominated in cage-housed isolates. Multilocus sequence typing showed reduced clonal diversity in floor-housed isolates, dominated by ST1718 and ST10, whereas cage-housed isolates displayed broader, more heterogeneous lineages. These findings indicate the association of layer housing systems with differences in AMR burden, β-lactamase allele distribution, and clonal structure of ESBL-producing E. coli, supporting housing-tailored biosecurity and farm-level surveillance to mitigate dissemination in layer production.

2026-07-01T00:00:00Z Oh, Hyungsuk Kim, Hyunsook Seo, Kun-Ho https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/213318 2026-06-17T02:00:19Z 2026-07-01T00:00:00Z

Title: Rapid detection of O157 and major Non-O157 Shiga toxin-producing Escherichia coli serogroups in ground beef, ready-to-eat vegetables, and shredded cheese using VIDAS–WGA real-time PCR after 6-h enrichment Authors: Oh, Hyungsuk; Kim, Hyunsook; Seo, Kun-Ho Abstract: Shiga toxin-producing Escherichia coli (STEC) may occur at trace levels in inhibitor-rich foods, which makes culture-independent PCR screening challenging without prolonged enrichment. To overcome this challenge, we evaluated a rapid workflow that combined 6-h enrichment in buffered peptone water with automated VIDAS immunocapture/DNA extraction, whole-genome amplification (WGA), and real-time PCR for same-day STEC detection in ground beef, ready-to-eat vegetables, and shredded cheese. In matrix-based limit-of-detection testing, WGA improved analytical performance compared with VIDAS real-time PCR alone by enabling earlier amplification, with Ct reductions of 2.76–4.66 cycles across matrix–inoculum combinations in which both methods yielded detectable Ct values. For practical assessment at ultra-low contamination, an AOAC-style fractional probability of detection design was applied using 500-g bulk samples divided into 20 test portions (approximately 0–2 CFU per portion). Across matrices, VIDAS–WGA real-time PCR detected 56 of 58 culture-positive fractions (96.6%) with no false positives and showed near-complete agreement with the reference culture method. The analytical workflow took approximately 10 h, excluding sample preparation, instrument setup, and result interpretation. These findings support VIDAS–WGA real-time PCR as a same-day screening approach for VIDAS-targeted STEC serogroups in tested food matrices, although broader non-O157 validation remains warranted. Copyright

2026-07-01T00:00:00Z Kim, Hyunsook Youn, Hye-Young Kim, Hyeon-Jin Jang, Yong-Seok Chon, Jungwhan Song, Kwang-Young Seo, Kun-Ho https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/211810 2026-03-31T04:31:17Z 2026-06-01T00:00:00Z

Title: Research note: Stage-associated differences in hygiene indicator bacteria from pre-chlorinated water immersion chilling (CWIC) carcasses through CWIC to packaged quail products Authors: Kim, Hyunsook; Youn, Hye-Young; Kim, Hyeon-Jin; Jang, Yong-Seok; Chon, Jungwhan; Song, Kwang-Young; Seo, Kun-Ho 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.

2026-06-01T00:00:00Z