Prevalence and characterization of foodborne bacteria from meat products in Korea

Integrating meta-analysis with a quantitative microbial risk assessment model to investigate Campylobacter contamination of broiler carcasses

This study investigated the prevalence and associated risk factors of Campylobacter in South Korean broilers using a random-effects meta-analysis. Subsequently, to facilitate the design of preventive measures, the prevalence estimate from the meta-analysis was incorporated into a stochastic risk assessment model to quantify the Campylobacter contamination levels on broiler carcasses. The baseline model was developed based on the most common practices along the South Korean broiler processing line, with no interventions. Meta-analysis results revealed Campylobacter prevalence across the chicken supply chain in the following order: farms (60.6 % [57.3-63.4]), retail markets (43.90 % [24.81-64.99]), slaughterhouses (27.71 % [18.56-39.21]), and processing plants (14.50 % [3.96-41.09]). The model estimated a 52 % (36.1-70.8) Campylobacter prevalence at the end of chilling, with an average contamination level of 4.62 (2.50-6.74) log CFU/carcass. Sensitivity analysis indicated that Campylobacter fecal shedding (r = 0.95) and the amount of feces on bird exteriors (r = 0.17) at pre-harvest were the main factors for carcass contamination, while soft scalding (r = -0.22) and air chilling (r = -0.12) can serve as critical control points (CCPs) at harvest. Scenario analysis indicated that a combination of hard scalding, inside-outside bird washing, spray washing, and chlorinated water immersion chilling can offer a 30.9 % reduction in prevalence and a reduction of 2.23 log CFU/carcass in contamination levels compared to the baseline model. Apart from disinfection and sanitation interventions carried out during meat processing, the implementation of robust control measures is indispensable to mitigate Campylobacter prevalence and concentration at broiler farms, thereby enhancing meat safety and public health. Furthermore, given the high Campylobacter prevalence in the retail markets, future studies should explore the potential risk of cross-contamination at post-harvest stage.

Bacterial profile of pork from production to retail based on high-throughput sequencing

Pork is a common vehicle for foodborne pathogens, including Salmonella spp. and Yersinia enterocolitica. Cross-contamination can occur at any stage of the pork production chain, from farm to market. In the present study, high-throughput sequencing was used to characterize bacterial profiles and track their changes along the whole supply chain. Tracked meat samples (pig on the farm, carcass in the slaughterhouse, unprocessed carcass and processed meat in the processing plant, and fresh pork at the local retail stores) and their associated environmental samples (e.g., water, floor, feed, feces, and workers' gloves) were collected from sequential stages (n = 96) and subjected to 16S rRNA metataxonomic analyses. At the farm, a total of 652 genera and 146 exclusive genera were identified in animal and environmental samples (pig, drain, floor, fan, and feces). Based on beta diversity analysis, it was demonstrated that the microbial composition of animal samples collected at the same processing step is similar to that of environmental samples (e.g., drain, fan, feces, feed, floor, gloves, knives, tables, and water). All animal and environmental samples from the slaughterhouse were dominated by Acinetobacter (55.37 %). At the processing plant, belly meat and neck meat samples were dominated by Psychrobacter (55.49 %). At the retail level, key bacterial players, which are potential problematic bacteria and important members with a high relative abundance in the samples, included Acinetobacter (8.13 %), Pseudomonas (6.27 %), and Staphylococcus (2.13 %). In addition, the number of confirmed genera varied by more than twice that identified in the processing plant. Source tracking was performed to identify bacterial contamination routes in pork processing. Animal samples, including the processing plant's carcass, the pig from the farm, and the unwashed carcass from the slaughterhouse (77.45 %), along with the processing plant's gloves (5.71 %), were the primary bacterial sources in the final product. The present study provides in-depth knowledge about the bacterial players and contamination points within the pork production chain. Effective control measures are needed to control pathogens and major pollutants at each stage of pork production to improve food safety.

Systematic Review and Meta-Analysis of Campylobacter Species Contamination in Poultry, Meat, and Processing Environments in South Korea

Campylobacter spp. constitute a significant global threat as a leading cause of foodborne illnesses, with poultry meat as a prominent reservoir for these pathogens. South Korea is known for its diverse poultry consumption habits, and continuous outbreaks make it a matter of concern to perform a meta-analysis to identify the primary source of contamination. This systematic review and meta-analysis aimed to assess and compare the prevalence of Campylobacter in various poultry and meat types while also considering the importance of environmental factors in South Korea. The meta-analysis revealed that duck meat exhibited the highest prevalence of Campylobacter, with a pooled estimate of 70.46% (95% CI: 42.80% to 88.38%), followed by chicken meat at a pooled prevalence of 36.17% (95% CI: 26.44% to 47.91%). Additionally, our analysis highlighted the predominance of C. jejuni and C. coli in South Korea. These findings underscore the importance of implementing rigorous food safety measures and establishing robust surveillance programs in the poultry industry to mitigate the risk of Campylobacter-related foodborne illnesses associated with meat consumption in South Korea.

Identification of risk profiles for Salmonella prevalence in pig supply chains in South Korea using meta-analysis and a quantitative microbial risk assessment model

International travel and the globalization of food supplies have increased the risk of epidemic foodborne infections. Salmonella strains, particularly non-typhoidal Salmonella (NTS), are major zoonotic pathogens responsible for gastrointestinal diseases worldwide. In this study, the prevalence and Salmonella contamination in pigs/carcasses throughout the South Korean pig supply chain and the associated risk factors were evaluated using Systematic reviews and meta-analyses (SRMA), and quantitative microbial risk assessment (QMRA). The prevalence of Salmonella in finishing pigs, which is one of the major starting inputs of the QMRA model was calculated through SRMA of studies conducted in south Korea in order to complement and enhance the robustness of the model. Our findings revealed that the pooled Salmonella prevalence in pigs was 4.15% with a 95% confidence interval (CI) of 2.56 to 6.66%. Considering the pig supply chain, the highest prevalence was detected in slaughterhouses (6.27% [95% CI: 3.36; 11.37]), followed by farms (4.16% [95% CI: 2.32; 7.35]) and meat stores (1.21% [95% CI: 0.42; 3.46]). The QMRA model predicted a 3.9% likelihood of Salmonella-free carcasses and a 96.1% probability of Salmonella-positive carcasses at the end of slaughter, with an average Salmonella concentration of 6.38 log CFU/carcass (95% CI: 5.17; 7.28). This corresponds to an average contamination of 1.23 log CFU/g (95% CI: 0.37; 2.48) of pork meat. Across the pig supply chain, the highest Salmonella contamination was predicted after transport and lairage, with an average concentration of 8 log CFU/pig (95% CI: 7.15; 8.42). Sensitivity analysis indicated that Salmonella fecal shedding (r = 0.68) and Salmonella prevalence in finishing pigs (r = 0.39) at pre-harvest were the most significant factors associated with Salmonella contamination in pork carcasses. Although disinfection and sanitation interventions along the slaughter line can reduce contamination levels to some extent, effective measures should be taken to reduce Salmonella prevalence at the farm level to improve the safety of pork consumption.

Prevalence of Escherichia coli generic and pathogenic in pork meat: systematic review and meta-analysis

This research aimed to analyze scientific information regarding the prevalence of generic and pathogenic E. coli in the production and supply chain of pork meat, considering different types of samples, places of sampling, and pathotypes using a systematic review and meta-analysis tools. The meta-analysis for the prevalence of generic and pathogenic E. coli was conducted by estimating the effects within subgroups. Data subsets were analyzed using the DerSimonian-Laird method for binary random effects. The average prevalence of generic E. coli in different types of pork meat samples was determined to be 35.6% (95% CI 19.3-51.8), with no significant differences observed between pork meat and carcasses. Conversely, the average prevalence of E. coli pathotypes in samples related to the supply chain of pork meat was found to be 4.7% (95% CI 3.7-5.7). In conclusion, these findings suggest the possibility of establishing an objective threshold for E. coli prevalence as a benchmark for comparison within the meat industry. By utilizing this data, it becomes possible to propose a standardized limit that can serve as a reference point for evaluating and improving processes in the industry.

Characterization of Toxin Genes and Antimicrobial Susceptibility of Staphylococcus aureus from Retail Raw Chicken Meat

The aim of this study was to investigate the toxin gene profile and antimicrobial resistance of Staphylococcus aureus isolates from raw chicken in the People's Republic of China. In total, 289 S. aureus isolates were characterized by antimicrobial susceptibility testing, and genes encoding enterotoxins, exfoliative toxins, Panton-Valentine leukocidin, and toxic shock syndrome toxin were revealed by PCR. Overall, 46.0% of the isolates were positive for one or more toxin genes. A high proportion of toxin genes were pvl (26.6%), followed by sej (12.5%), sea (9.0%), seh (8.3%), seb (6.9%), sec (6.9%), sed (4.8%), sei (3.1%), and see (2.4%). None of the isolates harbored seg, tsst-1, or exfoliative toxin genes. In total, 29 toxin gene profiles were obtained, and pvl (10.7%) was the most frequent genotype, followed by sea (5.9%), seb (4.8%), and sej (4.2%). Furthermore, 99.7% of the strains were resistant to at least one of the tested antimicrobial agents, and 87.2% of them displayed multidrug resistance. Resistance was most frequently observed to trimethoprim-sulfamethoxazole and erythromycin (86.2% for each), followed by tetracycline (69.9%), amoxicillin-clavulanic acid (45.0%), and ampicillin (42.6%). None of the strains were resistant to vancomycin. This study indicates that S. aureus isolates from raw chicken harbored multiple toxin genes and exhibited multiple antimicrobial resistance, which represents a potential health hazard for consumers.