• Korean Journal of Food Science and Technology
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• v.43 no.2
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• pp.161-168
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• 2011

The purpose of this study was to evaluate microbiological contamination of fresh vegetables in Korea. Twenty types of vegetables were tested for total aerobic bacteria, coliforms, Escherichia coli, yeast and mold, and pathogenic bacteria such as Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Salmonella, E. coli O157:H7, Cronobacter sakazakii, Shigella, and Campylobacter. Levels of total aerobic bacteria and coliform on 20 vegetables were between 3.74 and 8.04 log CFU/g, and 0.16 and 5.02 log CFU/g, respectively. The highest contamination levels of total aerobic bacteria were observed on water dropwort, sprouts, mungbean sprout, and ballflower root. There was no significant difference (p>0.05) in microbial contamination levels of total aerobic count, coliform, E. coli, yeast and mold between organic and nonorganic vegetables. When isolation methods using selective agars were applied, L. monocytogenes, B. cereus, Salmonella and Campylobacter were isolated from some fresh vegetable samples. Results of API kit tests showed that L. monocytogenes was identified on Chinese cabbage, cucumber, soybean sprouts, and iceberg lettuce while Salmonella was identified on Korean leek. Furthermore, Campylobacter jejuni was also identified in more than 50 of the 100 samples. However, when positive samples from API kit were tested for real-time PCR or 16S rRNA sequencing method, only B. cereus from perilla leaf, carrot, water dropwort, and sprouts showed positive results. These results indicate that selective agar and API kit detection methods might result in false positive results for some pathogens. Therefore, studies need to improve isolation or confirmation methods for such pathogens.

• Korean Journal of Food Science and Technology
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• v.53 no.5
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• pp.657-668
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• 2021

We prepared the growth and survival models of enterohemorrhagic Escherichia coli (EHEC) and Campylobacter jejuni in milk as a function of temperature and assessed the microbiological risks associated with the consumption of whole milk. EHEC and C. jejuni were not detected in whole milk (n=195) in the retail market. The minimum growth temperature of EHEC in milk was 7℃. The lag time of EHEC in whole milk was longer than that in skim milk. The survival ability of C. jejuni in milk was better at 4℃ than at 10℃. Lower delta values were observed in whole milk than in skim milk, indicating that C. jejuni survived better in skim milk. The probability of foodborne illness from whole milk consumption was 5.70×10^-5 for EHEC and 9.86×10^-9 for C. jejuni. Sensitivity analysis results show that the market temperature of EHEC and the dose-response model of C. jejuni are correlated with the probability of foodborne illness.

• Journal of Food Hygiene and Safety
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• v.33 no.2
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• pp.94-101
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• 2018

Although Kimchi has health benefits, food poisoning associated with consumption of Kimchi has been frequently reported. Accordingly, microbiological properties of Kimchi (100 samples) and washing effects on microbial reduction against its ingredients (200 samples) were examined. Total aerobic bacteria, coliforms, Escherichia coli, Bacillus cereus, and Clostridium perfringens were quantified. In addition, B. cereus, Salmonella spp., Enterohemorrhagic E. coli, C. perfringens, Campylobacter jejuni/coli, Staphylococcus aureus, Vibrio parahaemolyticus, Listeria monocytogenes, and Yersinia enterocolitica were analysed qualitatively. Total aerobic bacteria count was approximately 1.4-9.0 log CFU/g, which were highest in ginger (8.8 log CFU/g), and Chonggak Kimchi (9.0 log CFU/g). The range of coliform counts detected in all raw materials was 0.5-7.3 log CFU/g and ginger showed the greatest number 7.3 log CFU/g among others. Contamination was decreased to 0.2-3.2, 0.3-2.7, and 1.0-3.9 log CFU/g for total aerobic bacteria, coliforms, and B. cereus, respectively, after washing. Minimising microbial contamination in Kimchi ingredients is necessary to ensure the safety of Kimchi. These results indicate that washing is a useful method to reduce bacterial contamination in Kimchi.

• Korean Journal of Microbiology
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• v.41 no.1
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• pp.38-46
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• 2005

To determine the actual hygienic status of domestic chicken meats sold in public markets (conventional markets and department stores), microbial contamination levels (Total cells, Coliforms and Staphylococcal cells) and zoonotic pathogens (Salmonella species, Campylobacter species, Listeria species, and Staphylococcus aureus) isolation tests were conducted. Chicken meats and eggs tested were collected from the conventional markets (Si-Jang) and department-stores located in Seoul and Kyung-gi regions in 1996. In total cells and coliforms contamination tests, chicken meats sold in department stores were much lesser contamination status than those of Si-Jang, but staphylococcal cells level was much more higher than that of conventional markets. Salmonella isolation frequency was investigated as $68.8\%$, but Campylobacter jejuni and Listeria monocytogenes isolation frequency were appeared both $64.0\%\;and\;63.3\%$. In case of eggs sold in public markets, one of S. gallinarum strain $(0.7\%)$ was isolated only on the egg-shell part among the four-hundred and fourty-six. In comparison with foreign imported chicken meats, there were no big differences in microbial contamination status. On the other hand, both Salmonella and L. monocytogenes were isolated only in the chicken wings from Korea and China, but not from U.S.A. This data suggest that more hygienic control system in order to produce the safe and hygienic chicken meats and eggs is need in our country as soon as possible.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.27 no.2
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• pp.95-103
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• 2024

Purpose: Diarrhea is one of the leading causes of mortality in children living in developing countries. The etiology of acute diarrhea in each healthcare center varies depending on place, time, and population. This study aimed to identify pathogen patterns in human immunodeficiency virus (HIV)-infected and non-HIV children suffering from acute diarrhea, using multiplex real time reverse transcriptase polymerase chain reaction (RT-PCR), in an Indonesian tertiary hospital. Methods: This cross-sectional study was conducted at Dr. Cipto Mangunkusumo National Hospital from March 2019 to April 2020. Results: The study showed that multiplex RT-PCR results were positive in 58.9% of the specimens, with more positive results in HIV-infected children than in non-HIV-infected children (70% vs. 54.7%). Altogether 72 enteropathogens were detected from all specimens. Enteropathogens in non-HIV children with acute diarrhea consisted of bacteria (70.6%) and viruses (29.4%) with a predominance of enteroaggregative Escherichia coli (25.4%), followed by Campylobacter spp. (11.8%), enteropathogenic E. coli (9.8%), Norovirus GII (7.8%), and Clostridium difficile (7.8%). Enteropathogens in HIV-infected children consisted of viruses (57.1%), bacteria (28.6%), and parasites (14.3%) comprising Norovirus GII (24%), Cryptosporidium spp. (14.3%), Campylobacter spp. (14.3%), Norovirus GI (14.3%), and Astrovirus (14.3%). Cryptosporidium spp. was the only parasite found in this study and was found only in HIV-infected children. In non-HIV children with acute diarrhea, most pathogens were invasive bacteria, while in HIV-infected children, more viral and parasite infections occurred, primarily caused by opportunistic pathogens. Conclusion: The pattern of enteropathogens can help clinicians determine further examinations and appropriate empirical antimicrobial therapy for the patient.

• Journal of the FoodService Safety
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• v.3 no.2
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• pp.49-58
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• 2022

The objectives of this study were to investigate the behavior characteristics of pathogenic E. coli, Salmonella Typhimurium, Campylobacter jejuni, and Listeria monocytogenes in various kinds of meat (beef, chicken, and pork) and to compare their risk using FDA-iRISK. The growth of S. Typhimurium in chicken and pathogenic E. coli in pork and beef was well supported and posed a high risk. A similar trend was observed in the risk comparison results using the iRISK. When comparing total disability adjusted life years (DALY) per year based on the kinds of meat, chicken was the highest (88.2), followed by pork (58.5) and beef for "yukhoe" (18.8). When comparing scenarios grouped by bacteria, The highest total DALYs per year was observed with pathogenic E. coli (121), followed by S. Typhimurium (44.8) and L. monocytogenes (1.67E-³). These results indicate that the risk of combining meat and foodborne pathogens varies under the same distribution environment. Thus, strict management and supervision are required to store and deliver raw meat to prevent cross-contamination among the raw meats at the processing plant and retail market.

• Food Science and Preservation
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• v.16 no.6
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• pp.965-970
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• 2009

PCR technology has been widely used to detect and quantify microbial pathogens in foodstuffs, because the technique is rapid, sensitive, and selective. In this study, detection of contaminating pathogenic bacteria on shells of chicken eggs was performed using both a commercial multiplex polymerase chain reaction (PCR) kit and a viable count method employing a selective medium. The PCR kit was capable of detecting Campylobacter jejuni, Escherichia coli O157:H7, Staphylococcus aureus, Bacillus cereus, Vibrio parahaemolyticus, Listeria monocytogenes, Yersinia enterocolitica, Salmonella species, and Shigella species. Using the PCR method, five bacterial species were detected from 30 samples (33.3%) of 90 batches of eggs commercially available in a market. PCR products from B. cereus, S. aureus, L. monocytogenes, Y. enterocolitica, and E. coli O157:H7 were detected, and the numbers and frequencies of positive samples were 17 (18.8%), 12 (13.3%), 15 (16.6%), 16 (17.7%),and 4 (4.4%), respectively. None of any Salmonella species, C. jejuni, V. parahaemolyticus, or Shigella species was detected in this study. The results of PCR testing were confirmed using a typical viable count method employing a selective medium. We suggest that the multiplex polymerase chain reaction (mPCR) assay is a rapid and reliable method for detection of pathogenic bacteria contaminating eggs.

• Microbiology and Biotechnology Letters
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• v.36 no.2
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• pp.101-105
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• 2008

In order to obtain yeast cells producing a bacteriocin OR-7, the 180 bp polynucleotide corresponding to the OR-7 gene including codons for start and stop was chemically synthesized and cloned into pAUR123, an yeast expression vector. Transformed yeast cells exhibited growth inhibition of Bacillus subtilis, Campylobacter jeuni, Escherichia coli and Pseudomonas aeruginosa. This result indicates that yeast cells producing OR-7 possess bacteriocidal properties against both Gram positive B. subtilis and Gram negative C. jejuni, E. coli and P. aeruginosa cells. The recombinant yeast strain constructed in this study can be applied in the food preservative or animal feed.

• Journal of Food Hygiene and Safety
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• v.30 no.1
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• pp.1-12
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• 2015

This study was performed to determine risk ranking of the combination of pathogen-livestock or livestock products to identify the most significant public health risks and to prioritize risk management strategies. First, we reviewed foodborne outbreak data related to livestock products and determined main vehicles and pathogens according to the number of outbreak and case. Second, expert's opinion about management priority of pathogen-livestock product pairing was surveyed with 19 livestock experts in the university, research center, and government agency. Lastly, we used the outcome of Risk Ranger (semi-quantitative risk ranking tool) of 14 combinations of pathogen and livestock or livestock products. We have classified the combination of pathogen-livestock products into group I (high risk), II (medium risk), and III (low risk) according to their risk levels and management priority. Group I, which is the highest risk for foodborne outbreak, includes Salmonella spp./egg and egg products, Campylobacter spp./poultry, pathogenic E. coli/meat and processed ground meat. In conclusion, the results of this study will provide the specific guideline of mid- and long-term planning for risk assessment and risk management prioritization of the combination of pathogen and livestock, or livestock product.

• Korean Journal of Veterinary Service
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• v.37 no.2
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• pp.85-96
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• 2014

Total 99 strains of Campylobacter spp. were isolated from 117 cases of duck's fecal samples. Among 99 strains of Campylobacter spp. isolates, 93 strains (93.9%) were C. jejuni and 6 strains (6.1%) were C. coli. Prevalence of virulence and GBS associated genes of 72 C. jejuni isolates was determined by m-PCR. Among the 10 kinds of virulence associated genes, cadF, dnaJ, flaA and ceuE genes were detected in all of C. jejuni isolates from ducks, racR, pldA, iamA, ciaB, virB11 and docC genes were 87.5%, 84.7%, 77.8%, 48.6%, 13.9% and 11.1%, respectively. Antimicrobial susceptibility test was performed on 72 C. jejuni isolates. The rate of resistance were 62.5% for oxytetracycline, 55.6% for kanamycin, 54.2% for enrofloxacin, 50% for ciprofloxacin, 37.5% for tetracycline and nalidixic acid, 18.1% for ampicillin, 15.3% for streptomycin, and 6.9% for ofloxacin. All isolates were susceptible to erythromycin. The adherence (intracellular and extracellular bacteria) abilities of the 20 isolates to INT-407 cells were between $4.21{\pm}1.27{\times}10^4$ CFU/well and $1.053{\pm}0.451{\times}10^6$ CFU/well from the isolates of cj-55 and cj-52, respectively, and that can be expressed as 0.1033% to 5.2655% to the infecting inoculum. The invasion (intracellular bacteria) abilities of the 20 isolates to INT-407 were between $1.00{\pm}1.73{\times}10^3$ CFU/well and $8.47{\pm}5.16{\times}10^4$ CFU/well from the isolates of cj-13 and cj-47, respectively, and that can be expressed as 0.0050% to 0.4235% to the infecting inoculums. The average CFU/well of 20 campylobacters isolated from ducks for adherence to and invasion were $2.646{\pm}2.886{\times}10^5$ and $3.03{\pm}2.7{\times}10^4$ respectively, and that was $1.3230{\pm}1.2139%$ and $0.1516{\pm}0.1343%$ of the starting viable inoculum. There was considerable correlation ($R^2$=0.627) between the adherence and invasion ability of C. jejuni isolates for INT-407 cell.