• Food Science and Biotechnology
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• v.17 no.3
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• pp.483-488
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• 2008

Foodborne pathogenic bacteria in various food samples in Korea were monitored and the obtained data was statistically analyzed. A total of 1,240 food samples including 280 sashimi, 244 processed frozen products, 258 kimbab (cooked rice wrapped with seaweed), 337 soybean pastes were obtained from 7 cities including Seoul in Korea. Microorganisms tested were Bacillus cereus, Salmonella spp., Staphylococcus aureus, Escherichia coli, E. coli O157:H7, Vibrio parahaemolyticus, Yersinia enterocolitica, Listeria monocytogenes, Campylobacter jejuni, and Clostridium perfringens. The contaminated microorganisms in food samples were comprised of 10.55% B. cereus, 2.7% S. aureus, 2.0% V. parahaemolyticus, 0.8% C. perfringens, 0.2% Y. enterocolitica, and 0.1% of L. monocytogenes, respectively. Salmonella spp., C. jejuni, and E. coli O157:H7 were not detected in any of the food samples. Particularly, B. cereus that harbors the enterotoxin gene was detected in various foods and regions in Korea, therefore it should be a given special consideration not to allow the hazardous level of contamination.

• Korean Journal of Food Science and Technology
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• v.48 no.2
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• pp.128-132
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• 2016

In this study, polyethylene glycol (PEG) was used to improve DNA amplification efficiency during whole genome amplification (WGA). Amplification efficiency was determined by adding PEG with different molecular weights to the WGA reaction. The greatest increase in amplification efficiency was obtained with PEG 4,000 used at 1.5% concentration. Foodborne pathogenic DNA was amplified by WGA and quantitatively analyzed by real-time polymerase chain reaction. DNA of Salmonella serotype Typhimurium, Listeria monocytogenes, and Vibrio parahaemolyticus was amplified 7,777.01, 9,981.22, and 1,239.03 fold, respectively, by WGA. On adding PEG in the WGA reaction (i.e., enhanced WGA [eWGA]), 18-40-fold more DNA amplification was achieved. Thus, these analyses showed that foodborne pathogens, which are usually present at very low concentration in foods, can be detected by real-time PCR and WGA.

• Journal of Food Hygiene and Safety
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• v.34 no.6
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• pp.557-561
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• 2019

This study investigated the efficacy of DNA extraction methods for real-time PCR detection of foodborne pathogenic bacteria in livestock manure composts. Livestock manure composts were inoculated with Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, Bacillus cereus and incubated in enrichment broth. For DNA extraction, enriched samples were treated following boiling method, by chloroform, C₁₈ powder, and proteinase K. As a result, 4 species of bacteria were detected by real-time PCR when subjected to boiling for 30 min and treated with proteinase K. These results suggest that detection of foodborne pathogens by real-time PCR from livestock manure composts could be applicable using effective DNA extraction methodology such as the boiling method or proteinase K.

• Korean Journal of Plant Resources
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• v.23 no.5
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• pp.430-435
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• 2010

This study was performed to investigate the antimicrobial effects of Ampelopsis brevipedunculata ethanol-extract on food spoilage or foodborne disease microorganism. The antimicrobial activity of Ampelopsis brevipedunculata extract was determined by a paper disc method. The extract exhibited growth inhibiting activities in a concentration dependent manner on 7 species of microorganisms. The extract of Ampelopsis brevipedunculata showed the highest antimicrobial activity against Escherichia coli O157:H7. The growth inhibitory effects of the extract at the concentration of 250, 500, 1,000, 2,000 mg/L on food poisoning microorganism were determined against Salmonella typhimurium, Yersinia enterocolitica, Escherichia coli O157:H7 and Staphylococcus aureus. The growth of microorganisms was not affected by the extract at the concentration up to 250 mg/L, but was significantly (p<0.05) inhibited by the extract at the concentration higher than 500 mg/L. The results in the present study demonstrate antimicrobial effects of Ampelopsis brevipedunculata ethanol-extract against foodborne pathogens, suggesting that Ampelopsis brevipedunculata could be an effective natural antibacterial agent in food.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.8
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• pp.1227-1232
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• 2016

Electrolyzed activated water (EAW) has been reported to exhibit strong bactericidal effects on foodborne microorganisms. However, the disinfection efficacy of EAW is affected by factors such as water source and hardness. This study investigated bactericidal effects of EAW against three gram-positive (Bacillus cereus, Listeria monocytogenes, and Staphylococcus aureus) and three gram-negative (Cronobacter sakazakii, Escherichia coli O157:H7, and Salmonella Enteritidis) foodborne pathogens. Six strains were treated with EAW prepared at different water temperatures (4, 22, and $40^{\circ}C$) for 15 min, and D-values were generated. The results show that the lowest D-values for Lis. monocytogenes by EAW produced at $4^{\circ}C$ and $40^{\circ}C$ were 6.60 and 1.57 min, respectively. The lowest D-value for Sal. Enteritidis by EAW produced at $22^{\circ}C$ was 2.92 min. D-values of all strains treated by EAW produced at $40^{\circ}C$ decreased significantly compared to those treated by EAW produced at $4^{\circ}C$ (P<0.05). These results demonstrate that applying EAW produced at warm temperature is more effective for reducing foodborne pathogens for food safety.

• Korean Journal of Food Science and Technology
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• v.48 no.5
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• pp.437-444
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• 2016

Rapid and reliable identification of microorganisms is important to maintain food quality and to control safety. MALDI-TOF MS-based identification methods are relatively fast and simple compared to other conventional methods including gram staining and biochemical characterization. A colony on subcultured media can be directly prepared on the analysis plate without further complex treatments. In this study, we confirmed the applicability of MALDI-TOF MS-based identification of foodborne pathogens such as Salmonella Enteritidis/Typhimurium, Staphylococcus aureus, Vibrio parahaemolyticus, Clostridium perfringens, Listeria monocytogenes, Yersinia enterocolitica, Bacillus cereus, Campylobacter jejuni, Campylobacter coli, and Cronobacter sakazakii on the Korea Food Standard Codex. MALDI-TOF MS data of the pathogenic reference strains were incorporated into a commercial MicroID (ASTA Inc.) database. Other pathogenic reference strains and seven isolates from various food samples were correctly identified to the species level by using the MicroID database. In conclusion, MALDI-TOF MS is comparable with commercial biochemical identification.

• Korean Journal of Environmental Agriculture
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• v.39 no.4
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• pp.343-351
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• 2020

BACKGROUND: Irrigation water is known to be one of the major sources of bacterial contamination in agricultural products. In addition, anti-microbial resistance (AMR) bacteria in food products possess serious threat to humans. This study was aimed at investigating the prevalence of foodborne bacteria in irrigation water and evaluating their anti-microbial susceptibility. METHODS AND RESULTS: Surface water (n = 66 sites) and groundwater (n = 40 sites) samples were collected from the Gyeongi and Gangwon provinces of South Korea during April, July, and October 2019. To evaluate the safety of water, fecal indicators (Escherichia coli) and foodborne pathogens (E. coli O157:H7, Salmonella spp., and Listeria monocytogenes) were examined. E. coli isolates from water were further tested for antimicrobial susceptibility using VITEK2 system. Overall, detection rate of foodborne pathogens in July was highest among three months. The prevalence of pathogenic E. coli (24%), Salmonella (3%), and L. monocytogenes (3%) was higher in surface water, while only one ground water site was contained with pathogenic E. coli (2.5%). Of the 343 E. coli isolates, 22.7% isolates were resistant to one or more antimicrobials (ampicillin (18.7%), trimethoprim-sulfamethoxazole (7.0%), and ciprofloxacin (6.7%)). CONCLUSION: To enhance the safety of agricultural products, it is necessary to frequently monitor the microbial quality of water.

• Journal of Environmental Health Sciences
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• v.48 no.3
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• pp.176-182
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• 2022

Background: The risk of imported infectious diseases has been increasing with the annual rise in the number of international travelers. Objectives: This study aims to analyze the distribution and characteristics of intestinal bacteria isolated in 2019 from residents of Chungcheongnam-do Province with experience of travelling overseas. Methods: Twenty-three former overseas travelers with diarrhea were analyzed to detect viruses and bacteria according to the Manual for Detection of Foodborne Pathogens at Outbreaks. Additionally, antibiotic susceptibility tests and 16s rRNA sequencing were performed. Results: Twenty-five strains of ten pathogens were isolated from 18 samples. Pathogenic E. coli was the most common at 57.7%, followed by Clostridium perfringens (15.4%), Campylobacter spp. (7.7%), and Salmonella spp. (7.7%). The serotype of Salmonella was confirmed as Salmonella Braenderup, II 9,46:g,[m],[s],t:[e,n,x]. Conclusions: It was confirmed that the major enteric bacterial pathogens isolated from overseas travelers in Chungcheongnam-do Province were pathogenic E. coli, as found in other studies. The study on Plesiomonas shigelloides is meaningful in that it is reported as a rare case of infection in Korea. Antibiotic resistance and 16s rRNA analysis were performed, which is expected to provide important basic data for the prevention of traveler's diarrhea.

• Journal of Food Hygiene and Safety
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• v.22 no.4
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• pp.388-394
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• 2007

This study was conducted to evaluate the selective media listed in currently available Food Code in Korea. The 29 different types of media of five different types of foodborne bacteria including Salmonella spp., Bacillus cereus, Listeria monocytogenes, Vibrio parahaemolyticus, Staphylococcus aureus were tested in the broth and food. The recovery test for five different types of foodborne bacteria was performed in the artificially inoculated into chicken, rice, pork and mackerel. There was no significant differences in isolation capabilities among twenty nine different types of isolation selective media for five different types of foodborne bacteria in broth condition, while there was significantly a little differences in isolation capabilities among those on foods (P<0.05). The higher number of foodborne pathogens were isolated from conventional selective media approved in Food Code than newly developed selective media such as chromogenic media. This results suggest that there was differences of selectivities among currently available isolation selective media in many countries and further studies are needed to be approved by Korean Food and Drug Administration.

• Journal of Food Hygiene and Safety
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• v.26 no.4
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• pp.336-341
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• 2011

This study was carried out to investigate efficacy of aerosol sanitizer with natural antimicrobial and organic acids against Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes. The artificially inoculated pathogens on stainless steel coupon were treated with grapefruit seed extract (GFE), acetic acid, citric acid and lactic acid in model cabinet for 5 min. The number of three foodborne pathogens with individual treatment was reduced by 0.34-3.77 log units, treatment with GEF + organic acid was reduced by 1.72-3.89 log units and treatment with GEF + organic acid + alcohol was reduced by 1.46-5.05 log units. By treatment with GEF + lactic acid + alcohol in scale-up model system for 10 min. Populations of E. coli O157:H7, S. Typhimurium and L. monocytogenes were reduced by 3.42, 2.72 and 2.30 log units from the untreated control respectively. From the above result, aerosol sanitizer with natural antimicrobial agents and organic acid can be used as an environmental sanitation method with satisfying the consumer demand on safe food.