• Korean Journal of Food Science and Technology
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• v.38 no.5
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• pp.699-706
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• 2006

The antioxidative and antimicrobial activities of Euphorbia jolkini extracts were investigated. Total polyphenohc compounds extracted were approximately as follows: 162.08 mg/g from ethanol, 12.64 mg/g from n-hexane, 48.11 mg/g from dichloromethane, 544.08 mg/g from ethyl acetate, 176.42 mg/g from butanol, and 30.00 mg/g from water. The ethylacetate fraction of this extraction showed the highest antioxidative activity $(IC_{50})$: DPPH radical scavenging capacity was measured at $8.38\;{\mu}g/mL$, xanthine oxidase inhibitory activity was $466.01\;{\mu}g/mL$, superoxide radical scavenging capacity was $11.39\;{\mu}g/mL$, and nitric oxide scavenging capacity was $332.11\;{\mu}g/mL$. Antimicrobial activities were determined by paper disc method and minimum inhibitory concentration of E. jolkini extracts against food-borne pathogens and spoilage bacteria. The growth inhibition curves of E. jolkini extracts against Bacillus cereus, Listeria monocytogenes, and Escherichia coli were also determined. These results suggest that the ethylacetate fraction of E. jolkini has strong antimicrobial activity against the all species of microorganisms as well as strong antioxidant activity.

• Journal of Food Hygiene and Safety
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• v.28 no.2
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• pp.138-145
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• 2013

This study was conducted to evaluate the microbiological contamination on commonly used hand towels in the child care centers and to investigate the toxin gene and toxin production ability of food-borne pathogens. A total of 22 commonly used hand towels including 7 for before use and 15 for during use were tested. The average number of total aerobic bacteria and fungi were 6.2 log CFU/100 $cm^2$ and 4.1 log CFU/100 $cm^2$. Coliform bacteria were detected in 4 out of 7 before used towels (57.1%) and all of during used towels (100%). These results showed that the sanitary conditions of hand towels in the child care centers should be improved promptly. Among the pathogenic bacteria, Staph. aureus and B. cereus without Salmonella spp. were detected in 5 (22.7%) and 11 (50.0%) out of 22 hand towels. All of Staphy. aureus isolated in this study did not possess any toxin genes and did not produce enterotoxin. The detection rate of hblC, hblD, and hblA toxin genes in B. cereus was 72.7, 72.7, and 54.5% respectively. The possession rate of nheA, nheB, and nheC toxin genes showed 81.8, 72.7, and 54.5% respectively. The cytK and entFM toxin genes were presented at 45.5 and 90.0% in B. cereus. The HBL was detected in 8 out of 11 B. cereus isolates (72.7%) and 5 B. cereus isolates produced NHE (45.5%). Ten out of eleven B. cereus isolates (90.9%) produced one or more enterotoxin such as HBL and NHE. From the results, using a private hand towel or paper towel is required to prevent the cross-contamination between commonly used hand towel and children's hands in the child care center.

• Journal of Food Hygiene and Safety
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• v.35 no.4
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• pp.319-325
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• 2020

Widespread consumption of fresh-cut vegetables without cooking results in ingestion of major foodborne pathogens including Bacillus cereus. In this study, we aimed to develop a method to rapidly detect B. cereus in fresh-cut vegetables by combining commercial PCR analysis with enrichment of the pathogenic levels. A mixture of B. cereus strains (KCTC1013, KCTC1014, KCTC1092, KCTC1094, and KCTC3624) was inoculated on the surface of fresh-cut cabbage lettuce (20 g) and baby leafy vegetables (10 g) to concentration 1, 2, 3, 4, and 5 log CFU/g. Eighty milliliters of TSB with 0.15% polymyxin B was used for cabbage lettuce, and 90 mL of medium was used for baby leafy vegetables and incubated at 42℃ for 0, 2, 3, 4, 5, 6, and 7 h. One milliliter of the enriched media was plated on mannitol-egg yolk-polymyxin agar for quantification, and another 1 mL was used for DNA extraction for PCR analysis. Additionally, the minimum number of sub-samples to be tested from a pack of fresh-cut vegetable samples was determined using 5 sub-samples. The results from this study showed that for detecting B. cereus in fresh-cut cabbage lettuce, 3, 4, 5, 6, and 7 h enrichment were required to at least detect 5, 4, 3, 2, and 1 log CFU/g of B. cereus, respectively. B. cereus in fresh-cut baby leafy vegetables could be detected after 2, 3, 4, 5, and 6 h of enrichment at 5, 4, 3, 2, and 1 log CFU/g, respectively, using a combination of enrichment and PCR analysis. To determine if a pack of fresh-cut vegetable is positive, the minimum number of sub-samples should be 3. These results can be used to develop a rapid detection method to semi-quantify B. cereus in fresh-cut vegetable samples combining enrichment and PCR.

• Korean Journal of Food Science and Technology
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• v.41 no.4
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• pp.392-398
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• 2009

This study identified risk factors of cross-contamination of foodborne pathogens and established a good agricultural practice (GAP) system for an agricultural products processing center (APC) for perilla leaves. All samples were collected before and after a standard work shift at the APC, while perilla leaves were also collected after each step in the APC. In addition, the workers and their surroundings were sampled by swabbing. The total plate count (TPC) and coliform count in the water samples increased significantly (p<0.05) to 3.36 and 1.73 log CFU/mL after work, respectively. However, no Escherichia coli and Listeria monocytogenes were detected. The bacterial populations of the workers and their surroundings did not differ significantly (p${\geq}$0.05) before and after work. However, Staphylococcus aureus (<1.66 log CFU) was detected at a high rate (13-50%) in the basket, packing table, gloves and cloth. Although perilla leaves passed through the washing steps, the TPC and coliform bacterial populations on the final products were higher (p${\geq}$0.05) than those of unwashed perilla leaves, which indicates that the washing system was not functioning properly. Accordingly, a GAP system with a better washing system should be employed at this facility.

• Journal of Life Science
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• v.21 no.10
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• pp.1428-1433
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• 2011

In this study, we isolated and characterized plant-associated lactic acid bacteria which are able to produce angiotensin-converting enzyme (ACE) inhibitory and antioxidative activities. Five lactic acid bacteria were isolated from plants (grape and leek), a plant-associated fermentative product (Kimchi) and Korean traditional alcohol (Dongdongju). Strains K-1 and K-21 from Kimchi, strain L-5 from leek, strain G-3 from grape, and strain D-3 from Dongdongju were identified as Pediococcus pentosaceus, Lactobacillus plantarum, Weissella cibaria, L. plantarum, and L. brevis, respectively, by 16S rRNA gene analysis. ACE inhibitory activities of isolated strains ranged from 44.3 to 71.9% in the MRS broth. G-3, L-5 and K-1 strains especially showed high ACE inhibitory activities (59.8-98.69%) in the MRS broth containing skim milk. DPPH radical scavenging activities of the strains were in the range of 42.5-82.7%. All strains showed varying levels of resistance in artificial gastric fluid (pH 2.5), retaining viability ranging from 42.2 to 88.1% after 3 hr of incubation. All strains showed high resistance to 0.3% oxgall after 24 hr of incubation; survival rates were in the range of 55.4-112.8%. Isolated strains were found to be antagonistic to some pathogens including Pseudomonas aeruginosa.

• Journal of Life Science
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• v.24 no.11
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• pp.1231-1237
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• 2014

The objective of this study was to evaluate the safety and functional properties of four potential probiotic strains isolated from Kimchi, traditional Korean fermented vegetables. Based on being higher tolerance to bile salts and showing higher acid resistance or hydrophobic properties, one Lactobacillus arizonensis strain (BCNU 9032) and three L. brevis strains (BCNU 9037, BCNU 9098 and BCNU 9101) were selected in the screening experiment. All strains can survived up to 99% after 3h culture in pH 2.5 and resistant to 1% bile salts. These strains also showed good antimicrobial activities against a number of food borne pathogens, especially against Escherichia coli and Shigella sonnei. The ability to lower cholesterol levels of L. arizonensis BCNU 9032 and L. brevis 9037 were demonstrated by bile salt hydrolytic activity and cholesterol assimilation tests. Moreover, L. brevis BCNU 9098 and BCNU 9101 showed higher adherence to Caco-2 cells (12.76 and 11.86%, respectively) than Lactobacillus rhamnosus GG, a commercial probiotic strain used worldwide. The results suggest that these strains could be used as probiotics.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.3
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• pp.256-262
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• 2017

Essential oil from herb is known to exert pharmacological effects on the human body. In this study we investigated the antibacterial activity of 4 essential oils (teetree, rosemary, melisa, and lavender), as well as the blended mixture oil of teetree, rosemary, and melisa (TRM) on three bacteria, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Antibacterial analysis was performed using the standard disk diffusion method, and minimum inhibition concentration was determined by the broth microdilution method with different concentrations of essential oils (0.5, 1, 2 and 3 mg/mL). After incubation at $37^{\circ}C$ for 24 h, the antibacterial activity was assessed by measuring the zone of growth inhibition surrounding the disks. Herb oil with the inhibition zones showed varied values ranging from6 to 25 mm. However, the components of herb oil of TRM are as highly active as the teetree oil against pathogens, generating large inhibition zones for both gram negative and positive bacteria (13~22 mm and 8 mm inhibition zones). In the analysis for MIC, TRM showed growth-inhibitory effects at 0.0625% for S. aureus and E. coli, and 1.25% for P. aeruginosa. This result demonstrated that the anti-microbial activity of TRM was greater than a single herb oil, including oxacillin, rosemary, and teetrea. As a single herb oil, both rosemary and teetrea also had an anti-microbial effect by itself, and we can expect that the blended oil mixture may exert a synergistic effect against multidrug resistant bacteria, suggesting its future application in natural preservative agents for health food and cosmetics.

• Pediatric Infection and Vaccine
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• v.4 no.1
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• pp.73-78
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• 1997

Purpose : Escherichia coli O157 can produce diarrhea as well as hemorrhagic colitis and hemolytic uremic syndrome. In many parts of North America, E. coli O157 often is the second or third most commonly isolated enteric bacterial pathogens. Recently, intakes of fast food, including hamburgers have increased in Korea. Therefore, E. coli O157 infection in Korea are likely to be increased. Methods : Stool samples from 317 pediatric diarrheal patients were analyzed by culture on sorbitol-MacConkey agar. Sorbitol-negative colonies were teated by E. coli O157 latex agglutination test. Results : Of the 317 specimens, one (0.3%) were E. coli O157:NM that not produced Shiga toxin. The 7 year old male patient who had complained of abdominal pain, vomiting and non-bloody diarrhea for 2 days. The patient was improved for 2 days after admission. Conclusions 1 Only one (0.3%) of all fecal samples were isolated E. coli O157 that not produced Shiga toxin. Therefore, routine stool culture for the isolation of E. coli O157 was not likely to be neccessary so far.

• Korean Journal of Microbiology
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• v.43 no.1
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• pp.47-53
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• 2007

The DY1 strain of Gram-positive, rod-shaped bacteria was isolated from the soil sample collected from Daeam mountain, Korea. The culture filtrate of DY1 strain showed a broad spectrum of antimicrobial activity on various pathogenic and food poisoning enteric bacterial species tested in vitro. It showed significant growth-inhibitory effect on Salmonella enterica sp., Shigella sp., pathogenic Escherichia coli, Vibrio cholerae, Vibrio parahemolyticus, and Yersinia enterocolitica. For the identification of the DY1 strain, morphological, biochemical and molecular phylogenetic approaches were performed. The DY1 strain was found to be a member of the genus Paenibacillus on the basis of morphological and biochemical analyses. The 16S rDNA of DY1 showed the highest pairwise identity with Paenibacillus polymyxa with 99.79% (1,413 bp/1,416 bp). The antimicrobial entity from DY1 looked different from preciously reported ones and seems to have a great potential to be further studied as a candidate of new antibiotics to control multi-drug resistant pathogens.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.3
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• pp.359-369
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• 2018

An essential measure to prevent healthcare-associated infections (HAI) is to develop a consistent system of surveillance, thereby promoting a reliable situation diagnosis to perform efficient control for the problem. Patient-to-patient transmission of pathogens within the hospital plays a substantial role in the epidemiology of HAIs. Contamination of healthcare environments commonly occurs, including facilities surfaces (e.g., bed rails, bedside tables), drinking water, cooling tower water, endoscopic instruments, food, airborne, endotoxin test, sterile test and medical equipment, with pathogenic organisms. In addition, epidemiological analysis is performed by multi locus sequence tying, pulsed-field gel electrophoresis for active surveillance. Therefore, an environmental surveillance culture test for prevention improves patient safety and blocks infection agents. Effective infection control and increased safety are possible by controlling the national infection control system. In conclusion, this study contributes to an effective infection control system through the standardization of active surveillance culture laboratory and secure expertise as infection control specialist. The primary objective of the standardization is to improve the safety of the nation's healthcare system by reducing the rates of HAIs.