• The Plant Pathology Journal
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• v.16 no.5
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• pp.286-289
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• 2000

Mechanol extracts of three cold-tolerant eucalyptus trees-Eucalyptus darlympleana, E. gunnii and E. unigera were screened for antimicrobial activity against twenty two phyto-pathogenic fungi and six food-borne bacterial pathogens. E. unigera showed the antagonistic activity against all the tested pathogens. Among the tested fungal pathogens, Pythium species were highly sensitive to the leaf extracts. Especially, P. vanterpoolii, a causal agent of leaf blight in creeping bentgrass (Agrostis palustris), was completely inhibited by the extracts. The eucalyptus extracts were also effective in inhibiting the fungal growth of Botrytis cinerea and Phomopsis sp. isolated from the lesions of kiwifruit soft rot during post-harvest storage. Escherichia coli O-157 was less sensitive to the inhibition than the other bacterial pathogens tested. It was likely that Gram positive bacteria-Bacillus subtilis and Streptococcus mutans were more sensitive to the eucalyptus extracts than Gram negative bacteria-Escherichia coli, Salmonella enteritidis and Pseudomonas aeruginosa. Our findings suggest that the cold-tolerant eucalyptus species have antimicrobial properties that can serve the development of novel fungitoxic agents or food preservatives.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.285-295
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• 2014

This study was conducted to survey the epidemiological characteristics and the isolated strains for pathogenic E. coli which was the major causative organisms for food poisoning occurred at school food services in the Gyeonggi-do area during the past three years. We investigated 19 accidents of food-borne disease outbreaks by pathogenic E. coli at school food services from 2010 to 2012. Food-borne disease outbreaks by pathogenic E. coli were usually occurred at direct management type (18 accidents, 95%) and high schools. For the seasonal factors, 13 accidents (65%) were occurred in June to September, especially the end of August and September after the summer holidays. The first patients were occurred on Wednesday (7 accidents, 37%) and Thursday (7 accidents, 37%), and they were mainly reported on Thursday (7 accidents, 37%) and Friday (5 accidents, 26%). The exposure of risk was estimated in Monday (4 accidents, 21%), Tuesday (7 accidents, 37%) and Wednesday (4 accidents, 21%), and kimchi (5 accidents, 50%) was estimated as the food of the high risk responsible for the outbreaks. 98 isolates of pathogenic E. coli consisted of PEC (50%), ETEC (34%), EAEC (15%), and EHEC (1%). The antibiotic resistance of pathogenic E. coli showed in the descending order of ampicilline (40%), nalidixic acid (37%), trimethoprim/sulfamethoxazole (24%), and tetracycline (19%). The antibiotics of second and third generation cephalosporins, cabarpenem, aminoglycosides, and second generation quinolones had antimicrobial susceptibilities and cefalotin, ampicillin/sulbactam and chloramphenicol showed medium resistance at 29%, 25%, and 6% respectively, and 70% of isolates were resistant to more than one antibiotic. By the PFGE analysis, they were classified into nine major groups and 31 profiles with 57% pattern similarity. It was very difficult to find the correlation of antimicrobial susceptibilities and genotype in the small scale-food poisoning, but the similarity of antimicrobial resistance and PFGE patterns in the large scale-food poisoning enabled the outbreaks to estimate the same pathotype of E. coli derived from identical origins.

• Journal of Applied Biological Chemistry
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• v.48 no.4
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• pp.167-169
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• 2005

Crude extract of bioconverted linoleic acid using Pseudomonas aeruginosa PR3 was evaluated for its antibacterial activity against food-borne pathogenic bacteria. Crude extract showed antibacterial activity against four Gram-positive bacteria, Staphylococcus aureus (ATCC 6538), S. aureus (KCTC 1916), Listeria monocytogenes (ATCC 19166), and Bacillus subtilis (ATCC 6633), and one Gramnegative bacterium, Pseudomonas aeruginosa (KCTC 2004), with minimum inhibitory concentrations ranging from 750 to $1,500\;{\mu}g{\cdot}ml^{-1}$. S. aureus and B. subtilis were selected for growth inhibition assays with bioconverted linoleic acid. Major antibacterial effects occurred at lag phase.

• Food Science and Biotechnology
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• v.18 no.2
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• pp.425-431
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• 2009

Antimicrobial coating on chicken carcasses may reduce the effects of cross-contamination and improve product shelf-life and safety. Thyme oil was mixed at 0.5%(v/v) with a pre-gelatinized pea starch coating solution. The coating solution was spread on chicken breast meat after inoculation with selected spoilage and pathogenic bacteria. After inoculation, the chicken meats were packaged in plastic bags and stored at $4^{\circ}C$. During 12 day storage, total aerobic bacteria, lactic acid bacteria, and inoculated organisms were counted at 4 day intervals. Thyme oil treatments reduced the viability of Salmonella as well as the growth of Listeria and Pseudomonas by 2 log CFU/g, and appeared to eliminate inoculated Campylobacter during storage. The addition of thyme oil increased the viscosity of the pre-gelatinized pea starch solution. The results suggested that thyme oil inclusion in an edible starch coating may be a satisfactory delivery system to enhance the safety of processed fresh meat.

• Food Science of Animal Resources
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• v.30 no.5
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• pp.722-729
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• 2010

The aim of this study was to evaluate the physico-chemical, sensory, and microbiological properties of ready-to-eat Korean traditional seasoned beef ribs ("galbi-jjim") prepared by sous-vide/cookchill technology during storage at three different temperatures (4, 10, and $20^{\circ}C$). Beef short ribs marinated in soy sauce for 24 h at $3^{\circ}C$ were packed with vegetables under vacuum. Vacuum-packed beef ribs mixed with vegetables were heated at $90^{\circ}C$ for 90 min in a water bath, and then immediately chilled below $3^{\circ}C$ within 120 min in an ice slurry. Physicochemical (pH, water activity, TBARS, $L^*a^*b^*$ color, and texture profile), sensory (appearance, odor, flavor, texture, and acceptance) and microbiological (Coliform, Escherichia coli, food-borne pathogenic bacteria) properties of the samples were determined during storage at different temperatures. Results showed that pH, $a_w$, and sensory evaluation of products were not affected in any consistent way as a function of either storage duration or temperature. Coliform, E. coli and food-borne pathogens were not detected during storage at any temperature. However, TBARS significantly increased during storage period (p<0.05). Based on TBARS values, SV/CC "galbi-jjim" can be stored for 15 d, 12 d and 1 d at 4, 10 and $20^{\circ}C$, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.1
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• pp.27-34
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• 2019

The seasonal and spatial variation of pathogenic Vibrio species, such as V. parahaemolyticus, V. vulnificus, V. alginolyticus, and V. cholerae were investigated in seawater and in bivalves off the Gyeongnam coast of Korea, which is an important area for shellfish production, during the period 2013-2016. V. parahaemolyticus, V. vulnificus, V. alginolyticus, and V. cholerae were detected in 12.1%, 5.2%, 15.4%, and 0.9% of seawater samples, respectively. V. parahaemolyticus, V. vulnificus, V. alginolyticus, and V. cholera were detected in 21.9%, 7.1%, 12.2%, and 0.0% of shellfish samples, respectively. The Vibrio spp. in seawater and bivalve samples were detected at high levels during the summer to early autumn; however, the levels were low during the winter. Therefore, their occurrence was seasonally dependent and correlated with high water temperature, which is also the biggest factor contributing to foodborne outbreaks associated with Vibrio. Relatively high detection rates of the strains were also found in the sea area that was continually exposed to inland wastewater. Our findings show that continuous monitoring is needed to reveal the patterns of occurrence of these pathogens from marine samples collected off the Korean coast, to reduce seafood-borne outbreaks caused by Vibrio.

• Journal of Life Science
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• v.22 no.5
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• pp.692-696
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• 2012

$Listeria$ $monocytogenes$, a fatal food-borne pathogenic bacteria, can form a biofilm on many different supports. The biofilm gives $L.$ $monocytogenes$ more viability and resistance to disinfectants and sterilization procedures.$L.$ $monocytogenes$ formed biofilms on various culture vessels tested in this experiment and showed the maximum amount of biofilm when it was cultured for 4 days at $30^{\circ}C$ in BHI broth. In this study, biofilm formation was stimulated or inhibited by addition of different Kimchi samples. That was not in accordance with the effect of Kimchi on the growth of $L.$ $monocytogenes$.

• Korean Journal of Environmental Agriculture
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• v.40 no.4
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• pp.248-259
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• 2021

BACKGROUND: Contaminated water was a major source of food-borne pathogens in various recent fresh produce-related outbreaks. This study was conducted to investigate the microbial contamination level and correlations between the level of sanitary indicator bacteria and the detection ratio of pathogens in agricultural water by logistic regression analysis. METHODS AND RESULTS: Agricultural water was collected from 457 sites including surface water (n=300 sites) and groundwater (n=157 sites) in South Korea from 2018 to 2020. Sanitary indicator bacteria (total coliform, fecal coliform, and Escherichia coli) and food-borne pathogens (pathogenic E. coli, E. coli O157:H7, Salmonella spp., and Listeria monocytogenes) were analyzed. In surface water, the coliform, fecal coliform, and E. coli were 3.27±0.89 log CFU/100 mL, 1.90±1.19 log CFU/100 mL, and 1.39±1.26 log CFU/100 mL, respectively. For groundwater, three kinds of sanitary indicators ranged in the level from 0.09 - 0.57 log CFU/100 mL. Pathogenic E. coli, Salmonella and Listeria monocytogenes were detected from 3%-site, 1.5%- site, and 0.6%-site water samples, respectively. According to the results of correlations between the level of sanitary indicator bacteria and the detection ratio of pathogens by logistic regression analysis, the probability of pathogen detection increased individually by 1.45 and 1.34 times as each total coliform and E. coli concentration increased by 1 log CFU/100mL. The accuracy of the model was 70.4%, and sensitivity and specificity were 81.5% and 51.7%, respectively. CONCLUSION(S): The results indicate the need to manage the microbial risk of agricultural water to enhance the safety of fresh produce. In addition, logistic regression analysis is useful to analyze the correlation between the level of sanitary indicator bacteria and the detection ratio of pathogens in agricultural water.

• Microbiology and Biotechnology Letters
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• v.40 no.2
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• pp.144-151
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• 2012

In the course of this study aimed at the development of functional food ingredients from seaweeds, the in vitro antimicrobial activities of methanol extracts prepared from 35 different seaweeds (17 phaeophyta, 11 rhodophyta and 7 chlorophyta) were determined against food-borne diseases and pathogenic microorganisms including multi-drug resistant (MDR) Pseudomonas sp. and Candida sp. Based on disc-diffusion assays at 500 g/disc concentration of the methanol extracts, Ishige okamurai, I. foliacea, Sargassum confusum, and S. yamade exhibited strong antibacterial activities in a broad-spectrum, except against Pseudomonas aeruginosa. In addition to the latter four seaweeds, Ecklonia stolonifera, E. cava and Eisenia bicyclis also demonstrated antifungal activity against C. albicans. Among these 8 selected seaweeds, I. okamurai, I. foliacea, and S. yamade exhibited strong hemolytic activity (55-93%) at 500 g/ml against human RBC. Organic solvent sequential fractions using hexane, ethylacetate and butanol, and water residues were prepared from the 8 selected seaweeds and their anti-Candida sp. activities were further determined. The ethylacetate and butanol fraction of I. okamurai, and the hexane fraction of I. foliacea demonstrated antifungal activity against MDR-pathogenic Candida sp. Although the solvent fractions had no activity against MDR-Pseudomonas sp., our results suggest that seaweeds, especially Ishige okamurai, I. foliacea, S. confusum, and S. yamade could be developed as broad-spectrum antimicrobial ingredients.

• Food Science and Biotechnology
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• v.15 no.5
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• pp.792-798
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• 2006

The probiotic characteristics of a total of 137 lactic acid bacterial strains isolated from soybean paste were investigated. Among those tested, the D37 strain was selected as a probiotic bacteria due to its acid and bile tolerance, and its strong anti-cancer and antibacterial activities. The D37 strain showed highly stable viability at acidic pH for 2 hr, and was very stable in 10% bovine bile. The viability of human colon cancer HT-29 cells was inhibited more than 60% at a $200\;{\mu}/mL$ concentration of D37 cell-free culture supernatant, and the degree of inhibition was concentration-dependent. The D37 strain showed a wide range of antibacterial activities against food-borne pathogenic bacteria such as Escherichia coli O157, Listeria spp., Vibrio spp., Salmonella spp., and Staphylococcus aureus. According to phenotypic characteristics and the utilization of various sugars, the D37 strain was identified as Lactobacillus cellobiosus.