• Journal of the FoodService Safety
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• v.2 no.2
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• pp.84-90
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• 2021

This study was performed to assess the microbiological quality and safety of microgreen sampled from harvesting farms and food processing plant in Korea. The samples were analyzed for total viable counts, coliforms, Enterobacteriaceae, Escherichia coli, Salmonella spp., Listeria monocytogenes, Vibrio parahaemolyticus, Bacillus cereus, and Staphylococcus aureus. Total viable counts were highly contaminated in samples collected from farms (7.7~8.2 log CFU/g) and the final products (5.8~7.8 log CFU/g), respectively. B. cereus was detected less than 100 CFU/g, which was satisfied with Korean standards (<1,000 CFU/g) of fresh-cut produce. A predictive model was developed for the changes of total viable counts in microgreens during storage at 5~35℃. The predictive models were developed using the Baranyi model for the primary model and the square root model for the secondary model. The results obtained in this study can be useful to develop the safety management options along the food chain, including fresh-cut produce storage and distribution.

• Microbiology and Biotechnology Letters
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• v.51 no.1
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• pp.18-25
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• 2023

After random mutagenesis, the mutant Lactobacillus plantarum GNS300 showed improved exopolysaccharide production as determined by the quantification of total sugar. The mutant L. plantarum GNS300 produced 2.82 g/l of exopolysaccharide which showed 79.62% improved exopolysaccharide production compared with the parental strain. When exopolysaccharide of L. plantarum GNS300 was analyzed, the exopolysaccharide is composed of galactose (93.35%) and glucose (6.65%). Through the optimization of fermentation conditions using a bioreactor, 2.93 g/l of exopolysaccharide was produced from 20 g/l of glucose at 35℃, 500 rpm, and 0.1 vvm for 12 h. The mutant L. plantarum GNS300 exhibited 69.18% higher antioxidant activity than that from the parental strain, which might be caused by higher exopolysaccharide production. The concentrated supernatant of the mutant L. plantarum GNS300 inhibited the growth of gram-positive bacteria (Bacillus cereus and Staphylococcus aureus) and gram-negative bacteria (Escherichia coli, Vibrio parahaemolyticus, and Salmonella typhimurium).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.2
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• pp.122-128
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• 2024

We investigated the quality of 10 commercial eorigul-jeot, salt-fermented oysters with seasoning, by measuring their chemical composition and bacterial concentrations. The Eorigul-jeot had 5.07-6.06 pH (mean, 5.63), of 1.92-4.74% salinity (mean, 3.36%), 7.01-14.70 mg/100 g volatile basic nitrogen (mean, 11.91 mg/100 g), 139.22-267.11 mg/100 g amino acid nitrogen (mean, 212.69 mg/100 g), and 1.02-1.65 g/100 g total acidity (mean, 1.24 g/100 g). The total viable and lactic acid bacterial counts were 5.7×10⁴-8.7×10⁵ and 2.7×10³-2.0×10⁵ CFU/g, respectively, and fecal coliform was detected in only one Eorigul-jeot sample. Bacillus cereus and Clostridium perfringens were detected in two samples, and all Eorigul-jeot samples were negative for Staphylococcus aureus and Vibrio parahaemolyticus. These results strongly suggest the need to monitor food-poisoning bacteria in commercial Eorigul-jeot to ensure consumer health.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.313-318
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• 2008

This study was conducted to evaluate in vitro antioxidative and antimicrobial properties of ethanolic extracts from Allium victoriallis L. var. platyphyllum (AVP) with 6 different parts. The antioxidative activities of these samples were determined using the 4 separate methods that involved reducing power, DPPH, hydrogen radical scavenging, and lipid peroxidation with use of a $\beta$-carotene/linoleic acid system. The leaf part ethanolic extracts (1,000 ppm) showed the strongest inhibitory potential for reducing power, DPPH, and hydroxyl radicals to 99.8, 49.4, and 52.8%, respectively. Inhibition values of linoleic oxidation were calculated as 58.0, 39.5, and 38.0% for seed, flower, and leaf ethanolic extracts (1,000 ppm), respectively, from AVP. In addition, the ethanolic extracts of the root part showed the most effective antimicrobial activity. The inhibition zones of the root ethanolic extracts ($200\;{\mu}g/disc$) of AVP against Bacillus cereus and Staphylococcus aureus were 17 and 14 mm, respectively. In a micro-dilution assay, B. cereus, S. aureus, and Vibrio parahaemolyticus exhibited sensitivity to root part ethanolic extracts with an minimum inhibition concentration (MIC) value of 20, 28, and 18 mg/mL, respectively. Therefore, the AVP extracts may be suitable as antimicrobial and antioxidative agents in the food industry.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4910-4916
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• 2012

Changes of low concentrated nitrogen-phosphate removal efficiency were investigated in 4 strains of marine bacteria applied to ceramic media. Marine bacteria were isolated and identified from Gwangyang bay. Growth rates and removal efficiencies of $NH_3$-N of 4 strains of marine bacteria applied to ceramic media were increased approximately 3 fold and over 30% than control group, respectively. A. hydrophila and P. diminuta had highest ${NO_3}^-$-N and phosphate removal efficiencies, respectively. This results showed that ceramic media is very nice material for improvement of nitrogen-phosphate removal efficiency and isolated marine bacteria may be useful to control nitrogen-phosphate at low concentration in field.

• 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 Microbiology and Biotechnology
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• v.27 no.10
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• pp.1753-1762
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• 2017

Sea cucumber (Apostichopus japonicus) is a popular seafood source in Asia, including South Korea, and its consumption has recently increased with recognition of its medicinal properties. However, because raw sea cucumber contains various microbes, its ingestion can cause foodborne illness. Therefore, analysis of the microbiota in the whole body of sea cucumber can extend our understanding of foodborne illness caused by microorganisms and help to better manage products. We collected 40 sea cucumbers from four different sites in August and November, which are known as the maximum production areas in Korea. The microbiota was analyzed by an Illumina MiSeq system, and bacterial amounts were quantified by real-time PCR. The diversity and bacterial amounts in sea cucumber were higher in August than in November. Alpha-, Beta-, and Gammaproteobacteria were common dominant classes in all samples. However, the microbiota composition differed according to sampling time and site. Staphylococcus warneri and Propionibacterium acnes were commonly detected potential pathogens in August and November samples, respectively. The effect of experimental Vibrio parahaemolyticus infection on the indigenous microbiota of sea cucumber was analyzed at different temperatures, revealing clear alterations of Psychrobacter and Moraxella; thus, these shifts can be used as indicators for monitoring infection of sea cucumber. Although further studies are needed to clarify and understand the virulence and mechanisms of the identified pathogens of sea cucumber, our study provides a valuable reference for determining the potential of foodborne illness caused by sea cucumber ingestion and to develop monitoring strategies of products using microbiota information.

• Journal of Food Hygiene and Safety
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• v.16 no.3
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• pp.241-246
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• 2001

Distribution of pathogenic vibrios in the seawater of live fish tank and effect of environmental factors on their existence were investigated by collecting samples from fish markets and restaurants in 6 different cities. Pathogenic vibrios and coliforms were determined by using the most probable number (MPN) procedure, and aerobic plate count was enumerated by the standard pour plate method. No Vibrio chulerae O1 was detected in all the samples tested. Detection rates of V. cholerae non-O1, V. parahaemolyticus and V. vulnificus in all the smaples tested were 7.7%, 69.2% and 23.1%, respectively. Water temperature and trubidity of the seawater measured were higher in the pathogenic vibrios positive samples than in those negative samples. However, higher salinity and pH were shown in the pathogenic vibrios negative samples than in positive samples. The aerobic plate counts and MPN or total and focal coliforms in the seawater were higher in the presence of pathogenic vibrios than in the absence of pathogenic vibrios. In this study, the presence of pathogenic vibrios in the seawater tested was closely related with other physiochemical parameters and populations of coliforms, indicators far food safety.

• Journal of Life Science
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• v.16 no.2 s.75
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• pp.297-301
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• 2006

For developing natural antibacterial agents from Houttuynia cordata Thunb., antibacterial effects of volatile flavor component using various bacterial sp. were tested. Extraction from Houttuynia cordata Thunb. by using SDE (Simultaneous steam Distillation-Extraction) showed strong antibacterial activities against Vibrio and Bacillus genus, such as Vibrio. cholerae, V. parahaemolyticus, V. vulnificus, Bacillus. cereus, and B. subtilis. Then chemical compositions of leaf and stem were analyzed. The contents of crude protein, lipid, and ash in stem were less than those of leaf, but fiber contents were higher than those of leaf. Among the amino acids, aspartic acid, glutamic acid, glycine, and arginine were higher than those of other amino acids. Linolenic acid, linoleic acid, oleic acid, and palmitic acid were major fatty acids. Major minerals of Houttuynia cordata Thunb. were potassium, calcium, phosphorus, magnesium, iron, zinc, and copper. Especially, in the case of potassium, it was highest.

• Journal of Life Science
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• v.14 no.6 s.67
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• pp.986-990
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• 2004

Five strains of Vibrio vulnificus, which cause serious septicemia in human worldwidely, was isolated from marine environments of Korea costal area from May to July of 2002. The isolated strains were identified by API 20E kit and partial 16S rDNA sequence analysis. 16S rDNA sequence of the isolates showed $99\%$ similarity with V. vulnificus ATCC 27562. The proteins of V. vulnificus isolates were examined by analyzing patterns of the cell lysates and outer membrane proteins (OMP). The OMP separated from cell lysates showed the common protein band. Therefore OMP profiles might be useful for the identification of V. vulnificus sp.