• Korean journal of food and cookery science
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• v.14 no.1
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• pp.119-123
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• 1998

The purpose of this study was to evaluate the antimicrobial effect of green laver (Enteromorpha linza) on the muk (starch jelly) preservation. The methanol extract of green laver completely inhibited the growth of Vibrio parahaemolyticus at 500 $\mu\textrm{g}$/ml level, and inhibited the growth of Bacillus subtilis, Escherichia coli and Staphylococcus aureus at 100 $\mu\textrm{g}$/ml level. The Listeria monocytogenes was inhibited by 98.89% at the same concentration. When various amounts of green laver powder were added in muk (starch jelly), 5% of green laver powder-added muk showed very low level of total bacterial count compared with the control group. Also, green laver did not give negative sensory qualities such as color, flavor and overall quality. Five % green laver muk was selected as the most preferable sample among the green laver muks in overall quality test.

• Journal of Microbiology
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• v.42 no.3
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• pp.216-222
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• 2004

In a previous paper, the ogdH gene that encodes 2-oxoglutarat dehydrogenase was isolated from Salmonella typhimurium. The catalytic N-terminal region in the enzyme was found to be very specific for the Salmonella species. Therefore, the aim of the present study was to detect S. typhimurium in food sources using primers designed for OGDH-l and OGDH-2 which were based on the salmonella-specific region of the ogdH gene. A simple polymerase chain reaction (PCR) detection method was developed to detect low numbers of S. typhimurium in a chicken meat microbial consortium. Using the ogdH-specific primers under stringent amplification conditions and for gene probe analysis, fewer than 100 colony-forming units (CFUs) were detectable when pure cultures were employed. When the PCR assay was run on S. typhimurium-contaminated meat contents, only the positive meat samples containing as few as 200 CFUs reacted to the assay. The method employed for sample processing is simple and it was determined to provide a sensitive means of detecting trace amounts of S. typhimurium-specific sequences in the presence of mixed meat microbial populations. When compared with six representative intestinal gram-negative bacterial strains in foods, including Vibrio parahaemolyticus, V. vulnificus, Enterobacter cloacae, E. coli O157:H7, Pseudomonas aeruginosa, and Proteus sp., S. typhimurium had a unique and distinct PCR product (796 bp). In conclusion, the two OGDH primers were found to be rapid and sensitive detectors of Salmonella spp for the PCR method.

• Korean Journal of Food Science and Technology
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• v.36 no.3
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• pp.507-513
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• 2004

Microbiological safety investigation of 36 commercial salt-fermented shrimps revealed presence of coliform and Gram(+) cocci, whereas pathogenic bacteria such as Escherichia coli O26, Salmonella, Shigella, Staphylococcus aureus, Vibrio parahaemolyticus, and V. cholerae were not detected. When pathogenic bacteria were inoculated into 9, 18, and 27% salted shrimps, Salmonella so., E. coli O26, and S. aureus were not detected up to 13, 80, and 90 days of fermentation at $20^{\circ}C$, respectively, whereas up to 15 day in commercial salt-fermented shrimps.

• Journal of Microbiology and Biotechnology
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• v.24 no.6
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• pp.862-868
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• 2014

Certain Escherichia coli (E. coli) strains have the ability to cause diarrheal disease. Five types of diarrheagenic E. coli have been identified, including EHEC, ETEC, EPEC, EAEC, and EIEC. To detect these five diarrheagenic types rapidly, we developed a one-step multiplex PCR (MP-PCR) assay using nine primer pairs to amplify nine virulence genes specific to the different virotypes, with each group being represented (i.e., stx1 and stx2 for EHEC, lt, sth, and stp for ETEC, eaeA and bfpA for EPEC, aggR for EAEC, and ipaH for EIEC). The PCR primers were constructed using MultAlin. The sensitivity and specificity of the constructed multiplex PCR primers were measured using DNA isolated from diarrheagenic E. coli strains representing each group. The limits of detection were as follows: $5{\times}10^1CFU/ml$ for EHEC, $5{\times}10^3CFU/ml$ for ETEC expressing lt and sth, $5{\times}10^4CFU/ml$ for ETEC expressing stp, $5{\times}10^2CFU/ml$ for EPEC, $5{\times}10^4CFU/ml$ for EAEC, and $5{\times}10^2CFU/ml$ for EIEC. To confirm the specificity, C. jejuni, C. perfringens, S. Typhimurium, V. parahaemolyticus, L. monocytogenes, Y. enterocolitica, B. cereus, and S. aureus were used as negative controls, and no amplification was obtained for these. Moreover, this kit was validated using 100 fecal samples from patients with diarrhea and 150 diarrheagenic E. coli strains isolated in Korea. In conclusion, the multiplex PCR assay developed in this study is very useful for the rapid and specific detection of five diarrheagenic E. coli types. This single-step assay will be useful as a rapid and economical method, as it reduces the cost and time required for the identification of diarrheagenic E. coli.

• Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.197-201
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• 2014

This study was performed to identify and assess food hazards during dry laver processing. Samples including raw materials, intermediates, and finished products during dried-laver processing were collected from seven dried-laver processing facilities, and microbial analyses were conducted. Microbial levels such as total coliforms and total viable cell count (TVC) increased as the processing steps progressed. TVC and total coliforms ranged from <30 to $9.1{\times}10^7$ CFU/g and <18 to 27,600 MPN/100 g for intermediates and finished products obtained during dried-laver processing, respectively. However, no fecal coliform was detected in the samples. Additionally, food-borne bacteria including Bacillus cereus, Listeria monocytogenes, Salmonella sp., Staphylococcus aureus, and Vibrio parahaemolyticus were not identified in finished products. For heavy metal content, arsenic ranged from 30.18 to 39.05 mg/kg, mercury from 0.005 to 0.009 mg/kg, and cadmium from 0.076 to 0.318 mg/kg dry mass in all finished products. However, lead was not detected in samples tested in this study. In conclusion, dried-laver products were safe based on the levels of food-borne bacteria and heavy metal contents. However, it is important to reduce total viable cell counts and total coliforms during dried-laver processing.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.1
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• pp.18-26
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• 2013

This study examined the taste, nutritional and functional characterizations of commercial seasoned sea squirt Halocynthia roretzi (CSS). Total taste values of CSS ranged from 7.6 to 69.5 and the major free amino acids were glutamic acid and aspartic acid. Total contents of amino acids in CSS ranged from 5.91 to 7.59 g/100 g and the major amino acids were also glutamic acid and aspartic acid. When taking 100 g of CSS, the minerals that could be expected to have functional health effects (minerals whose levels were above 10% of the recommended daily requirements) were P, Mg and Fe. Other minerals were also present in non-negligible quantities. In terms of the functional properties of CSS, ACE inhibitory activity was 21.2-37.1%, antioxidative activity was 55.4-90.4%, xanthine oxidase inhibitory activity was 52.9-76.6% and ${\alpha}$-glucosidase inhibitory activity was 0-32%. Antimicrobial activity against Vibrio parahaemolyticus was not detected, but activity against Staphylococcus aureus, groups such as KB, GG, CY, DN, HC and KH, and against Escherichia coli groups such as SF, WD, KB and GG, was detected.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.3
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• pp.243-249
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• 2017

Crabs are a popular seafood item. However, they can harbor many microorganisms, heavy metals, radioactivity, and benzo(a)pyrene, which are potential health risks to humans. The objective of this study was to assess the potential of swimming crabs for use in foods such as Ganjang-gejang, by measuring their sanitary biological and chemical properties. Viable microbial cell counts in swimming crab samples were $3.4{\times}10^2-6.7{\times}10^4CFU/g$, but no coliform, Escherichia coli, or pathogenic bacteria, such as Vibrio parahaemolyticus, Enterohemorrhagic E. coli, Listeria monocytogenes, Staphylococcus aureus, or Salmonella spp., were detected. Heavy metal concentrations in swimming crab samples were non-detectable to 0.112 mg/kg for total mercury, non-detectable to 0.435 mg/kg for lead, and 0.115-0.836 mg/kg for cadmium. Benzo(a)pyrene concentrations ranged from $0.025-0.060{\mu}g/kg$, and the volatile basic nitrogen content ranged from 8.7-15.6 mg/100 g. No radioactivity was detected in samples. These results suggest that swimming crabs are viable for use in seafood products.

• Korean Journal of Veterinary Service
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• v.40 no.4
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• pp.265-275
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• 2017

The production of enzymes that help digestion, assimilation of essential nutrients, and prevent pathogenic bacteria are important for probiotics used in aquaculture. The objective of this study was to investigate enzyme activities for macromolecular organic matters and antimicrobial properties of the selected potential probiotics isolated from gut of surf clam (Tresus keenae) against well-known shellfish-pathogenic bacteria. Among 65 isolates from guts of 60 surf clams, seven Bacillus strains with outstanding degradation capability of macromolecule organic matter were selected as potential probiotics as follows: TKI01 (B. vietnamensis), TKI02, TKI26 (B. thuringiensis), TKI14, TKI32, TKI42 (B. amyloliquefaciens), and TKI18 (B. stratosphericus). After in vitro antimicrobial activity test was performed against five shellfish-pathogenic bacteria including Listonella anguillarum, Vibrio parahaemolyticus, V. splendidus, V. harveyi, V. tubiashii, PCR assay was performed to detect bacteriocin-producing strain. PCR results revealed that the five Bacillus strains possessed diverse bacteriocin genes including ericinA, coagulin, surfactin, iturin, bacyllomicin, fengycin, bacylisin, subtilin, and lantibiotics. In the present study, the selected seven Bacillus strains showed different enzyme activities according to types of macromolecule organic matters. And their antimicrobial activities varied based on the species of pathogenic bacteria. In addition, at least five Bacillus strains had genetic potential to produce several natural lipopeptide antibiotics that may help biological control of surf clam aquaculture. Therefore, mixed use of probiotics might show co-operative effect and increase the efficiency of probiotics rather than separate use. To the best of our knowledge, it is the first report on antimicrobial properties of Bacillus species isolated from surf clam.

• Fisheries and Aquatic Sciences
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• v.5 no.3
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• pp.178-182
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• 2002

The authors identified 68 Vibrio strains from Gwangan beach seawater from June to October in 2001. We identified them as 19 strains of Vibrio alginolyticus, 15 strains of V. vulnificus, 15 strains of V. parahaemolyticus, 11 strains of V. cholerae non O1, 7 strains of V. fluvialis and just one strain of V. hollisae. They showed their typical biochemical characteristics by API 20E kit (bioMerieux), respectively. It was examined whether their cultural supernatants had enzymatic activities such as hemolysin, protease or urease. The 46 strains showed hemolytic activities and/or protease activities. But we could not find any strain which had urease activity. All isolates of V. cholerae non O1 showed $\beta$ hemolysis. The others showed $\alpha$ hemolysis or did not show clear zones on sheep blood agar plates. These results of Kanagawa phenomenon were not always correspondant with hemolytic activities of cultural supernatants at late log phase. Some strains had higher hemolytic activities despite of showing protease activities on skim milk agar plates and in litmus milk media. On the other hand, some strains showed protease activities but did not show hemolytic activities. Therefore we could guess that there were the relationships between hemolysins and proteases produced by pathogenic vibrios.

• Advances in Traditional Medicine
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• v.8 no.4
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• pp.339-348
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• 2008

Butea frondosa has been used traditionally as a topical formulation in the treatment of many diseases and disorders. Two compounds [BF-1 (crystalline flavonol quercetin) and BF-2 (tannin) from ethyl acetate fraction of ethanolic extract] were isolated from the bark of Butea frondosa. The stereostructures of the compounds were determined on the basis of chemical and physicochemical evidence. BF-1 and BF-2 were screened in vitro for possible antibacterial property against 112 bacteria comprising 3 genera of Gram-positive and 12 genera of Gram-negative types. It was found that both BF-1 and BF-2 exhibited inhibitory activity against several bacteria. Most of these strains were inhibited by BF-1 at $50-200\;{\mu}g/ml$, while BF-2 ($MIC_{50}$ $400\;{\mu}g/ml$) was much less active. The bacteria could be arranged in the decreasing order of sensitivity towards BF-1 in the following manner: S. aureus, Bacillus spp., Salmonella spp., Vibrio spp., Shigella spp., E. coli and Pseudomonas spp. The $MIC_{50}$ of the compound was $50\;{\mu}g/ml$ while the $MIC_{90}$ was $100\;{\mu}g/ml$. The decreasing order of sensitivity towards BF-2 was V. cholerae, Bacillus spp., S. aureus, V. parahaemolyticus, Salmonella spp. and Proteus spp. BF-1 was bactericidal in action. In vivo studies with this extract showed that it could offer statistically significant protection (p < 0.01) to mice challenged with a virulent bacterium. The inhibitory activity of Butea frondosa against Gram-positive and Gram-negative bacteria indicates its usefulness in the treatment of common bacterial infections. The potentiality of BF-1 as an antibacterial agent may be confirmed further by pharmacological studies.