• Food Science of Animal Resources
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• v.30 no.5
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• pp.804-810
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• 2010

This study was performed to select protease-producing Bacillus sp. as a potential probiotic starter for fermented meat products. In order to isolate protease-producing bacterium from meju, measured the diameter of the clear zone on agar plate (TSA, 1% (w/v) skim milk) and analyzed for intracellular protease activity, then 10 Bacillus-like strains were isolated. Three Bacillus-like strains (P19, P27, and P33) among 10 strains were able to tolerate in acidic condition (TSB, pH 2.5, 2 h incubation). These 3 strains were showed antimicrobial activity against food-borne pathogenic bacteria. These vegetative cells of 3 strains were showed a survival rate of 0.04% to 0.08% under the artificial gastric acidic condition (TSB, pH 2.5 with 1% (w/v) pepsin), but spore-forming cells were 56.29% to 84.77%. Vegetative cells of 3 strains were the least bile-resistant, while spore-forming cells of 3 strains showed higher survival rate more than 76% under artificial bile condition (TSB, 0.1% (w/v) oxgall bile). In these strains, P27 strain was finally selected as a good probiotic strain. P27 strain was tentatively identified as Bacillus amyloliquefaciens by API CHB kit and 16S rDNA sequence analysis. The results of this study suggest that B. amyloliquefaciens P27 can be used as a potential probiotic starter for fermented meat product.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.8
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• pp.1132-1136
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• 2010

After Cheonnyuncho (Opuntia humifusa) was extracted by 70% ethanol and partitioned with hexane, chloroform, ethyl acetate, butanol, and water in order, ethyl acetate fraction with excellent antioxidant activities was acquired. Ethyl acetate fraction was conducted by TLC, and the third spot of 10 spots was selected due to its best antioxidant activities. When the third fraction further isolated on silica gel chromatography, the fourth fraction of 10 fractions had the best antioxidant activities and purified by HPLC. The molecular weight on EI-MS, and $^1H$- and $^{13}C$-NMR spectrum showed that the purified compound was taxifolin. In addition, antioxidant activities were analyzed, and the purified compound from Cheonnyuncho was found to be effective as much as $\alpha$-tocopherol, BHA. According to the analysis on antibacterial activities, the purified compound also showed more activity than benzoic acid against all pathogenic bacteria.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.533-540
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• 2016

This study assessed the risk of an oyster-shucking site to establish the hazard analysis critical control point (HACCP) system model by measuring viable cell counts, coliform group Staphylococcus aureus foreign material on oysters, oyster-producing equipment, and washing water. The viable cell count and coliform group levels of the harvested raw oysters were 4.00 log CFU/g and 1.1×10² MPN/100 g, while those of washed oysters were 2.99 log CFU/g and (3.2−4.6) × 10 MPN/100 g, respectively. After washing the oysters, no Escherichia coli or pathogenic bacteria (E. coli O157:H7, Listeria monocytogenes, S. aureus, Salmonella spp., Vibrio parahaemolyticus, and Clostridium perfringens) were detected. Regardless of the location of foreign matter, up to 100% more metallic and non-metallic foreign matter was detected at 1.5 mmΦ than at 3.5 mmΦ, using a metal detector with increased sensitivity. According to the results, the critical control points (CCP) are the washing and metal-detection processes. These results can be used as basic data to improve sanitation at oyster-shucking sites in factories with an HACCP system.

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.177-184
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• 2009

Three hundred lactic acid bacteria isolated from human feces were studied their probiotic characters to develop potential probiotics. The properties were tested on the basis of guideline for probiotic selection protocol such as tolerance for acid or bile salt, thermal stability, antimicrobial, anticancer cell, and antiviral activity. Strain Miny-148 was selected as a potential probiotic bacterium which showed resistance to low pH, bile salts and thermal stability. On the basis of fatty acid profiles and 16S rDNA sequences analysis, the strain was identified as Lactobacillus pentosus (similarity 99.9%). The strain, L. pentosus Miny-148, showed broad antimicrobial spectrum against E. coli O157:H7, Shigella flexneri, Bacillus anthracis, Staphylococcus aureus, E. coli, Vibrio cholerae, V. vulnificus, Salmonella typhimurium, and Methicillin-resistant S. aureus (MRSA). Cell-free culture supernatant of the strain also inhibited against the growth of HT-29 colon cancer cell and transmissible gastroenterits virus.

• KSBB Journal
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• v.23 no.2
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• pp.125-130
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• 2008

We investigated the biological activities of ethanol extract from the seawater algae, Chlorella elliposidea C020 such as antibacterial activity, anti-oxidant activity, tyrosinase inhibitory activity and hemolytic activity against human erythrocytes. Extract was obtained from various solvent, methanol, ethanol, acetone and ethanol + acetone (1:1, v/v%), 95% ethanol proved to be best extraction solvents. The contents of ethanol extract were higher in freeze-dried sample than that in frozen-thawing. Antibacterial activities of ethanol extract showed strong inhibitory effect against Bacillus subtilis PM125, Bacillus licheniformis and fish pathogenic bacteria, Vibrio parahaemolyticus KCTC2471 and Edward tarda NUF251. However, this extract didn't worked against antifungal activity against Candida albicans KCTC1940. And, ethanol extract was without hemolytic activity against human erythorocytes. The ethanol extract showed 75% of free radical scavanging effect on 2.0 mg/mL using DPPH method. In tyrosinase inhibition assay of ethanol extract, $IC_{50}$ (Inhibition Concentration) was measured as 10.87 mg/mL. Conclusionally, ethanol extract of Chlorella elliposidea C020 has good candidate for bioactive materials.

• Restorative Dentistry and Endodontics
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• v.20 no.1
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• pp.71-95
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• 1995

Bacteria have been regarded as a one of major etiologic factors in root canal infections. In endodontic treatment the effective removal of pathogenic microorganisms in the root canal is the key to successful outcome. Bacterial cell wall components may play an important role in the development of pulpal and periapical disease. The purpose of this study was to evaluate the effect of sonic extracts of Streptococcus spp. on cultured L929 cells and to characterize cell wall protein profiles of Streptococcus spp. Streptococcus spp. were isolated from infected root canals and identified with Vitek Systems(Biomeriux, USA). Five streptococci, namely S. sanguis, S. mitis, S uberis, S. mutans (ATCC 10449) and S. faecalis (ATCC 19433) weere enriched in brain heart infusion broth. Cell pellets were sonicated and cell wall extracts were dialyzed and membrane filtered. Prepared cell wall proteins were applied to cultured L929 cell. The cell reaction were evaluated by monitoring DNA synthesis, cell numbers and the change of cell morphology. The total cell wall protein profiles of microorganisms were characterized by sodium dodecyl sulfate polyacrylamide-gel eledruphoresis(SDS-PAGE). DNA synthesis of L929 cells were reduced by the increasing concentration of sonic extracts. DNA synthesis was significantly suppressed in more than $50{\mu}g$/ml of sonic extract conentration in five streptococci. S. nutans (ATCC 10449) showed stronger suppression on DNA synthesis than remaining four streptococci, which had the similar effect on DNA synthesis. Analysis of DNA synthesis measured by [$^3H$]-thymidine uptake was more sensitvie method than cell counting. Sonic extracts affected the microscopic findings of L929 cells. The protein profiles indicated that all five strains shared two major proteins with molecular masses of 70.8 and 57.5 kD respectively. S. uberis and S. mutans shared common minor proteins of which molecular weights were 147.9 and 112.2 kD respectively. However some minor proteins were unique for S. mitis, S. uberis and S. faecalis.

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.284-289
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• 2004

A PCR assay for the rapid detection of Vibrio vulnificus strains was developed using a virulence gene for elastase found in various Vibrio species. The DNA sequences in the elastase gene facilitated the identification of a species-specific probe for pathogenic V. vulnificus strains from both clinical and environmental sources. Using an elastase gene-based PCR reaction, a species-specific 507-bp PCR product was visualized by agarose gel electrophoresis. Three different DNA extraction methods were then compared to improve the simplicity and rapidity of detection. A PCR assay using the conventional DNA extraction or boiling method was able to detect as few as 25 V. vulnificus cells, making the detection limits at least 1-log-scale lower than that for the EDT A-treated DNA extraction method. In particular, the boiling method, which does not require purification of the chromosomal DNA, was very effective in terms of simple and rapid detection. Meanwhile, the detection limit in a mixed bacterial culture that included other bacteria, such as Escherichia coli or Bacillus subtilis, was two V. vulnificus cells, which was 1-log-scale lower than that for the control. Accordingly, when coupled with a new DNA extraction method, the elastase gene-based PCR can provide a rapid, specific, and sensitive method for identifying V. vulnificus in clinical and environmental samples.

• Journal of Microbiology and Biotechnology
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• v.27 no.11
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• pp.1942-1951
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• 2017

Campylobacter jejuni and Campylobacter coli are important foodborne pathogenic bacteria, particularly in poultry meat. In this study, the presence of extracellular DNase activity was investigated for biofilm-deficient Campylobacter strains versus biofilm-forming Campylobacter strains isolated from chickens, to understand the relationship between extracellular DNase activity and biofilm formation. A biofilm-forming reference strain, C. jejuni NCTC11168, was co-incubated with biofilm non-forming strains isolated from raw chickens or their supernatants. The biofilm non-forming strains or supernatants significantly prohibited the biofilm formation of C. jejuni NCTC11168. In addition, the strains degraded pre-formed biofilms of C. jejuni NCTC11168. Degradation of C. jejuni NCTC11168 biofilm was confirmed after treatment with the supernatant of the biofilm non-forming strain 2-1 by confocal laser scanning microscopy. Quantitative analysis of the biofilm matrix revealed reduction of extracellular DNA (16%) and proteins (8.7%) after treatment. Whereas the biofilm-forming strains C. jejuni Y23-5 and C. coli 34-3 isolated from raw chickens and the C. jejuni NCTC11168 reference strain showed no extracellular DNase activity against their own genomic DNA, most biofilm non-forming strains tested, including C. jejuni 2-1, C. coli 34-1, and C. jejuni 63-1, exhibited obvious extracellular DNase activities against their own or 11168 genomic DNA, except for one biofilm non-former, C. jejuni 22-1. Our results suggest that extracellular DNase activity is a common feature suppressing biofilm formation among biofilm non-forming C. jejuni or C. coli strains of chicken origin.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.4
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• pp.343-351
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• 2017

Sanitary evaluation of seawater and Pyropia sp. laver collected from the five major laver growing areas in Korea was performed four times over the course of a year. The seawater quality in four of these five areas was regarded as the clean area according to Korean criteria, but the seawater at one investigation site in Seoheon area was found to exceed the standard for fecal coliform. In the bacteriological safety analysis of laver (raw source), the percentages of samples not conforming to Chinese criteria at the five sites were 55.6% (Seocheon), 70.0% (Shinan), 81.8% [Jindo (Haenam)], 63.6% (Wando), and 28.6% [Goheung (Jangheung)]. Pathogenic bacteria were not detected in all laver samples. The food safety of laver (raw source) based on heavy metal concentration was confirmed using Korean criteria; the concentrations of heavy metals in laver samples collected from the major laver growing areas were 0.008-0.632 mg/kg wet weight (ww) lead, 0.024-0.137 mg/kg ww cadmium, 0.908-2.892 mg/kg ww total arsenic, and 0.003-0.013 mg/kg ww total mercury. Therefore, pollution source management and periodic monitoring of heavy metals may be required to improve the food safety of laver produced in these laver growing areas.