• Restorative Dentistry and Endodontics
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• v.25 no.4
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• pp.561-574
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• 2000

Poly-P has been used to prevent decomposition of foods and has been shown to have inhibitory effect on the growth of gram positive bacteria. The purpose of this study was to evaluate the effect of poly-P on the growth of Porphyromonas endodontalis, a gram negative obligate anaerobic rod, endodontopathic bacterium. P. endodontalis ATCC 35406 was in BHI broth containing hemin and vitamin K with or without poly-P. Inhibitory effect of each poly-P which was added at the beginning(lag phase) or during(exponential phase) the culture, MIC(minimum inhibitory concentration) was determined by measuring the optical density of the bacterial cell at 540nm. Viable cell counts were measured to determined whether poly-P has a bactericidal effect. Leakage of intracellular nucleotides from P. endodontalis was determined at 260nm and morphological change of P. endodontalis was observed under the TEM(transmission electron microscope). Binding of 32P-labeled poly-P to P. endodontalis was examined. SDS-polyacrylamide gel electrophoresis and zymography were performed to observe the changes in protein and enzyme profiles of P. endodontalis, respectively. The results from this study were as follows : 1. The minimal inhibitory concentration(MIC) of poly-P to P. endodontalis appeared to be 0.04~0.05%. 2. Poly-P added to the P. endodontalis culture during the exponential phase of P. endodontalis was as much effective as poly-P added at the begining of the culture, suggesting that the antibacterial effect of poly-P is not much dependent on the initial inoculum size of P. endodontalis. 3. Poly-P are bactericidal to P. endodontalis, demonstrating the decrease of the viable cell counts. 4. Intracellular nucleotide release from the P. endodontalis, was not increased in the presence of poly-P and was not reversed by the addition of divalent cations like $Ca^{2+}$ and $Mg^{2-}$. 5. Under the TEM, it was observed that fine electro-dense materials were prominent in the poly-P grown P. endodontalis, appearing locally in the cell, and the materials were more abundant and more dispersed in the cell as the incubation time with poly-P increased. In addition, highly electron dense granules accumulated in many poly-P grown cells, most of which were atypical in their shape. 6. Binding of 32P-labeled poly-P to P. endodontalis appeared to be 32.8 and 45.5 and 53.4% at 30 minutes, 1 hours and 2 hours, respectively. 7. In the presence of poly-P. the synthesis of proteins with apparent molecular masses of 25, 27, 35, 45 was lost or drastically decreased whereas expression of a protein with an apparent molecular mass of 75 was elevated. 8. Proteolytic activity of P. endodontalis was decreased by poly-P. The overall results suggest that use of poly-P may affect the growth of P. endodontalis, and the anti-bacterial activity of poly-P seems largely bactericidal. Changes in shape, protein expression, and proteolytic activity of P. endodontalis by poly-P may be directly and indirectly attributed to the antibacterial effect of poly-P. Further studies will be needed to confirm the effect of poly-P.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.5
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• pp.774-783
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• 2013

This study investigated the quality characteristics of boiled pork with different amounts (0.5, 1, 1.5, or 2%) of green tea, oolong tea and black tea extracts. Characteristics measured included approximate composition, water holding capacity (WHC), hardness, pH, Hunter's color value, total aerobic bacterial counts, volatile basic nitrogen (VBN), 2-thiobarbituric acid reactive substances (TBARS), and sensory qualities. Green tea approximately contained 3.4%, 31.8%, 5.5%, and 57.7% of moisture, crude protein, crude ash, and carbohydrate, respectively. There were no significant differences with the type of tea. However, the crude fat content of green tea, oolong tea, and black tea were 1.6%, 1.0%, and 0.9%, respectively. Green tea had the highest content of crude fat (p<0.05). Boiled pork approximately contained 55.1%, 38.6%, 5.2% and 0.9% moisture, crude protein, crude fat and crude ash, respectively. The WHC of boiled pork, with tea extract added, significantly increased and there were no significant differences according to the type of tea. The hardness of boiled pork significantly increased as the amount of tea extract added increased (p<0.05). The pH of the boiled pork was not significantly different after storage for one day, but significantly decreased in control groups and boiled pork with 0.5% of any tea extract added during storage. However, in boiled pork with 1%, 1.5%, or 2% of any tea extract added, pH was not significantly different during storage. The Hunter's L and b values decreased in all boiled pork. The Hunter's a-values also decreased in boiled pork with green and black tea extract added, but increased in boiled pork with oolong tea extract added. In boiled pork with tea extract added, total aerobic bacterial counts significantly decreased as the amount of tea extract added increased during storage (p<0.05). The VBN values significantly increased during storage in all groups. TBARS values were significantly lower in boiled pork with green tea extract added, oolong tea added (at concentrations of 1%, 1.5%, or 2%), and black tea extract added compared to control groups on the first day. The sensory evaluation results showed that the color, flavor, and overall acceptance of boiled pork containing 1% of oolong or black tea extracts had the highest scores but there were no significant differences. However, taste scores were significantly different (p<0.05). These results indicate that boiled pork has improved quality characteristics with 1% of oolong or black tea extracts added.

• Korean Journal of Food Science and Technology
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• v.24 no.3
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• pp.209-214
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• 1992

In order to save foreign currency and to domesticize the dairy products, various fresh cheeses and whey drinks were developed and some physicochemical, microbiological and sensory evaluation were performed. The yield of fresh cheese was 22.3%, while that of whey 77.7%. The pH-values of fresh cheeses were $5.90{\sim}6.49$, while those of whey drinks $6.07{\sim}6.49$, and fermented whey drinks $3.97{\sim}4.91$. The acidities of fresh cheeses were $0.09{\sim}0.26%$, while those of whey drinks $0.09{\sim}0.36%$. The contents of solid substances, protein and lactose in fresh cheeses were $25.67{\sim}34.18%$, $7.45{\sim}9.11%$ and $3.61{\sim}4.14%$, while those of whey drinks $7.39{\sim}7.70%$, $0.88{\sim}0.94%$ and $4.93(\sim}6.17%$, respectively. The lactic acid contents of whey drinks varied from $0.01{\sim}0.38%$, where the content in the fermented sample was the highest. The general colony counts of fresh cheeses were $0{\sim}30/g$, while those of whey drinks $0{\sim}80/ml$. The psychrotrophs counts of fresh cheeses were $0{\sim}20/g$, while those of whey drinks $0{\sim}60/ml$. Lactic acid bacterial counts in both products were not detected except for $97{\sim}401{\times}10^8/ml$ in fermented whey drinks. E. coli and fungi were not detected in both products. In sensory evaluation of both products, the strawberry added fresh cheese was the best of fresh cheeses, while the garlic added fresh cheese was the worst. Pure whey drink was the best of whey drinks, while the ginseng added whey drink was the worst.

• Journal of Animal Science and Technology
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• v.46 no.4
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• pp.667-676
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• 2004

Yogurt was prepared from skim milk added with 1, 2, 4 or 6% of rice- or skim milk powders and commercial lactic acid bacterial starters. Changes in pH, titratable acidity, viable cell counts, viscosity, organic acid contents and carbohydrates during fermentation were monitored and its sensory evaluation was also performed. The optimum level of additives such as rice- and skim milk powders for yogurt manufacture was selected. Fermentation properties of yogurt added with rice and skim milk powders were studied. The control yogurt reached pH 4.5 after 10 hours of fermentation, whereas the samples added with 4 or 6% rice powders reached pH 4.5 in 6 hours and those added with skim milk powder reached in 8 hours. After 4 hours of fermentation, the control yogurt reached a titratable acidity at 1.0 %, whereas other samples exceeded 1.0%. After 4 hours of fermentation, the viable cell counts in the samples added with 4% rice powders were the highest. At the level of 4% rice powders, the curd viscosity decreased. Except for the sample added with 6% skim milk powders, all the samples produced higher lactic acid during fermentation, and galactose level in yogurt was the highest when added with 4% rice powder or 6% skim milk powder. In overall sensory evaluation using 5 parameters, the sensory scores of all the yogurts were not significantly different. However, the sample added with 4% skim milk powders was the best for color and overall acceptability. The sample added with 4% rice powders was the best for the flavor and texture. From this experiment, the optimun level of additives such as rice or skim milk powders was selected to be 4%.

• Food Science of Animal Resources
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• v.23 no.4
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• pp.333-341
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• 2003

The effect of water extract of Schizandra chinensis on the growth of yoghurt starter was investigated in order to manufacture the drink type yoghurt added with water extract of Schizandra chinensis. It was the most desirable extraction conditions for Schizandra chinensis to soak in 50 times of water for 15 hours at 20$^{\circ}C$. The water extract of Schizandra chinensis showed pH 3.07, 2.39％ acidity, 1.10％ total sugars, and 0.15 optical density for color. The water extract of Schizandra chinensis was added to MRS broth medium from 0.1％ to 1.0％ and the medium was fermented by 4 types of lactic acid bacteria such as Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus bulgaricus, and Streptococcus thermophilus. The addition of water extract of Schizandra chinensis inhibited the growth of the lactic acid bacteria. The maximum addition amounts of water extract of Schizandra chinensis was 0.9％ for Lac. acidophilus, 0.8％ for Lac. casei, 0.2％ for Lac. bulgaricus and 0.1％ for Str. thermophilus in order to maintain the propagation of the lactic acid bacteria. When the drink type yoghurts added with 0.4％, 0.6％, 0.8％ and 1.0％ water extract of Schizandra chinensis were kept at 4$^{\circ}C$ for 15 days, it was showed that the number of lactic acid bacteria was not significantly changed during the storage. The viable cell counts of the drink type yoghurts by addition of 0.4∼l.0％ of water extract of Schizandra chinensis were 1.13${\times}$10$\^$9/∼2.29${\times}$10$\^$9/ CFU/mL, and these bacterial counts were still more than the legal standard(1.0${\times}$10$\^$8/ CFU/mL) even at 15 days of storage.

• Food Science and Preservation
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• v.16 no.5
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• pp.605-611
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• 2009

Korean Baechu cabbage(known as Chinese cabbage) brined in 0%, 5% and 10% (all w/v) salt solutions were packed using high-density polyethylene film (HDPE-film), low-density polyethylene film (LDPE-film), or Mirafresh film (MF-film, US patent No. 5972815), and stored at 4C for 4 weeks. Changes in pH and salinity, and microorganism counts (lactic acid bacteria and total bacteria), were investigated. There was no significant difference in the pH change in cabbage stored using various films when the vegetables were not salted. However, the pH was most stable in Baechu cabbage prepared using 10% salt solution. Cabbage treated with 0%, 5%, and 10% salt showed salinity values of 0.83%, 1.17% and 1.62%(all w/w), respectively, after 4 weeks of storage by LDPE-film. When cabbage was treated with the highest concentration of salt solution, the count of lactic acid bacteria increased but that of total bacteria decreased. The pH from pH 6.10 to pH 4.32, pH 5.68, and pH 5.92 in brined cabbage packed in HDPE-film, LDPE-film, and MF-film, respectively, after 4 weeks. When MF-film was used, the pH showed the greatest stability of all films tested, regardless of the concentration of salt solution employed in brining. The counts of lactic acid bacteria and total bacteria increased by all tested films during storage. Cabbage packed by MF-film showed the lowest increase in bacterial counts. In conclusion, MF-film was found to be the most effective packaging material for Baechu cabbage and brining in 10% salt solution was optimal to enhance the shelf life of the vegetable. LDPE-film was more effective than was HDPE-film for storage of brined cabbage.

• Food Science of Animal Resources
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• v.30 no.3
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• pp.472-478
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• 2010

The effects of rosemary and $\alpha$-tocopherol, added individually or in combination, on broiler performance, thiobarbituric acid reactive substance (TBARS), total plate count (TPC) and meat color of chicken thigh meat were investigated. Three hundred broiler chicks divided into five groups were fed a basal diet (control) or basal diet supplemented with 5 g rosemary/kg (T1), 10 g rosemary/kg (T2), 200 mg $\alpha$-tocopherol/kg (T3), or 5 g rosemary/kg + 200 mg $\alpha$-tocopherol/kg (T4) for 5 weeks. Following slaughter, chicken meat was stored at $4^{\circ}C$ for 10 days. All treatments did not influence the performance. Rosemary supplementation delayed lipid oxidation in thigh meat during refrigerated storage. T2 was significantly (p<0.05) more effective in delayed lipid oxidation compared to T1, but was inferior to T3. Samples containing a combination of antioxidant had lower TBARS values than those containing the individual antioxidants, indicating a synergistic effect. TPC was significantly increased (p<0.05) in thigh meat of all groups throughout the refrigerated storage. The T3 and control groups showed TPC counts that did not differ from each other during the entire storage period. However, rosemary supplementation was associated with bacterial counts that were significantly lower (p<0.05) than the control and $\alpha$-tocopherol groups at day 3 of storage and thereafter. For this period, T1 presented TPC counts that were significantly higher than the T2 group (p<0.05). At all storage times, the thigh meat of rosemary-fed chickens was redder than control (higher $a^*$), while no differences in $L^*$ and $b^*$ values were found. A synergistic effect was obtained from the combination of rosemary with $\alpha$-tocopherol, whereas individual use of the antioxidants significantly improved color stability compared to the control.

• Korean Journal of Ecology and Environment
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• v.37 no.1 s.106
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• pp.26-35
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• 2004

We investigated the effect of physicochemical environmental factors on the community dynamics of phytoplanktons and bacteria at the Hoeya Dam Reservoir, a drinking water reservoir for Ulsan city. Water samples were collected and analyzed every two to four weeks at three sites along the reservoir from April to October, 2001. During the study period, the Secchi depths were between 0.4 and 3.5 m. At the surface layer of water column, temperature ranged 10.2 ~ $32.0^{\circ}C$, pH 7.3${\sim}$9.6, dissolved oxygen 5.5 ${\sim}$ 12.4 mg $L^{-1}$, $BOD_5$ 0.8 ${\sim}$ 5.0 mg $L^{-1}$, $COD_{Mn}$ 3.7 ${\sim}$ 10.0 mg $L^{-1}$, and Chl-a 8.9 ${\sim}$ 60.9 mg $m^{-3}$. At the bottom layer, temperature varied 7.2 ${\sim}$ $28.9^{\circ}C$, pH 7.1 ${\sim}$ 9.3, dissolved oxygen 0.6 ${\sim}$ 9.7 mg $L^{-1}$, $BOD_5$ 0.8 ${\sim}$ 4.5 mg $L^{-1}$, $COD_{Mn}$ 3.9 ${\sim}$ 10.0 mg $L^{-1}$, and Chl-a 4.3 ${\sim}$ 81.9 mg $m^{-3}$. The numbers of phytoplanktons were 7.4${\pm}10^2{\sim}2.6{\pm}10^5$ cells $mL^{-1}$ at surface and 2.5${\pm}10^2{\sim}2.4{\pm}10^4$ cells $mL^{-1}$ at bottom, and were positively correlated with water temperature and Chl- a concentration. Genus Stephanodiscus and genus Oscillatoria dominated on April and on May, respectively. Cyanobacterial blooms of Aphanizomenon, Microcystis, Anabaena were observed from June to early September, and thereafter Stephanodiscus and Aulacoseiral dominated again. Total microbial counts ranged 1.73${\pm}10^4{\sim}1.68{\pm}10^5$ cells $mL^{-1}$, and were positively correlated with water temperature and phytoplankton counts at surface water. Heterotrophic plate counts (HPCs) ranged 30${\sim}4.1{\pm}10^3$ CFU $mL^{-1}$, and were positively correlated with $BOD_5$ and $NO^3\;^-$-N concentration at bottom water. Unlike the total microbial counts, the numbers of fecal coliforms and fecal streptococci as well as HPCs were higher at the bottom than the surface layer and were highest at the upper a site among the three sampling sites. Since the concentrations of fecal coliforms and streptococci were still high at the bottom of site c, where intake for water treatment plant is located, it appeared that special management of water treatment processes may be needed especially after strong rainfall.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.4
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• pp.241-246
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• 2013

The purpose of this study was to investigate the synergistic effects of erythrosine sensitized with a conventional halogen curing unit and sub-minimal bactericidal concentration(sub-MBC) of chorhexidine on bacterial viability of Streptococcus mutans in planktonic state. Sub-minimal bactericidal concentration of chlorhexidine was added into wells containing bacteria and erythrosine. The range of concentrations tested for chorhexidine was from 0.0000001% to 0.001%. The irradiation of the bacterial suspensions was performed for 15 sec with a conventional halogen curing unit light. In another set of experiment, the effects of 0.001% chlorhexidine were observed by adding chlorhexidine into wells containing the sub-minimal bactericidal concentration of erythrosine. At the concetration of 0.001% chlorhexidine, there were no antibacterial effects in the absence of erythrosine PDT(p < 0.05). At the concentraton of $1{\mu}M$ erythrosine, there was no photodynamic therapy effect in the absence of chlorhexidine(p < 0.05). But in the presence of sub-minimal bactericidal concentration of erythrosine with light exposure, the addition of 0.001% chlorhexidine increased the bactericidal rate(p < 0.05). A combination of erythrosine PDT with sub-MBC chlorhexidine resulted in a significant reduction in bacterial counts when compared to the case with the absence of chlorhexidine.

• Korean Journal of Microbiology
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• v.44 no.3
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• pp.244-250
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• 2008

To evaluate bacteriological water quality, samples were taken from drinking water dispensers placed at S company (S-C) and U highschool (U-H) in Ulsan. The medians of heterotrophic plate counts (HPCs) were 53 CFU/ml for the 74 water samples of S-C and 80 CFU/ml for the 36 cold water samples of U-H, and 38% of the S-C and 42% of the U-H samples showed HPC bacterial concentrations higher than 100 CFU/ml. Coliform bacteria were detected from one sample of S-C. To determine the major source of bacterial contamination, water samples were taken daily for $6\sim8$ days from the bottled water containers as well as the faucets of an experimental water dispenser. While the average HPCs in the bottled water containers were 33 CFU/ml for the first and 132 CFU/ml for the 2nd analysis, the HPC concentration in the cold water samples was 1,022 CFU/ml for the 2nd analysis. These results suggest that the majority of bacteria detected in the cold water samples were originated from the biofilms on the surface of water passages within the water dispensers. There was no significant increase in HPC bacterial concentrations within the bottled water container after installation on the water dispenser. We could isolate and tentatively identify 3 genera 6 species of Gram-positive and 7 genera 7 species of Gram-negative bacteria from the plate count agar plates of U-H samples. Among the isolates, 72% were observed as Gram-positive, and Micrococcus spp. was the most abundant with 54% of the total, followed by Sphingomonas paucimobilis with 16%. It appears that most of the HPC bacteria detected in water dispensers originate from indoor airborne bacteria, which may play important roles in the formation of biofilms on the surface of water passages within the water dispensers.