• Food Science and Preservation
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• v.23 no.6
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• pp.759-764
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• 2016

This purpose of this study was to determine the best enrichment medium for rejuvenating and recovering Salmonella placed in cold temperature prior to the employment of the gold biosensor combined with a light microscopic imaging system. A mixture of nalidixic-resistant Salmonella Typhimurium and Enteritidis were inoculated onto chicken (1,000 CFU/chicken). After cold injury at $4^{\circ}C$ for 24 hr, Salmonella on chicken was enriched for 6 hr with six non-selective media including buffered peptone water broth, lactose broth, brain heart infusion broth (BHI), universal pre-enrichment broth, nutrient broth, and tryptic soy broth, and five selective media including brilliant green broth (BG), rappaport-vassiliadis R10 broth, selenite cystine broth, selenite broth, and tetrathionate brilliant green broth (TBG) for the comparison of Salmonella growth. Various concentrations of Salmonella (10, 50, 100, 500, and 1,000 CFU/chicken) were then enriched for 6 hr in both BHI and BG media to select the best media. BHI was selected as the most effective non-selective enrichment medium, while BG was selected as the most effective selective enrichment medium. Finally, BHI medium was selected as the most efficient enrichment medium for Salmonella growth injured from cold temperature during processing or storage.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.4
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• pp.373-385
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• 2004

Statement of problem: The microbial adhesion on the surface of materials used in prosthodontics and restorative dentistry significantly influences microbial infection. Purpose: The purpose of this study was to evaluate the effect of how the degree of surface roughness of acrlyic resin affect the adhesion of bacteria. Material and methods: Resins were finished with $50{\mu}m$ and $250{\mu}m$ aluminium oxide particles by using sandblaster, by using stone point, and high polished with $Opa^{(R)}$ and Lace $motor^{(R)}$. The surface of acrylic resin attached by bacteria was directly touched on the surface of BHI agar, which was incubated. Bacteria colonies formed on BHI agar were counted in accordance with the degree of the surface roughness. Results: 1. The viable cell number of Streptococcus mutans increased on the acrylic resins incubated in BHI broth than in PBS. 2. The viable cell number of Streptococcus mutans increased on the acrylic resins incubated without agitation than with agitation, washed three times than six times, and incubated in broth added with 5% sucrose than without sucrose. 3. When Streptococcus mutans incubated in BHI broth, the number of Streptococcus mutans colonies formed on BHI agar was the largest on the acrylic resins finished with $250{\mu}m$ aluminium oxide particle using sandblaster. But when incubated in BHI broth containing sucrose, the number of colonies formed on that was the largest on the acrylic resins high polished using $Opal^{(R)}$ and Lace $motor^{(R)}$. 4. When Streptococcus sanguis was incubated in BHI broth with or without sucrose, the number of Streptococcus mutans colonies formed on BHI agar was the largest on the acrylic resins finished with $250{\mu}m$ aluminium oxide particle using sandblaster. 5. When Actinomyces viscosus was incubated in BHI broth with or without sucrose, the number of Streptococcus mutans colonies formed on BHI agar was the largest on the acrylic resins high polished using $Opal^{(R)}$ and Lace $motor^{(R)}$. Conclusion: These results indicated that when acrylic resins attached by bacteria were touched on the surface of BHI agar, the number of bacterial colonies formed on the agar was dependent on the bacterial species. Also, the result of this study was showed that increase in the surface roughness and the addition of sucrose increased retention of microbial cells.

• Preventive Nutrition and Food Science
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• v.15 no.3
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• pp.239-243
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• 2010

The antimicrobial effects of a commercially available, buffered sodium citrate (BSC) were evaluated for the reduction of total aerobic bacteria count, Salmonella Typhimurium, Escherichia coli O157:H7, Listeria monocytogenes and Staphylococcus aureus in a liquid medium and ground beef. BSC at 0, 1, 2 and 4.8% (wt/vol) or 0, 3, and 4.8% (wt/wt) was mixed into inoculated brain heart infusion (BHI) broth and ground beef (80% lean), respectively. BSC at concentrations of 1 and 2% did not inhibit growth of the pathogens tested in BHI broth. E. coli O157:H7 in BHI broth with 4.8% BSC was significantly reduced (p<0.05) by 3～4 log CFU/mL compared with the control for up to 4 days. At 4.8%, BSC treatment of ground beef most significantly reduced (p<0.05) total aerobic count and E. coli O157:H7 by 2.1 and 2.0 log CFU/g, respectively. This study indicates that the legally allowable level of 1.3% (wt/wt) BSC is not effective for reducing the pathogens tested in ground beef stored at $7^{\circ}C$.

• Journal of Dairy Science and Biotechnology
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• v.41 no.3
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• pp.103-112
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• 2023

This study aimed to assess the effectiveness of 10 different pre-enrichment methods using Real-Time polymerase chain reaction (PCR) in support of the FDA method. When the initial Cronobacter spp. (Enterobacter sakazakii) inoculation was 7.2 CFU/g, the Ct values were observed in the following order: 21.37 (Enterobacteriaceae enrichment [EE] broth), 21.95 (brain heart infusion [BHI]), 22.72 (tryptic soy broth [TSB]), 23.02 (violet red bile lactose [VRBL]), 22.31 (TSB-0.1% sodium pyruvate [SP]), 23.43 (distilled water [DW]), 24.34 (phosphate buffered saline [PBS]), 24.95 (nutrient broth [NB]), 25.82 (TSB-0.6% yeast extract [YE]), and 28.27 (violet red bile glucose [VRBG]). For an inoculation of 1.82% CFU/g of Cronobacter spp. (E. sakazakii), the Ct values were recorded in this sequence: 20.34 (EE broth), 22.16 (TSB-0.6% YE), 22.37 (BHI), 22.71 (VRBL), 22.88 (TSB), 23.01 (DW), 23.19 (NB), 23.79 (TSB-0.1% SP), 24.66 (VRBG), and 24.70 (PBS). Finally, when the inoculum of Cronobacter spp. (E. sakazakii) was 0.182 CFU/g, the Ct values followed this order: 21.93 (VRBL), 23.07 (TSB-0.6% YE), 23.31 (DW), 23.47 (PBS), 23.70 (BHI), 24.14 (TSB-0.1% SP), 25.14 (TSB), 29.00 (VRBG), 31.55 (EE broth), and were undetected in the case of NB. Consequently, these results indicate that there were no significant differences among the 10 different pre-enrichment broths. Future studies should focus on exploring pre-enrichment broths that can improve the limit of detection at very low Cronobacter spp. (E. sakazakii) concentrations and enhance the selective recovery of Cronobacter spp. (E. sakazakii) under acid, antibiotic, cold, and heat damage conditions.

• The Journal of the Korean Society for Microbiology
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• v.9 no.1
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• pp.13-18
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• 1974

Blood is one of the most important clinical specimens for the isolation of bacteria. A rapid isolation and a high isolation rate of bacteria are very important in blood culture because bacteremic patients are mostly in grave condition. Various blood culture media which support growth of most fastidious bacteria are available commercially. However, growth of bacteria are frequently delayed because of antibacterial activity of blood. Sodium polyanethol sulfonate(Liquoid) has been reported to inactivate the antibacterial substance and disrupt phagocytic cells. The beneficial effect of SPS is well recognized in the isolation of gram-positive bacteria. However, the effect does not seem to be prominent for gram-negative bacilli isolation mainly due to the rapidity of their growth. It has been experienced with Sal. typhi that the growth is much slower than that of other gram-negative bacilli. For the rapid growth of the organism, use of bile broth has been recommended. Although Sal. typhi is the most frequently isolated organism at present, about one half of total isolates are other organisms and, in case bile broth is used, other media which support growth of these organisms should be used together. Fluid thioglycollate medium(FTM) which is always used in blood culture to isolate anaerobes is inferior to brain heart infusion(BHI) for the isolation of aerobes. This study was done to determine the effect of SPS on the isolation of Sal. typhi from blood. During the Sep. 1973 to Sep. 1974 study period, 2460 blood cultures were made from the Severance hospital patients: BHI and FTM sets 1431 specimens, BHI with SPS(0.05%) and FTM sets 396 specimens, BHI and FTM with SPS sets 359 specimens, BHI and BHI with SPS sets 274 specimens. Mean incubation time required for the macroscopic detection of growth of Sal. typhi were 3.5 days on BHI and 2.7 days on BHI with SPS. The 0.8 day difference was statistically significant. On FTM the mean incubation time was 3.8 days while it was 2.9 days on FTM with SPS. The 0.9 day difference was statistically significant. The result on BHI with and without SPS sets showed faster growth on BRI with SPS in 7 specimens and slower growth in one specimen and the remaining 12 showed growth at the same time. These specimens had mean incubation time of 3.2 days on BHI and 2.3 days on BHI with SPS. The 0.9 day difference was statistically significant. This study indicates beneficial effect of SPS for the rapid isolation of Sal. typhi from clinical blood specimens.

• Restorative Dentistry and Endodontics
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• v.46 no.3
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• pp.35.1-35.11
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• 2021

Objectives: Endosequence Bioceramic Root Repair Material (BC-RRM) is used in endodontic microsurgery. It is available as a paste and a putty. However, no studies to date have examined the sealing ability of these forms alone or in combination as root-end filling materials. Hence, this study aimed to compare the sealing properties of these 2 forms of BC-RRM. Materials and Methods: Forty-two extracted upper anterior teeth were divided into 3 experimental groups, a positive and negative control. After the root canal treatment, the root ends were resected, retroprepared and retrofilled with either putty, paste + putty or mineral trioxide aggregate (MTA). The teeth were mounted in tubes so the apical 3 mm was submerged in Brain Heart Infusion (BHI) broth. The coronal portions of the canals were inoculated with Enterococcus faecalis and BHI broth and incubated for 30 days. The broth in the tubes was analyzed for colony forming units to check for leakage of bacteria from the canal. The teeth from the groups were sectioned and analyzed using scanning electron microscopy (SEM). The Kruskal-Wallis test and analysis of variance were used to analyze the data with a significance level p < 0.05. Results: The BC-RRM and MTA groups showed similar sealing ability. The positive control showed leakage in all samples. The SEM imaging showed the presence of bacteria in all experimental groups at the material-tooth interface. Conclusions: No significant differences were noted in the experimental groups, providing sufficient evidence that any combination could be effectively used during endodontic microsurgery.

• Korean Journal of Microbiology
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• v.51 no.4
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• pp.407-418
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• 2015

This study is focused on establishing the optimal conditions to enhance the production of antilisterial substances by Lactobacillus paracasei BK57 isolated from Baikkimchi. In addition, the growth and in situ lactic acid and bacteriocin production of this strain were investigated during the manufacture of fresh cheese. And then the efficacy of using Lactobacillus starter as a protective culture to improve the safety of fresh cheese against Listeria monocytogenes KCTC 3569 was estimated. Maximum growth rate and activity of antibacterial substances were obtained in Lactobacilli MRS broth at $37^{\circ}C$ with controlled pH 6.0 after 30 h of incubation under aerobic condition. However, the growth rate and antimicrobial activity of bacteriocin produced in whole milk supplemented with yeast extract (2.0%) as a substrate were lower than those obtained in MRS broth. Live cells and cell-free culture supernatant of BK57 strain were effective in the suppression of L. monocytogenes in milk, whereas the inhibitory of the bacteriocin obtained from BK57 strain was higher in BHI broth than in milk. During storage at $4^{\circ}C$ and $15^{\circ}C$ for 6 days, no significant difference was found in the cell viability and antimicrobial activity of BK 57 strain in fresh cheese. In samples held at two temperatures, there was at least a 15% reduction in the numbers of the pathogen in fresh cheese artificially contaminated with approximately $10^5CFU/ml$ of L. monocytogenes within 6 days. Our results demonstrated the usefulness of L. paracasei BK57 having antilisterial activity as a biopreservative in the cheese making process.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.1
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• pp.92-99
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• 2002

There have been efforts that inhibit development of dental caries by sugar substitution. But, it is controversial if xylitol has anticariogenic effect in the presence of sucrose. And there are few papers dealing with the combined action of xylitol and sucrose. For the purpose of resolving this controversy, the author investigated the effect of xylitol on enamel demineralization and on adhesiveness of S. mutans to hydroxyapatite in the presence of sucrose. Five experimental solutions were prepared as follows: (S: sucrose, X: xylitol) Group 1: BHI broth Group 2: BHI+1% S Group 3: BHI+0.75% S+0.25% X Group 4: BHI+0.5% S+0.5% X Group 5: BHI+0.25% S+0.75% X Group 6: BHI+1% X Each solution was inoculated with $100{\mu}l$ of S. mutans JC-2. And saliva coated hydroxyapatite beads were put into each experimental solution. And then each solution was incubated at $37^{\circ}C$ under anaerobic condition. After incubation, the adhesiveness of S. mutans on hydroxyapatite was evaluated. The Vickers hardness numbers were measured on extracted human primary teeth, and these teeth were dipped into the same experimental solution and incubated at $37^{\circ}C$ under anaerobic condition for 48hours. Surface microhardness were measured again after incubation. The obtained results were as follows; 1. In the presence of sucrose, xylitol can reduce the adhesiveness of S. mutans on hydroxyapatite surface from the ratio of 25% sucrose to 75% xylitol(P<0.05). 2. In the presence of sucrose, xylitol can reduced demineralization of primary teeth enamel surface from the ratio of 50% sucrose to 50% xylitol(P<0.01).

• Journal of Microbiology
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• v.43 no.4
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• pp.370-374
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• 2005

Bacteriocin ST311LD is approximately 2.3 kDa in size. Low levels of bacteriocin activity were recorded in BHI and M17 broth (800 AU/ml) and in $10\%$ (w/v) soy milk (3,200 AU/ml). No bacteriocin pro-duction was recorded in $10\%$ (w/v) molasses, despite good growth. Optimal levels (12,800 AU/ml) were detected in MRS broth which had been supplemented with tryptone (20.0 g/l), saccharose (5.0 or 10.0 g/l) or vitamin C (1 ppm). Increased potassium levels did not result in higher levels of activity, and glycerol (1.0 g/l) inhibited the production of bacteriocin ST311LD.

• Food Science of Animal Resources
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• v.41 no.1
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• pp.164-171
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• 2021

Listeria monocytogenes is a representative foodborne pathogen and causes listeriosis. Enterococcus faecium CJNU 2524 was confirmed to produce a bacteriocin with anti-listerial activity. To establish optimal culture conditions for the production of the bacteriocin from E. faecium CJNU 2524, different media (MRS and BHI broth) and temperatures (25℃, 30℃, and 37℃) were investigated. The results showed that the optimal culture conditions were MRS broth and 25℃ or 30℃ temperatures. The crude bacteriocin was stable in a broad range of pH conditions (2.0-10.0), temperatures (60℃-100℃), and organic solvents (methanol, ethanol, acetone, acetonitrile, and chloroform). The bacteriocin activity was abolished when treated with protease but not α-amylase or lipase, indicating the proteinaceous nature of the bacteriocin. Finally, the bacteriocin showed a bactericidal mode of action against L. monocytogenes. Therefore, it can be a biopreservative candidate for controlling L. monocytogenes in dairy and meat products.