• Korean journal of food and cookery science
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• v.18 no.1
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• pp.57-62
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• 2002

The purpose of this study was to investigate the antibacterial activity of green tea in mayonnaise against pathogenic bacteria (Escherichia coli O157:H7 and Salmonella typhimurium). Mayonnaise was prepared with salad oil, egg yolk, sugar, salt and vinegar, and green tea powder was added to the mayonnaise at 0.1, 0.3 and 0.5% for the experiment. Then, the mayonnaise samples with various levels of green tea were inoculated with about 10$\^$6/ cells/g of E. coli and S. typhimurium per 1 gram of mayonnaise and stored at 5$^{\circ}C$, 15$^{\circ}C$ and 25$^{\circ}C$ for 3∼9 days. Antibacterial activity of green tea was tested by the colony counting method for E. coli on violet red bile agar(VRBA) and S. typhimurium on xylose lysine desoxycholate agar(XLDA). The D-values of E. coli controls were 2.89, 2.73 and 2.13 days while those of S. typhimurium controls were 0.58, 0.53 and 0.52 days at 5$^{\circ}C$, 15$^{\circ}C$ and 25$^{\circ}C$, respectively Inhibitory effect of green tea in mayonnaise on the survival of E. coli and S. typhimurium was increased with increasing concentration of green tea and/or increasing storage temperature. The most effective antibacterial activity of green tea was shown against E. coli in mayonnaise during storage at 25$^{\circ}C$.

• Journal of Food Hygiene and Safety
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• v.34 no.4
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• pp.374-379
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• 2019

This study developed predictive growth models of Salmonella enterica Serovar Typhimurium on lettuce washed with chlorine (100~300 ppm) and ultrasound (US, 37 kHz, 380 W) treatment and stored at different temperatures ($10{\sim}25^{\circ}C$) using a polynomial equation. The primary model of specific growth rate (SGR) and lag time (LT) showed a good fit ($R^2{\geq}0.92$) with a Gompertz equation. A secondary model was obtained using a quadratic polynomial equation. The appropriateness of the secondary SGR and LT model was verified by coefficient of determination ($R^2=0.98{\sim}0.99$ for internal validation, 0.97~0.98 for external validation), mean square error (MSE=-0.0071~0.0057 for internal validation, -0.0118~0.0176 for external validation), bias factor ($B_f=0.9918{\sim}1.0066$ for internal validation, 0.9865~1.0205 for external validation), and accuracy factor ($A_f=0.9935{\sim}1.0082$ for internal validation, 0.9799~1.0137 for external validation). The newly developed models for S. Typhimurium could be incorporated into a tertiary modeling program to predict the growth of S. Typhimurium as a function of combined chlorine and US during the storage. These new models may also be useful to predict potential S. Typhimurium growth on lettuce, which is important for food safety purposes during the overall supply chain of lettuce from farm to table. Finally, the models may offer reliable and useful information of growth kinetics for the quantification microbial risk assessment of S. Typhimurium on washed lettuce.

• Journal of Naturopathy
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• v.7 no.1
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• pp.20-25
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• 2018

The purpose of this study was investigated to observe the relatively low amino acid mutations in six different strains of ATCC or KCTC Salmonella strains (four species and two isolates). The mutations in the strains were to be detected and compared with the genes csgA and csgB corresponding to the Thin aggregative fimbriae. Amino acid mutations in the strains were observed from Ser20→ Gly(AGT→GGT) in the csgA gene, Asp25→Ala(GAT→GCT) and Lys66→Thr(AAA→ACA) in the csgB gene. Among the six strains, the two most common amino acid variations were observed in S. typhimurium - TH strains. On the other hand, no mutation of nucleotide sequence was observed in the strains of S. typhimurium ATCC 13311 and S. typhimurium KCTC 1925. In conclusion the genes csgA and csgB in the strains may be useful for the evaluation and detection of amino acid mutation.

• The Korean Journal of Food And Nutrition
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• v.11 no.1
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• pp.72-76
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• 1998

Gardenia yellow pigment produced by Gardenia jasminoides Ellis was tested for reverse mutagenic test in Salmonella typhimurium stains TA1535, TA1537, TA98 and TA100 at concentrations raging form 6.25 to 200$\mu\textrm{g}$/$m\ell$ per plate. No significant reverse mutagenic activity was observed in any of the S. typhimurium strains, in either presence or absence of S9 mix. There was no toxicity to the bacteria. These result indicate that yellow pigment doesn't have mutagenicity.

• Korean Journal of Veterinary Research
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• v.50 no.4
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• pp.285-295
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• 2010

Protein expression patterns in Salmonella enterica subspecies enterica serovar Typhimurium (S. Typhimurium) strains with diverse phenotypes, such as phage type, antibiotic resistance pattern and plasmid profiles were examined. For detailed analysis of proteins expressed by different S. Typhimurium strains, protein fractions were divided into detergent-rich phase (DP) and aqueous phase (AP) using triton X-114 detergent. The two phases were subjected to two-dimensional gel electrophoresis (2-DE), followed by protein identification using peptide mass fingerprinting (PMF). In the results, PMF showed that DP fractions consisted mainly of outer membrane proteins, whereas the AP fractions included cytosolic proteins. Comparison of 2-DE profiles of DP did not show any distinct protein spots which could be correlated with phage type, antibiotic resistance pattern or plasmid profile. However, comparisons of 2-DE profiles of the AP revealed differences in the protein spots, which could be correlated with the plasmid profile and phage types. Among these protein spots, flagellin was specific for strains containing a 90 kb plasmid. Compared to DT193 phage type, three protein spots in the range of pI 5.0-5.5 and MW 8-15 kDa of AP 2-DE profiles were absent in the DT104 phage types. Additionally, a protein spot with PI in the range of 4.5-5.0 and molecular weight (MW) between 51-69 kDa was specific for phage type DT104, while a protein spot with pI in the range of 4.0-4.8 and MW between 18-20 kDa was specific for DT193 phage type. These protein spots may be useful for discriminating phage types of S. Typhimurium.

• Food Science and Preservation
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• v.6 no.2
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• pp.239-244
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• 1999

Antimicrobial activity to the extracts of Perilla frutescens Briton var. acuta Kudo was investigated against various foodborne pathogenes or food poisioning microorganisms(Aspergillus flavus KCTC 6143 and KCTC 6961, Aspergillus niger ATCC 4695, Listeria monocytogenes ATCC 15313, Staphylococcus aureus 196E ATCC 13565, Escherichia coli O157:H7 ATCC 43895, Salmonella typhimurium ATCC 13311 and Yersinia enterocolitica). The ethanol extract of Perilla frutescens Briton var. acuta Kudo was very stable over heat at $121^{\circ}C$ for 15 min. In concentration of $1000\mu\textrm{g}$/mL into culture broth(TSB), the ethanol extract of Perilla frutescens Briton var. acuta Kudo showed the strongest antimicrobial activities against Listeria monocytogenes, followed by Staphylococcus aureus 196E, Salmonella typhimurium. Gram negative bacteria(Escherichia coli O157:H7, Salmonella 쇼phimurium, Yersinia enterocolitica) were less sensitive than Cram positive bacteria but the growth of Escherichia coli O157:H7 and Yersinia exterocolitica were inhibited with increasing concentrations of the extract in culture broth.

• Korean Journal of Microbiology
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• v.27 no.3
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• pp.201-209
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• 1989

Using Mu dJ(Km lac) operon fusion, several oxygen-regulated genetic loci were identified in Salmonella typhimurium. Nine aerobically inducible(oxi) and thirteen anaerobically inducible(ani) operon fusions were newly identified. Based on the control by oxrA regulatory locus, the ani-lacZ fusions were grouped into two classes: class I loci were regulated by oxrA regulatory locus; class II genes were not affected by this locus. Some of the ani-lacZ fusions had required growth in CAA and LB before they exhibited the inducible phinotype. Most of all ani-lacZ fusions were repressed by nitrate and fumarate. Three of the ani loci were mapped into $59{\pm}0.14$ map unit (YK114), $64{\pm}0.5$ map unit(YK120), and $93{\pm}0.29$ map unit(YK112) by testing the cotransduction frequency, respectively.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.450-455
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• 1998

Pine has been known as a traditional medicinal plant and as showing a physically beneficial function to a human being. Therefore, this study was performed to investigate the physiological activities of main pine neddles. Ethanol extracts from pinus needles did net exhibit any mutagenicity. On the contrary, inhibitory effects of ethanol extract were observed on mutagenicity induced by N-methyl-N'-nitro-N-nitrosoguanidine(MNNG), 4-nitroquinoline-1-oxide (4NQO), 3-amino-1,4-dimethyl-5H-pyrido-(4,3-b)indol (Trp-P-1) and benzo(a)pyrene $(B({\alpha})P)$ using Salmonella typhimurium reversion assay. On direct-acting mutagen (MNNG, 4NQO) and indirect-acting mutagen (Trp-P-1, $(B({\alpha})P)$, we observed higher inhibitory effect. Stepwise fractionation of the ethanol extract was done by using ether, chloroform, ethyl acetate, butanol and water to obtain effective fraction. Among them, water fractions $(100\;{\mu}g/plate)$ of Pinus thunbergii, Pinus rigida, Pinus densiflora and Pinus koraiensis showed high inhibition of 91.65%, 94.7%, 84.22% and 79.02%, respectively, on the mutagenicity of MNNG in Salmonella typhimurium TA100.

• Molecules and Cells
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• v.37 no.2
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• pp.100-108
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• 2014

Salmonella enterica serovar Typhimurium (S. Typhimurium) is an intracellular pathogen that has evolved to survive in the phagosome of macrophages. The periplasmic copper-binding protein CueP was initially known to confer copper resistance to S. Typhimurium. Crystal structure and biochemical studies on CueP revealed a putative copper binding site surrounded by the conserved cysteine and histidine residues. A recent study reported that CueP supplies copper ions to periplasmic Cu,Zn-superoxide dismutase (SodCII) at a low copper concentration and thus enables the sustained SodCII activity in the periplasm. In this study, we investigated the role of CueP in copper resistance at a high copper concentration. We observed that the survival of a cueP-deleted strain of Salmonella in macrophage phagosome was significantly reduced. Subsequent biochemical experiments revealed that CueP specifically mediates the reduction of copper ion using electrons released during the formation of the disulfide bond. We observed that the copper ion-mediated Fenton reaction in the presence of hydrogen peroxide was blocked by CueP. This study provides insight into how CueP confers copper resistance to S. Typhimurium in copper-rich environments such as the phagosome of macrophages.

• Korean Journal of Veterinary Research
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• v.30 no.2
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• pp.203-214
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• 1990

A total of 166 strains of Salmonella (S) typhimurium var copenhagen isolated from pigeons (164 strains) and aquatic birds (2 strains) were examined for the biochemical characteristics and plasmid profiles. All the strains were sensitive to ampicillin, chloramphenicol, gentamicin, kanamycin and sulfadimethoxine. But 13 strains(7.8%) were resistant to streptomycin (Sm), 2 (1.2%) to tetracycline, 2 (1.2%) to rifampicin, and 1 (0.6%) to nalidixic acid. Among drug resistant strains, only one strain resistant to Sm contained conjugative R plasmid which was fertility inhibition and incompatibility group $I_{\alpha}$. All the strains were sensitive to cobalt chloride, cupric sulfate, lead nitrate, mercuric chloride and silver nitrate. Of 166 isolates, 6 (3.6%) were resistant to sodium arsenate and 1 (0.6%) to potassium tellurite. Among 166 isolates, 1 (0.6%) was colicinogenic, 12 (7.2%) sucrose fermenters, and 166 (100%) maltose fermenters. Plasmid profiles were confirmed as being 4 or 5 plasmids, and their molecular weight ranged 3.2 to 60 megadalton (MD). All the strains harbored 60 Md plasmid. There are three patterns by the plasmid profile, 150 isolates (90.4%) were pattern I (3.2, 3.5, 33, 60Md), 14 (8.4%) pattern II (3.2, 3.5, 29, 60Md), and 2 (1.2%) pattern III (4.2, 7.8, 8.5, 15, 60Md). S typhimurium var copenhagen strains containing 60Md plasmid were resistant to killing by 90% normal guinea pig serum.