• Korean Journal of Food Science and Technology
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• v.38 no.2
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• pp.290-294
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• 2006

Inactivation rates of Salmonella enteritidis in vitro and in vivo were assessed using confocal microscopy and flow cytometry. S. enteritidis was inactivated with 1% (w/v) trisodium phosphate (TSP) and live cells, and inactive cells were distinguished by staining with fluorescent probe, LIVE/DEAD BacLight Bacteria Viability stain. After TSP treatment for 1 min, most of Salmonella cells changed from green (live cells) fluorescence to red (inactive cells) fluorescence, indication of effective sanitizing. Inactivation efficiency and contamination sites of S. enteritidis on chicken skin by TSP treatment were assessed using confocal laser microscopy. Precise flow cytometry histograms for viability changes of S. enteritidis. after TSP treatments were obtained. Efficiency of various sanitizer treatments on foodborne pathogens could be assessed using this method.

• YAKHAK HOEJI
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• v.54 no.2
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• pp.122-125
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• 2010

The essential oil fraction was extracted from the aerial parts of the plant by steam distillation method and its composition was analyzed by GC-MS (gas chromatography-mass spectrometry) which led to the identification of 43 compounds. Dehydroelsholtzia ketone (56.81%) and elsholtzia ketone (30.05%) were identified as the predominant components of this oil. The antibacterial activities of the essential oil fraction were assessed by micro-dilution tests against antibioticsusceptible and -resistant strains of Streptococcus pneumoniae, Staphylococcus aureus, Salmonella enteritidis, and S. typhimurium. The oil inhibited most of the tested strains significantly resulting MICs (minimum inhibiting concentrations) between 2 mg/ml and >16 mg/ml. In most cases of this study Streptococcus pneumoniae and Staphylococcus aureus showed higher sensitivity to this oil than Salmonella strains.

• Journal of Dairy Science and Biotechnology
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• v.36 no.4
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• pp.208-219
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• 2018

Emergence of drug resistant strains of Salmonella enterica threatens milk processing and related dairy industries, thereby increasing the need for development of new anti-bacterials. Developments of antibacterial drugs are largely aimed to target the bacterial envelope, but screening their efficacy on bacterial envelope is laborious. This study presents a potential biosensor for envelope-specific stress in which a gfp reporter gene fused to spy gene encoding a periplasmic chaperone protein Spy (spheroplast protein y) that can sense envelope stress signals transduced by two major two-component signal transduction systems BaeSR and CpxAR in Salmonella enterica serovars Enteritidis and S. Gallinarum. Using spy-gfp operon fusions in S. Enterititis and S. Gallinarum, we found that spy transcription in both serovars was greatly induced when Salmonella cells were forming the spheroplast and were treated with ethanol or a membrane-disrupting antibiotic polymyxin B. These envelope stress-specific inductions of spy transcription were abrogated in mutant Salmonella lacking either BaeR or CpxR. Results illustrate that induction of Spy expression can be efficiently triggered by two-component signal transduction systems sensing envelope stress conditions, and thereby suggest that monitoring the spy transcription by spy-gfp operon fusions would be helpful to determine if developing antimicrobials can damage envelopes of S. Enteritidis and S. Gallinarum.

• Journal of Veterinary Clinics
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• v.24 no.2
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• pp.130-136
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• 2007

Artemisia capillaris THUNB is a perennial herb that belongs to the family Compositae spp and the most common plant among the various herbal folk remedies used in treatment of abdominal pain, hepatitis, chronic liver disease, jaundice and coughing in Korea. In this study, antimicrobial effects of Artemisia capillaris extracts on the food poisoning bacteria were investigated for further clinical application, which is an alternative for the use of antibiotics and their unexpected resistance. Artemisia capillaris extract using ethyl acetate showed the highest antimicrobial effects on S. enteritidis, E. coli O157 : H7, L. monocytogenes and S. aureus. The chloroform extract showed strong effects on all kinds of bacteria; whereas ethanol and methanol extracts showed weaker effects. Finally, ether and water extracts showed the weakest effects under the same conditions. The minimum inhibitory concentration (MIC) of ethyl acetate extract was 1 mg/mL for E. coli O157 : H7 and L. monocytogenes, and 2 mg/mL for S. enteritidis and S. aureus. The inhibitory effects on all the bacteria continued for 12 hours after incubation using 20 mg/mL and 30 mg/mL of ethyl acetate extract. The inhibitory effects continued maximally for 72 hours. The results of these studies indicate Artemisia capillaris extract exhibited excellent antimicrobial and inhibitory effects on the food poisoning pathogenic bacteria; S. enteritidis, E. coli O157 : H7, L. monocytogenes and S. aureus.

• Food Science and Preservation
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• v.15 no.2
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• pp.300-305
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• 2008

We investigated an antibacterial substance produced by Bacillus subtilis HS 25. Antibacterial activity was relatively heat-stable, with no effect caused by heating at $100^{\circ}C$ for 10 min, but a gradual decrease in activity after 15 min at $100^{\circ}C$. The antibacterial substance was more stable at pH 7.42-12 than at pH 4.5-5.0. There was strong antibacterial activity against E. coli and P. mirabilis at pH 12. The minimum inhibition concentration (MIC) of the substance was 5 mg/mL for E. coli 7.5 mg/mL for P. mirabilis and S. aureus and 15 mg/mL for S. enteritidis, K. pneunoniae, and V. parahaemolyticus. When the substance was added to cultures of E. coli, S. enteritidis, and P. mirabilis, the bacterial surfaces became irregular and deeply changed. The substance produced from B. subtilis HS 25 was not degraded by Papain but was degraded by a protease from Aspergillus orzae, pancreatin, and pepsin.

• Journal of Biosystems Engineering
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• v.30 no.2 s.109
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• pp.121-126
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• 2005

In this study, a commercial electronic nose system was used to detect contamination of Salmonella bacteria. Odors from growth media contaminated with Salmonella typhimurium, Salmonella enteritidis, or Escherichia coli were collected and analyzed to evaluate a possibility of rapid detection of pathogen. Odor chromatograph showed that S. typhimurium, S. enteritidis, and E. coli had 7,6, and 9 main peaks, respectively. Retention time and intensity of the peaks were distinct for different bacteria species. Principal component analysis (PCA) were also performed to clarify odor differences. Analysis results showed that the odors for uncontaminated growth medium were differently grouped from the odors of contaminated one. The odor from the bacteria growth identified with two principal components, PC 1 and PC2. In PCA figures, odor groups were moved from left to right of PC 1 with elapse of the bacteria growth time. The electronic nose system could detect odors of S. typhimurium, S. enteritidis, E. coli when their concentration were $1.85\times10^6\;cfu/g,\;2.25\times10^6\;cfu/g,\;and\;1.8\times10^5 cfu/g$, respectively.

• Horticultural Science & Technology
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• v.32 no.3
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• pp.408-414
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• 2014

The antimicrobial and antioxidant activities of different cultivars and parts of broccoli were investigated. The screening of antimicrobial activities for the floret and leaf extracts of 11 cultivars against selected gram positive (Staphylococcus aureus and Listeria monocytogenes) and gram negative bacteria (Escherichia coli O157:H7 and Salmonella enteritidis) were conducted. The AMG cultivar showed the highest antimicrobial activity against S. aureus with the floret and leaf extracts (12.83 and 13.00 mm). Antibacterial activity against L. monocytogenes was strongest with floret extract of NJ cultivar (13.58 mm) and leaf extract of YDR cultivar (13.92 mm). Moreover, the size of inhibition zone against L. monocytogenes was bigger than those of 4 kinds of pathogenic bacteria. Both floret and leaf extracts of Grd cultivar showed the highest antimicrobial activity against E. coli O157: H7, but there was no difference between floret and leaf extracts. Floret extract o f NJ cultivar and leaf extract of NY and 0c cultivars were effective against S. enteritidis whereas leaf extract exhibited better antimicrobial effect than floret extract. These results showed that floret extract of NJ and leaf extract of 0c had the highest antioxidant activity which was 39.90 and 43.64%, respectively. The antioxidant activity of leaf extract was 1.5 times higher than that of floret extract. All cultivars except NJ showed that electron donating ability of leaf extract was higher than that of floret extract.

• Korean Journal of Food Science and Technology
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• v.48 no.5
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• pp.486-491
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• 2016

Efficacy of dielectric barrier discharge-cold plasma treatment (DBD-CPT) for microbial decontamination of onion powder was evaluated. Onion powder, inoculated with Escherichia coli O157:H7, Salmonella Enteritidis, or Listeria monocytogenes, was treated with helium DBD-CPT. DBD-CPT (9 kV, 20 min) inhibited E. coli O157:H7, S. Enteritidis, and L. monocytogenes by $1.4{\pm}0.5$, $2.3{\pm}0.3$, and $1.2{\pm}0.0log\;CFU/cm^2$, respectively. The inactivation levels of E. coli O157:H7, S. Enteritidis and L. monocytogenes increased by $2.2{\pm}0.1$, $2.5{\pm}0.1$ and $1.9{\pm}0.3log\;CFU/cm^2$, respectively, as water activity increased from 0.4 to 0.8, and increased by $2.3{\pm}0.4$, $2.1{\pm}0.1$ and $1.6{\pm}0.1log\;CFU/cm^2$, respectively, as the particle size increased from 0.3 to $1.0cm^2$. Neither the ascorbic acid and quercetin concentrations nor the color of onion powder was changed by DBD-CPT (p>0.05). These results demonstrate the potential for application of DBD-CPT in improving microbiological safety of onion powder while preserving the physicochemical properties.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.584-587
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• 2000

The invasion genes from Salmonella typhimurium were identified by the construction of a cosmid library and subcloning genes into a plasmid vector, pGEM-7Z. The 4.65 kb fragment of the invasion-conferring genomic region of the subclone, pSV6235 was sequenced in both direction. The three open reading frames, which were located at downstream of a promoter region, were designated as sir (Salmonella invasion region)A coding for the 36 amino acids, sirB coding for the 132 amino acids and sirC for the 82 amino acids, respectively. Interesingly, the genomic region of pSV6235 was highly homologous to Yersinia enterocolitica genomic DNA for a high pathogenicity island and Salmonella enteritidis insertion element IS1351 and IS200 DNA. These results show that there could be a significant relationship between S. typhimurium, Y. enterocolitica and S. enteritidis with respect to horizontal evolution process and acquisition of virulence determinants by means of transposon, plasmid or bacteriophage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.110-116
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• 2019

To investigate the antagonistic inhibitory effects in a mixed culture between probiotics and various pathogenic microorganisms, 140 probiotics were identified using a 16 rRNA sequencing phylogenetic analysis method, and various probiotics strains were isolated from Korean kimchi from January to December 2016. The antagonistic inhibition test of a mixed culture of four probiotics (Enterococcus faecalis, Lactobacillus plantarum, Lactobacillus rhamnosus, and Lactobacillus reuteri) with excellent antimicrobial activity and six pathogenic microorganisms (Candida albicans, Salmonella Enteritidis, E. coli O157:H7, Shigella flexneri, Staphylococcus aureus, and Pseudomonas aeruginosa)showed that the growth of most probiotics strains increased normally after culture, but growth was inhibited almost completely in most pathogenic microorganisms, except for S. Enteritidis. This antagonistic inhibitory effect in vitro was attributed to the low pH of the lactic acid and organic acid produced during fermentation. As a result, four probiotics strains isolated from Korean Kimchi are very likely to be developed as therapeutic agents for female yeast infections and colon and skin care. In the future, these therapeutic agents will help improve public health related to probiotics.