• Food Science and Preservation
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• v.11 no.4
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• pp.530-537
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• 2004

This study was conducted to determine the inactivation effect of electrolyzed water and organic acids either alone or in combination on L. monocytogenes or natural microflora on lettuce. Acidic electrolyzed water completely inactivated L. monocytogenes in broth system within 60 sec, but alkalin electrolyzed water caused approximate 1.7 log CFU/g reduction. However, acidic electrolyzed water reduced only 2.5 log CFU/g of L. monocytogenes on lettuce, and similar antimicrobial effect was observed with alkalin electrolyzed water. In the meantime, acidic and alkaline electrolyzed water caused approximately 2 log CFU/g reduction compared to control, whereas both electrolyzed water combined with $1\%$ organic acids ranged from 2.6 to 3.7 log CFU/g reduction. Among the organic acids, both electrolyzed water combined with $1\%$ citric acid showed the strongest synergistic antimicrobial effect to reduce L. monocytogenes on lettuce as well as total counts, yeast and molds. When antimicrobials, alone or in combination were treated into L. monocytogenes inoculated lettuce at $5^{\circ}C\;and\;15^{\circ}C$ for designed periods, the combined alkalin electrolyzed water with $1\%$ citric acid showed the greatest potential to inhibit growth of the bacteria. According to Scanning Electron Microscopy(SEM), the treatment of electrolyzed alkali water in combination with $1\%$ citric acid highly reduced the growth of the L. monocytogenes compared to single treatment and resulted in causing the destruction of cell membrane.

• Korean Journal of Veterinary Service
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• v.34 no.2
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• pp.167-178
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• 2011

Garlic (Allium sativum L.) has long history of reputed value and actual use for its medicinal, antimicrobial and pesticidal properties. This study was conducted to find possible developments to natural food preservatives and natural antimicrobials from garlic extracts. The antimicrobial activities of raw garlic extract, heat, pH, temperature against pathogenic bacteria were investigated. E. coli, S. Enteritidis, L. monocytogenes, and S. aureus exhibited antimicrobial activities at 20% garlic extract, but no antimicrobial activity was seen in E. faecium. Raw garlic extract and garlic extract heated for 2 min at $95^{\circ}C$ showed strong antimicrobial activities, but the antimicrobial activity of garlic extract heated for 10 min at $95^{\circ}C$ was much less. The antimicrobial activities of 50% garlic extract adjusted pH 4.0~7.0 showed much the same, but the antimicrobial activities decreased at pH 8.0 or higher. The antimicrobial activities by storage $-18^{\circ}C$ of garlic extract showed much the same. When five strains were cultured for 72 hr at $35^{\circ}C$ in the TSB containing 1~10% garlic extract, viable cell number of five strains were decreased to $10^0{\sim}10^4$ CFU/ml even at 1% or 2.5% (E. faecium) after 24 hr, but later increased to $10^4{\sim}10^9$ CFU/ml after 72 hr. When five strains were cultured for 21 day at $4^{\circ}C$ in the TSB containing 1%, 2.5%, 5%, and 10% garlic extract, viable cell number of E. coli, S. Enteritidis, and S. aureus were decreased to $10^3$, $10^0{\sim}10^2$, $10^1{\sim}10^4$ CFU/ml after 21 day, respectively, but L. monocytogenes and E. faecium increased to $10^8$ and $10^6$ CFU/ml after 21 day.

• Korean Journal of Veterinary Service
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• v.34 no.4
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• pp.341-352
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• 2011

Colibacillosis in pigs remain a major swine industry bruden worldwide. Although some progress has been made in treating collibacillosis in pigs by using biosecurity and antimicrobials, it still remain a considerable problem. The use of host-specific bateriophages as a biocontrol is one possible alternative. The purpose of this study was to evaluate the effect of bacteriophage against enterotoxigenic Escherichia coli (ETEC) K88 infection in piglets. Twenty-eight piglets were randomly divided into four groups and each group was allocated with 7 pigs. Group B, C and D were inoculated with 5 ml of ETEC K88 ($1{\times}10^8$ CFU/ml) per head of piglet via oral. Group C and D were fed with bacteriophages (Group C, $1.0{\times}10^6$ PFU/g; Group D, $1.0{\times}10^8$ PFU/g; CJ CheilJedang Corp., Korea) orally as treatment. In piglets administrated bacteriophages and challenged with ETEC K88 (Group C and D), Clinical signs and the growth performance were improved and antibody titers were maintained low level compared with piglets challenged with ETEC K88 (Group B, P<0.05). Group B were shown high pH in the alimentary tracts compared with other piglets (P<0.05). In quantitative analysis by real-time PCR, the results of Group C and D were lower than those Group B in faecal and intestinal samples (P<0.05). Severe villus atrophy and crypt hyperplasia were observed in Group B consequently V/C ratio increased, compared with other piglets. These results indicate that feeding with bacteriophage has effect to prevent ETEC K88 infection in piglets and suggest that use of bacteriophage can be considered a valid antibiotic alternative.

• Applied Biological Chemistry
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• v.51 no.1
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• pp.49-54
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• 2008

The concentration of total phenolic compounds of the water extracts and 80% ethanol extracts form Portulaca oleracea were 3.05 ${\mu}g/ml$ and 6.33 ${\mu}g/ml$, respectively. The total antioxidant activities of water extracts and 80% ethanol extracts of Portulaca oleracea were 89.2% and 72.9% in DPPH assay, 69.0% and 96.5% in ABTS assay, antioxidant protection factor of the water and 80% ethanol extracts were each 2.73 PF and 3.63 PF. Tyrosinase inhibitory activities were water extracts and 80% ethanol extracts of Portulaca oleracea were 20.2% and 38.7%. Portulaca oleracea showed high antimicrobial activites against Helicobater pylori, Staphylococcus epidermidis, Staphylococcus aureus, Eschericia coli and Streptococcus mutans. Minimum inhibitory concentrations (MICs) on Helicobacter pylori, Staphylococcus epidermidis, Staphylococcus aureus, Escheichia coli and Streptococcus mutans were 200, 50, 100, 100 and 150 ${\mu}g/ml$, respectively. The result suggest that Portulaca oleracea extracts may be useful as potential source as antioxidant and antimicrobials.

• Korean Journal of Plant Resources
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• v.31 no.4
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• pp.330-341
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• 2018

This study was performed to investigate and measure the antimicrobial activity of evergreen woody species extracts on Trichophyton mentagrophytes. To do this, leaves and stems were collected from Wando and Jeju islands, and were used for the extraction with different solvents (i.e., distilled water, 80% ethanol, and 100% methanol), and at different ultrasonic extracting times (i.e., 15, 30, and 45 minutes). The experiment was conducted by using the agar diffusion method. The clear zone was measured after incubating the paper disc containing the plant extract in a bacterial culture medium. The controls were synthetic antimicrobials, methylparaben and phenoxyethanol, at concentrations of 0.4, 1, 2, and 4 mg/disc. Altogether, extracts of 56 out of 64 species used in this study had inhibitory activity, which confirmed their antimicrobial activity against Athlete's foot. Among them, the crude ethanolic extract of Elaeocarpus sylvestris in 45 min showed a zone of inhibition < 20.2 mm, while the clear zone of Actinodaphne lancifolia ethanolic extraction for 30 min was 23.5 mm. Also, Quercus acuta, Dendropanax morbiferus and Daphne odora showed clear zones of 28.0 mm (45 minutes ethanolic extraction), 20.5 mm (45 minutes crude methanolic extraction) and 19.7 mm (45 minutes methanolic extraction), respectively. Thus, these results confirm that the extracts of evergreen woody species have therapeutic potential against Athlete's foot, and suggest that in order to extract adequate amounts of antimicrobial substance from the plant sources, ideal extraction condition has to be considered.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.4
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• pp.438-443
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• 2018

The emergence of biofilms have generated urgent alarm in clinical and medicine manufacturing fields engaged in the search for novel antimicrobials from ethno-medicinal plants. The National Institutes of Health (NIH) has estimated that 70% of all microbial infections in the world are associated with biofilms. In addition, the emergence of strains resistant to conventional antibiotics has become a serious threat to global public health. Therefore, finding alternative medicines is a major issue in the field of integrative medicine. In this study, four different herb extracts were screened for biofilm formation and the activities of Klebsiella pneumoniae. Of them, Scutellaria scordifolia Fisch. ex Schrank extracts had inhibitory effects on bacterial growth and biofilm formation. The Scutellaia scordifolia Fisch. ex Schrank extracts did not cause any cytotoxicity to L929 cells. The growth of K. pneumoniae was inhibited compared to other comparators in the experimental group containing Scutellaia scordifolia Fisch. ex Schrank. In a group of experiments with plant extracts, a maximum of 60 times the level of living bacteria was confirmed compared to the controls without the addition of the Scutellaia scordifolia Fisch. ex Schrank extracts. In a group of experiments with a significantly lower level of fluorescence extraction, differential interference contrast imaging showed that the number of K. pneumonae was reduced. These results suggest that extracts of this plant be applied as antimicrobial agents against K. pneumoniae, particularly in biofilm forms.

• 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.

• Korean Journal of Environmental Agriculture
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• v.39 no.4
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• pp.343-351
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• 2020

BACKGROUND: Irrigation water is known to be one of the major sources of bacterial contamination in agricultural products. In addition, anti-microbial resistance (AMR) bacteria in food products possess serious threat to humans. This study was aimed at investigating the prevalence of foodborne bacteria in irrigation water and evaluating their anti-microbial susceptibility. METHODS AND RESULTS: Surface water (n = 66 sites) and groundwater (n = 40 sites) samples were collected from the Gyeongi and Gangwon provinces of South Korea during April, July, and October 2019. To evaluate the safety of water, fecal indicators (Escherichia coli) and foodborne pathogens (E. coli O157:H7, Salmonella spp., and Listeria monocytogenes) were examined. E. coli isolates from water were further tested for antimicrobial susceptibility using VITEK2 system. Overall, detection rate of foodborne pathogens in July was highest among three months. The prevalence of pathogenic E. coli (24%), Salmonella (3%), and L. monocytogenes (3%) was higher in surface water, while only one ground water site was contained with pathogenic E. coli (2.5%). Of the 343 E. coli isolates, 22.7% isolates were resistant to one or more antimicrobials (ampicillin (18.7%), trimethoprim-sulfamethoxazole (7.0%), and ciprofloxacin (6.7%)). CONCLUSION: To enhance the safety of agricultural products, it is necessary to frequently monitor the microbial quality of water.

• Animal Bioscience
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• v.35 no.1
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• pp.87-95
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• 2022

Objective: This study was conducted to investigate the effect of associating calcium butyrate with tannin extract, compared to an antimicrobial on the growth performance, incidence of diarrhea, intestinal histology, immune-expression of cyclooxygenase-2 (COX-2) and tumor necrosis factor α (TNF-α) in piglets. Methods: Seventy-two piglets (36 barrows and 36 gilts) weaned at 28±2 d and initial body weight of 7.17±1.07 kg were allocated to 3 treatments in a randomized complete block design with 8 replicates per treatment and 3 animals per experimental unit. Treatments were composed of NC, negative control: basal diet without additives; PC, positive control: basal diet + 40 mg/kg of colistin sulfate; or BT, basal diet + calcium butyrate + tannin extract. The butyrate and tannin inclusion levels were 0.15% in the pre-starter phase and 0.075% in the starter phase. Incidence of diarrhea was monitored daily, and on d 14 and 35 of experiment, 1 animal from each experimental unit was slaughtered to collect intestinal samples. Results: No significant differences were observed for growth performance. The butyrate-and tannin-based additive resulted in reduced (p<0.05) incidence of diarrhea in piglets during d 1 to 14 and d 1 to 35 in comparison with the other treatments. Piglets that consumed the diet containing the calcium-butyrate and tannin showed a lower (p<0.05) crypt depth in the duodenum than those receiving the NC treatment at 14 d of experimentation. The BT treatment provided a lower (p<0.05) immune-expression of COX-2 at 14 d and TNF-α at 35 d in the duodenum. Conclusion: Association between calcium butyrate and tannin extract resulted in a significant decrease in the incidence of diarrhea and inflammatory process in the duodenum of piglets. Therefore, calcium-butyrate combined with tannin could be a part of an alternative program to reduce the use of antimicrobials in the diet of weaned piglets.

• Korean Journal of Food Science and Technology
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• v.53 no.4
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• pp.495-500
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• 2021

This study investigated the prevalence, serotypes, virulence genes, and antimicrobial resistance patterns of Listeria monocytogenes isolates collected from salmon products. A total of 16 out of 65 salmon products (24.6%) were positive for L. monocytogenes. Bacteria were most frequently identified in smoked salmon products (15/53, 28.3%). Serological tests revealed that serotype 1/2b (62.5%) was the predominant serotype of L. monocytogenes, followed by 1/2a (37.5%). All isolates harbored 10 virulence-associated genes (inlA, inlB, plcA, plcB, hlyA, actA, prf, fbpA, iap, and mpl), confirming their potential pathogenicity. The isolates of L. monocytogenes showed resistance to cefotetan (100%), cefotaxime (87.5%), cefepime (31.3%), erythromycin (6.3%), and tetracycline (6.3%); however, most of the strains were susceptible to antimicrobials except cephalosporins. These results provide useful information regarding the contamination of salmon products with L. monocytogenes, which may have implications for public health.