• Korean Journal of Food Science and Technology
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• v.47 no.5
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• pp.574-578
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• 2015

The purpose of this study was to examine the antimicrobial effects of natural additives on pathogenic microorganisms in commercial chicken during storage. Chicken skin ($20cm^2$) inoculated with Salmonella Typhimurium or Pseudomonas aeruginosa was treated with 2% natural additives, including chitosan, epigallocatechin gallate (EGCG) and garlic, during storage at $4^{\circ}C$ for 12 days. A combination of the three natural additives significantly inhibited growth of S. Typhimurium compared to treatment with chitosan, EGCG or garlic alone (p<0.05). This combination also inhibited growth of P. aeruginosa compared to treatment with one or two of the natural additives (p<0.05). These results suggest that combined chitosan, EGCG, and garlic may be used as an antimicrobial agent in commercial chicken during refrigerated storage.

• Food Science of Animal Resources
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• v.42 no.6
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• pp.1009-1019
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• 2022

In recent years, biocontrol of foodborne pathogens has become a concern in the food industry, owing to safety issues. Listeria monocytogenes is one of the foodborne pathogens that causes listeriosis. The major concern in the control of L. monocytogenes is its viability as it can survive in a wide range of environments. The purpose of this study was to isolate lactic acid bacteria with antimicrobial activity, evaluate their applicability as a cheese starter, and evaluate their inhibitory effects on L. monocytogenes. Lactococcus lactis strain with antibacterial activity was isolated from raw milk. The isolated strain was a low acidifier, making it a suitable candidate as an adjunct starter culture. The commercial starter culture TCC-3 was used as a primary starter in this study. Fresh cheese was produced using TCC-3 and L. lactis CAU2013 at a laboratory scale. Growth of L. monocytogenes (5 Log CFU/g) in the cheese inoculated with it was monitored during the storage at 4℃ and 10℃ for 5 days. The count of L. monocytogenes was 1 Log unit lower in the cheese produced using the lactic acid bacteria strain compared to that in the cheese produced using the commercial starter. The use of bacteriocin-producing lactic acid bacteria as a starter culture efficiently inhibited the growth of L. monocytogenes. Therefore, L. lactis can be used as a protective adjunct starter culture for cheese production and can improve the safety of the product leading to an increase in its shelf-life.

• Food Science and Preservation
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• v.19 no.2
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• pp.167-172
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• 2012

The antimicrobial activities of $Smilax$ $china$ L. against spoilage bacteria isolated from $Mang-gae$ rice cake were investigated and the storage stability of the $Mang-gae$ rice cake was enhanced. Spoilage bacteria, which cause $Mang-gae$ rice cake to rot, were isolated from commercial $Mang-gae$ rice cake, and most of the isolated strains were identified as $Bacillus$ sp. After the leaves, roots, shoots, and stalks of the $Smilax$ $china$ L. were extracted using 50% ethanol as the solvent, their antimicrobial activities were investigated using the paper disc method by treating them with 50 ${\mu}L$ of $Bacillus$ $cereus$, which is known as a major pathogenic micro-organism in foods that contain starch, as the test organism. The antimicrobial activities of the extracts were compared according to the size of the clear zones around the paper discs. The root extract showed significant antimicrobial activities. When red beans, which are used as stuffing for $Mang-gae$ rice cake, were treated with the root extract of the $Smilax$ $china$ L., the viable cell count of the $Mang-gae$ rice cake was 5.04 Log CFU/g after 48-hr storage, and the cake showed significantly slower growth of bacteria than with commercial products. These results show that treatment of red beans with $Smilax$ $china$ root extract could improve the storage stability of $Mang-gae$ rice cake.

• Journal of fish pathology
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• v.32 no.2
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• pp.97-104
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• 2019

The purpose of this study was to investigate the antimicrobial resistance and resistance transfer of Vibrio parahaemolyticus and Morganella morganii isolated from fish products purchased from fish markets in Yeosu April - December 2017. These bacteria were identified by biochemical test and PCR results, and the transfer of antimicrobial resistance was confirmed by the broth mating method. To isolate the transconjugants formed during conjugation, TSA medium containing 50 ㎍/ml of ampicillin (AMP), and 150 ㎍/ml of streptomycin (SM) or 30 ㎍/ml of oxytetracycline (OT) was used. M. morganii isolates showed low susceptibility to AMP, amoxicillin (AML), and colistin (CT), erythromycin, OT, and tetracycline, compared to V. parahaemolyticus resistance to AMP, AML, and CT. The conjugation of V. parahaemolyticus or M. morganii with Escherichia coli resulted in the separation of V. parahaemolyticus and M. morganii showing SM resistance as transconjugants. Meanwhile, Edwardsiella tarda transconjugants showing AMP and AML resistance were obtained from the broth mating of V. parahaemolyticus and E. tarda. But the transfer of the VPA0477 which is a β-lactamase gene of V. parahaemolyticus was not confirmed. These results suggest that resistance transfer between pathogenic bacteria is bidirectional and progresses in a wide variety of patterns.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1640-1650
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• 2016

In this study, the effect of the polychaete antimicrobial peptide as feed additives on fish, olive flounder (Paralichythys olivaceus) and black rockfish (Sebastes schlegelii), immune activity was described. The antimicrobial peptide of the polychaete was induced by peptidoglycan from Micrococcus luteus. The fish were fed an experimental diet supplemented with 0%, 0.05%, 0.1%, 0.5% or 1% of immune induced the polychaete to a commercial diet. Haematological parameters, nonspecific immunes and stress were evaluated 2, 4, 6 and 8 weeks during fed. The resistance against bacteria, Edwardsiella tarda and Streptococcus iniae, were analysed on after 8 weeks. The haematological parameters were not significantly changed among tested groups. But the lysozyme activities were significantly high in the 0.1% and 0.5% supplement group of olive flounder and black rockfish, respectively. Additionally, cortisol in plasma was low in the 0.1% and 0.5% supplement group of olive flounder and black rockfish, respectively. And resistance of these supplement groups were significantly induced against bacterial injection.

• Food Science of Animal Resources
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• v.35 no.2
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• pp.189-196
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• 2015

The aim of this study was to manufacture functional high protein fermented beverage, using whey protein concentrate (WPC) and Lactobacillus plantarum DK211 isolated from kimchi, and to evaluate the physicochemical, functional, and sensory properties of the resulting product. The fermented whey beverage (FWB) was formulated with whey protein concentrate 80 (WPC 80), skim milk powder, and sucrose; and fermented with Lactobacillus plantarum DK211 as single, or mixed with Lactococcus lactis R704, a commercial starter culture. The pH, titratable acidity, and viable cell counts during fermentation and storage were evaluated. It was found that the mixed culture showed faster acid development than the single culture. The resulting FWB had high protein (9%) and low fat content (0.2%). Increased viscosity, and antioxidant and antimicrobial activity were observed after fermentation. A viable cell count of 10⁹ CFU/mL in FWB was achieved within 10 h fermentation, and it remained throughout storage at 15℃ for 28 d. Sensory analysis was also conducted, and compared to that of a commercial protein drink. The sensory scores of FWB were similar to those of the commercial protein drink in most attributes, except sourness. The sourness was highly related with the high lactic acid content produced during fermentation. The results showed that WPC and vegetable origin lactic acid bacteria isolated from kimchi might be used for the development of a high protein fermented beverage, with improved functionality and organoleptic properties.

• Journal of Periodontal and Implant Science
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• v.48 no.3
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• pp.164-173
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• 2018

Purpose: The aim of this study was to evaluate the antimicrobial effect of a newly devised toothbrush with light-emitting diodes (LEDs) on Porphyromonas gingivalis attached to sandblasted and acid-etched titanium surfaces. Methods: The study included a control group, a commercial photodynamic therapy (PDT) group, and 3 test groups (B, BL, and BLE). The disks in the PDT group were placed in methylene blue and then irradiated with a diode laser. The B disks were only brushed, the BL disks were brushed with an LED toothbrush, and the BLE disks were placed into erythrosine and then brushed with an LED toothbrush. After the different treatments, bacteria were detached from the disks and spread on selective agar. The number of viable bacteria and percentage of bacterial reduction were determined from colony counts. Scanning electron microscopy was performed to visualize bacterial alterations. Results: The number of viable bacteria in the BLE group was significantly lower than that in the other groups (P<0.05). Scanning electron microscopy showed that bacterial cell walls were intact in the control and B groups, but changed after commercial PDT and LED exposure. Conclusions: The findings suggest that an LED toothbrush with erythrosine treatment was more effective than a commercial PDT kit in reducing the number of P. gingivalis cells attached to surface-modified titanium in vitro.

• Korean Journal of Veterinary Service
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• v.44 no.4
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• pp.247-256
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• 2021

The recombinant lysozyme-HJL34 proteins were expressed and purified using commercial Escherichia (E.) coli expression system. Stx2e⁺ F18⁺ E. coli, Actinobacillus pleuropneumoniae (APP), Streptococcus (S.) suis, and Clostridium (C.) perfringens strains were isolated from pigs. The minimum inhibitory concentrations (MICs) of the recombinant lysozyme-HJP34 proteins were examined by means of the microtiter plate method, according to the NCCLS recommendations. The possibility of its as the alternatives to antibiotics was tested in piglets. The MICs were determined as 75 ㎍/mL, 300 ㎍/mL, 75 ㎍/mL, 35.5 ㎍/m against Stx2e⁺ F18⁺ E. coli, APP, S. suis, C. perfringens, respectively. A total of 25 piglets were divied 5 groups. The piglets in group A~C were fed with commercial feed and those in groups D, E were fed with commercial feedstuff. All piglets in groups B~E were challenged with virulent Stx2e⁺ F18⁺ E. coli, APP, S. suis strains. Groups C and D were treated with antimicrobial from 24 h after challenge. All piglets in group B died within 3 days after challenge. Among 5 piglets in groups C and D piglets, 80% survived after challenge. Among group E piglets, 60% were alive until the end of this study. Therefore, this study indicates that recombinant lysozyme-HJP34 proteins is a suitable possibility as a feed additive for reduction of diseases by bacterial pathogens in piglet feed.

• Journal of Microbiology and Biotechnology
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• v.6 no.6
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• pp.461-467
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• 1996

Four strains of lactic acid bacteria (LAB), that lower the pH of sausage $\leq$ 4.2 within 24 h of incubation at $37^{\circ}C$, were screened from 57 bacteriocin producing LAB which were isolated from kajamie shikhae and natural fermented sausages. The proteinaceous nature of the bacteriocin was confirmed by losing antimicrobial activity after pronase treatment. Inhibitory activity against pathogens, times of bacteriocin production and sensory tests were compared between 4 isolates and 3 commercial starters. Especially, strain NFS #8-1, screened from natural fermented sausage and identified as Pediococcus acidilactici, antagonized a large number of foodborne pathogens including Listeria monocytogenes, Aeromonas hydrophila, Bacillus cereus, Clostridium perfringens, Salmonella typhimurium and Staphylococcus aureus. Production of bacteriocin by strain NFS #8-1 was early in the growth phase (mid log phase) and its sensory acceptance was high. The feasibility of using strain NFS #8-1 as a starter for the production of microbiologically safe fermented sausage is envisaged.

• Korean Journal of Organic Agriculture
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• v.23 no.2
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• pp.323-334
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• 2015

This study was conducted to develop environment-friendly agricultural products with anti-microbial activity against Acidovorax avenae subsp. citrulli as a pathogen of bacterial fruit blotch in cucurbit. Schlechtendalia chinensis was extracted by MeOH and solvent fraction. The hexane fraction, which showed highest value of anti-microbial activity, was analyzed by GC-MS. Each mass spectra, corresponding to each peak of chromatogram, was compared to MS database of Wiley library. As a result, myristic acid, palmitic acid and 3-n-pentadecylphenol were identified as maine compounds showing antimicrobial activity against A. avenae subsp. citrulli. Bioassay using commercial myristic acid, palmitic acid and 3-n-pentadecylphenol to test for the anti-microbial activity conformed the anti-microbial activity of potential active compounds, and myristic acid and 3-n-pentadecylphenol showed strong activity. In conclusion, myristic acid and 3-n-pentadecylphenol identified from S. chinensis were anti-microbial chemicals.