• Title/Summary/Keyword: Listeria monocytogenes

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Antimicrobial Effects of Pinus densiflora Sieb. et Zucc. Ethanol Extract on Listeria monocytogenes (소나무(Pinus densiflora Sieb. et Zucc.) 에탄올 추출물의 Listeria monocytogenes에 대한 항균효과)

  • 임용숙;배만종;이신호
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.31 no.2
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    • pp.333-337
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    • 2002
  • To develope food preservative, antimicrobial activities of Pinus densiflora (PD) ethanol extract against Listeria monocytogenes Scott A. Listeria monocytogenes Brie I and Listeria monocytogenes ATCC 19111 were investigated. The ethanol extracts of PD showed strong antimicrobial activities on Listeria monocytogenes. The crude ethanol extracts of PD were further fractionated by ether, ethyl acetate and butanol. The ether fraction from ethanol extract showed the strongest antimicrobial effects on Listeria monocytogenes in tryptic soy broth containing 40 mg/mL ether fractions compared with other fractions. The effect of ethanol extract of pinus densiflora against Listeria monocytogenes culture for growth stage in tryptic soy broth at 35$^{\circ}C$ showed the strongest antimicrobial activites for lag phase. The morphological changes of the cells were observed with transmission electron microscope (TEM) and scanning electron microscope (SEM) and the cells were injured by treatment of 40 mg/mL ethanol extract of Pinus densiflora.

Isolation and Serotyping of Listeria monocytogenes in Pork Fabrication processing Environment (돈육가공 작업환경에서 Listeria monocytogenes의 분리와 혈청형 분포조사)

  • 홍종해;안상철
    • Journal of Food Hygiene and Safety
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    • v.13 no.4
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    • pp.425-429
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    • 1998
  • Three pork fabrication processing were examined for isolation and serotyping of Listeria monocytogenes. Three hundred thirty samples were collected from gloves, knife sharpeners, knives, cutting boards, conveyer belts, skinning machines, working room air, pig carcasses, and cut meat. Among the 234 samples taken from processing environment, the isolation rates of Listeria monocytogenes and other Listeria spp. were 17.5%, 34.2% respectively. Isolation rates of Listeria monocytogenes from different specimens during processing were 20.8% in gloves, 21.3% in knife sharpeners, 14.6% in knives, 20.8% in cutting boards, 28.6% in conveyer belts, 16.7% in skinnig machines. Listeria monocytogenes and other Listeria spp. were not detected in working room air. Isolation rate of Listeria monocytogenes 14.6% in pork was increased compared to that of 8.5% in pig carcasses (p<0.05). The serovars of 41 isolates from processing environment were 4b 36.6%, 1/2a 24.4%, 4ab 17.0%, 4a 4.9%, 1/2c 2.4%, and 4c 2.4%. The serovars of 4b, 1/2a, 4ab were detected from carcassess and cut meats.

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Development of a Fiber-Optic Biosensor for the Detection of Listeria monocytogenes (리스테리아 식중독균 검출을 위한 광학식 바이오센서 개발)

  • Kim G.;Choi K.H.
    • Journal of Biosystems Engineering
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    • v.31 no.2 s.115
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    • pp.128-134
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    • 2006
  • Frequent outbreaks of foodborne illness demand the need for rapid and sensitive methods for detection of these pathogens. Recent development of biosensor technology has a great potential to meet the need for rapid and sensitive pathogens detection from foods. An antibody-based fiber-optic biosensor and an automated reagents supply system to detect Listeria monocytogenes were developed. The biosensor for detection of Listeria monocytogenes in PBS and bacteria spiked food samples was evaluated. The automated reagents supply system eliminated cumbersome sample and detection antibody injection procedures that had been done manually. The biosensor could detect $10^4$ cfu/ml of Listeria monocytogenes in PBS. By using the fiber-optic biosensor, $2x10^8$ cfu/ml of Listeria monocytogenes in the food samples were detectable.

Application of Flow Cytometry to Monitoring of Liposomal Restructuring Induced by Listeria monocytogenes

  • Kim, Hyung-Joo;Bennetto, H.-Peter;Halablab, Mahmoud-A.
    • Journal of Microbiology and Biotechnology
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    • v.14 no.5
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    • pp.1099-1102
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    • 2004
  • Liposomal restructuring induced by hemolytic Listeria monocytogenes was investigated by using flow cytometry. When added to calcein-entrapped liposomes, hemolytic, but not non-hemolytic, Listeria monocytogenes were able to induce reformation of vesicles. Such restructuring of liposomes was easily monitored by flow cytometry. Electron microscopy also indicated major changes in the challenged liposomal structures. The preliminary results described may offer a simple and fast method for monitoring liposomal restructuring and for differentiating between hemolytic and non-hemolytic bacteria.

Growth Inhibition of Listeria monocytogenes by Pure Compound Isolated from Extract of Morus alba Linne Bark (상백피 추출물중 Listeria monocytogenes 증식억제 물질의 분리 및 효과)

  • An, Eun-Young;Han, Ji-Sook;Shin, Dong-Hwa
    • Korean Journal of Food Science and Technology
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    • v.29 no.6
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    • pp.1236-1240
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    • 1997
  • The crude extract of Morus alba Linne bark which showed strong antimicrobial activity on Listeria monocytogenes was fractionated by some solvents and applied column chromatography for purification of active component. By silica gel column chromatography, active fraction (F-5') was purely isolated and confirmed their strong bactericidal effect on Listeria monocytogenes tested at level of 100 and 300 ppm in tryptic soy broth. The cell wall observed by SEM was abnormal after treatment of F-5'.

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Inactivation of Listeria monocytogenes and Campylobacter jejuni in Chicken by Aqueous Chlorine Dioxide Treatment

  • Hong, Yun-Hee;Ku, Gyeong-Ju;Kim, Min-Ki;Song, Kyung-Bin
    • Preventive Nutrition and Food Science
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    • v.12 no.4
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    • pp.279-283
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    • 2007
  • Aqueous chlorine dioxide $(ClO_2)$ treatment was used for the inactivation of Listeria monocytogenes and Campylobacter jejuni in chicken. Chicken breasts and legs were inoculated with $8{\sim}9log\;CFU/g$ of Listeria monocytogenes and Campylobacter jejuni, respectively, and then treated with 0, 50, and 100 ppm of $ClO_2$ solution. Aqueous $ClO_2$ treatment decreased the populations of the pathogenic bacteria on the chicken samples. One hundred ppm $ClO_2$ treatment on the chicken breast and leg reduced the populations of Listeria monocytogenes and Campylobacter jejuni by $0.61{\sim}1.93\;and\;0.99{\sim}1.21log\;CFU/g$, respectively. Aqueous $ClO_2$ treatment affected the microbial growth during storage at $4^{\circ}C$ by decreasing the initial microbial populations. These results clearly suggest that aqueous $ClO_2$ treatment should be useful in improving the microbial safety of chicken during storage and extending the shelf life.

Isolation of Lactococci Inhibiting Listeria monocytogenes from Kimchi Habitat and Its Identification by 16S rDNA Analysis (김치 서식처에서 Listeria monocytogenes를 억제하는 lactococci의 분리와 16S rDNA분석에 의한 동정)

  • 박은주;한홍의;민봉희
    • The Korean Journal of Ecology
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    • v.22 no.1
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    • pp.45-50
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    • 1999
  • A bacteriocin-producing strain was isolated from kimchi at the early stage of kimchi fermentation. It was identified as Lactococcus lactis by morphological, cultural and physiological characteristics and partial sequence of 16S rDNA. The bacteriocin from isolate had antimicrobial activity against gram positive pathogenic bacteria, such as Listeria monocytogenes. Staphylococcus aureus and several strains of lactic acid bacteria but not to gram negative bacteria, Yersinia enterocolitica. The bacteriocin was sensitive to protease, protease ⅩⅣ, a-chymotrypsin and pepsin but not to lipase, trypsin and lysozyme. The bacteriocin activity was stable at pH 2-11 and temperature of 100 for 10 min. Thus, Listeria monocytogenes could be inhibited by Lactococcus lactis at early stage of fermentation.

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Outbreaks and Control of Listeriosis Attributed to Agricultural, Marine and Animal Husbandry Products (농축수산문 식품원료 및 그 가공식품에 대한 Listeria 균주의 오염실태조사와 Listeriosis 발생억제방법)

  • 조성환;김기옥;정진환;류충호
    • Journal of Food Hygiene and Safety
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    • v.9 no.4
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    • pp.191-198
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    • 1994
  • The major purpose of the present study is to syrvey vegetables, meats, seafoods, processed foods and imported foods for the presence of Listeria spp. and to prevent listeriosis caused by the contamination of Listeria monocytogenes. Listeria spp. was not found in vegetables and processed foods. The optimum growth condition of isolates indentified as Listeria monocytogenes was pH 7.0 and 37$^{\circ}C$. the antimicrobial effect of grapefruit seed extract(GFSE) was observed in the level of more than 100ppm by disk method. When 1ml(2.5$\times$106 CFU/ml) of Listeria monocytogenes was inoculated and incubated for 3 days at 3$0^{\circ}C$, the total cell number of the organism was 4.5$\times$109 in the control, 7.2$\times$103 in 100 $\mu\textrm{g}$/ml of GFSE medium, and 3.5 $\mu\textrm{g}$/ml of GFSE medium. Direct visualization of microbial cells by using both transmission electron microscope and scanning electron microscope showed microbial cell membrane the function of which was destroyed by treating with the dilute solutions of GFSE. It could be confirmed that GFSE completely inhibited the growth of the test strain of Listeria monocytogenes.

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Heat Resistance of Vegetative and Starved Listeria monocytogenes Sott A (Listeria monocytogenes Scott A의 세포상태에 따른 열 저항성)

  • 이신호;손수정
    • Microbiology and Biotechnology Letters
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    • v.21 no.2
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    • pp.176-180
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    • 1993
  • Survival and heat resistance of Listeria monocytogenes Scott A in various nutritional environments and cell type on stainless steel were determined. Viable cell of L. monocytogenes Scott A was most rapidly decreased in phosphate buffer among various media such as NSM (30 g TSB/1 l D.W.), LNM (2 g TSB/1 l D.W.) and phosphate buffer (pH=7) during incubation at 21 and 35C but survived for 15 days at 21C. Vegetative and starved L. monocytogenes Scott A were survived after heat treatment for 5 min at 65C while not detected at 72C.

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Effect of Organic Acids on Growth and Heat Resistance of Listeria monocytogenes Scott A (Listeria monocytogenes Scott A 의 성장과 열저항성에 미치는 유기산의 영향)

  • 이신호;조현순;김순희
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.23 no.2
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    • pp.293-297
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    • 1994
  • The effect of organic acids on growth and heat resistance of Listeria monocytogenes Scott A were investigated. The growth of L. monocytogenes was inhibited in Tryptic Soy Broth(TSB) with 0.1 or 0.2% of acetic , tartic , propionic , citric and lactic acid at 35$^{\circ}C$, respectively. The growth of l. Monocytogenes did not occur in TSB with 0.2% of acetic acid or propionic acid during 48h of incubation. The heat resistance of L.monocytogenes was affected by kind of organic acid, ph and heating substrate. L.monocytogenes showed more heat resistant in TSB with various organic acids than in 0.1M sodium phosphate with the same organic acids. Heat resistance decreased as pH of heating substrate decreased . Surface-adherent microcolony was more heat resistant than planktonic cell of L. monocytogenes. Propionic and lactic acids more affected on heat resistance of L.monocytogenes than acetic , tartaric and citric acids.

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