• 한국식품위생안전성학회지
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• 제33권1호
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• pp.65-70
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• 2018

L. monocytogenes는 Listeriosis를 일으키는 중요한 식중독 균으로 현재 국내 식품공전에서는 증균배양을 기초로 검출하며, 규격은 불검출로 관리하고 있다. 그러나 Listeria종 간의 혼합오염시 증균 과정에서 경쟁생육이 존재하여 L. monocytogenes 위음성의 가능성이 있다고 보고되고 있다. 국내 식품공전은 L. monocytogenes 증균을 위한 1차 배지로 규정되어 있으나 LEB 배지에서의 Listeria 종 간의 생육 연구는 보고된 바 없다. 본 연구는 식품에서 주로 검출되는 Listeria 속 4종(L. monocytogenes, L. innocua, L. ivanovii, L. seeligeri)을 LEB배지에 혼합배양하며 증균과정에서 생육의 차이가 존재하는 것을 확인하였다. 특히, L. innocua에 의해 L. monocytogenes의 생육이 저해되며, L monocytogenes가 L. innocua보다 초기균수가 2.0 log CFU/mL 이상 오염이 되어있어야지만 L. innocua보다 생육이 잘 되는 것을 확인하였다. Listeria 종 간의 혼합오염이 있을 경우 현재 검출법으로는 L. monocytogenes의 검출이 어려울 수 있다고 판단된다. 따라서 L. monocytogenes 검출율을 높이는 새로운 증균배지 개발의 필요성을 확인하였다. 향후 본 연구는 L. monocytogenes 검출률을 높여 국내 식품의 식품 안전에 기여 할 수 있으며 국내 식품 관리 규격 개정 시 기초가 되는 참고 자료로 활용 할 수 있을 것으로 생각된다.

• 대한수의학회지
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• 제45권3호
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• pp.359-367
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• 2005

This study was carried out to understand the contamination patterns of Listeria in pork processing plants. A total of 402 samples were collected from carcass, pork during processing, surfaces of equipment and environment, and 238 isolates of Listeria species were identified. L. innocua was found in 64.7% of the isolates, L. monocytogenes in 33.2%, and L. welshimeri in 2.1%. Random amplified polymorphic DNA (RAPD) analysis performed to investigate the origin and routes of Listeria contamination, showed 21 composite types of L. monocytogenes and 26 composite types of L. innocua. It was confirmed that Listeria contamination begins with contaminated incoming carcass and ever-present contaminants in the processing environments. The persistence and dissemination of the same strain of L. monocytogenes and L. innocua throughout the processing line revealed that the sanitation standard operating procedure should be implemented to minimize the risk of colonization in the workplace. Molecular subtyping of L. innocua allowed us to tracing the possibility of cross-contamination during processing.

• 생명과학회지
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• 제13권4호
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• pp.390-399
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• 2003

본 연구는 경남지역의 해수와 해산물에서 Listeria 속을 분리하여 증균배양방법에 따른 균의 분리율, 선택배지에 따른 균의 분리율, 검체에 따른 균종 별 분리율, 생화학 시험과 분리된 L. monocytogenes에 대하여는 혈청형 시험을 실시하였다. 총 100건의 검체에서 증균배양에 따른 Listeria 속의 분리율은 1일 증균배양에서 L. monocytogenes가 4% (4건), L. innocua가 35%(35건), L. ivanovii가 4%(4건), L. welshimeri가 1%(1건)였고, 7일간 증균배양에서는 L. monocytogenes가 1%(7건), L. innocua가 38%(38건), L. ivanovii가 5%(5건), L. welshimeri가 1%(1건)로 동정되어 1일 증균배양 보다 7일간의 증균배양이 Listeria속의 분리에 휠씬 효과적이었다. 이와 함께 Oxford 선택배지나 LPM 선택 배지를 사용하였을 경우 증균배양과 비교하여 검출율이 조금 낮았다. 검체에 따른 Listeria 속의 분리율은 새우와 가재에서 80%(16/20)로 분리율이 가장 높았으며, 바지락에서 50% (10/20), 해수에서 25%(5/20), 홍합에서 20%(4/20)의 순으로 나타났다. 그리고 Listeria 속의 균종 별 분리율은 L. irnnocua가 38%(38건), L. monocytogenes가 7%(7건), L. ivanovii가 5%(5건), L. welshimeri가 1%(1건)순으로 분리되었다. 각 검체에서 Listeria 속의 균종 별 분리율은 새우에서 L. innocua가 65%(13건), L. monocytogenes가 15%(3건), 가재에서 L. innocua가 70%(14건), L. monocytogenes가 10%(2건), 바지락에서 L. innocua가 45%(9건), L. monocytogenes가 5%(1건), 홍합에서 L. innocua가 10%(2건), L. monocytogenes가 5%(1건), L. welshimeri가 5%(1건), 해수에서 L. ivanovii가 25%(5건)분리되었다. L. monocytogenes로 분리 동정된 7주에 대한 혈청형 분류는 type I이 2주, type IV가 5주로 나타났다.

• Food Science and Biotechnology
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• 제16권2호
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• pp.255-259
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• 2007

The effects of temperature heating-up rate and pressure building-up phase on the inactivation of Listeria innocua ATCC 33090 were evaluated in buffered peptone water. The number of L. innocua was reduced by 5.57 and 6.52 log CFU/mL during the nonisothermal treatment (the come-up time followed by isothermal process) and the isothermal treatment, respectively, at $60^{\circ}C$. When compared to the isothermal treatment (0.76$33.2^{\circ}C/min$ of temperature heating-rate. The effect of the combined high pressure and thermal processing on the inactivation of L. innocua increased with increasing pressure and temperature. At all temperature levels from 40 to $60^{\circ}C$ under 700 MPa, L. innocua was not detected by enrichment culture (>7 log reduction).

• 한국동물위생학회지
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• 제28권2호
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• pp.113-119
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• 2005

We surveyed the distribution of Listeria spp in intestinal contents of slaughtered cattle from Daegu between March and October 2003. Fourteen Listeria spp were isolated from a total of 100 samples. Two samples contained only L innocua and other six samples contained both L monocytogenes and L innocua. Of the 99 samples positive to esculin reaction in Fraser broth, Listeria spp were isolated only from $8\%$ of the samples. Three selective plating medium were examined for detection of Listeria species including Enhanced hemolysis agar, Oxford agar and Palcam agar, It was found that Enhanced hemolysis agar was more effective than Oxford agar and Palcam agar, and that L monocytogenes needed 48 hour growth to give positive reaction.

• 대한수의학회지
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• 제43권2호
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• pp.231-237
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• 2003

Listeria (L.) monocytogenes in samples could not be detected occasioally by faster growth of other Listeria spp. especially L. innocua. The aim of this study was to develop the differential media and multiplex polymerase chain reaction (PCR) assays for the rapid detection of L. monocytogenes. L. monocytogenes colonies were characterized by their ${\beta}$-hemolysis with fluorescence under 366 nm UV light on the Listeria hemolysis agar (LHA). L. innocua, a species commonly present in foods, did not produce ${\beta}$-hemolysis on LHA. Therefore, one or more colonies of L. monocytogenes were easily distinguished from large populations of L. innocua. The multiplex PCR assays were developed to distinguish from L. monocytogenes and other Listeria spp. with two pairs of primers. The primers were designed in 16S rRNA and listeriolysin O gene for specific amplification of all members of the genus Listeria and L. monocytogenes, respectively. The multiplex PCR assays produced 560 and 938 bp products in L. monocytogenes; only 938 bp products in the genus Listeria. The multiplex PCR assays could detect as little as 50 pg of L monocytogenes DNA. These results indicated that the differential media and multiplex PCR assays might be useful diagnostic tools for the rapid detection of L. monocytogenes.

• Journal of Microbiology and Biotechnology
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• 제14권3호
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• pp.515-519
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• 2004

Listeria spp. were isolated from a total of 402 naturally contaminated domestic ready-to-eat (RTE) vegetable samples by the conventional Food and Drug Administration protocol and confinned by API-Listeria kit. Also, the susceptibility to 12 antibiotics, polymerase chain reaction (PCR) assay for virulence gene of pathogenic Listeria monocytogenes isolates, and in vitro virulence assay using myeloma and hybridoma cells from murine and human sources were tested. Among the samples, 17 samples (4.2％) were found to be contaminated with Listeria species. Among the 17 strains of Listeria spp. isolates, only 2 strains (11.8％) of L. monocytogenes and 15 strains (88.2％) of L. innocua were identified. Antibiotic susceptibility test showed that the Listeria spp. isolates were very susceptible to the antibiotics tested, except for nalidixic acid. Among 17 strains of Listeria spp., PCR analysis showed that 2 strains of L. monocytogenes isolates proved to have a virulence hly gene, but none of L. innocua had the hly gene. Also, hybridoma Ped-2E9 cells assay showed that only L. monocytogenes isolates killed approximately 95-99％ hybridoma cells after 6 h, but L. innocua isolates had about 0-5％ lethal effect. These results indicate that PCR assay with hly primer or hybridoma Ped-2E9 cells assay could be used as a good monitoring tool or in vitro virulence test for L. monocytogenes.

• Fisheries and Aquatic Sciences
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• 제5권2호
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• pp.79-86
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• 2002

Listeria spp. were isolated from the samples submitted from various seafood plants such as raw materials, products, swab samples of plants floor and conveyor belts through the whole processing procedures. All the samples were collected from 3 kinds of seafood plants such as a imitation crab meat plant, jeotgal plant and frozen seafood plant. And also serotypes of the identified L. monocytogenes were determined. Among the 301 strains of isolated Llsteria spp., 96 strains, 179 strains and 26 strains were identified as L. monocytogenes, L. innocua and L. welshimeri, respectively. While among the 145 strains of Listeria spp. isolated from the imitation crab meat plant, $74\;(51.0\%)$ strains, $64\;(44.1\%)$ strains and $7\;(4.8\%)$ strains were identified as L. monocytogenes, L. innocua and L. welshimeri, respectively. In the case of the 126 strains of Listeria spp. isolated from the frozen seafood plant, $22\;(17.5\%)$ strains of L. monocytogenes,$93\;(73.8\%)$ strains of L. innocua, and $11\;(8.5\%)$ strains of L. wdshimeri were detected. Among the 30 strains isolated from a jeotgal plant, $22\;(73.3\%)$ strains of L. innocua and $8\;(26.7\%)$ strains of L. welshimeri were detected. The detection rates of L. monocytogenes, one of the very important food poisoning bacteria especially in frozen and/or refrigerated seafoods, were relatively high as $77.1\%$ (74/96 strains) in a imitation crab meat plant and $22.9\%$ (22/96 strains) in a frozen seafood plant, but not detected from jeotgal plant. Distribution of L. monocytogenes serotypes and characterization were examined. The serotypes of 96 L. monocytogenes isolated from pork skin, pork fat, the floor and conveyor belts were 1/2a $(59.4\%)$, l/2b $(6.2\%)$, 1/2c $(12.5\%)$ and unknown serotypes $(21.9\%)$. Unknown serotypes were divided into three specific groups by the O antigen they have.

• 한국식품위생안전성학회지
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• 제11권2호
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• pp.107-114
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• 1996

The distribution of Listeria spp. in various foods and its fatty acid composition were examined. A total 60 samples of dairy products(15), seafoods(20), meat products(18), factory waster(2), and salades(5) were tested. Listeria spp. was found 10 samples, showing about 16.7% detection ratio; dairy products 0(0%),,seafoods 1(5%), meat product 7(38.9%), and factory wastes 2(100%). Whereas L. welshimeri was isolated from meat products 1(5.6%) and factory wastes 1(50%). The cellular fatty acid composition determined by gas chromatography was found not to differ among L. innocua isolated from food has similar fatty acid profiles when grown at 3$0^{\circ}C$,24 hrs on the tryptic soy plate with C15 and C17 anteiso branched acids accounting for about 80% of total.

• Journal of Microbiology and Biotechnology
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• 제19권3호
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• pp.238-249
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• 2009

The genus Listeria consists of six closely related species and forms three phylogenetic groups: L. monocytogenes-L. innocua, L. ivanovii-L. seeligeri-L. welshimeri, and L. grayi. In this report, we attempted to examine the evolutionary relationship in the L. monocytogenes-L. innocua group by probing the nucleotide sequences of 23S rRNA and 16S rRNA, and the gene clusters lmo0029-lmo0042, ascB-dapE, rplS-infC, and prs-ldh in L. monocytogenes serovars 1/2a, 4a, and 4b, and L. innocua. Additionally, we assessed the status of L. monocytogenes-specific inlA and inlB genes and 10 L. innocua-specific genes in these species/serovars, together with phenotypic characterization by using in vivo and in vitro procedures. The results indicate that L. monocytogenes serovar 4a strains are genetically similar to L. innocua in the lmo0035-lmo0042, ascB-dapE, and rplS-infC regions and also possess L. innocua-specific genes lin0372 and lin1073. Furthermore, both L. monocytogenes serovar 4a and L. innocua exhibit impaired intercellular spread ability and negligible pathogenicity in mouse model. On the other hand, despite resembling L. monocytogenes serovars 1/2a and 4b in having a nearly identical virulence gene cluster, and inlA and inlB genes, these serovar 4a strains differ from serovars 1/2a and 4b by harboring notably altered actA and plcB genes, displaying strong phospholipase activity and subdued in vivo and in vitro virulence. Thus, by possessing many genes common to L. monocytogenes serovars 1/2a and 4b, and sharing many similar gene deletions with L. innocua, L. monocytogenes serovar 4a represents a possible evolutionary intermediate between L. monocytogenes serovars 1/2a and 4b and L. innocua.