• 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.

• 한국식품위생안전성학회지
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• 제38권6호
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• pp.449-456
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• 2023

본 논문은 적은 농도로 존재하는 Vibrio parahaemolyticus를 6시간이내에 10⁶ CFU/mL까지 신속하게 배양가능한 배지인 Rapid Enrichment Broth for V. parahaemolyticus(REB-V)를 개발하여 V. parahaemolyticus를 신속하게 검출할 수 있도록 하였다. Modified Gompertz model과 RSM를 활용하여 V. parahaemolyticus를 신속하게 증균할 수 있도록 첨가 성분을 최적화하였다. 그 결과 2%(w/v) NaCl BPW에 D-(+)-mannose 0.3 g/L, L-valine 0.2 g/L, magnesium sulfate 0.2 g/L를 첨가하였을 때 V. parahaemolyticus의 증균량이 최대였다. REB-V의 배양조건을 pH 7.84와 37℃으로 최적화하였으며, 2%(w/v) NaCl BPW와 비교하여 REB-V의 증균 효율을 확인하기 위해 7시간 증균을 통해 증균량을 평가하였다. 또한 매시간마다 배양액에서 DNA를 추출하였고, 추출한 DNA로 real-time PCR을 수행하여 REB-V의 분자진단법 적용가능성을 확인하였다. 그 결과 7시간 동안 2%(w/v) NaCl BPW에서 V. parahaemolyticus는 5.452±0.151 Log CFU/mL까지 증균되었고, REB-V에서는 7.831±0.323 Log CFU/mL의 V. parahaemolyticus가 증균되었다. 최종적으로 REB-V에서 6시간 이내에 10⁶ CFU/mL 이상으로 증균된 것을 확인하였고, REB-V의 증균속도가 2%(w/v) NaCl BPW보다 빠르고 같은 시간 내의 증균량이 2%(w/v) NaCl BPW보다 많았음을 통해 REB-V의 증균효율이 우수한 것으로 확인되었다.

• 한국축산식품학회지
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• 제38권4호
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• pp.829-834
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• 2018

The objective of this study was to determine the minimum enrichment time for different types of food matrix (pork, beef, and fresh-cut lettuce) in an effort to improve Escherichia coli detection efficiency. Fresh pork (20 g), beef (20 g), and fresh-cut lettuce (20 g) were inoculated at 1, 2, and 3 Log CFU/g of Escherichia coli. Samples were enriched in filter bags for 3 or 5 h at $44.5^{\circ}C$, depending on sample type. E. coli cell counts in the samples were enriched in E. coli (EC) broth at 3 or 5 h. One milliliter of the enriched culture medium was used for DNA extraction, and PCR assays were performed using primers specific for uidA gene. To detect E. coli (uidA) in the samples, a 3-4 Log CFU/mL cell concentration was required. However, E. coli was detected at 1 Log CFU/g in fresh pork, beef, and fresh-cut lettuce after 5, 5, and 3-h enrichment, respectively. In conclusion, 5-h enrichment for fresh meats and 3-h enrichment for fresh-cut lettuce in EC broth at $44.5^{\circ}C$, and PCR analysis using uidA gene-specific primers were appropriate to detect E. coli rapidly in food samples.

• 한국식품위생안전성학회지
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• 제25권4호
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• pp.320-324
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• 2010

돼지사료에 있는 여시니아균의 효율적인 검출을 위해서 다섯 종류의 증식 방법들이 비교 연구되었다. Yersinia enterocolitica GER-C(혈청형 O:3) 가 1000CFU/g 사료 수준으로 들어 있을 때에 $4^{\circ}C$에서의 인산완충용액과 $4^{\circ}C$ 혹은 $21^{\circ}C$에서의 솔비톨과 담즙산염을 함유한 인산완충용액은 효과적이지 못했다. 하지만, irgasan-ticarcillin-potassium chlorate (ITC) 방법과 polymyxin과 novobiocin을 함유한 tryptic soy broth(TSBPN) 방법은 100-1000 CFU/g 사료 수준에서 탁월한 증식효과틀 보였다. ITC와 TSBPN 방법은 10 CFU/g 사료 수준에서도 종식 및 검출 효과가 있었다. Y. enterocolitica ATCC 9610 (혈청형 O:8)을 연구한 결과, 1000 CFU/g 사료 수준에서 TSBPN 증식방볍이 가장 효과적이었으며, 100 CFU/g 사료 수준에서도 증식 및 검출 되었지만, 10 CFU/g 사료 수준에서는 검출되지 않았다. 검출의 민감도와 상대적으로 간단한 조성방법 면에서 볼 때, TSBPN이 돼지사료에서 Y. enterocolitica를 증식, 검출하는데 있어서 가장 효과적인 방법이었다.

• 대한미생물학회지
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• 제22권2호
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• pp.103-108
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• 1987

Vibrio vulnificus septicemia is nor-rare diease in Korea. Carriage rate of the orgaism by shellfish is not well known. In this study performance of SPS agar and SGP broth and effect of storage of specimen in the isolaton was determined using the shellfish specimens collected from the coast and market of Koonsan city. Isolation rate was similar with TCBS and with SPS, but the rate became much highher after enrichment in SGP broth. 80% of oyster speimes were positve when inoculated immediately, but the rate dropped rapidly after storage of specimens at freezing temperature for sometime. All of the isolates fermented lactose in 2 days. A few isolates were not identfiable with API 20E system, because of acid prduction from melibiose. Serover 04 was the frequent isolates.

• 대한수의학회지
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• 제42권3호
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• pp.327-333
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• 2002

The study was carried out to examine the distribution and survival rate of Listeria monocytogenes (L monocytogenes) from various source of waters using improved isolation method. In comparision of enrichment media for isolation of L monocytogenes from water, the isolation rate and 50% detection limit of the pathogen were higher in UVM modified Listeria enrichment broth (UVM) than Listeria enrichment broth (LEB). On the other hand, when compared the selective media for isolation of the pathogen from water, the isolation rate was highest in culture at Oxford agar followed by Fraser agar, and LEB agar. In order to improve enrichment method, 100 ml of water samples with 0.1 CFU/ml of L monocytogenes was inoculated into 10 ml of UVM concentrated at 10-fold, and incubated for 24 h at $36^{\circ}C$. Isolated frequency of the pathogens in improved enrichment method completely corresponded with common (filter) method. Of a total mumber of 147 water samples from river, lake and sea, the pathogen was isolated from 1 of 39 (2.6%) river water samples and 1 of 75 (1.3%) sea water samples, but no pathogen was isolated from 33 lake water samples. Serotypes of 2 isolates were identified as type 1. L monocytogenes decreased in number from 7.2-7.4 to 4.2-4.7 log CFU/ml for 1 week poststorage (5 and $20^{\circ}C$), but the pathogens were able to be detected in river and sea water until 8 weeks after storage. However, in tap water, L monocytogenes were decreased to undetectable level after 2 weeks of storage.

• 한국미생물·생명공학회지
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• 제50권4호
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• pp.584-591
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• 2022

Identifying carbapenem-resistant Enterobacteriaceae (CRE) is necessary to prevent nosocomial CRE infection outbreaks. Here, a rapid identification method with reduced enrichment time was developed without compromising accuracy. A total of 49 rectal swabs requested for CRE screening at the Department of Diagnostic Medicine at Hospital B in Busan, Korea, were included in this study. Specimens were inoculated on MacConkey and CHROMID Carba media either directly or following enrichment for 3, 6, and 24 h in 100 μl trypticase soy broth containing an ertapenem disk. The enriched cultures were further inoculated on CHROMID Carba or MacConkey media containing an ertapenem disk. In total, 19 CRE and 5 carbapenem-intermediate Enterobacteriaceae isolates were obtained from the 49 swabs. Among the 19 CRE isolates, carbapenemase-producing Enterobacteriaceae constituted 13 strains. Moreover, of the 19 CRE isolates, 16 (81.25%) and 17 (88.24%) were identified from the direct cultures on MacConkey and CHROMID Carba media, respectively. After 3 h of enrichment, the proportions of the CRE identified in the media were: MacConkey medium, 16/19 (81.25%); CHROMID Carba medium, 17/19 (88.24%); and MacConkey medium containing an ertapenem disk, 17/19 (88.24%). The detection rates after 6 h of enrichment were the same for all three media (19/19 strains, 100%), whereas those after 24 h of enrichment were 21, 22, and 24 strains, respectively, but included false positives. These findings suggest that a 6-h enrichment before inoculation on the CHROMID Carba medium is optimal for the rapid and accurate detection of CRE in clinical samples.

• 대한수의학회지
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• 제18권1호
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• pp.15-18
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• 1978

Ten strains of Salmonella were isolated from feces and lymph nodes of swine slaughtered at Daegu slaughter-house and the rate of isolation was 6.0 percent. Nine strains of Salmonella were isolated by enrichment in selenite F broth and one strain by direct culture on SS agar, but none of Salmonella were isolated from MacConkey ager and in SS broth. Among Salmonella isolated, Salmonella typhimurium occupied over half (6 strains) and the importance of Salmonella in swine for the incidence of food poisoning in man was discussed.

• 대한수의학회지
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• 제16권1호
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• pp.53-57
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• 1976

The growth of Sal. choleraesuis and its kunzendorf variety in tetrathionate broth containing various amounts of iodine solution was studied and compared with that of Sal. typhi, Sal. typhimurium and E. coli. The results obtained were as followings. 1. When 2.0 ml of iodine solution, normal amount, was added to 100 ml of tetrathionate broth base, the number of Sal. choleraesuis decreased rapidly until 24 hours after inoculation and slightly increased 48 hours after inoculation. The numbers of Sal. choleraesuis var. kunzendorf and E. coli decreased rapidly and none of the organisms recovered 24 and 48 hours after inoculation, respectively. The growth of Sal. typhi and Sal. typhimurium, however, was not inhibited at all. 2. When 4.0 ml of iodine solution was added, to 100 ml of tetrathionate broth base, the growth of all the organisms was inhibited, among which Sal. choleraesuis, Sal. choleraesuis var. kunzendorf, and E. coli were not recovered 24 and 48 hours after inoculation. 3. When reduced amounts of iodine solution, 1.0 ml and 0.5 ml, were added to 100 ml of tetrathionate broth base, the growth of all the organisms was not inhibited.

• 한국식품위생안전성학회지
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• 제35권4호
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• pp.334-340
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• 2020

기존의 L. monocytogenes 증균배지를 개량함으로써 증균배지를 개발하여 L. monocytogenes의 증균 효율을 높이며, DNA 추출에 사용되는 용해버퍼 및 용해조건을 개발함으로써 식육 및 식육가공품에서 L. monocytogenes를 효율적이고 신속하게 검출하고자 하였다. 식품공전에 등재되어 있는 L. monocytogenes 증균배지의 증균 효율을 비교하였으며, Listeria Enrichment Broth (LEB)가 가장 우수한 증균 효율을 보였다. LEB에 탄소원, 질소원, 미네랄 등 다양한 성분을 첨가하여 증균배지를 개발하였으며, 그 결과 LEB에 0.1% pyruvate, 0.1% ferric citrate를 첨가한 개발 증균배지에서 L. monocytogenes가 가장 빠르게 증균되었다. L. monocytogenes의 DNA를 신속하고 효율적으로 추출하기 위해 용해버퍼와 용해조건을 개발하였으며, 그 결과 0.5% 또는 1% N-lauroylsarcosine sodium salt에 0.5 N NaOH와 0.5 M EDTA가 혼합된 용해버퍼를 이용하여 실온에서 30분 간 L. monocytogenes 세포를 용해시키는 것이 DNA의 순도와 수율, 신규성과 경제적 측면에서 가장 우수한 것으로 확인되었다. 결론적으로 본 연구에서 개발된 증균배지 및 DNA 추출법을 활용한다면 식육 및 식육 가공품에서 L. monocytogenes를 보다 신속하게 검출할 수 있을 것이다.