국내 유통식품에서 분리된 Verotoxin 생성 Escherichia coli의 특성

곽효선,차진,강길진,김훈,박선희,김창민,Kwak, Hyo-Shun,Cha, Jin,Kwang, Kil-Jin,Kim, Hun,Park, Sun-Hee,Kim, Chang-Min 한국식품위생안전성학회 2000 한국식품위생안전성학회지 Vol.15 No.3

국내 유통식품에서 verotoxin(VT)을 생성하는 대장균의 오염도를 조사하고 이로 인한 식중독의 발생을 사전에 예방하기 위하여 1997년부터 1999년 사이 햄버거. 식육 및 채소류에서 VT생성 대장균의 분포조사를 실시하였으며, 이 결과 분리된 대장균에 대한 분자생물학적 특성을 조사하였다 식육, 햄버거 및 채소류 총 1,700건의 식품 중에서 VT를 생성하는 대장균이 검출된 것은 3건으로 매우 낮은 검출율을 보였는데, 분리주의 혈청형은 각각 026 : H4, 0157 : H7 및 055 : Hl2였다. 혈청형 026 : H4 분리주는 VT I과 VT II를 생성하였고,055 : Hl2주는 VT I을 각각 생성하였으며, 두 분리주에서 eae유전자와 60 MDa plasmid DNA는 검출되지 않았다. 혈청형 0157 : H7주는 VT II를 생성하였고 60 MDa plasmid DNA는 검출되었으나 eae유전자는 확인되지 않았다. 따라서 분리된 VT생성 대장균들은 eae 유전자가 검출되지 않아 질병유발 가능성은 낮은 것으로 추정되었다. 항생제 내성능에서 혈청형 0157 : H7 분리주는 ampicillin과 streptomycin에 내성을 나타낸 반면, 혈청형 026 : H4주와 혈청형 055 : Hl2주는 ampicillin, carbenicillin, cephalothin, trimethoprim/sulfamethoxazole과 tetracycline에 내성을 보여 분리주의 다재내성능을 확인하였다 세포배양액으로 실시한 vero cell과 HeLa cell에 대한 세포독성능은 3주의 분리주에서 확인되었다. The incidence of verotoxin-producing Escherichia coli(VTEC) was surveyed in domestic foods including hamburger, raw meats and vegetables from 1997 to 1999. The molecular biological characteristics of the isolates were analyzed. Three VTEC strain were isolated from 1,700 samples. Serotypes of those isolates were 0157 : H7, 026 H4, and 056 : Hl2, respectively. Serotype O26 : H4 produced VT I and VT II, and 055 Hl2 isolate produced VT I, however the 60 MDa plasmid DNA and eae gene were not found from both strains. One 0157 : H7 isolate produced VT II and harbour 60 MDa plasmid DNA, however eae gene was not found in the strain. Although they produced VT, it seemed that the virulence of two strains were relatively weak because of the lack of the eae gene. In addition, the serotype O157 : H7 isolate resistant to ampicillin and streptomycin, while isolates of serotype O26 : H4 and O55 : Hl2 were multi-resistant to antibiotics including ampicillin, carbenicillin , cephalothin, trimethoprim/sulfamethoxazole and tetracycline. Supernatants of cultures of all three isolates were showed cytotoxic effect to vero and HeLa cell

중요 항생제의 분류와 식품안전분야에서 활용

곽효선,함준혁,김이슬,채은화,정상희,김해영,Hyo-Sun Kwak,Jun-Hyeok Ham,Eiseul Kim,Yinhua Cai,Sang-Hee Jeong,Hae-Yeong Kim 한국식품위생안전성학회 2023 한국식품위생안전성학회지 Vol.38 No.4

Antimicrobials in human medicine are classified by The World Health Organization (WHO) into three groups: critically important antimicrobials (CIA), highly important antimicrobials (HIA), and important antimicrobials (IA). CIA are antibiotic classes that satisfy two main criteria: that they are the sole or the only available limited therapeutic option to effectively treat severe bacterial infections in humans (Criterion 1), and infections where bacteria are transmitted to humans from non-human sources or have the potential to acquire resistance genes from non-human sources (Criterion 2). WHO emphasizes the need for cautious and responsible use of the CIA to mitigate risk and safeguard human health. Specific antimicrobials within the CIA with a high priority for management are reclassified as "highest priority critically important antimicrobials (HP-CIA)" and include the 3^rd generation of cephalosporins and the next generation of macrolides, quinolones, glycopeptides, and polymyxins. The CIA list is the scientific basis for risk assessment and risk management policies that warrant using antimicrobials to reduce antimicrobial resistance in several countries. In addition, the CIA list ensures food safety in the food industry, including for the popular food chain companies McDonald's and KFC. The continuous update of the CIA list reflects the advancement in research and emerging future challenges. Thus, active and deliberate evaluation of antimicrobial resistance and the construction of a list that reflects the specific circumstances of a country are essential to safeguarding food security.

회원논단 : 식품에서 항생제 내성균 관리를 위한 국제 동향

곽효선 ( Hyo Sun Kwak ) 한국식품위생안전성학회 2010 Safe Food Vol.5 No.1

Complete genome sequence of Salmonella Enteritidis MFDS1004839 isolated from food

이우정,박세욱,유란희,주인선,곽효선,김순한,Lee, Woojung,Park, Sewook,Yoo, Ran Hee,Joo, In-Sun,Kwak, Hyo Sun,Kim, Soon Han The Microbiological Society of Korea 2018 미생물학회지 Vol.54 No.2

본 연구에서는 2014년 국내에서 식중독 원인식품인 김밥으로부터 분리된 Salmonella Enteritidis의 유전체 분석을 수행하였다. Salmonella Enteritidis MFDS1004839는 한 개의 chromosome (4,679,649 bp)과 plasmid (96,994 bp)로 구성되어있고, 각각의 G + C contents는 52.2%와 49.3%로 확인되었다. chromosome와 plasmid DNA에 예측된 유전자의 총 수는 4,482개의 단백질 코딩유전자와 84개 tRNA, 그리고 22개의 rRNA였다. Salmonella enterica subsp. enterica is a foodborne pathogen that has been detected throughout the world. Here, we present the complete genome sequence of Salmonella Enteritidis isolated from a commercial kimbap that caused foodborne illness in the Republic of Korea in 2014. Complete genome sequence analysis of Salmonella Enteritidis MFDS1004839 revealed a 4,679,649 bp chromosome and a 96,994 bp plasmid, with G + C contents of 52.2% and 49.3%, respectively. The chromosome and plasmid genome included 4,482 predicted protein-coding sequences, 84 tRNAs and 22 rRNAs genes.

가공식품과 비가공식품에서의 황색포도상구균 검출을 위한 배지법과 Real-time PCR법의 비교

이재훈,송광영,현지연,황인균,곽효선,한정아,정윤희,서건호,Lee, Jae-Hoon,Song, Kwang-Young,Hyeon, Ji-Yeon,Hwang, In-Gyun,Kwak, Hyo-Sun,Han, Jeong-A,Chung, Yun-Hee,Seo, Kun-Ho 한국축산식품학회 2010 한국축산식품학회지 Vol.30 No.3

Staphylococcus aureus is one of the major pathogens that can cause staphylococcal infection and food poisoning. In this study, we compared conventional culture methods and real-time PCR for detection of S. aureus in artificially inoculated milk, sausage, raw pork, and vegetable salad. The performance of a coagulase test for confirming S. aureus was also compared with a colony PCR test. Bulk food samples (500 g each) were artificially inoculated with S. aureus and divided into 20 samples (25 g or mL each). All samples were added to tryptic soy broth (225 mL/sample) with 10% NaCl and incubated at $37^{\circ}C$ for 24 h. After the enrichment, broth cultures were streaked onto Baird-Parker (BP) agar with egg yolk tellulite, and incubated at $37^{\circ}C$ for 24 h. In addition, 1 mL of broth cultures was collected to perform real-time PCR. Two suspicious colonies from the BP agar were picked up and plated on nutrient agar and incubated at $37^{\circ}C$ for 24 h followed, by a coagulase confirmation test and a colony PCR analysis. There were no statistical differences between culture methods and realtime PCR in food samples with low background microflora, such as milk and sausage. However, a significant statistical difference was found between the culture methods and real-time PCR for raw pork and vegetable salad. Furthermore, the colony PCR test of the presumptive colonies on BP agar for confirming S. aureus is more accurate and efficient than the coagulase test for unprocessed foods.

Filtration과 Integrated Cell Culture/Real-Time Reverse Transcription PCR 기법을 이용한 채소류에서 Human Rotavirus 신속 검출

현지연,천정환,송광영,황인균,곽효선,이정수,김무상,이중복,서건호,Hyeon, Ji-Yeon,Chon, Jung-Whan,Song, Kwang-Young,Hwang, In-Gyun,Kwak, Hyo-Sun,Lee, Jung-Soo,Kim, Moo-Sang,Lee, Jung-Bok,Seo, Kun-Ho 한국미생물학회 2011 미생물학회지 Vol.47 No.2

본 연구는 human rotavirus (HRV)의 검출법을 최적화하기 위해 real-time RT-PCR과 세포 배양법을 이용하여 여러 가지 탈리 농축법을 비교 및 평가하는 것을 목적으로 하였다. 채소류 중 배추, 상추, 깻잎을 선정하여 바이러스 희석액을 접종하고 탈리액 비교를 위하여 buffer A (100 mM Tris-HCl, 50 mM glycine, 3% beef extract, pH 9.5)와 buffer B (250 mM Threonine, 300 mM NaCl, pH 9.5)를 이용하여 탈리하였고, 농축방법을 비교하기 위하여 PEG (polyethylene glycol) 침전법 또는 filtration [Nanoceram filter$^{(R)}$ (Argonide corporation)]을 이용하여 농축하였다. 또한 바이러스의 감염성 평가를 위하여 MA-104 cell을 배양하여 탈리, 농축 방법을 거쳐 회수된 HRV를 접종하고 1, 48, 72, 96, 120, 144, 168시간 후 세포를 수거하여 real-time RT-PCR을 시행하고 세포병변을 관찰하였다. 탈리 용액은 buffer A가 회수율 29.54%로 buffer B의 18.32%보다 더 뛰어난 탈리효과를 보였으며 농축방법을 비교했을 때 filtration 방법이 회수율 51.89%를 나타내며 PEG 침전법에 비해서 바이러스의 농축에 효과적이었으며 검출 소요시간이나 간단한 과정 면에서 효율적이었다. ICC/real-time RT-PCR을 시행하였을 때 세포병변 72시간 후부터 나타나기 시작했지만 Ct value는 48시간부터 감소하기 시작하여 더 빠른 시간 내에 감염성을 평가할 수 있었다. 따라서, filtration과 integrated/cell culture real-time RT-PCR을 이용하면 기존의 검출방법보다 빠른 시간 내에 바이러스 검출이 가능할 것으로 여겨진다. The purpose of this study was to evaluate and compare different elution and concentration methods for optimization of human rotavirus (HRV) detection method using real-time RT-PCR and cell culture techniques. The leafy vegetable samples (lettuce, Chinese cabbage) were artificially inoculated with HRV. Viruses were extracted from the vegetables by two different elution buffers, buffer A (100 mM Tris-HCl, 50 mM glycine, 3% beef extract, pH 9.5) and buffer B (250 mM Threonine, 300 mM NaCl, pH 9.5), and the extracted viruses were concentrated by filtration and PEG precipitation sequentially. To determine infectivity of the viruses, the viruses recovered from the samples were infected to the MA-104 cells, and integrated cell culture real-time RT-PCR was performed at 1, 48, 72, 96, 120, 144, 168 h post-infection (p.i.). The elution buffer A was more efficient in extracting the virus from the produce samples tested than the buffer B, 29.54% and 18.32% of recoveries, respectively. The sensitivity of real-time RT-PCR method was markedly improved when the virus was concentrated by the filtration method. When the viruses were eluted and concentrated by buffer A and filtration, respectively, the average recovery rate was approximately 51.89%. When the viruses recovered from samples were infected to MA-104 cell, infectious HRV was detected within 48 h p.i. by ICC/real-time RT-PCR, whereas cytopathic effects were not observed until 72 h p.i. The optimized detection method evaluated in this study could be useful for rapid and reliable detection of HRV in fresh produce products and applied for detection of other food-borne viruses.

Complete genome sequence of Salmonella Thompson strain MFDS1004024 isolated from crab-stick

박세욱,이우정,유란희,주인선,곽효선,김순한,Park, Sewook,Lee, Woojung,Yoo, Ran Hee,Joo, In-Sun,Kwak, Hyo Sun,Kim, Soon Han The Microbiological Society of Korea 2018 미생물학회지 Vol.54 No.2

Salmonella enterica subsp. enterica serovar Thompson strain MFDS1004024 는 2014 년 한국에서 발생한 식중독 사고의 게맛살에서 분리되었다. 본 연구에서는 4,742,942 bp 의 크기와 약 52%의 G + C 함량을 가진 MFDS1004024 균주의 완전한 유전체 염기서열을 분석하였다. 이 유전체에는 4,373 개의 코딩 서열, 22 개의 리보솜 RNA 유전자 및 84 개의 전사 RNA 유전자가 존재한다. 또한 유전체 분석 결과를 통해 살모넬라 감염과 베타락탐계 항생제 내성에 관련이 있는 유전자를 발견하였다. Salmonella enterica subsp. enterica serovar Thompson strain MFDS1004024 was isolated from crab-stick in Korean food-borne outbreak in 2014. Here, we present the complete genome sequence of strain MFDS1004024 with a size of 4,742,942 bp and a mean G + C content of 52%. The genome included 4,373 coding sequences, and 22 ribosomal RNA and 84 transfer RNA genes. Also, we found that strain MFDS1004024 has some genes for Salmonella infection and beta-lactam resistance in its genome based on the result of genome analysis.

즉석섭취·편의식품류의 미생물 오염도 조사를 통한 기준·규격 재평가

송보라,김순한,김진광,한정아,곽효선,정경태,허은정,Song, Bo Ra,Kim, Soon Han,Kim, Jin-Kwang,Han, Jeong-A,Kwak, Hyo Sun,Chung, Kyung-Tae,Heo, Eun Jeong 한국식품위생안전성학회 2017 한국식품위생안전성학회지 Vol.32 No.5

본 연구에서는 단일 시료를 검사하는 식품공전의 방법을 통계적 개념인 n, c, m, M을 도입하여 국제기준에 발맞춘 시스템을 확립하고자 식품 중 미생물 오염실태 조사 및 기준 규격 재평가를 실시하였다. 즉석섭취 편의식품류에 대한 미생물의 오염도 조사를 위한 모니터링을 실시하였으며, 이를 바탕으로 통계적 개념을 도입하여 새로운 기준 규격을 마련하고자 하였다. 즉석섭취 편의식품류 총 2,040건(즉석섭취식품 630건, 즉석조리식품1,020건, 신선편의식품390건)을 구입하여 일반세균수, 대장균군, E. coli, B. cereus, S. aureus, C. perfringens 에 대한 모니터링을 진행하였다. 즉석섭취 편의식품류의 일반세균수는 평균 2.10 log CFU/g, 대장균군은 평균 -0.60 log CFU/g, E.coli은 평균 -1.33 log CFU/g, B.cereus은 평균 -1.23 log CFU/g으로 검출되었으며, S.aureus은 신선편의식품에서만 평균 -1.35 log CFU/g, C. perfringens은 즉석조리식품에서만 평균 -1.37 log CFU/g 검출되었다. 일반세균수, B. cereus, S. aureus, C. perfringens은 현 기준규격을 초과하지 않은 것으로 나타났으나, 신선편의식품에 한하여 E. coli 는 34건이 식품기준 및 규격을 초과 하였다. 즉석섭취 편의식품류의 모니터링 결과를 바탕으로 Newsamplesplan 2 프로그램을 활용하여 이론적 규격을 도출하였다. 오염 분포도가 넓어 사실상 규격 마련의 실효성이 없는 것으로 파악되었고, 대장균은 즉석섭취식품 및 즉석조리식품에서 n=5 c=1 m=0 M=10으로, 신선편의식품에서는 n=5 c=1 m=10 M=100으로 이론적 규격이 필요할 것으로 판단된다. Internationally different food safety regulation and standards could cause troubles in trade unless those are built on scientific knowledge. In this research, we monitored the microbial population and analyzed the results to determine the level of microbial contamination in foodstuffs using relatively new statistical analysis (microbiological sampling plan, International Commission on Microbiological Specification for Foods). The goal of this research falls on establishing entirely new standards for various food categories addressed in the Korean "Food Code". Targets for monitoring were indicator organisms (i.e. total aerobic count, coliform and Escherichia coli) and foodborne pathogens (i.e. Bacillus cereus, Staphylococcus aureus and Clostridium perfringens) in ready-to-eat (RTE) products. As the result of the monitoring, total aerobic count, coliform, E. coli, and B. cereus in RTE products were found at the mean values of 2.10 log CFU/g, -0.60 log CFU/g, -1.33 log CFU/g and -1.23 log CFU/g, respectively. S. aureus was detected with the level of -1.35 log CFU/g only in fresh-cut food, while C. perfringens was -1.37 log CFU/g only in ready-to-cook food. Other samples did not have any food borne pathogens. Total aerobic count, B. cereus, S. aureus and C. perfringens satisfied the Food Code (the MFDS). On the basis of the analysis, we proposed a draft of microbial criteria for RTE products.

회원논단 : 식품위해요소로서의 메치실린내성 황색포도상구 (MRSA)

황인균 ( In Gyun Hwang ),곽효선 ( Hyo Sun Kwak ),윤상현 ( Sang Hyeon Yoon ) 한국식품위생안전성학회 2010 Safe Food Vol.5 No.1

식육 및 식육가공품 섭취에 따른 안전성 및 식중독 위험성 인식

최소정,박진화,김한솔,조준일,주인선,곽효선,허진재,윤기선,Choi, So Jeong,Park, Jin Hwa,Kim, Han Sol,Cho, Joon Il,Joo, In Sun,Kwak, Hyo Sun,Heo, Jin Jae,Yoon, Ki Sun 한국식품조리과학회 2016 한국식품조리과학회지 Vol.32 No.4

Purpose: This study investigated consumers' perception of food safety and risk from foodborne illness and consumption pattern of meat and processed meat products in Korea. Methods: A quantitative survey was performed by trained interviewers, surveying 1,500 adults who were randomly selected from six major provinces in Korea. Results: Most of the respondents reported foodborne illness risk related to the consumption of raw meat but not related to heated meat and processed meat products. As respondents perceived the risk of food poisoning from raw meat, the purchase and intake decreased (p<0.001). Most of the respondents considered a low possibility of foodborne illness at home. Seventy-seven percent of the respondents thought that bacteria and virus are the main causes of foodborne illness. Improper storage practice (40.7%) and unsafe food material (29.3%) were the main risk factors contributing to foodborne illness. Perception and practice of food safety was significantly different by the residency area. The most preferred meat, processed meat, and processed ground meat products were pork (58%), ham (31.1%), and pork cutlet (40.4%), respectively. The most preferred cooking method was roasting, regardless of the type of meat, but the second preference for cooking method was significantly affected by the type of meat (p<0.001): stir-fried pork, beef with seasoning, fried-chicken and boiled duck. Frequency of eating out was 0.75/day on weekdays and 0.78/day on weekends at the mainly Korean BBQ restaurant. Conclusion: The results of this study could be used to develop science-based education materials for consumer and the specific guideline of risk management of meat and processed meat products.