• 농업생명과학연구
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• 제46권5호
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• pp.65-72
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• 2012

Salmonellosis is a widespread bacterial zoonosis that commonly causes enterocolitis and foodborne poisoning leading to an extensive economic loss in domestic animal industry. Considerably, the emergence of multidrug resistant strains of Salmonella spp. induces further severe problems affecting public health. The present report was designated to investigate the antibacterial efficacies of three common disinfectants including an oxidizing compound disinfectant (OXC), a triple salt (TS) and a quaternary ammonium compound (QAC) against Salmonella typhimurium subjected to the preliminary changes of drug temperature. All solutions of three disinfectants were pre-incubated at different temperature (22, 37 and $63^{\circ}C$) for 1 h prior to exposure to bacteria. The disinfectants and bacteria were diluted with distilled water (DW), hard water (HW) or organic matter suspension (OMS) according to treatment condition. Under the DW condition, the disinfectant efficacy of the QAC at $63^{\circ}C$ was higher than that of $22^{\circ}C$. Furthermore, under HW diluent the disinfectant efficacy of the TS pre-warmed at both of 37 and $63^{\circ}C$ were increased compared to that of $22^{\circ}C$. Considerably, the efficacy of pre-warmed QAC at both of 37 and $63^{\circ}C$ under the OMS diluent were higher than that of $22^{\circ}C$. Conclusively, prewarming at higher temperatures have positive effects on the stability of the antibacterial efficacies of TS and QAC.

• 한국식품저장유통학회지
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• 제18권3호
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• pp.423-428
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• 2011

주요 식중독균인 E. coli O157:H7, L monocytogenes, S. aureus, S. Typhimurium과 S. Enteritidis를 주어진 이산화염소수 농도에서 시간별로 처리한 inactivation data를 first-order kinetic model과 Weibull model을 이용하여 kinetic parameter를 비교, 분석하였다. 그 결과 Weibull model이 first-order kinetic model보다 inactivation kinetic data에 더 적합한 것을 보였다. 또한 특정 농도의 이산화염소수에서 처리한 survival plot의 tR values(특정 이산화염소수 농도에서 미생물 90%를 감소시키기 위해 필요한 시간)는 Weibull model을 적용 시, E. coli O157:H7가 5 ppm에서 2.49 min, L. monocytogenes가 5 ppm에서 1.47 min, S. aureus가 5 ppm에서 0.94 min, S. Typhimurium이 1 ppm에서 0.87 min 그리고 S. Enteritidis가 1 ppm에서 0.08 min으로 측정 되었다.

• 한국토양비료학회지
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• 제50권6호
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• pp.538-546
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• 2017

The occurrence of various pathogenic microorganisms on farms is a concern if they are able to contaminate fresh produce, which provides entry into the food supply. This study was undertaken to assess the microbiological quality and prevalence of pathogens in Chinese cabbage cultivated soil in Korea. A total of 57 Chinese cabbage cultivated soils were collected in 4 locations in Korea from February to August 2017. The soils were analyzed for the presence of total aerobic bacteria, Escherichia coli, coliforms, Salmonella spp., Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus. The total aerobic plate counts in soils were in the range of 5.7 to $8.7log\;CFU\;g^{-1}$. The coliforms and E. coli were detected in 39 and 8 out of 57 soil samples, respectively, in the range of 1.1 to $6.3log\;CFU\;g^{-1}$ and 0.7 to $4.0log\;CFU\;g^{-1}$. Salmonella spp., E. coli O157:H7, L. monocytogenes, and S. aureus were not detected from any samples. Results from these studies may help control the spread of bacterial species such as E. coli and Salmonella spp. through the farm environment.

• Journal of Microbiology and Biotechnology
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• 제29권6호
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• pp.962-972
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• 2019

Non-typhoidal Salmonella (NTS) is one of the most frequent causes of bacterial foodborne illnesses. Considering that the main reservoir of NTS is the intestinal tract of livestock, foods of animal origin are regarded as the main vehicles of Salmonella infection. In particular, poultry colonized with Salmonella Typhimurium (S. Typhimurium), a dominant serotype responsible for human infections, do not exhibit overt signs and symptoms, thereby posing a potential health risk to humans. In this study, comparative genomics approaches were applied to two S. Typhimurium strains, ST1539 and ST1120, isolated from a duck slaughterhouse and a pig farm, respectively, to characterize their virulence and antimicrobial resistance-associated genomic determinants. ST1539 containing a chromosome (4,905,039 bp; 4,403 CDSs) and a plasmid (93,876 bp; 96 CDSs) was phylogenetically distinct from other S. Typhimurium strains such as ST1120 and LT2. Compared to the ST1120 genome (previously deposited in GenBank; CP021909.1 and CP021910.1), ST1539 possesses more virulence determinants, including ST64B prophage, plasmid spv operon encoding virulence factors, genes encoding SseJ effector, Rck invasin, and biofilm-forming factors (bcf operon and pefAB). In accordance with the in silico prediction, ST1539 exhibited higher cytotoxicity against epithelial cells, better survival inside macrophage cells, and faster mice-killing activity than ST1120. However, ST1539 showed less resistance against antibiotics than ST1120, which may be attributed to the multiple resistanceassociated genes in the ST1120 chromosome. The accumulation of comparative genomics data on S. Typhimurium isolates from livestock would enrich our understanding of strategies Salmonella employs to adapt to diverse host animals.

• 한국융합학회논문지
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• 제10권6호
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• pp.73-78
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• 2019

본 연구는 국내 의료기관 500명의 식품 취급자들의 식품안전에 관한 지식, 인식 및 행태 수준을 평가하고 지식, 인식, 행태와 사회인구학적 특성과의 연관성을 분석하였다. 자가보고 설문지는 식품안전에 관한 지식 15문항, 인식 15문항, 행태 20문항 등 총 50문항으로 구성되었으며 연령별, 교육수준별, 경력별에 따른 지식, 인식, 행태와 KAP과의 관련성분석은 t 또는 ANOVA test를 실시하였다. 분석 결과 식품안전에 관한 평균 지식점수는 3.25, 인식 3.65, 행태 3.36으로 나타났다. 연령그룹별 식품안전에 관한 지식, 인식, KAP score는 차이가 나타났으며, KAP과 교육수준과의 관련성은 교육수준이 증가할수록 KAP score가 증가하는 것을 확인하였다(P < 0.05). 식품위해를 최소화하기 위해서 식품 취급자에게 공중보건학적차원의 지속적인 식품안전 예방교육 및 프로그램을 제공해야 할 것으로 사료된다.

• 한국축산식품학회지
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• 제39권1호
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• pp.84-92
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• 2019

Listeria monocytogenes is a major cause of serious foodborne illness in the dairy foods. Although Caenorhabditis elegans model is well established as a virulence model of pathogenic bacteria, its application on L. monocytogenes is critically unclear. The objective of this study was to carry out an evaluation of L. monocytogenes toxicity using C. elegans nematode as a simple host model. We found that C. elegans nematodes have high susceptibility to L. monocytogenes infection, as a consequence of accumulation of bacteria in the worms' intestine. However, L. innocua, which is known to be non-toxic, is not accumulate in the intestine of worms and is not toxic similarly to Escherichia coli OP50 known as the normal feed source of C. elegans. Importantly, immune-associated genes of C. elegans were intensely upregulated more than 3.0-fold when they exposed to L. monocytogenes. In conclusion, we established that C. elegans is an effective model for studying the toxicity of L. monocytogenes and we anticipate that this system will result in the discovery of many potential anti-listeria agents for dairy foods.

• 한국수산과학회지
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• 제52권1호
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• pp.27-34
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• 2019

The seasonal and spatial variation of pathogenic Vibrio species, such as V. parahaemolyticus, V. vulnificus, V. alginolyticus, and V. cholerae were investigated in seawater and in bivalves off the Gyeongnam coast of Korea, which is an important area for shellfish production, during the period 2013-2016. V. parahaemolyticus, V. vulnificus, V. alginolyticus, and V. cholerae were detected in 12.1%, 5.2%, 15.4%, and 0.9% of seawater samples, respectively. V. parahaemolyticus, V. vulnificus, V. alginolyticus, and V. cholera were detected in 21.9%, 7.1%, 12.2%, and 0.0% of shellfish samples, respectively. The Vibrio spp. in seawater and bivalve samples were detected at high levels during the summer to early autumn; however, the levels were low during the winter. Therefore, their occurrence was seasonally dependent and correlated with high water temperature, which is also the biggest factor contributing to foodborne outbreaks associated with Vibrio. Relatively high detection rates of the strains were also found in the sea area that was continually exposed to inland wastewater. Our findings show that continuous monitoring is needed to reveal the patterns of occurrence of these pathogens from marine samples collected off the Korean coast, to reduce seafood-borne outbreaks caused by Vibrio.

• 식품과학과 산업
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• 제49권3호
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• pp.55-61
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• 2016

Even though the food safety system in the United States is one of the best in the world, many millions of people become sick and thousands die from foodborne illnesses caused by any of a number of microbial pathogens and other contaminants. Large recalls of United States Department of Agriculture (USDA) and the Food Drug and Administration (US FDA)-regulated food products due to findings of E. coli O157:H7, Listeria, Salmonella, and other problems occur each year. As the US FDA Food Safety Modernization Act (FSMA) passed in 2011, FSMA will require food processing, manufacturing, shipping, and other regulated entities to conduct an analysis of the most likely safety hazards and to design and implement risk-based controls to reduce or eliminate these hazards. FSMA also mandates increased scrutiny of food imports, which account for a growing share of U.S. food consumption; food import shipments will have to be accompanied by documentation showing that they can meet safety standards that are at least equivalent to those in the U.S. On September 17, 2015, the US FDA published final rules for Preventive Controls for Human and Animal Food and, continuing into 2016, the US FDA intends to finalize the remaining five rules it has proposed to implement FSMA. Among these rules, this article will review and discuss Preventive Controls for Human Food Rule and its components, and suggest how to comply with these FSMA rules as foreign human food and ingredients suppliers to the US.

• Journal of Veterinary Science
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• 제19권6호
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• pp.771-781
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• 2018

Staphylococcus aureus is one of the major pathogens causing bovine mastitis and foodborne diseases associated with dairy products. To determine the genetic relationships between human and bovine or bovine isolates of S. aureus, various molecular methods have been used. Previously we developed an rpoB sequence typing (RSTing) method for molecular differentiation of S. aureus isolates and identification of RpoB-related antibiotic resistance. In this study, we performed spa typing and RSTing with 84 isolates from mastitic cows (22 farms, 72 cows, and 84 udders) and developed a molecular prophage typing (mPPTing) method for molecular epidemiological analysis of bovine mastitis. To compare the results, human isolates from patients (n = 14) and GenBank (n = 166) were used for real and in silico RSTing and mPPTing, respectively. Based on the results, RST10-2 and RST4-1 were the most common rpoB sequence types (RSTs) in cows and humans, respectively, and most isolates from cows and humans clearly differed. Antibiotic resistance-related RSTs were not detected in the cow isolates. A single dominant prophage type and gradual evolution through prophage acquisition were apparent in most of the tested farms. Thus, RSTing and mPPTing are informative, simple, and economic methods for molecular epidemiological analysis of S. aureus infections.

• 한국식품과학회지
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• 제53권3호
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• pp.334-343
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• 2021

본 연구에서는 16S rRNA 염기서열 분석을 통하여 시설재배 오이 내 상재균총 군집 특성을 분석하였으며, 수확 시기 및 지역에 따른 상재균총에 대한 정보를 제공하였다. 상재균총 다양성 분석(α-diversity)의 경우 5월 시료에서 더 높은 수치의 Observed OTUs와 Chao1 index가 나타났다. PCoA (β-diversity)분석을 통해서 수확 시기에 따른 상재균총의 차이가 존재함을 확인하였다. Phylum 수준에서는 Proteobacteria, Firmicutes, Actinobacteria가 우점하였고, class 수준에서는 Gammaproteobacteria, Bacilli, Alphaproteobacteria, Actinobacteria가 주로 존재하였다. Genus 수준에서는 시기적인 요인이 주로 상재균총에 영향을 끼치는 것을 확인할 수 있었으며, 일부 지역적 요인의 영향도 관찰 되었다. 5월 시료에서는 Aureimonas, Escherichia, Microbacterium이 11월 시료에서는 Enterococcus, Pseudomonas, Rhizobium이 더 높은 비율을 차지하였다. 이외에도, Acinetobacter, Aerococcus, Aureimonas, Enterobacter, Enterococcus, Escherichia, Pantoea, Pseudomonas, Staphylococcus와 같이 잠재적인 위험성을 가지는 genus가 존재함을 확인하였다.