Quantitative Microbial Risk Assessment for Campylobacter jejuni in Ground Meat Products in Korea

Lee, Jeeyeon,Lee, Heeyoung,Lee, Soomin,Kim, Sejeong,Ha, Jimyeong,Choi, Yukyung,Oh, Hyemin,Kim, Yujin,Lee, Yewon,Yoon, Ki-Sun,Seo, Kunho,Yoon, Yohan Korean Society for Food Science of Animal Resource 2019 한국축산식품학회지 Vol.39 No.4

This study evaluated Campylobacter jejuni risk in ground meat products. The C. jejuni prevalence in ground meat products was investigated. To develop the predictive model, survival data of C. jejuni were collected at $4^{\circ}C-30^{\circ}C$ during storage, and the data were fitted using the Weibull model. In addition, the storage temperature and time of ground meat products were investigated during distribution. The consumption amount and frequency of ground meat products were investigated by interviewing 1,500 adults. The prevalence, temperature, time, and consumption data were analyzed by @RISK to generate probabilistic distributions. In 224 samples of ground meat products, there were no C. jejuni-contaminated samples. A scenario with a series of probabilistic distributions, a predictive model and a dose-response model was prepared to calculate the probability of illness, and it showed that the probability of foodborne illness caused by C. jejuni per person per day from ground meat products was $5.68{\times}10^{-10}$, which can be considered low risk.

Combination of Hydrophobic Filtration and Enrichment Methods for Detecting Bacillus cereus in Fresh-Cut Cabbage

Lee, Sujung,Choi, Yukyung,Lee, Heeyoung,Kim, Sejeong,Lee, Jeeyeon,Ha, Jimyeong,Oh, Hyemin,Lee, Yewon,Kim, Yujin,Yoon, Yohan,Lee, Soomin The Korean Society of Food Hygiene and Safety 2018 한국식품위생안전성학회지 Vol.33 No.5

본 연구에서는 신선편이 양배추 내 Bacillus cereus의 최적 증균 온도를 선정하고 증균배양액에 소수성필터를 적용하여 multiplex PCR의 검출률을 확인하였다. B. cereus 증균온도는 B. cereus 균주 5 개를 혼합하여 1 Log CFU/mL이 되도록 증균배지에 접종하고 $30^{\circ}C$, $37^{\circ}C$, $42^{\circ}C$에서 증균한 뒤 3시간 간격으로 MYP agar에 도말한 후 계수하여 선정하였다. 소수성필터 미적용 그룹은 B. cereus 균주 5 개를 혼합하여 신선편이 양배추에 접종한 뒤 최적 증균온도에서 증균하였으며, 증균배양액을 가열하여 DNA를 추출한 뒤 multiplex PCR을 진행하였다. 소수성필터 적용 그룹은 증균배양액을 소수성 필터에 적용하고 필터에 있는 균을 멸균증류수로 현탁한 뒤 가열하여 추출된 DNA로 multiplex PCR을 진행하였다. 증균온도 확인 결과, 6시간 증균 시 $42^{\circ}C$에서 증균된 샘플($5.4{\pm}0.3Log\;CFU/mL$)과 $30^{\circ}C$에서 증균된 샘플($4.6{\pm}0.6Log\;CFU/mL$) 간 유의차가 확인되었다(p < 0.05). 소수성필터 적용 유무에 따른 multiplex PCR 결과, 1 Log CFU/g 접종된 샘플의 검출률이 소수성 필터 적용 전 60%(3/5)에서 100%(5/5)로 향상되었다. 2 Log CFU/g 접종 샘플은 소수성필터 적용 전 80%(4/5)에서 소수성 필터 적용 후 100%(5/5)로 검출률이 증가하였으나, 3 Log CFU/g 접종 샘플은 소수성 필터 적용 전후 모두 100%(5/5)로 확인되었다. 이상의 결과를 통해 신선편이 양배추 내 B. cereus 검출 시 증균배양액에 소수성필터를 적용하고 multiplex PCR을 적용했을 때 신속하고 효율적인 검출이 가능할 것으로 판단된다. This study developed a rapid detection method for Bacillus cereus in fresh-cut cabbages. Fresh-cut cabbage samples were inoculated at 1-, 2- and 3-Log CFU/g, and pathogens were enriched in tryptic soy broth containing 0.15% polymyxin B at $30^{\circ}C$, $37^{\circ}C$, and $42^{\circ}C$ to determine the detection limit and appropriate enrichment temperature for multiplex PCR detection. Enriched bacterial cells in enrichment broth were collected in a hydrophobic filter prior to DNA extraction for multiplex PCR. Filters were resuspended in distilled water, and DNA was extracted from the suspension. DNA samples were further analyzed by multiplex PCR. Detection limit of multiplex PCR was 5-Log CFU/mL. B. cereus cell counts were higher (P < 0.05) at $42^{\circ}C$ than other temperatures. Detection rate of 1-, 2-, and 3-Log CFU/g inoculated samples were 60%, 80%, and 100% after enrichment respectively. However, when enriched samples were filtered with hydrophobic membrane filter, detection rates became 100%, regardless of inoculation level. Results indicate a combination of enrichment with hydrophobic filtration improves rapid detection efficiency of B. cereus in fresh-cut cabbage by multiplex PCR.

Combination of Hydrophobic Filtration and Enrichment Methods for Detecting Bacillus cereus in Fresh-Cut Cabbage

Sujung Lee,Yukyung Choi,Heeyoung Lee,Sejeong Kim,Jeeyeon Lee,Jimyeong Ha,Hyemin Oh,Yewon Lee,Yujin Kim,Yohan Yoon,Soomin Lee 한국식품위생안전성학회 2018 한국식품위생안전성학회지 Vol.33 No.5

본 연구에서는 신선편이 양배추 내 Bacillus cereus의 최 적 증균 온도를 선정하고 증균배양액에 소수성필터를 적용하여 multiplex PCR의 검출률을 확인하였다. B. cereus 증균온도는 B. cereus 균주 5 개를 혼합하여 1 Log CFU/ mL이 되도록 증균배지에 접종하고 30oC, 37oC, 42oC에서 증균한 뒤 3시간 간격으로 MYP agar에 도말한 후 계수하여 선정하였다. 소수성필터 미적용 그룹은 B. cereus 균 주 5 개를 혼합하여 신선편이 양배추에 접종한 뒤 최적 증균온도에서 증균하였으며, 증균배양액을 가열하여 DNA 를 추출한 뒤 multiplex PCR을 진행하였다. 소수성필터 적용 그룹은 증균배양액을 소수성 필터에 적용하고 필터에 있는 균을 멸균증류수로 현탁한 뒤 가열하여 추출된 DNA 로 multiplex PCR을 진행하였다. 증균온도 확인 결과, 6시간 증균 시 42oC에서 증균된 샘플(5.4 ± 0.3 Log CFU/mL) 과 30oC에서 증균된 샘플(4.6 ± 0.6 Log CFU/mL) 간 유의 차가 확인되었다(p < 0.05). 소수성필터 적용 유무에 따른 multiplex PCR 결과, 1 Log CFU/g 접종된 샘플의 검출률이 소수성 필터 적용 전 60%(3/5)에서 100%(5/5)로 향상 되었다. 2 Log CFU/g 접종 샘플은 소수성필터 적용 전 80%(4/5)에서 소수성 필터 적용 후 100%(5/5)로 검출률이 증가하였으나, 3 Log CFU/g 접종 샘플은 소수성 필터 적용 전후 모두 100%(5/5)로 확인되었다. 이상의 결과를 통해 신선편이 양배추 내 B. cereus 검출 시 증균배양액에 소수성필터를 적용하고 multiplex PCR을 적용했을 때 신속하고 효율적인 검출이 가능할 것으로 판단된다. This study developed a rapid detection method for Bacillus cereus in fresh-cut cabbages. Fresh-cut cabbage samples were inoculated at 1-, 2- and 3-Log CFU/g, and pathogens were enriched in tryptic soy broth containing 0.15% polymyxin B at 30oC, 37oC, and 42oC to determine the detection limit and appropriate enrichment temperature for multiplex PCR detection. Enriched bacterial cells in enrichment broth were collected in a hydrophobic filter prior to DNA extraction for multiplex PCR. Filters were resuspended in distilled water, and DNA was extracted from the suspension. DNA samples were further analyzed by multiplex PCR. Detection limit of multiplex PCR was 5-Log CFU/mL. B. cereus cell counts were higher (P < 0.05) at 42oC than other temperatures. Detection rate of 1-, 2-, and 3-Log CFU/g inoculated samples were 60%, 80%, and 100% after enrichment respectively. However, when enriched samples were filtered with hydrophobic membrane filter, detection rates became 100%, regardless of inoculation level. Results indicate a combination of enrichment with hydrophobic filtration improves rapid detection efficiency of B. cereus in fresh-cut cabbage by multiplex PCR.

Rapid Detection of Escherichia coli in Fresh Foods Using a Combination of Enrichment and PCR Analysis

Yukyung Choi,Sujung Lee,Heeyoung Lee,Soomin Lee,Sejeong Kim,Jeeyeon Lee,Jimyeong Ha,Hyemin Oh,Yewon Lee,Yujin Kim,Yohan Yoon 한국축산식품학회 2018 한국축산식품학회지 Vol.38 No.4

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 freshcut 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℃, 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℃, and PCR analysis using uidA gene-specific primers were appropriate to detect E. coli rapidly in food samples.

Highly luminescent silica-coated CdS/CdSe/CdS nanoparticles with strong chemical robustness and excellent thermal stability

Wang, Nianfang,Koh, Sungjun,Jeong, Byeong Guk,Lee, Dongkyu,Kim, Whi Dong,Park, Kyoungwon,Nam, Min Ki,Lee, Kangha,Kim, Yewon,Lee, Baek-Hee,Lee, Kangtaek,Bae, Wan Ki,Lee, Doh C IOP 2017 Nanotechnology Vol.28 No.18

<P>We present facile synthesis of bright CdS/CdSe/CdS@SiO<SUB>2</SUB> nanoparticles with 72% of quantum yields (QYs) retaining ca 80% of the original QYs. The main innovative point is the utilization of the highly luminescent CdS/CdSe/CdS seed/spherical quantum well/shell (SQW) as silica coating seeds. The significance of inorganic semiconductor shell passivation and structure design of quantum dots (QDs) for obtaining bright QD@SiO<SUB>2</SUB> is demonstrated by applying silica encapsulation via reverse microemulsion method to three kinds of QDs with different structure: CdSe core and 2 nm CdS shell (CdSe/CdS-thin); CdSe core and 6 nm CdS shell (CdSe/CdS-thick); and CdS core, CdSe intermediate shell and 5 nm CdS outer shell (CdS/CdSe/CdS-SQW). Silica encapsulation inevitably results in lower photoluminescence quantum yield (PL QY) than pristine QDs due to formation of surface defects. However, the retaining ratio of pristine QY is different in the three silica coated samples; for example, CdSe/CdS-thin/SiO<SUB>2</SUB> shows the lowest retaining ratio (36%) while the retaining ratio of pristine PL QY in CdSe/CdS-thick/SiO<SUB>2</SUB> and SQW/SiO<SUB>2</SUB> is over 80% and SQW/SiO<SUB>2</SUB> shows the highest resulting PL QY. Thick outermost CdS shell isolates the excitons from the defects at surface, making PL QY relatively insensitive to silica encapsulation. The bright SiO<SUB>2</SUB>-coated SQW sample shows robustness against harsh conditions, such as acid etching and thermal annealing. The high luminescence and long-term stability highlights the potential of using the SQW/SiO<SUB>2</SUB> nanoparticles in bio-labeling or display applications.</P>

The review of the clinical usefulness and price of currently listed drugs in South Korea

CHO Jung Sook,KIM Jung Ock,PARK Eun Yeong,LIM Min Kyoung,LEE Jin Hee,LEE Jong Hwan,SUNG Ye Na,YOON Sang-heon,NA Yewon,KIM Ji Yeon,LEE Seung Yeon,LEE Sook Hyun,LEE Yeun Hee,SO Soo Mi,KIM Byung Soo,LEE 대한약학회 2012 大韓藥學會 總會 및 學術大會 Vol.2012 No.1

Quantitative assessment of the food-borne Salmonella contamination using a quantitative real-time polymerase chain reaction

Yewon Cheong,Ji Seung Jung,Won Jae Lee,Jun Bong Lee,Jang Won Yoon 한국예방수의학회 2020 예방수의학회지 Vol.44 No.1

Salmonella is one of the most important bacterial pathogens responsible for many zoonotic food-related infectious diseases. Quantitative detection of the foodborne Salmonella contamination in various food sources is therefore critical for preventing the related disease outbreaks. In this study, we developed and evaluated a reliable real-time polymerase chain reaction (RT-PCR) assay to detect the Salmonella contamination quantitatively. The experimental results showed that our invA gene-specific quantitative RT-PCR (qRT-PCR) assay provides a strong correlation between the Cq values and the direct plate counts of Salmonella species in the artificially formulated samples. Further study may be necessary to identify more accurate correlation and equation that can apply to Salmonella spp.

Probiotics-Mediated Bioconversion and Periodontitis

Yewon Lee,Yohan Yoon,Kyoung-hee Choi 한국축산식품학회 2021 한국축산식품학회지 Vol.41 No.6

Novel bioactive metabolites have been developed through a bioconversion of dairy products or other foods using probiotics isolated from dairy products or other fermented foods. These probiotics-mediated bioconversion (PMB) metabolites show antioxidant, anti-inflammatory, antimicrobial, epithelial barrier, and anticancer activities. In addition, the effect of PMB metabolites in periodontitis is recently reported in several studies. Periodontitis is a chronic inflammatory disease caused by infections, and the tooth support tissue is destroyed. Common treatments for periodontitis include scaling and root planning with systemic antibiotics. However, the overuse of antibiotics has led to the emergence of drug-resistant microorganisms and disturbs the beneficial bacteria, including lactobacilli in the oral cavity. For this reason, PMB metabolites, such as fermented milk, have been suggested as substitutes for antibiotics to reduce periodontitis. This paper reviews the recent studies on the correlation between periodontitis and PMB metabolites and classifies the efficacy of major PMB metabolites for periodontitis. The review suggests that PMB is effective for periodontitis, and further studies are needed to confirm the therapeutic effect of PMB metabolites on periodontitis.

Antimicrobial Effects of EcoCal ® and GF Bactostop ® Formulated in Emulsified Sausages against Lactic Acid Bacteria

Yewon Lee,정성희,윤요한 한국식품위생안전성학회 2020 한국식품위생안전성학회지 Vol.35 No.3

In this study we evaluated the antimicrobial effects of EcoCal ® (calcium oxide) and GF Bactostop ® (organic acids mix) in sausages during storage at 10 o C. The sausages were formulated with 0.1% EcoCal ® (0.1ECO), 0.1% EcoCal ® +0.5% GF Bactostop ® (0.1ECO+0.5GF), 0.2% EcoCal ® (0.2ECO), and 0.2% EcoCal ® +0.5% GF Bactostop ® (0.2ECO+0.5GF). Total aerobic and lactic acid bacteria in the sausages were enumerated on tryptic soy agar and Lactobacilli MRS agar, respectively, during storage at 10 o C for 10 weeks. The 0.1ECO+0.5GF showed the most effective antimicrobial effects on the sausages, and 0.1ECO showed the second most effective antimicrobial effect. Total aerobic bacterial cell counts gradually increased in the control, 0.2ECO, and 0.2ECO+0.5GF groups, but cell growth was generally inhibited in 0.1ECO by approximately day 42 (P<0.05) and 0.1ECO+0.5GF by approximately day 49 (P<0.05). Lactic acid bacterial cell counts gradually increased in the control, 0.2ECO, and 0.2ECO+0.5GF groups, but the lactic acid bacteria growth was inhibited in 0.1ECO by approximately day 49 (P<0.05) and in 0.1ECO+0.5GF by approximately day 64. These results suggest that using 0.1% EcoCal ® +0.5% GF Bactostop ® in sausage formulation is useful for inhibiting lactic acid bacteria growth, thereby extending the shelf-life of the sausage product.

Geriatric Dwelling Depression Measurement Based on Projective Image Analysis Modeling

Yewon Lee,Chongwook Park,Sungju Woo 국제문화기술진흥원 2018 International Journal of Advanced Culture Technolo Vol.6 No.4

The growth of the older population is expected to further increase social problems associated with population aging, such as isolation, poverty, and depression. The emerging issues associated with the older population are also expected to provide further momentum on studies about the dwelling environment as factors that ensure the health of older people as well as improve their quality of life. Therefore, approaches for explaining the issues of the older age group should be diversified using a variety of factors and appropriate analytic tools. Studies on measuring depression have principally focused on assessing an objective self-report questionnaire, usually in a highly structured, textual form which may not reflect the cognitive impairment of older adults. The aim of this study was to define and measure dwelling depression among older adults in Korea. There are two specific hypotheses in this study as follows: (a) there will be statistically significant relationships with dwelling dissatisfaction and depression, and (b) dwelling depression tools containing text and images will be, respectively, assessment tools that have a good construct with content validity and reliability. In the first experiment, to define and measure dwelling depression, 301 people over 65 years old living in single and two-person households were surveyed using a text-based dwelling depression questionnaires from September 1–30, 2017. In the second experiment, to examine whether the projective image questionnaire could serve as a suitable replacement for the text-based questionnaires, the same participants were surveyed from January 22 to February 2, 2018. The results show that depression has a close correlation with dwelling dissatisfaction. In addition, the geriatric dwelling depression index (GDDI) based on the projective image was refined. Additionally, the projective image questionnaire has a close correlation with the text-based questionnaire. Finally, through ROC curve analysis, it was found that the projective image questionnaire can accurately predict a depression group. To this end, this preliminary study examined the validity of the projective image questionnaire in older adults to make this instrument feasible for older populations and to contribute to a profound understanding of geriatric depression due to the living environment. We hope they will provide a basis for further research on psychological diagnoses using projective images.