낙농산업에서 항생제 사용의 문제점과 프로바이오틱스의 활용을 통한 생산성 향상

서영은 ( Yeongeun Seo ),유윤정 ( Yoonjeong Yoo ),윤요한 ( Yohan Yoon ) 한국낙농식품응용생물학회(구 한국유가공학회) 2021 Journal of Dairy Science and Biotechnology (JMSB) Vol.39 No.2

Antibiotics are widely used to improve productivity in the dairy industry. However, the inappropriate use of antibiotics causes the deterioration in the quality of dairy products undergoing fermentation and maturation. Hence, probiotic use is emerging as an alternative to curb the increased utilization of antibiotics. Probiotics are defined as “living microorganisms that, when administered in appropriate amounts, confer health benefits on the host.” They may improve host disease resistance by regulating intestinal microflora balance and promote animal growth and development. In the dairy industry, probiotics have been studied to increase milk production by improving digestion in dairy cows, enhance the content of dairy components such as milk fat and protein, reduce the risk of mastitis in cows, and increase calf weight. Thus, the use of probiotics can improve the production and safety of dairy products. However, some probiotics are still unstable during storage and have low quality and safety issues. Therefore, to reduce the use of antibiotics in the dairy industry, probiotics should be developed and produced considering the above-mentioned problems.

Gas-Permeable Inorganic Shell Improves the Coking Stability and Electrochemical Reactivity of Pt toward Methane Oxidation

Seo, Jongsu,Tsvetkov, Nikolai,Jeong, Seung Jin,Yoo, Yeongeun,Ji, Sanghoon,Kim, Jeong Hwan,Kang, Jeung Ku,Jung, WooChul American Chemical Society 2020 ACS APPLIED MATERIALS & INTERFACES Vol.12 No.4

<P>Solid oxide fuel cells produce electricity directly by oxidizing methane, which is the most attractive natural gas fuel, and metal nanocatalysts are a promising means of overcoming the poor catalytic activity of conventional ceramic electrodes. However, the lack of thermal and chemical stability of nanocatalysts is a major bottleneck in the effort to ensure the lifetime of metal-decorated electrodes for methane oxidation. Here, for the first time, this issue is addressed by encapsulating metal nanoparticles with gas-permeable inorganic shells. Pt particles approximately 10 nm in size are dispersed on the surface of a porous La<SUB>0.75</SUB>Sr<SUB>0.25</SUB>Cr<SUB>0.5</SUB>Mn<SUB>0.5</SUB>O<SUB>3</SUB> (LSCM) electrode via wet infiltration and are then coated with an ultrathin Al<SUB>2</SUB>O<SUB>3</SUB> layer via atomic layer deposition. The Al<SUB>2</SUB>O<SUB>3</SUB> overcoat, despite being an insulator, significantly enhances the immunity to carbon coking and provides high activity for the electrochemical oxidation of methane, thereby reducing the reaction impedance of the Pt-decorated electrode by more than 2 orders of magnitude and making the electrode activity of the Pt-decorated sample at 650 °C comparable with those reported at 800 °C for pristine LSCM electrodes. These observations provide a new perspective on strategies to lower the operation temperature, which has long been a challenge related to hydrocarbon-fueled solid oxide fuel cells.</P> [FIG OMISSION]</BR>

GC-MS/MS method for determination of 2-Chloroethanol in topical anesthesia using QueChERS

Yeongeun Jeong,Ilyoung Ahn,So-yeon Lee,Seo Jeong Jang,Pan Soon Kim,Jung Yun Chang 한국분석과학회 2023 학술대회논문집 Vol.2023 No.11

Quantitative microbial risk assessment indicates very low risk for Vibrio parahaemolyticus foodborne illness from Jeotgal in South Korea

최유경,강주현,이예원,Yeongeun Seo,Sejeong Kim,하지명,오혜민,김유진,박은영,이희영,이수민,Min Suk Rhee,윤요한 한국수산과학회 2022 Fisheries and Aquatic Sciences Vol.25 No.9

In this study, a microbial risk assessment was performed for the bacteria Vibrio parahaemolyticus, which causes a foodborne illness following the consumption of Jeotgal, a fermented seafood in South Korea. The assessment comprised of six stages: product, market, home, consumption, dose-response, and risk. The initial contamination level (IC) was calculated based on the prevalence of V. parahaemolyticus in 90 Jeotgal samples. The kinetic behavior of V. parahaemolyticus was described using predictive models. The data on transportation conditions from manufacturer to market and home were collected through personal communication and from previous studies. Data for the Jeotgal consumption status were obtained, and an appropriate probability distribution was established. The simulation models responding to the scenario were analyzed using the @RISK program. The IC of V. parahaemolyticus was estimated using beta distribution [Beta (1, 91)]. The cell counts during transportation were estimated using Weibull and polynomial models [δ = 1 / (0.0718 – 0.0097 × T + 0.0005 × T2)], while the probability distributions for time and temperature were estimated using Pert, Weibull, Uniform, and LogLogistic distributions. Daily average consumption amounts were assessed using the Pareto distribution [0.60284,1.32,Risk Truncate(0,155)]. The results indicated that the risk of V. parahaemolyticus infection through Jeotgal consumption is low in South Korea.

Prevalence and Kinetic Behavior of Escherichia coli in Smoked Duck at Changing Temperature

Eunyoung Park,Yujin Kim,Yewon Lee,Yeongeun Seo,Joohyun Kang,Hyemin Oh,Joo-Sung Kim,Yohan Yoon 한국식품위생안전성학회 2021 한국식품위생안전성학회지 Vol.36 No.6

본 연구에서는 훈제오리 슬라이스에서 Escherichia coli 유통 중 생장 예측을 위한 dynamic model을 개발하였다. E. coli는 2개의 훈제 오리 시료(16.7%) 에서 1.23 log CFU/ g검출되었다. 10-30oC 보관에 따라 E. coli의 μmax는 0.05- 0.36 log CFU/g/h, LPD는 4.39-1.07h, h0 값은 0.24-0.51을 나타내었다. 개발된 모델의 검증은 15oC, 23oC에서 수행 하였다. 모델 검증 결과 RMSE값이 0.130으로 개발된 모델이 다른 온도에 적용하기에 적합하다고 판단하였다. 이 러한 결과는 E. coli로 개발된 모델은 훈제오리 슬라이스에서 E. coli의 변화하는 온도에 따른 생장을 예측하는 데 유용하다. The objective of this study was to develop dynamic model to describe the kinetic behavior of E. coli in sliced smoked duck. E. coli was detected in 2 sliced smoked duck samples (16.7%) at 1.23 log CFU/g. The maximum specific growth rate (μmax) of E. coli ranged from 0.05 to 0.36 log CFU/g/h, and lag phase duration (LPD) ranged from 4.39 to 1.07 h, depending on the storage at 10-30oC, and h0 value ranged from 0.24 to 0.51. The developed model was validated with observed values obtained at 13oC and 25oC. The model performance was appropriate with 0.130 of root mean squared error (RMSE), and the dynamic model also described properly kinetic behavior of E. coli in sliced smoked duck samples. These results indicate that E. coli can contaminate sliced smoked ducks and the models developed with the E. coli isolates are useful in describing the kinetic behavior of E. coli in sliced smoked duck.

Quantitative microbial risk assessment of Vibrio parahaemolyticus foodborne illness of sea squirt (Halocynthia roretzi) in South Korea

Kang, Joohyun,Lee, Yewon,Choi, Yukyung,Kim, Sejeong,Ha, Jimyeong,Oh, Hyemin,Kim, Yujin,Seo, Yeongeun,Park, Eunyoung,Rhee, Min Suk,Lee, Heeyoung,Yoon, Yohan The Korean Society of Fisheries and Aquatic Scienc 2021 Fisheries and Aquatic Sciences Vol.24 No.2

The annual consumption of fishery products, particularly sea squirt (Halocynthia roretzi), per person has steadily increased in South Korea. However, the quantitative risk of Vibrio parahaemolyticus following intake of sea squirt has not been analyzed. This study focuses on quantitative predictions of the probability of consuming sea squirt and getting of V. parahaemolyticus foodborne illness. The prevalence of V. parahaemolyticus in sea squirt was evaluated, and the time spent by sea squirt in transportation vehicles, market displays, and home refrigerators, in addition to the temperature of each of these, were recorded. The data were fitted to the @RISK program to obtain a probability distribution. Predictive models were developed to determine the fate of V. parahaemolyticus under distribution conditions. A simulation model was prepared based on experimental data, and a dose-response model for V. parahaemolyticus was prepared using data from literature to estimate infection risk. V. parahaemolyticus contamination was detected in 6 of 35 (17.1%) sea squirt samples. The daily consumption quantity of sea squirt was 62.14 g per person, and the consumption frequency was 0.28%. The average probability of V. parahaemolyticus foodborne illness following sea squirt consumption per person per day was 4.03 × 10^-9. The objective of this study was to evaluate the risk of foodborne illness caused by Vibrio parahaemolyticus following sea squirt consumption in South Korea.

Mathematical Models to Describe the Kinetic Behavior of Staphylococcus aureus in Jerky

Jimyeong Ha,Jeeyeon Lee,Soomin Lee,Sejeong Kim,Yukyung Choi,Hyemin Oh,Yujin Kim,Yewon Lee,Yeongeun Seo,Yohan Yoon 한국축산식품학회 2019 한국축산식품학회지 Vol.39 No.3

The objective of this study was to develop mathematical models for describing the kinetic behavior of Staphylococcus aureus (S. aureus) in seasoned beef jerky. Seasoned beef jerky was cut into 10-g pieces. Next, 0.1 mL of S. aureus ATCC13565 was inoculated into the samples to obtain 3 Log CFU/g, and the samples were stored aerobically at 10°C, 20°C, 25°C, 30°C, and 35°C for 600 h. S. aureus cell counts were enumerated on Baird Parker agar during storage. To develop a primary model, the Weibull model was fitted to the cell count data to calculate Delta (required time for the first decimal reduction) and ρ (shape of curves). For secondary modeling, a polynomial model was fitted to the Delta values as a function of storage temperature. To evaluate the accuracy of the model prediction, the root mean square error (RMSE) was calculated by comparing the predicted data with the observed data. The surviving S. aureus cell counts were decreased at all storage temperatures. The Delta values were longer at 10°C, 20°C, and 25°C than at 30°C and 35°C. The secondary model well-described the temperature effect on Delta with an R2 value of 0.920. In validation analysis, RMSE values of 0.325 suggested that the model performance was appropriate. S. aureus in beef jerky survives for a long period at low storage temperatures and that the model developed in this study is useful for describing the kinetic behavior of S. aureus in seasoned beef jerky.

High Prevalence of Listeria monocytogenes in Smoked Duck: Antibiotic and Heat Resistance, Virulence, and Genetics of the Isolates

Park, Eunyoung,Ha, Jimyeong,Oh, Hyemin,Kim, Sejeong,Choi, Yukyung,Lee, Yewon,Kim, Yujin,Seo, Yeongeun,Kang, Joohyun,Yoon, Yohan Korean Society for Food Science of Animal Resource 2021 한국축산식품학회지 Vol.41 No.2

This study aimed at determining the genetic and virulence characteristics of the Listeria monocytogenes from smoked ducks. L. monocytogenes was isolated by plating, and the isolated colonies were identified by PCR. All the obtained seven L. monocytogenes isolates possessed the virulence genes (inlA, inlB, plcB, and hlyA) and a 385 bp actA amplicon. The L. monocytogenes isolates (SMFM2018 SD 1-1, SMFM 2018 SD 4-1, SMFM 2018 SD 4-2, SMFM 2018 SD 5-2, SMFM 2018 SD 5-3, SMFM 2018 SD 6-2, and SMFM 2018 SD 7-1) were inoculated in tryptic soy broth (TSB) containing 0.6% yeast extract at 60℃, followed by cell counting on tryptic soy agar (TSA) containing 0.6% yeast extract at 0, 2, 5, 8, and 10 min. We identified five heat resistant isolates compared to the standard strain (L. monocytogenes ATCC13932), among which three exhibited the serotype 1/2b and D-values of 5.41, 6.48, and 6.71, respectively at 60℃. The optical densities of the cultures were regulated to a 0.5 McFarland standard to assess resistance against nine antibiotics after an incubation at 30℃ for 24 h. All isolates were penicillin G resistant, possessing the virulence genes (inlA, inlB, plcB, and hlyA) and the 385-bp actA amplicon, moreover, three isolates showed clindamycin resistance. In conclusion, this study allowed us to characterize L. monocytogenes isolates from smoked ducks, exhibiting clindamycin and penicillin G resistance, along with the 385-bp actA amplicon, representing higher invasion efficiency than the 268-bp actA, and the higher heat resistance serotype 1/2b.

Development of Hydrogels to Improve the Safety of Yukhoe (Korean Beef Tartare) by Reducing Psychrotrophic Listeria monocytogenes Cell Counts on Raw Beef Surface

Hyemin Oh,Sejeong Kim,Soomin Lee,Jimyeong Ha,Jeeyeon Lee,Yukyung Choi,Yewon Lee,Yujin Kim,Yeongeun Seo,Yohan Yoon 한국축산식품학회 2018 한국축산식품학회지 Vol.38 No.6

This study developed an antimicrobial hydrogel to control Listeria monocytogenes in Yukhoe (Korean beef tartare). Four hydrogels (hydrogel 1: 5% alginate+1% chitosan+0.2% CaCl2, hydrogel 2: 1% κ-carrageenan+1% chitosan, hydrogel 3: 2%κ-carrageenan+1% CaCl2, and hydrogel 4: 2% κ-carrageenan+3% CaCl2) were prepared. The hydrogels then absorbed 0.1% grapefruit seed extract (GSE) and 0.1% citrus extract (CE) for 30, 60, 120, and 240 min to be antimicrobial hydrogels. To select the most effective antimicrobial hydrogel, their swelling ratio (SR) and antilisterial activities were determined. The selected hydrogel (2×2 cm) was then placed on surface of beef (round; 3×3 cm), where L. monocytogenes (ca. 106 CFU/g) were inoculated, and the cell counts were enumerated on PALCAM agar. Among the hydrogels, the SR of hydrogel 1 increased with absorbing time, but other hydrogels showed no significant changes. Antimicrobial hydrogel 1 showed higher (p<0.05) antilisterial activity than other antimicrobial hydrogels, especially for the one absorbed the antimicrobial for 120 min. Thus, the antimicrobial hydrogel 1 absorbed antimicrobials for 120 min was applied on raw beef at 4℃, and reduced (p<0.05) more than 90% of L. monocytogenes on raw beef. These results indicate that antimicrobial hydrogel 1 formulated with 0.1% GSE or 0.1% CE is appropriate to improve the safety of Yukhoe by reducing psychrotrophic L. monocytogenes cell counts on raw beef.

Profiling of immunotoxicity in mice exposed to polyethylene microplastics through intragastric intubation for 4 weeks

Yong Heo,JiHun Jo,Ravi Gautam,Manju Acharya,Pramod KC,Anju Maharjan,DaEun Lee,ChangYul Kim,HyoungAh Kim,GyoungWoo Lee,HyeJin Kang,JunHo Sin,YeongEun Yu,SeungYi Seo 한국실험동물학회 2021 한국실험동물학회 학술발표대회 논문집 Vol.2021 No.7

Microplastics (MPs) have been recently recognized as a global environmental threat and its exposure as a risk factor to human health. Health effects through MPs exposure have been recently reported, whereas not much evaluation on immunotoxicity of MP has been reported. The present study was designed to evaluate whether polyethylene MPs (PE-MPs) subacute exposure through intragastric intubation could be immunotoxic to ICR mice. PEs with 5 or 50 μm diameter were administered to 6 wk old female and male mice at 0 (distilled water, vehicle control), 500 (low), and 1000 (middle), or 2000 (high) mg/day for 4 wks. No influence of the exposure on thymic T lymphocyte development was observed due to no difference in thymic lymphocyte subpopulation through flow cytometer analysis among the groups. Proportions of splenic CD4(+) and B lymphocyte were higher without statistical significances in the exposure groups than the vehicle control regardless of dose and gender. Serum IgG2a:IgG1 ratio was dose-dependently elevated in the male and female 5 μm PE exposure group, which pattern was not observed with 50 μm exposure group. Furthermore, ratios of IFN-gamma:IL-4, a parameter for predicting balance between type-1 and type-2 immune reactivity in helper T lymphocytes stimulated ex vivo with phytohemagglutinin for 48h, were higher in the male 5 μm PE exposure group than the control, but not observed in the female 5 μm and the 50 μm exposure group of both genders. Overall, the present study indicates that exposure to PE-MPs could alter immune homeostasis, especially to smaller size of MPs. Investigation on size-dependent and plastic type-related immune modulation should be advanced. [supported by the Korea Environmental Industry & Technology Institute (No.2020003120002) and the Ministry of Environment-Educational training program for the management of information on the hazards and risk of chemical substances]