A Multiplex PCR Assay for the Detection of Food-borne Pathogens in Meat Products

Hyoun Wook Kim,Ji Hyun Kim,Seong Ryul Rhim,Kyung A Lee,Cheon Jei Kim,Hyun Dong Paik 한국축산식품학회 2010 한국축산식품학회지 Vol.30 No.4

Meat and meat products are a potential source of food-borne pathogens, including Staphylococcus aureus, Salmonella spp., Escherichia coli O157:H7, and Bacillus cereus. A sensitive and specific PCR assay for the detection of these pathogens in meat and meat products was developed in this study, as part of a broader effort to reduce the potential health hazards posed by these pathogens. Initially, PCR conditions were standardized with purified DNA. Under standard conditions, the detection level for PCR was as low as 10 pg of purified bacterial DNA. After overnight growth of bacteria in a broth medium, as few as 102 CFU of bacteria were detected by PCR assay. The primers employed in the PCR assay were found to be highly specific for individual organisms, and evidenced no cross-reactivity with heterologous organisms. Additionally, the multiplex PCR assays also amplified some target genes from the four pathogens, and multiplex amplification was obtained from as little as 10 pg of DNA, thus illustrating the excellent specificity and high sensitivity of the assay. In conclusion, this PCR-based technique provides a sensitive and specific method for the detection of S. aureus, Salmonella spp., E. coli O157:H7, and B. cereus in meat and meat products.

Development of Kinetic Models Describing Kinetic Behavior of Bacillus cereus and Staphylococcus aureus in Milk

Hyoun Wook Kim,Sun Ah Lee,Yo Han Yoon,Hyun Dong Paik,Jun Sang Ham,Sang Ha Han,Kuk Hwan Seol,Ae Ra Jang,Bum Young Park,Mi Hwa Oh 한국축산식품학회 2013 한국축산식품학회지 Vol.33 No.2

This study developed predictive models to evaluate the kinetic behaviors of Bacillus cereus and Staphylococcus aureus in milk during storage at various temperatures. B. cereus and S. aureus (3 Log CFU/mL) were inoculated into milk and stored at 10oC, 15oC, 20oC, and 30oC, as well as 5oC, 15oC, 25oC, and 35oC, respectively, while bacterial populations were enumerated. The growth data were fitted to the modified Gompertz model to estimate kinetic parameters, including the maximum specific growth rate (μmax; Log CFU/[mL·h]), lag phase duration (LPD; h), lower asymptote (N0; Log CFU/mL), and upper asymptote (Nmax; Log CFU/mL). To describe the kinetic behavior of B. cereus and S. aureus, the parameters were fitted to the square root model as a function of storage temperature. Finally, the developed models were validated with the observed data, and Bias (B) and Accuracy (A) factors were calculated. Cell counts of both bacteria increased with storage time. Primary modeling yielded the following parameters; μmax: 0.14-0.75 and 0.06-0.51 Log CFU/mL/h; LPD: 1.78-14.03 and 0.00-1.44 h, N0: 3.10-3.37 and 2.09-3.07 Log CFU/mL, and Nmax: 7.59-8.87 and 8.60-9.32 Log CFU/mL for B. cereus and S. aureus, respectively. Secondary modeling yielded a determination of coefficient (R2) of 0.926-0.996. B factors were 1.20 and 0.94, and A factors were 1.16 and 1.08 for B. cereus and S. aureus, respectively. Thus, the mathematical models developed here should be useful in describing the kinetic behaviors of B. cereus and S. aureus in milk during storage.

The Changes of Natural Microflora in Liver Sausage with Kimchi Powder during Storages

Hyoun Wook Kim,Na Kyoung Lee,Mi Hwa Oh,Cheon Jei Kim,Hyun Dong Paik 한국축산식품학회 2011 한국축산식품학회지 Vol.31 No.6

The objectives of this study were to apply the Baranyi model to predict the growth of natural microflora in liver sausage with added kimchi powder. Kimchi powder was added to the meat products at 0, 1, 2, and 3% levels. To determine and quantify the natural microflora in the meat products, total plate counts and counts of anaerobic bacteria and lactic acid bacteria were examined throughout the 28 d of storage. The obtained data were applied to the Baranyi growth model. The indices used for comparing predicted and observed data were Bf, Af, root mean square error (RMSE), and R2. Twelve predictive models were characterized by a high R2 and small RMSE. The Baranyi model was useful in predicting natural microflora levels in these meat products with added kimchi powder during storage.

Effects of Edible Films Containing Procyanidin on the Preservation of Pork Meat during Chilled Storage

Hyoun Wook Kim,Jin Young Jeong,Kuk Hwan Seol,Pil Nam Seong,Jun Sang Ham 한국축산식품학회 2016 한국축산식품학회지 Vol.36 No.2

Procyanidins, which are natural antioxidants and antimicrobials found in grapes, enhance the quality and extend the shelf life of meat. We explored the effects of edible films incorporating procyanidins on pork loin stored for various times. Procyanidins (0, 0.1, and 0.3%, w/w) were incorporated into the edible films. We assessed meat color, pH, levels of volatile basic nitrogen (VBN) and 2-thiobarbituric acid-reactive substances (TBARS), and microbial populations for 14 d. The chromaticities and pH values of pork loin wrapped in film containing procyanidins (0.1% and 0.3%) generally increased (p<0.05) with storage time. VBN and TBARS levels, and total bacterial and Escherichia coli (E. coli) counts, significantly decreased (p<0.05) in the procyanidin groups. In particular, procyanidins strongly inhibited TBARS formation. Thus, our findings suggest that edible film impregnated with procyanidins inhibits lipid oxidation and microbial growth, thereby enhancing the quality and shelf life of pork meat.

Standardization of the Korean Version of the Patient Health Questionnaire-4 (PHQ-4)

Hyoun-Wook Kim,Cheolmin Shin,Seung-Hoon Lee,Changsu Han 대한정신약물학회 2021 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.19 No.1

Objective: The Patient Health Questionnaire-4 (PHQ-4) has been used for screening owing to ease of use and brevity. In this study, we developed the Korean version of the PHQ-4 and tested its validity. Methods: One hundred sixteen new adult outpatients at the Department of Psychiatry of the Korea University Ansan Hospital participated in the study. We simultaneously administered other depression/anxiety scales: the Hamilton Rating Scale for Depression, the Hamilton Anxiety Scale, the Beck Depression Inventory, and the Beck Anxiety Inventory. Results: The mean PHQ-4 score was 6.52 (standard deviation = 3.45). Cronbach’s  was 0.792, and the intraclass correlation coefficient of test and 2-week interval retest was 0.827 (p < 0.01). The Pearson correlation coefficients between the PHQ-4 total score and other depression/anxiety scales were all over 0.6. Confirmatory factorial analysis showed acceptable convergent validity and reliability but questionable discriminant validity for some model fit values. Conclusion: The Korean version of the PHQ-4 has sufficient internal consistency, test-retest reliability, and construct validity, but its two-factor structure showed incompleteness. However, we suggest that it should be used as a brief screening measure for common psychiatric distress that warrants further detailed assessment, but not to separately assess the severity of depression and anxiety symptoms.

Distribution of Indicator Organisms and Incidence of Pathogenic Bacteria in Raw Beef Used for Korean Beef Jerky

Hyoun Wook Kim,Hye-Jung Kim,Cheon-Jei Kim,Hyun-Dong Paik 한국식품과학회 2008 Food Science and Biotechnology Vol.17 No.6

The objective of this study was to evaluate the microbial safety of raw beef used to produce Korean beef jerky. The raw beef samples harbored large populations of microorganisms. In particular, psychrophilic bacteria were found to be most numerous (9.2×10³-1.0×10? CFU/g) in the samples. Mesophilic bacteria and anaerobic bacteria were present in average numbers (10³-10? CFU/g). Spore-forming bacteria and coliforms were not detected below detection limit. Yeast and molds were detected at 2.2×10¹-7.8×10² CFU/g in the raw beef. Ten samples of raw beef were analyzed for the presence of pathogenic bacteria. Bacillus cereus was isolated from sample B, G, and H. The B. cereus isolates from raw beef samples were identified with 99.8% agreement according to the API CHB 50 kit.

Altered expression of microRNA miR‐21, miR‐155, and let‐7a and their roles in pulmonary neuroendocrine tumors

Lee, Hyoun Wook,Lee, Eun Hee,Ha, Seung Yeon,Lee, Chang Hun,Chang, Hee Kyung,Chang, Sunhee,Kwon, Kun Young,Hwang, Il Seon,Roh, Mee Sook,Seo, Jeong Wook Blackwell Publishing Asia 2012 Pathology international Vol.62 No.9

<P>MicroRNA (miRNA) has a critical effect on tumorigenesis through post‐transcriptional modification and is considered to be potential biomarkers for cancer diagnosis and treatment monitoring. We evaluated the expression pattern of three selected miRNAs (miR‐21, miR‐155, and let‐7a) to evaluate their potential roles by quantitative reverse transcription‐polymerase chain reaction using formalin‐fixed and paraffin‐embedded tissues of 63 surgically resected pulmonary neuroendocrine (NE) tumors (19 typical carcinoids (TCs), 6 atypical carcinoids (ACs), 19 large cell NE carcinomas (LCNECs), and 19 small cell lung carcinomas (SCLCs). Control amplification for U6 small nuclear RNA (U6) was performed in all samples. Normalized Ct values were calculated (Ct<SUB>Experimental miRNA</SUB>‐Ct<SUB>U6</SUB>) for each case and recorded. The expression levels of miR‐21 and miR‐155 were significantly higher in high‐grade NE carcinomas (LCNECs and SCLCs) than in carcinoid tumors (TCs and ACs) (each <I>P</I> < 0.001). The expression level of miR‐21 in carcinoid tumors with lymph node metastasis was significantly higher than in carcinoid tumors without lymph node metastasis (<I>P</I>= 0.010). To the best of our knowledge, the present study is the first to examine the expression patterns of miR‐21 and miR‐155 as an adjunctive diagnostic tool or clinically relevant biomarkers for pulmonary NE tumors.</P>

The Changes of Natural Microflora in Liver Sausage with Kimchi Powder during Storages

Kim, Hyoun-Wook,Lee, Na-Kyoung,Oh, Mi-Hwa,Kim, Cheon-Jei,Paik, Hyun-Dong Korean Society for Food Science of Animal Resource 2011 한국축산식품학회지 Vol.31 No.6

The objectives of this study were to apply the Baranyi model to predict the growth of natural microflora in liver sausage with added kimchi powder. Kimchi powder was added to the meat products at 0, 1, 2, and 3% levels. To determine and quantify the natural microflora in the meat products, total plate counts and counts of anaerobic bacteria and lactic acid bacteria were examined throughout the 28 d of storage. The obtained data were applied to the Baranyi growth model. The indices used for comparing predicted and observed data were $B_f$, $A_f$, root mean square error (RMSE), and $R^2$. Twelve predictive models were characterized by a high $R^2$ and small RMSE. The Baranyi model was useful in predicting natural microflora levels in these meat products with added kimchi powder during storage.

Development of Kinetic Models Describing Kinetic Behavior of Bacillus cereus and Staphylococcus aureus in Milk

Kim, Hyoun Wook,Lee, Sun-Ah,Yoon, Yohan,Paik, Hyun-Dong,Ham, Jun-Sang,Han, Sang-Ha,Seo, Kuk-Hwan,Jang, Aera,Park, Bum-Young,Oh, Mi-Hwa Korean Society for Food Science of Animal Resource 2013 한국축산식품학회지 Vol.33 No.2

This study developed predictive models to evaluate the kinetic behaviors of Bacillus cereus and Staphylococcus aureus in milk during storage at various temperatures. B. cereus and S. aureus (3 Log CFU/mL) were inoculated into milk and stored at $10^{\circ}C$, $15^{\circ}C$, $20^{\circ}C$, and $30^{\circ}C$, as well as $5^{\circ}C$, $15^{\circ}C$, $25^{\circ}C$, and $35^{\circ}C$, respectively, while bacterial populations were enumerated. The growth data were fitted to the modified Gompertz model to estimate kinetic parameters, including the maximum specific growth rate (${\mu}_{max}$; Log CFU/[$mL{\cdot}h$]), lag phase duration (LPD; h), lower asymptote ($N_0$; Log CFU/mL), and upper asymptote ($N_{max}$; Log CFU/mL). To describe the kinetic behavior of B. cereus and S. aureus, the parameters were fitted to the square root model as a function of storage temperature. Finally, the developed models were validated with the observed data, and Bias (B) and Accuracy (A) factors were calculated. Cell counts of both bacteria increased with storage time. Primary modeling yielded the following parameters; ${\mu}_{max}$: 0.14-0.75 and 0.06-0.51 Log CFU/mL/h; LPD: 1.78-14.03 and 0.00-1.44 h, $N_0$: 3.10-3.37 and 2.09-3.07 Log CFU/mL, and $N_{max}$: 7.59-8.87 and 8.60-9.32 Log CFU/mL for B. cereus and S. aureus, respectively. Secondary modeling yielded a determination of coefficient ($R^2$) of 0.926.0.996. B factors were 1.20 and 0.94, and A factors were 1.16 and 1.08 for B. cereus and S. aureus, respectively. Thus, the mathematical models developed here should be useful in describing the kinetic behaviors of B. cereus and S. aureus in milk during storage.

우유 및 유제품의 안전성 평가를 위한 바이오센서의 이용

김현욱 ( Hyoun Wook Kim ),한상하 ( Sang Ha Han ),함준상 ( Jun Sang Ham ),설국환 ( Kuk Hwan Seol ),장애라 ( Ae Ra Jang,),김동훈 ( Dong Hun Kim ),오미화 ( Mi Hwa Oh ) 한국유가공기술과학회 2011 Journal of Dairy Science and Biotechnology (JMSB) Vol.29 No.2

Milk and dairy products are nutritionally one of the most important food in human health and the quality of raw milk is significantly important to ensure safety of dairy products. However, milk and dairy products are commonly related with chemical and microbial contaminations. Therefore, rapid and reliable detection of hazardous (e.g. pathogenic bacteria, pesticides, antibiotics, microbial toxins) in milk and dairy products is essential to ensure human health and food safety. Conventional methods for detection of food hazardous are mostly time-consuming to yield a results. Recently, biosensors have been focused as its rapidity and high sensitivity to analyse chemical and microbial hazardous from a variety of foods and environments. This study reviewed the recent trends and applications of biosensors as rapid detection method of hazardous in milk and dairy products.