• Korean Journal of Food Science and Technology
• /
• v.38 no.2
• /
• pp.176-182
• /
• 2006

Sensitive and specific monoclonal antibody (MAb) was produced from hybridoma (1H11-5) obtained by fusion of myeloma cell (V653) and spleen cell isolated from mouse immunized sulfamthazine (SMZ)-HG-KLH. Direct competitive ELISA was developed for rapid detection of SMZ in milk samples using MAb against SMZ with optimized conditions between MAb and SMZ-HG-HRP conjugate, and applicable conditions for analysis of milk samples were established. Detection range of immunoassay was 0.1 to 100 ppb. Recoveries from spiked raw milk and processed milk samples averaged 82.1-120.7 and 82.1-97.1%, respectively.

• Korean Journal of Food Science and Technology
• /
• v.31 no.5
• /
• pp.1324-1329
• /
• 1999

This study was carried out to investigate the distribution and characteristics of Listeria monocytogenes isolated from frozen Mandoo and pizza in 1998. A total 72 samples were examined and USDA, FDA and modified cold enrichment methods were used for the detection of Listeria spp. Overall prevalence of L. monocytogenes in frozen foods was 9.7% and L. monocytogenes was isolated from 11.1% of frozen Mandoo and 5.6% of frozen pizza. The highest detection rate of Listeria spp. in frozen Mandoo was found at USDA method and the serotype of L. monocytogenes isolates was 4. Isolated L. monocytogenes was confirmed by PCR method with Hly 1 and 2 as primers. It would be necessary to develop more rapid and specific method to isolate and confirm L. monocytogenes from foods because USDA and PCR methods used in this study took 3-4 days. D value of L. monocytogenes isolate in tryptic soy broth was 49.2 sec at $60^{\circ}C$ and 8.8 sec $at\;65^{\circ}C$, and D value of L. monocytogenes in foods with high distribution rate of Listeria spp. would be necessary to evaluate for the safe use of frozen foods.

• Biomedical Science Letters
• /
• v.28 no.4
• /
• pp.334-339
• /
• 2022

African swine fever virus (ASFV) is a highly contagious and lethal pathogen that poses a threat to the global pork industry. The World Organization for Animal Health (WOAH) has placed strict surveillance measures for ASFV. The possibility of long-term survival of ASFV in raw meat or undercooked pork has been reported. Accordingly, the problem of secondary infection in food waste from households or waste disposal facilities has emerged, raising the need for ASFV monitoring of food waste. However, most of the previously reported ASFV gene detection methods are focused on clinical monitoring of pigs. There are very few cases in which their application in waste has been verified. Since ASFV diagnosis requires rapid monitoring and immediate action, loop-mediated isothermal amplification (LAMP) may be suitable, but this requires conformity assessment for LAMP to be used as a diagnostic technique. In this study, six LAMP methods were evaluated, and two methods (kit and manual) were recommended for use in diagnosing ASFV in food waste.

• Journal of Food Hygiene and Safety
• /
• v.30 no.2
• /
• pp.150-158
• /
• 2015

This article reports the development of an effective test procedure for detection of norovirus (NoV) in foods of diverse matrices. In this study, target foods included fermented milk, soybean paste, powders made from uncooked grains and vegetables, sesame leaves preserved in soy sauce, pickled mooli, and mooli. Viral recovery varied depending on the food matrices or elution buffers tested. Buffers were compared to determine effective elution buffers from artificially virus-contaminated foods. The conventional test procedure for concentrating viruses from food (elution-polyethylene glycol(PEG) precipitation-chloroform-PEG precipitation) was modified to save time by eliminating one PEG precipitation step. The modified procedure (elution-chloroform-PEG precipitation) was able to concentrate viruses more effectively than the conventional procedure. It also removed RT-PCR inhibitors effectively. The modified procedure was applied to target food for genogroup II NoV detection. NoV RNA was detected at the initial inoculum levels 3.125-12.5 RT-PCR units per 10-25 g tested food. The use of this newly established procedure should facilitate detection of low levels of norovirus in diverse foods.

• Journal of Veterinary Clinics
• /
• v.29 no.4
• /
• pp.309-314
• /
• 2012

The study was undertaken to evaluate sensitivity and specificity of rapid Avian Influenza (AI) and Newcastle Disease virus (NDV) combo antigen kits from field samples of domestic (broiler and layer chicken, native chicken) and semi-domestic (duck, goose, pigeon and quail) birds of Bangladesh. Samples were collected from naturally infected AI suspected domestic and semi-domestic birds of five different outbreak areas in Bangladesh. From each area two birds were selected for sampling, and from each bird three types of samples (tracheal, cloacal and oro-nasal swabs) were collected. A total of 210 field samples from a total of 70 birds were collected and tested using AI and NDV combo antigen rapid diagnostic kits in the study. All three different samples from a bird showed similar pattern of reaction. Out of 210 samples, 15 samples (5 birds), 63 samples (21 birds) and 27 samples (9 birds) were positive for AIV, NDV and both for AIV and NDV, respectively; whereas the remaining birds were negative for either AIV or NDV in this screening test. Among the five AIV positive, a layer chicken from wet market in Mymensingh, Netrokona, Gibandha and Kurigram and a native chicken from wet market in Kurigram area was positive to AIV. The semi-domestic birds are either positive to NDV or free from both AIV and NDV. This study revealed that the AIV and NDV rapid diagnostic kits could be effectively use to diagnose the respective virus in trachea, oro-nasal and cloacal samples simultaneously. AIV-NDV combo Ag test result clearly indicates that the test kit designed for AIV and NDV could diagnose the disease rapidly with less effort and higher scientific know how which could be used for the detection of AIV and NDV using field samples in large scale.

• Pediatric Infection and Vaccine
• /
• v.26 no.2
• /
• pp.81-88
• /
• 2019

Purpose: Early detection of Mycoplasma pneumoniae is important for appropriate antimicrobial therapy in children with pneumonia. This study aimed to evaluate the diagnostic value of a rapid antigen test kit in detecting M. pneumoniae from respiratory specimens in children with lower respiratory tract infection (LRTI). Methods: A total of 215 nasopharyngeal aspirates (NPAs) were selected from a pool of NPAs that had been obtained from children admitted for LRTI from August 2010 to August 2018. The specimens had been tested for M. pneumoniae by culture and stored at $-70^{\circ}C$ until use. Tests with Ribotest $Mycoplasma^{(R)}$ were performed and interpreted independently by two investigators who were blinded to the culture results. Results: Among the 215 NPAs, 119 were culture positive for M. pneumoniae and 96 were culture negative. Of the culture-positive specimens, 74 (62.2%) were positive for M. pneumoniae by Ribotest $Mycoplasma^{(R)}$, and 92 of the 96 (95.8%) culture-negative specimens were negative for M. pneumoniae by Ribotest $Mycoplasma^{(R)}$. When culture was used as the standard test, the sensitivity and specificity of Ribotest $Mycoplasma^{(R)}$ were 62.2% and 95.8%, respectively. Additionally, the positive predictive value, negative predictive value, and overall agreement rates with Ribotest $Mycoplasma^{(R)}$ were 94.9%, 67.2%, and 77.2%, respectively. Conclusions: A positive test result of Ribotest $Mycoplasma^{(R)}$ suggests a high likelihood of culture-positive M. pneumoniae infection. However, a negative test result should be interpreted with caution because nearly one-third of negative test results reveal culture-positive M. pneumoniae infections.

• Journal of Life Science
• /
• v.28 no.7
• /
• pp.835-840
• /
• 2018

Quantitative determination of the protein expression levels is one of the most important parts in assessment of the safety of foods derived from genetically modified (GM) crops. Overexpression of AtCYP78A7, a gene encoding cytochrome P450 protein, has been reported to improve tolerance to abiotic stress, such as drought and salt stress, in transgenic rice (Oryza sativa L.). In the present study, an enzyme-linked immunosorbent assay (ELISA) kit for diagnosing AtCYP78A7 protein including AtCYP78A7-specific monoclonal antibody was developed. GST-AtCYP78A7 recombinant protein was induced and purified by affinity column. Four monoclonal antibodies (mAb 6A7, mAb 4C2, mAb 11H6, and mAb 7E8) against recombinant protein were also produced and biotinylated with avidin-HRP. After pairing test using GST-AtCYP78A7 protein and lysate of rice samples, mAb 4C2 and mAb 7E8 were selected as a capture antibody and a detecting antibody, respectively, for ELISA kit. Product test using rice samples indicated that percentages of detected protein in total protein were greater than 0.1% in AtCYP78A7-overexpressing transgenic rice (Line 10B-5 and 18A-4), whereas those in negative control non-transgenic rice (Ilpum and Hwayoung) were less than 0.1%. The ELISA kit developed in this study can be useful for the rapid detection and safety assessment of transgenic rice overexpressing AtCYP78A7.

• Tuberculosis and Respiratory Diseases
• /
• v.43 no.1
• /
• pp.30-37
• /
• 1996

Background: The extraction methods of DNA from clinical samples are the major obstacle to use the PCR(polymerase Chain Reaction) in routine labortary for early detection of M. tuberculosis. We tried to improve the extraction method of DNA from sputum for establishment of the PCR in routine labortary by reducing the possibility of cross contamination and performing it easily and safely. Methods: We used the $InstaGene^{TM}$ DNA extraction kit(BioRad Co.) using Chelex 100 ion exchange resin for preparation of DNA. We compared InstaGene method in 100 cases of sputum from proteinase K method which is known as the most commonly used method for DNA purification(Experiment 1). And we compared InstaGene method in 98 cases of sputum from Microwave method developed by a company in Korea(Experiment 2). In experiment 1,245bps of IS6110 were amplified and then 188bps were amplified by nested PCR. In experiment 2,536bps in primary PCR and 276bps in nested PCR were amplified and analysed by agarose gel electrophoresis and EtBr staining. Results: When we chose AFB smear, culture, or AFB smear and culture as a standard test, PCR had low specificity and positive predictive value in both experiments. The InstaGene method has higher value in sensitivity and negative predictive value significantly than proteinase K method. The InstaGene method and the Microwave methods were similar in sensitivity, specificity, positive predictive value and negative predictive value. Conclusion: Even though both methods had lower possibility of cross contamination, shorter time requirement, simplicity, and economic advantages than Proteinase K method, the InstaGene method was a little simpler than the Microwave method. Therefore, in terms of usefulness in clinical application, the Instagene method seems to be the most useful method in DNA extraction for detection of M. tuberculosis using PCR. The reliability of this method will be clarified by further studies with enough clinical samples.

• Tuberculosis and Respiratory Diseases
• /
• v.49 no.5
• /
• pp.546-557
• /
• 2000

Background : Oligonucleotide chip technology has proven to be a very useful tool in the rapid diagnosis of infectious disease. Rifampin resistance is considered as a useful marker of multidrug-resistance in tuberculosis. Mutations in the rpoB gene coding $\beta$ subunit of RNA polymerase represent the main mechanism of rifampin resistance. The purpose of this study was to develop a diagnosis kit using oligonucleotide chip for the rapid and accurate detection of rifampin-resistance in Mycobacterium tuberculosis. Method : The sequence specific probes for mutations in the rpoB gene were designed and spotted onto the glass slide, oligonucleotide chip. 38 clinical isolates of Mycobacterium were tested. A part of rpoB was amplified, labelled, and hybridized on the oligonucleotide chip with probes. Results were analyzed with a laser scanner. Direct sequencing was done to verify the results. Result : The low-density oligonucleotide chip design어 to determine the specific mutations in the rpoB gene of M. tuberculosis accurately detected rifampin resistance associated with mutations in 28 clinical isolates. Mutations at codons 531, 526, and 513 were confirmed by direct sequencing analysis. Conclusion : Mutant detection using oligonucleotide chip technology is a reliable and useful diagnostic tool for the detection of multidrug-resistance in M. tuberculosis.

• Korean Journal of Clinical Laboratory Science
• /
• v.49 no.4
• /
• pp.446-454
• /
• 2017

Human papillomaviruses (HPVs) are major causes of cervical cancer. Sixteen high risk HPVs, including HPV 16, HPV 18, HPV31, HPV 33, HPV 35, HPV 39, HPV 45, HPV 51, HPV 52, HPV 53, HPV 56, HPV 58, HPV 59, HPV 66, HPV 68, and HPV 69 are found in cervical cancer. HPVs 16 and 18 are mainly presented in 70% of cervical cancer. Therefore, identifying the presence of these high-risk HPVs is crucial. The objective of this study is to establish the HPV ViroCheck for detecting 16 HR-HPVs and genotypes of HPVs 16 and 18, as well as to analyze the analytical performance of HPV ViroCheck. We performed the analytical sensitivity of HPV E6 / E7 genes of 16 high risk HPVs to confirm the limit of detection. Then, a cross reactivity of HPV ViroCheck with microorganisms and viruses related to the cervix were analyzed for analytical specificity. Analytical sensitivity of high risk HPV genotypes ranged from 1 to 100 copies when using cloned DNAs. The limit of detection was 10 cells for both SiHa and HeLa cells. Cervical-related microorganisms and viruses did not show cross-reactivity to HPV DNA. Moreover, the intra- and inter-assay coefficient variations (CVs) were below 5%. In conclusion, HPV Virocheck will be useful for the detection of 16 HR HPVs, as well as HPV 16 and HPV 18 genotypes rapidly.