• 대한의생명과학회지
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• 제23권4호
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• pp.333-338
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• 2017

This study was performed to assess microbial contamination of Aronia melanocarpa, blueberry, raspberry, and cranberry sold in several markets. We investigated total aerobic bacteria and detected foodborne bacteria by multiplex PCR from Aronia melanocarpa, blueberry, raspberry, and cranberry. Total aerobic bacteria of each sample showed mean 3.54 log CFU/g for Aronia melanocarpa, mean 1.90 log CFU/g for blueberry, and mean 1.40 log CFU/g for raspberry, but not detected in cranberry. Specially, Aronia melanocarpa contained high total aerobic bacteria contamination among various berries and contamination level reached 4.17 log CFU/g in sample 5. To evaluate the effect of distribution conditions, we also investigated total aerobic bacteria of various berries. Total aerobic bacteria showed mean 2.89 log CFU/g for berries in refrigerated distribution and 1.40 log CFU/g in frozen distribution, but not in dry distribution. For assessment of foodborne bacteria contamination, we conducted PCR with multiplex primers of E. coli O157, S. aureus, B. cereus, V. parahaemolyticus, L. monocytogenes, Y. enterocolitica, Salmonella spp., Shigella spp. Among these foodborne bacteria, B. cereus was amplified in Aronia melanocarpa in sample 4 and blueberry in sample 1, 2, 3, and 5. The result of quantitative analysis of B. cereus contamination showed 4.08 log CFU/g of Aronia melanocarpa in sample 4 and higher contamination rate 4.07 log CFU/g of blueberry in sample 3. These results suggest that strict food safety control in harvest and distribution of various berries is necessary to prevent foodborne disease and improve microbiological safety.

• Preventive Nutrition and Food Science
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• 제8권2호
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• pp.191-195
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• 2003

We investigated the effects of gamma irradiation on the microbiological, chemical and sensory qualities of bulgogi, a traditional Korean meat product. Gamma irradiation reduced the number of coliform bacteria and bacterial colonies counted in Salmonella-Shigella selective agar to a non-detectable level. Thermophillic microorganisms (mainly Bacillus spp.) in bolgogi refrigerated for 20 days were also significantly reduced by 3 log cycles by 2.5 to 7.5 kGy of irradiation, compared to the control. Electron donating ability and shear force of ready-to-cook bulgogi was not significantly affected by gamma irradiation. Irradiation increased the 2-thiobarbituric acid reactive substances (TBARS) value. The irradiated, raw, ready-to-cook bulgogi had significantly higher scores in color and appearance than those of non-irradiated controls from sensory evaluation. The overall acceptance of cooked bulgogi had higher scores in non-irradiated or 2.5 kGy-irradiated bulgogi than the 5.0- or 7.5-kGy irradiated counterparts. In conclusion, irradiation at 2.5 kGy is recommended as a method to improve shelf-life, safety, and to achieve acceptable quality of ready-to-cook bulgogi without any adverse changes in the sensory characteristics.

• 한국동물위생학회지
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• 제20권2호
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• pp.151-159
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• 1997

This study was carried out to isolate of causative agents from CMT-positive and mean somatic cell count(SCC) $\geq$500,000 cells/ml mastitic milk, and evaluate to antimicrobial susceptibility of isolates in Iksan branch area from January to November, 1996. 1. The CMT-positivity(SCC 500,000 cells/ml) of 610 heads was 36.2% (221), and of 2,373 quarter milks was 16.1% (383). 2. The Gram-positive isolates were 153 strains which was Staphylococcus sp (115), Micrococcus sp (18), Streptococcus sp (10), Listeria monocytogenes (5) and Enterococcus faecalis(5). 3. The Gram-negative isolates were 66 strains including E coli(14), Yersinia sp (13), Shigella sp(8), Enterobacillus sp(8), Cedecea sp(5), Pseudomonas aeruginosa(5), Proteus sp(5), Klebsiella sp(4), Salmonella sp(2), kluyvera ascorbate(1) and Tatumella ptyseos (1). 4. The Gram positive strains of isolates were moderately susceptible to T/s, Cp, Fd, Imp, Aug, Rif, Cft and Va. And the Gram negative strains of Isolates were moderately susceptible to T/s, Cp, Imp, Pi and Ti, In order. 5. Multiple antimicrobial resistant patterns were encountered 62 and 36 from Gram positive and negative isolates, respectively.

• 한국축산식품학회지
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• 제40권2호
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• pp.172-182
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• 2020

In the present study, we determined the degree of hydrolysis (DH) of porcine blood plasma proteins, albumin, and globulin hydrolyzed by six proteases (alcalase, neutrase, flavourzyme, protamex, trypsin, and papain) for various reaction times. Moreover, antimicrobial activities of hydrolysates against five pathogenic microorganisms (Bacillus cereus, Staphylococcus aureus, Salmonella Typhimurium, Escherichia coli, and Shigella flexneri) were investigated. Alcalase, trypsin, and papain hydrolysates of the three porcine blood proteins showed higher DH values than hydrolysates produced by the other three proteases. DH of the three porcine blood proteins hydrolyzed by the six proteases failed to increase after 2 h of hydrolysis. In antimicrobial tests, hydrolysates (hydrolysis time of 2 h) showed antibacterial activity only against B. cereus. Albumin hydrolysates showed higher antimicrobial activity than globulin and plasma hydrolysates. Albumin hydrolysates obtained with flavourzyme, protamex, and trypsin showed higher antimicrobial activity than those obtained with the other three proteases.

• 대한의생명과학회지
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• 제8권1호
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• pp.29-37
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• 2002

Listeria monocytogenes poses an increasing health risk, which in part is due to increasing health risk, consumption of ready-to-eat food products and the introduction of increasing numbers of food products from regions with different dietary habits. L. monocytogenes can be present in meat, shellfish, vegetables, unpasteurised milk and soft cheese and poses a risk if food containing these products is stored at refrigeration temperature and is not properly heated before consumption, as L. monocytogenes is psychrophilic. Amplified-fragment length polymorphism (AFLP) analysis is the method of genotypic techinique in which adaptor oligonucleotides are ligated to restriction enzyme fragments and then used as target sites for primers in a PCR amplification. The amplified fragments are electrophoretically separated to give strain-specific band profiles. Single-enzyme approach that did not require costly equipment or reagents for the fingerprinting of strains of Listeria monocytogenes was developed. Single-enzyme amplified fragment length polymorphism (SE-AFLP) analysis was used to perform species and strain identification of Salmonella, Shigella, Yersinia and E. coli. By careful selection of AFLP primers, it was possible to obtain reproducible and sensitive identification to strain level. The AFLP patterns of L. monocytogenes are divided by the kinds of specimens in which were isolated. SE-AFLP fragments can be analyzed using standard gel electrophoresis, and can be easily scored by visual inspection, due to the low complexity of the fingerprint obtained by this method. These features make SE-AFLP suitable for use in either field or laboratory applications.

• Food Science and Biotechnology
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• 제16권4호
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• pp.615-620
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• 2007

Commercially packed kimchi products from 6 different manufacturers, which are exported overseas as well as sold domestically, were analyzed to determine their microorganism distributions and presence of pathogenic bacteria. All samples showed decreasing pH levels (from 5.7-6.2 to 3.9-4.3) and increasing titratable acidities (from 0.3-0.4 to 0.8-1.2%) during 15 days of storage at $4^{\circ}C$. Total bacterial counts ranged from $2.1{\times}10^5-1.9{\times}10^6\;CFU/mL$ in the initial kimchi samples, and then increased to $1.1{\times}10^8-1.8{\times}10^9\;CFU/mL$. The coliform numbers decreased from approximately $2.5{\times}10^2-1.7{\times}10^4\;CFU/mL$ to zero. Major foodborne pathogens such as Salmonella spp., Staphylococcus aureus, Escherichia coli O157:H7, Listeria monocytogenes, Bacillus cereus, Yersinia enterocolitica, and Shigella spp. were not detected in any of the samples. However, 2 out of the 6 samples carried E. coli, emphasizing the need for improved hygiene practice. Interestingly, Hafnia alvei, belonging to the Enterobacteriaceae family, was isolated in all of the samples. Further study is needed on this newly reported bacterium in kimchi.

• 한국균학회지
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• 제9권2호
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• pp.103-108
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• 1981

The antibiotic-producing Streptomyces strains were isolated from the soils of various localities in Yeang-Kwang and tested for the activity against some of gram positive and negative microorganisms, especially against Pseudomonas aeruginosa. The results are summarized as follows. 1. A total of 1464 Streptomyces strains were isolated from 336 soil samples. Of all the strains tested, 636 strains of the isolates showed antibiotic activity against either gram positive or negative test organisms. And 408 of the 636 strains were strongly active against one or all of those test­organisms. 2. Ninety-three of Streptomyces strains among the active isolates showed the antibiotic activity against Pseudomonas aeruginosa, and 24 of 93 strains showed the strong antibiotic activity against all of the test organisms i.e. Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Salmonella typhi and Shigella jlexneri. 3. Antibiotic-producing Streptomyces strains active against Pseudomonas aeruginosa were isolated from the soil samples taken from vegetable field, paddy field, sandy ground and roadway, but not isolated from the soil taken from dwelling area, grass field and piers.

• 대한미생물학회지
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• 제17권1호
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• pp.43-47
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• 1982

C. fetus suhsp. jejuni has been reported to be an important enteric pathogen in many parts of the world. Although the infection has been reported in Korea, the incidence is not known. In this study the results of stool culture during the period of August 1981 to July 1982 at Yonsei Medical Center was analyzed and the following results were obtained. 1. C. fetus subsp. jejuni was isolated from 0.8% of stool specimens. The isolation rate was lower than that of salmonella(3.3%) and shigella(7.1%). The isolation was most frequent in June and from $\leq$15-year-old patients. 2. All of the isolates from the patients were susceptible to chloramphenicol and erythromycin. It was noteworthy that 4 isolates were resistant to all of the aminoglycosides, i.e., amikacin, gen tamicin, kanamycin and tobramycin. 3. We also isolated C. fetus subsp. jejuni from chicken. When the susceptibility of the isolates was compared to that of the isolates from human the former were less susceptible to erythromycin(34.1%) and tetracycline(38.6%).

• 대한임상검사과학회지
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• 제36권1호
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• pp.1-6
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• 2004

The enterobacterial repetitive intergenic consensus (ERIC)-PCR is a recently described DNA fingerprinting technique based on amplification of repetitive element distributed in bacteria. We applied of ERIC-PCR to clinical isolates of Vibrio parahaemolyticus and other bacteria associated diarrhea. Twenty isolates of V. parahaemolyticus were used for intragenic genotyping, which were isolated from 2001 to 2002 in Chungbuk National University hospital. For interspecies genotyping, V. vulnificus, V. alginolyticus, V. parahaemolyticus, Escherichia coli, Salmonella and Shigella spp. were used. The genotyping were analyzed by ERIC-PCR. The genotyping of V. parahaemolyticus were grouped two major pattern (A, B) and were subdivided into 10 subtypes (A1, A2, B1-B8) by ERIC-PCR. These method distinctly differentiated bacterial species associated diarrhea. Those results show that ERIC-PCR can be reliable and efficient method for genotyping of V. parahaemolyticus and bacteria associated diarrhea.

• 대한의생명과학회지
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• 제24권3호
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• pp.270-274
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• 2018

Chlorine dioxide ($ClO_2$) gas is a neutral chlorine compound. $ClO_2$ gas was proven to effectively decontaminate different environments, such as hospital rooms, ambulances, biosafety level 3 laboratories, and cafeterias. In this study, to evaluate the effects of $ClO_2$ gas, bacteria of clinical importance were applied. Staphylococci, Streptococci and Bacillus strains were applied and Klebsiella, and others e.g., Escherichia coli, Shigella, Salmonella, Serratia were also done for the inhibitory analysis. Bacteria plates were applied with a hygiene stick, namely, "FarmeTok (Medistick/Puristic)" to produce $ClO_2$. $ClO_2$-releasing hygiene stick showed the very strong inhibition of bacterial growth but had different inhibitions to the bacteria above 96.7% except for MRSA of 90% inhibition. It is difficult to explain why the MRSA were not inhibited less than others at this point. It can be only suggested that more releasing $ClO_2$ should be essential to kill or inhibit the MRSA. B. subtilis, S. agalactiae, S. pyogenes, E. coli O157:H7, S. typhi (S. enterica serotype typhi) and S. marcesence were inhibited over 99%. This study will provide fundamental data to research growth inhibition by $ClO_2$ gas with bacteria of clinical importance value.