• 대한수의학회지
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• 제15권1호
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• pp.83-91
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• 1975

A total of 119 raw milk samples from ten dairy farms were examined for total bacterial count, and 739 quarter milk samples of 118 dairy cows of 14 herds were examined for mastitis. The results obtained were as follows: 1. The mean of total bacterial counts of the 119 raw milk samples was 132,000 per ml. The total bacterial counts of 81 samples (68.1%) were under the standard of 100,000 per ml and those of the 38 samples (31. 9%) were over the standard. The number of bacteria showed a tendency to increase in summer. 2. One hundred and ninety five quarters (26.4%) of 98 cows (52.7%) were proved to be infected with mastitis. Clinical mastitis was found at 7 qtarters (3.5%) of 5 cows (5.0%). 3. Staphylococcus (44.9%) and Streptococcus (26.7%) were two main causative organisms of mastitis. Coliform bacteria (4.6%), Pseuedomonas spp. (4.6%), yeasts (1. 3%) and corynebacterium sp. (0.7%) were also isolated from the infected quarters. 4. The isolates were more sensitive to chloramphenicol ((96.1%), leukomycin (78.8%), streptomycin (75.5%) and tetracycline (72.4%). On the other hand, they were less sensitive to colistin (11.0%), oreandomycin (18.1%), sulfisoxazole (24.6%), penicilline (27.6%), kanamycin (43.3%) and erythromycin (49.7%). Especially the strains of Pseudomonas spp. isolated from the infected quarters were resistant to almost all the drugs examined.

• Asian-Australasian Journal of Animal Sciences
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• 제27권8호
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• pp.1088-1097
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• 2014

The study aimed to investigate the effects of gynosaponin on in vitro methanogenesis under different forage-concentrate ratios (F:C ratios). Experiment was conducted with two kinds of F:C ratios (F:C = 7:3 and F:C = 3:7) and gynosaponin addition (0 mg and 16 mg) in a $2{\times}2$ double factorial design. In the presence of gynosaponin, methane production and acetate concentration were significantly decreased, whereas concentration of propionate tended to be increased resulting in a significant reduction (p<0.05) of acetate:propionate ratio (A:P ratio), in high-forage substrate. Gynosaponin treatment increased (p<0.05) the butyrate concentration in both F:C ratios. Denaturing gradient gel electrophoresis (DGGE) analysis showed there was no apparent shift in the composition of total bacteria, protozoa and methanogens after treated by gynosaponin under both F:C ratios. The real-time polymerase chain reaction (PCR) analysis indicated that variable F:C ratios significantly affected the abundances of Fibrobacter succinogenes, Rumninococcus flavefaciens, total fungi and counts of protozoa (p<0.05), but did not affect the mcrA gene copies of methanogens and abundance of total bacteria. Counts of protozoa and abundance of F.succinogenes were decreased significantly (p<0.05), whereas mcrA gene copies of methanogens were decreased slightly (p<0.10) in high-forage substrate after treated by gynosaponin. However, gynosaponin treatment under high-concentrate level did not affect the methanogenesis, fermentation characteristics and tested microbes. Accordingly, overall results suggested that gynosaponin supplementation reduced the in vitro methanogenesis and improved rumen fermentation under highforage condition by changing the abundances of related rumen microbes.

• International Journal of Oral Biology
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• 제37권3호
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• pp.103-108
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• 2012

The purpose of this study was to assess the efficacy of photodynamic therapy (PDT) using erythrosine and a halogen light source to treat a biofilm formed on a machined surface titanium disk in vivo. Ten volunteers carried an acrylic appliance containing six machined surface titanium disks on the upper jaw over a period of five days. After the five days of biofilm formation period, the disks were removed. PDT using 20 ${\mu}M$ erythrosine and halogen light was then applied to the biofilms formed on the disks. Experimental samples were divided into a negative control group (no erythrosine and no irradiation), E0 group (erythrosine 60s + no irradiation), E30 group (erythrosine 60s + halogen light 30s), and E60 group (erythrosine 60s + halogen light 60s). Following PDT, the bacteria in the biofilm were found to be detached from each disk. Each suspension with detached bacteria were diluted and cultivated on a blood-agar plate for five days under anaerobic conditions. The cultivated bacterial counts in the E60 group were significantly lower than the control group (86.4%) or E0 group (76.7%). In the experimental groups also, the light exposure time and bacterial counts showed a negative correlation. In conclusion, PDT using erythrosine and halogen light has bactericidal effects on biofilms formed on a titanium disk in vivo. Notably, applying 20 ${\mu}M$ erythrosine and 60 seconds of halogen light irradiation had a significantly potent effect.

• Journal of Microbiology and Biotechnology
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• 제27권10호
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• pp.1744-1752
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• 2017

Myeolchi jeotgals (MJs) were prepared with purified salt (PS), solar salt aged for 1 year (SS), and bamboo salt (BS) melted 3 times at 10% and 20% (w/w) concentrations, and fermented for 28 weeks at $15^{\circ}C$. BS MJ showed higher pH and lower titratable acidities than the other samples because of the alkalinity of bamboo salt. Lactic acid bacteria counts increased until 4-6 weeks and then decreased gradually, and were not detected after 20 weeks from MJs with 10% salt. Yeast counts of PS MJs were higher than those of BS and SS MJs. Bacilli were detected in relatively higher numbers throughout the 28 weeks, like marine bacteria, but archae were detected in lower numbers during the first 10 weeks. When 16S rRNA genes were amplified from total DNA from PS MJ (10% salt) at 12 weeks, Tetragenococcus halophilus was the major species. However, Staphylococcus epidermidis was the dominant species for BS MJ at the same time point. In SS MJ, T. halophilus was the dominant species and S. epidermidis was the next dominant species. BS and SS MJs showed higher amino-type nitrogen, ammonia-type nitrogen, and volatile basic nitrogen contents than PS MJs. SS and BS were better than PS for the production of high-quality MJs.

• 한국대기환경학회지
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• 제27권5호
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• pp.569-579
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• 2011

This study evaluated the indoor air quality of 26 government offices located in Seoul. The pollutant samples were taken from Jan. 13th to Jan. 29th and Feb. 20th to Feb. 23rd, 2010 in the offices. The target indoor pollutants for this study were $PM_{10}$, formaldehyde, carbon monoxide, carbon dioxide, total bacteria counts, total volatile organic compounds, radon, nitrogen dioxide, ozone, and asbestos which were controlled by the indoor air quality law for the multiple-use facilities management. The results of this study showed that some pollutants of the 38.5% offices exceeded the standards of the air quality guideline. The correlation analysis of the same pollutants between indoor and outdoor represented that $NO_2$ (r=0.629, p<0.05) and $O_3$ (r=0.459, p<0.01) were significant, however, $PM_{10}$ and CO were not. The correlation analysis between different pollutants showed that CO and TVOC (total volatile organic compounds: r=0.724; p<0.01), CO and $NO_2$ (r=0.674; p<0.01), HCHO and humidity (r=0.605; p<0.01), $CO_2$ and TVOC (r=0.534; p<0.01), TBC (total bacteria counts) and Asbestos (r=0.520; p<0.01) were significant. The energy-saving system of government buildings in winter caused under-ventilated and poor air quality. This study suggests that the concentrations of radon and $CO_2$ should be used as an indicator for monitoring indoor air quality and maintaining effective ventilations.

• 한국수산과학회지
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• 제50권2호
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• pp.120-129
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• 2017

This study assessed the safety of raw oysters Crassostrea gigas for consumption during processing in a processing plant. Bacterial contamination (e.g., viable cell counts, coliform groups, Escherichia. coli and pathogenic bacteria) and chemical contamination (e.g., heavy metals and shellfish toxins) were measured on raw oysters, a processing equipment, employees and work areas. No total mercury, lead, paralytic shellfish poison, diarrheic shellfish poison or norovirus was detected in any post-harvested oyster samples. However, the cadmium level ranged from 0.1-0.2 mg/kg. The viable cell count, E. coli and coliform group levels in post-harvested oysters ranged from 4.00-4.54 log CFU/g, ND-210 MPN/100 g and 110-410 MPN/100 g, respectively. The viable contaminating cell counts on employees, equipment and work areas were in the range of $0.90-3.46log\;CFU/100cm^2$. Airborne bacteria in the work areas ranged from 0.60 to 1.81 log CFU/plate/15 min. Thus, no significant health risks were detected in the processing plant.

• 한국축산식품학회지
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• 제35권3호
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• pp.322-329
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• 2015

This study investigated the effects of glucono-δ-lactone (GdL) addition on physicochemical and microbiological characteristics of fermented sausages during ripening and drying. Five batches of sausages were produced under ripening conditions: without GdL and with 0, 0.1, 0.25, 0.5 and 0.75% of GdL addition. Samples from each treatment were taken for physicochemical and microbiological analyses on the 0, 1, 3, 5, 7, 10, 15, 20 and 25th day of ripening. Chemical analysis showed a significant decrease in moisture content of sausages with increasing amounts of GdL added (p<0.05). The moisture contents decreased, whereas the fat, protein and ash contents increased throughout ripening (p<0.05). Increasing levels of GdL caused a decrease in the pH values (p<0.05), which can have an inhibitory effect against microflora. Water holding capacity content of samples decreased with increasing GdL concentration (p<0.05). The shear force values of fermented sausages showed the highest in T4 (p<0.05). During ripening, the shear force values of sausages were increased on the 25th day compared to day 0 (p<0.05). The higher GdL level produced lighter and more yellow sausages. The addition of 0.75% GdL was effective in controlling bacteria counts. Addition of GdL in sausages resulted in the physicochemical and microbiological attributes equal to or better than no addition of GdL without any harmful effect.

• 한국식품조리과학회지
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• 제25권1호
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• pp.45-54
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• 2009

Contamination levels of aerobic colony counts, coliforms and pathogenic bacteria were tested in fried rice dishes to monitor quality for risk management. The prevalence of Bacillus cereus in dishes from 8 Chinese-style restaurants and 2 institutional foodservices was 10%, and the bacteria's contamination levels was 3.47 log CFU/g. Echerichia coli, Staphylococcus aureus, and Salmonella were not detected in any of the 10 samples. However, for their aerobic colony counts and numbers of isolated coliforms, the samples were 30% and 70% over the microbial criteria, respectively, for ready-to-eat foods presented in the Korean Food Code. This suggests that fried rice dishes, although cooked with oil at high temperature, require special care. For the prediction of the growth curve of B. cereus spp. in the fried rice samples, an experiment design of 3 storage temperatures ($7^{\circ}C$, $35^{\circ}C$, $57^{\circ}C$) x 5 storage times (0 h, 2 h, 4 h, 6 h, 24 h) was applied. The sample exposed to $35^{\circ}C$ showed no B. cereus spp. at 0 h; however, there was a tendency of slow growth (1.0 log CFU/g) after 4 hours of storage and then faster growth at 6 h (3.7 log CFU/g) and 12 h (4.7 log CFU/g), showing a growth rate of 0.56 log CFU/g/hr. These results indicate that fried rice, despite being heat-treated, can become heavily contaminated with B. cereus spp. when held over 2 hours at room temperature. However, the samples stored at $7^{\circ}C$ and $57^{\circ}C$ over 24 hours were not contaminated with B. cereus. Based on these results, management guidelines for controlling B. cereus are suggested.

• 미생물학회지
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• 제27권1호
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• pp.48-55
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• 1989

HA 비드에 부착한 S. sanguis 세포는 방사능 측정시 칵테일 속에서 비드에 여전히 부착되어 있음으로 비드에 의한 방사능의 sel-absorpiton이 일어났으며 그 정도는 염산용액으로 비드를 용해시킬 때 측정한 반사능값의 34.5% 이었다. 현탁액으로 준비한 세포의 방사능 측정과는 달리 HA 또는 SHA에 부착한 세포의 경우에는 소량의 scintillation 용액(2.5ml) 사용에서 더 좋은 측정값을 얻었다 . HA 비드에 의한 칭은 약 18% 이었다. 부착 assay 에 사용할 HA 비드 준비에 보통 이용되는 3가지의 dqkdqjqdm 비교에서는 차이가 없었다. 부착실험용의 세균세포는 초소리파로 세균사슬을 끊었는데 30초간의 파절로 세포하나 또는 두개로 주로 구성된 현탁액을 얻을 수 있었다. 본 연구에서는 HA 비드에 부착한 S. sanguis 세포를 측정할 때 self-absorpiton이 일어남을 발견하였고 부착한 세균을 비드에서 탈락하거나 또는 비드를 용해시킨 후 측정함으로써 self-absorption을 제거할 수 있었다. 그리고 부착한 세균의 방사능 측정에서는, 적정의 칵테일량을 발견하여 사용하므로 측정값을 유의하게 증가시킬 수 있었다. 수 있었다.

• 한국식품과학회지
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• 제28권1호
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• pp.190-196
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• 1996

고차단성 포장재를 이용하여 김치를 각기 다르게 진공포장한 후 $10^{\circ}C$와 $0^{\circ}C$의 저온조건에 저장하면서 진공도 차이에 따른 pH, 산도, 색상, 젖산균수 등의 변화를 측정하고 관능검사를 병행하여 진공포장이 김치 품질에 미치는 영향을 살펴보았다. 전체적으로 진공도 차이는 저장중 김치의 pH와 적정 산도, 색상, Leuconostoc과 Lactobacilli를 포함한 젖산균수, 관능검사 결과 등에 거의 영향을 미치지 않았다. 이로부터 저온 유통되는 소포장 김치의 품질보존을 위해서는 고도의 진공포장이 아닌 포장재 내부의 head space를 제거하는 수준으로도 충분히 효과적임을 확인할 수 있었다.