• Journal of Microbiology
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• 제44권4호
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• pp.417-422
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• 2006

This study investigated the antibacterial effect of electrolyzed water on oral bacteria both in vitro and in vivo. Tap water was electrolyzed in a water vessel using platinum cell technology. The electrolyzed tap water (called Puri-water) was put in contact with five major periodontopathogens or toothbrushes contaminated with these bacteria for 30 sec. In addition, Puri-water was used as a mouthwash for 30 sec in 16 subjects and the antibacterial effect on salivary bacteria was evaluated. Puri-water significantly reduced the growth of all periodontopathogens in culture and on toothbrushes, and that of aerobic and anaerobic bacteria in saliva, when compared to the effect of tap water. It also significantly reduced mutans streptococci growing on mitis salivarius-bacitracin agar. Our results demonstrate that the electrolyzed tap water is effective as a mouthwash and for toothbrush disinfection.

• Journal of Microbiology and Biotechnology
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• 제27권10호
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• pp.1798-1807
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• 2017

The differentiations in nitrogen-converting activity and microbial community structure between granular size fractions in a continuous completely autotrophic nitrogen removal over nitrite (CANON) reactor, having a superior specific nitrogen removal rate of $0.24g/(g\;VSS{\cdot}h)$, were investigated by batch tests and high-throughput pyrosequencing analysis, respectively. Results revealed that a high dissolved oxygen concentration (>1.8 mg/l) could result in efficient nitrite accumulation with small granules (0.2-0.6 mm in diameter), because aerobic ammonium-oxidizing bacteria (genus Nitrosomonas) predominated therein. Meanwhile, intermediate size granules (1.4-2.0 mm in diameter) showed the highest nitrogen removal activity of $40.4mg/(g\;VSS{\cdot}h)$ under sufficient oxygen supply, corresponding to the relative abundance ratio of aerobic to anaerobic ammonium-oxidizing bacteria (genus Candidatus Kuenenia) of 5.7. Additionally, a dual substrate competition for oxygen and nitrite would be considered as the main mechanism for repression of nitrite-oxidizing bacteria, and the few Nitrospira spp. did not remarkably affect the overall performance of the reactor. Because all the granular size fractions could accomplish the CANON process independently under oxygen limiting conditions, maintaining a diversity of granular size would facilitate the stability of the suspended growth CANON system.

• 한국식품위생안전성학회지
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• 제15권3호
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• pp.256-261
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• 2000

숙면에 감마선을 조사하여 상온에 보관하면서 보존기간중의 미생물 및 일반 품질특성 변화를 조사하였다. 숙면의 곰팡이는 5 kGy의 감마선 조사에 의하여 완전 사멸되었으며 일반세균은 5 kG)에서 2 log cycle, 10 kGy에서 4 log cycle수준으로 감소하였고 10 kGy에서 안정적으로 미생물의 생장이 억제되었다 숙면의 pH는 보존기간을 통하여 점차 낮아졌으나 감마선을 조사한 시료는 pH의 강하가 지연되었고 수분활성도는 보존기간을 통하여 증가하였으나 감마선 조사에 의한 각 시료간의 차이는 없었다 기계적 물성 측정결과, 감마선 조사는 보존초기에는 면의 stickiness를 낮추었으나 보존기간의 경과에 따라 오히려 대조구에 비하여 stickiness가 높아졌다.

• 한국동물위생학회지
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• 제40권1호
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• pp.35-40
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• 2017

In order to find a way to reduce histamine formation when storing salted mackerel at home, a series of experiments were carried to monitor the time-related changes of histamine content, total aerobic bacteria and coliform quality of mackerel marketed in Incheon by the type of storage containers (clean, zipper and vacuum bag) during storage at $4^{\circ}C$, $24^{\circ}C$ and $-20^{\circ}C$ for 10 days. Histamine formation was continuously increased with passing time during storage at $4^{\circ}C$, whereas it was decreased after 3 days during storage at $24^{\circ}C$. The initial value of histamine was maintained during storage at $-20^{\circ}C$ for 10 days. During storage at $4^{\circ}C$, total aerobic bacteria and coliform showed a tendency to increased rapidly till 3day and then decreased gradually. The formation of histamine was increased in the order of vacuum bag$4^{\circ}C$.

• 한국환경보건학회지
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• 제32권4호
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• pp.353-358
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• 2006

This study was performed to evaluate the effects of input ratios of bulking material in aerobic composting of food wastes on variation of colony forming units of heterotrophic bacteria. Wood chips were used as a bulking material. Volume ratios of food wastes to wood chips in reactor of Control, WC-1 and WC-2 were 10/0, 10/5 and 10/10, respectively. Reactors were operated for 24 days with 1hour stirring by 1rpm and 2 hours of the forced aeration per day. WC-2 reached high temperature range faster than WC-1, and the maximum temperature of WC-2 was higher than that of WC-1. This means that the reaction velocity of composting of WC-2 was faster than that of WC-1. Judging from the profile of pH changes, composting of WC-1 proceeded slowly and continuously. Composting of WC-2 proceeded rapidly in the former half reaction period, and kept steady state of high pH in the latter half reaction period. Namely, composting of WC-2 was nearly completed in the former half reaction period. In the case of WC-1 and WC-2. the maximum temperature was followed by the rapid pH increase in 2-3 days, and this was followed by the maximum Colony Forming Units(CFU) in 3 days. But, these three items of WC-2 always appeared faster and higher than those of WC-1.

• 한국식품영양학회지
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• 제27권4호
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• pp.742-750
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• 2014

This study was done in order to investigate the changes in quality of Cheonggukjang for soybean cultivars during fermentation. Cheonggukjang of 14 cultivars that were inoculated with Bacillus subtilis 15893 was produced, and, then, it was measured for hardness, proximate composition, amino nitrogen, enzyme activity, and total aerobic bacteria counts. In a raw bean, the highest hardness value was 16,975 g from Sunyu. In a steaming bean, Jangwon had the highest hardness value and the lowest aerobic bacteria counts of forty-eight hours fermented Cheonggukjang. Saedanbaek, whose protein contents was highest in raw bean, was also highest in Cheonggukjang. The amino nitrogen content of twenty-four hours fermented Cheonggukjang was highest in Saeol and Sunyu while forty-eight hours fermented Cheonggukjang was highest in Singi, Daol, and Milyang 231. In the protease activity, Saedanbaek had the highest and total aerobic bacteria count that were either increased or held as time went on ; twenty-four hours fermented Cheonggukjang was highest in Milyang 231 and Keunol while forty-eight hours fermented Cheonggukjang was highest in Chunsang.

• Animal Bioscience
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• 제34권12호
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• pp.2003-2011
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• 2021

Objective: The aim of this study was to evaluate the effect of marinating turkey meat with buttermilk and acid whey on the technological traits and microbiological quality of the product. Methods: Slices of turkey meat muscles were marinated for 12 hours in buttermilk (n = 30), acid whey (n = 30) and comparatively, in lemon juice (n = 30). The control group (n = 30) consisted of unmarinated slices of turkey breast muscles. Physical parameters (pH, water holding capacity, colour L^*a^*b^*, shear force, weight loss) were assessed and quantitative and qualitative microbiological evaluation of raw and roasted products was performed. The microbiological parameters were determined as the total viable counts of mesophilic aerobic bacteria, of the Enterobacteriaceae family, and Pseudomonas spp. Bacterial identification was performed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Results: Marinating turkey meat in buttermilk and whey compared to marinating in lemon juice and the control sample resulted in a higher (p<0.05) degree of yellow color saturation (b^*) and a reduction (p<0.05) in the number of mesophilic aerobic bacteria, Pseudomonas spp. and Enterobacteriaceae family as well as the number of identified mesophilic aerobic bacteria in both raw and roasted samples. The lowest (p<0.05) shear force values were found in products marinated in whey. Conclusion: The use of buttermilk and acid whey as a marinade for meat increases the microbiological safety of the product compared to marinating in lemon juice, while maintaining good technological features of the product.

• 대한영양사협회학술지
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• 제28권3호
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• pp.205-217
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• 2022

School meals are prepared based using the HACCP system, which is designed to ensure the physical and mental health of students. However, operational recommendations in school cafeterias have changed due to COVID-19 and include delays in serving time to restrict the number of meals and the installation of screens to prevent droplet transmission. Unfortunately, these changes may have detrimentally affected hygiene practices and generated new food poisoning sources. This study aimed to determine the hygiene state of school cafeterias in the Gyeongnam area from December 2020 to September 2021 based on the monitoring of total aerobic and coliform bacteria. Kitchen floors were the most contaminated areas with an average number of total aerobic bacteria of 4.3 log CFU/100 cm², whereas counts in dining areas were relatively low at 0.1~3.5 log CFU/100 cm². Newly installed partitioned areas had the lowest contamination level of 0.1~2.8 log CFU/100 cm². Escherichia coli was not detected on any surface, while coliform was detected on workbenches and floors. In conclusion, hygienic practices appear to have been adequately managed in school cafeterias despite COVID-19 driven changes. Nonetheless, continuous monitoring is recommended to ensure prompt response to changing environments.

• 환경생물
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• 제41권2호
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• pp.167-178
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• 2023

Large amounts of waste and wastewater from aquaculture have negatively impacted ecosystems. Among them, shrimp aquaculture wastewater contains large amounts of nitrogen contaminants derived from feed residues in an aerobic environment. This study isolated candidate strains from adult rockworms to treat shrimp aquaculture wastewater (SAW) in an aerobic environment. Among 87 strains isolated, 25 grew well at the same temperature as the shrimp aquaculture with excellent polymer degradation ability (>0.5 cm clear zone). Six isolates (strains AL1, AL4, AL5, AL6, LA10, and PR15) were finally selected after combining strains with excellent polymer degradation ability without antagonism. 16S rRNA sequencing analysis revealed that strains AL1, AL4, AL5, AL6, LA10, and PR15 were closely related to Bacillus paramycoides, Bacillus pumilus, Stenotrophomonas rhizophila, Bacillus paranthracis, Bacillus paranthracis, and Micrococcus luteus, respectively. When these six isolates were applied to SAW, they reached a maximum cell viability of 2.06×10⁵ CFU mL^-1. Their chemical oxygen demand (COD_Cr) and total nitrogen(TN) removal rates for 12h were 51.0% and 44.6%, respectively, when the COD_Cr/TN ratio was approximately 10.0. Considering these removal rates achieved in this study under batch conditions, these six isolates could be used for aerobic denitrification. Consequently, these six isolates from rockworms are good candidates that can be applied to the field of aquaculture wastewater treatment.

• 한국식품위생안전성학회지
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• 제26권2호
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• pp.182-185
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• 2011

본 연구는 학교 주변에서 판매되고 있는 어린이기호식품의 정확한 실태 파악과 위해분석을 통하여 어린이 기호식품의 적절한 관리방안을 마련하기 위해 수행되었다. 현재 학교 주변에서 판매되고 있는 과자류, 캔디류, 초콜릿류, 빙과류, 음료류의 어린이기호식품 총 598종을 구매하여 시료로 사용하였으며, 미생물학적 위해요소(일반세균, 진균, 대장균군, 대장균, Bacillus cereus)에 대해 식품공전법을 사용하여 분석하였다. 과자류는 일반세균, 진균이 각각 2.69, 2.65 $log_{10}$ CFU/g 이하 수준으로 검출되었고 검출율은 각각 54.55, 62.12%이었다. 파자 1개 제품에서 Bacillus cereus가 검출되었으나(1.39 $log_{10}$ CFU/g), 법적 허용기준(3 log) 이하였다. 캔디류는 일반세균, 진균이 각각 최대 2.86, 3.36$log_{10}$ CFU/g 검출되었고 검출율은 각각 46, 8%였다. 초콜릿류는 일반세균, 진균이 각각 최대 2.52, 1.87 $log_{10}$ CFU/g 검출 되었고, 검출율은 각각 33, 22%로 나타났다. 빙과류와 음료류는 일반세균이 각각 최대 3.39, 1.35 log10CFU/mL 검출되었고, 검출율은 각각 82, 5%였으며, 빙과류 1개 제품에서 대장균군이 1.00 $log_{10}$ CFU/mL 수준으로 검출되었다. 본 연구결과, 시판되는 모든 어린이 기호식품이 미생물기준에 적합한 것으로 나타났다. 그러나 대부분의 학교 주변 어린이기호식품 판매점이 보관 온도나 취급조건 등을 갖추지 못한 채 제품이 유통, 판매되어지기 때문에 어린이기호식품에 대한 지속적인 미생물 관리가 필요할 것으로 판단된다.