• 한국식품위생안전성학회지
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• 제14권1호
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• pp.1-8
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• 1999

There were few data for the distribution of the indicator organisms in the commercial plant foods, and for the normal flora and for the foodborne agents within the country. First of all it must be investigated the distribution of the indicator organisms. And also it is very important to prepare the sanitation criteria for the plant foods through the microbiological examination and the investigation of tendency to change of the indicator organisms according to the storage temperature and period. The average number of total viable counts for grains was 2.9$\times$105/g, psychrophilic bacteria 2.9$\times$105/g, heterotrophic bacteria 3.1$\times$105/g, heat-resistant bacteria 2.1$\times$103/g, Pseudomonas aeruginosa 23/g. That for beans was 6.3$\times$102/g, psychrophile 34/g, heterotroph 1.7$\times$102/g. That for sesames was 1.4$\times$105/g, coliform 350/g, psychrophile 7.4$\times$104/g, heterotroph 5.8$\times$104/g, Pseud. aeruginosa 2.3$\times$103/g. heat-resistant bacteria 150/g. That for potatoes was 2.0$\times$107/g, coliform 5.0$\times$104/g, psychrophile 1.8$\times$107, heterotroph 1.4$\times$107/g, heat-resistant bacteria 3.3$\times$104/, Staphylococcus 2.7$\times$105/g, fecal streptococcus 4.5$\times$103/g, Pseud. aeruginosa 7.0$\times$103/g. That for mushrooms was 1.2$\times$108/g, psychrophile 9.4$\times$107/g, heterotroph 1.0$\times$109/g, heat-resistant bacteria 1.6$\times$105/g, Pseud. aeruginosa 1.3$\times$103/g. That for vegetables was 5.9$\times$1011/g, coliform 1.8$\times$106g/, Staphylococcus 1.1$\times$1012/g, heterotroph 8.4$\times$1011/g, heat-resistant bacteria 7.6$\times$106/g, Staphylococcus 1.1$\times$107/g, fecal streptococcus 1.1$\times$104/g, Pseud. aerugniosa 5.2$\times$104/g. That for nuts 3.9$\times$104/g, coliform 3.9$\times$103/g, psychrophile 4.0$\times$104/g, heterotroph 3.2$\times$104/g, heat-resistant bacteria 400/g. In commercial grains and beans, SPC, psychrophile, heterotroph and heat-resistant bacteria stored at 1$0^{\circ}C$, 2$0^{\circ}C$, 3$0^{\circ}C$ were constant. Staphylococcus, coliform, Pseud. aeruginosa were decreased a little n grains, but were not detected in beans. In mushrooms, all indicator organisms were increased as time goes on and were increased rapidly at 2$0^{\circ}C$. In sesames, coliform was not detected at all temperature. psychrophile was increased for 7 days, the others were constant. In potatoes, SPC, psychrophile, heat-resistant bacteria, heterotroph had a tendency to increase and the others were constant. In vegetables, indicator organisms were had a tendency to increase, psychrophile, heterotroph were rapidly increased after 7 days. In nuts, SPC, coliform, psychrophile heterotroph, heat-resistant bacteria, Pseud. aeruginosa were constant, staphylococcus and fecal streptococcus were not detected.

• 한국미생물·생명공학회지
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• 제50권2호
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• pp.235-239
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• 2022

Psychrophiles have evolved to produce cold-adapted enzymes to enable survival in low-temperature environments. In this study, the cold adaptation of 5-enolpyruvylshikimate-3-phosphate synthase (CpsEPSPS) from Colwellia psychrerythraea, a model psychrophile, was analyzed. The optimum temperature for the activity of CpsEPSPS was found to be 25℃, with 35% activity remaining at 5℃. However, the unfolding temperature of CpsEPSPS was 54℃. This phenomenon is frequently observed in cold-active enzymes. As is the cases for most cold-active enzymes, the K_m values of CpsEPSPS for its substrates were higher than those of Escherichia coli EPSPS. These results indicate that CpsEPSPS is cold-adapted, but not perfectly.

• 한국식품위생안전성학회지
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• 제13권4호
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• pp.430-440
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• 1998

식육류에서의 오염지표세균의 분포를 보면 돈육에서는 일반세균 19/g, 대장균군 1.8/g, 저온세균 15/g, 종석영양세균 12/g, 분원성연쇄상구균 6.2/100 g, 슈도모나스 13/100 g이었으며, 내열성세균 및 포도상구균은 검출되지 않았다. 우육에서는 일반세균수 $1.3{\times}10^{2}/g$, 대잔균군 5.2/g, 저온세균 $1.4{\times}10^{2}/g$, 종속영양세균 28/g, 포도상구균 1.2/g, 분원성연쇄상구균 9.5/100 g, 슈도모나스균 1.9/100 g이었으며 내열성세균은 검출되지 않았다. 계육은 일반세균수 $8.8{\times}10^{3}/g$, 대장균군 53/g, 저온 세균 $4.6{\times}10^{3}/g,\;종속영양세균\;4.7{\times}10^{3}/g$ 분원성연쇄상구균 9.9/100g, 슈모나스균 1.5/100 g이었으며, 내열성세균 및 포도상구균은 검출되지 않았다. 우유에서는 일반세균 $4.7{\times}10^{3}/m;\l,\;저온세균\;1.2{\times}10^{2}/ml,\;종속영양세균\;4.2{\times}10^{2}/ml$이었으며, 대장균군, 내열성세균, 포도상구균, 분원성연쇄상구균 및 슈도모나스균은 검출되지 않았다. 치즈에서는 일반세균 3.2/g, 저온세균 2.3/g, 종속영양세균 1.6/g, 포도상구균 1/g, 분원성연쇄상구균 9.1/100g 이었으며, 대장균군, 저온세균, 종속영양세균, 포도상구균 및 슈도모나스균은 검출되지 않았다. 치즈에서는 일반세균 3.2g, 저온세균 2.3/g, 종속영양배균 1.6/g, 포도 상구균 1/g, 분원성연쇄상구균 9/100 g이었으며, 대장균군, 내열성세균 및 슈도모나스균은 검출되지 않았다. 발효유에서는 유산균의 영향을 받아 일반세균수 $1{\times}10^{7}/ml,\;내열성세균\,1.0{\times}10^{6}/ml,\;분원성연쇄상구균\;2.4{\times}10^3/100\,m;,\;유산균수\;3.2{\times}10^{15}/ml$이었으며, 대장균군, 저온세균, 종속영양세균, 포도상구균 및 슈도모나스균은 검출되지 않았다. 그 밖의 햄, 소시지, 버터, 계란, 메추리알에서는 오렴지표세균이 모두 검출되지 않았다. 시판동물성 식품을 $10^{\circ}C,\;20^{\circ}C\;30^{\circ}C$에서 보관하면서 저장기간별로 오염지표세균의 변화를 조사한 결과 식육류는 $10^{\circ}C$에서 보존할 경우 일반세균, 대장균군, 저온세균 및 종속영양세균은 시간이 지날수록 급격히 균수가 증가하였으나 내열성세균, 포도상구균, 분별성연쇄상구균 및 슈도모나스균은 거의 변화하지 않았다. $20^{\circ}C$에서 보존할 경우 일반세균, 대장균군, 저온세균, 종속영양세균 및 분변성연쇄상구균은 7일 보존시 가장 높은 균수를 나타내었으며, 내열성세균, 포도상구균 및 슈도모나스균은 약간 증가하였다. $30^{\circ}C$에서 보존할 경우에는 3일부터 7일 사이에 가장 높은 균수를 나타내었고, 7일부터 급격히 감소하는 경향을 나타내었다. 식육가공품은 $10^{\circ}C$에서 보존할 경우 17일 보존시 $10^{1}/g$ 수준까지 증가하였을 뿐이었고, $20^{\circ}C$에서 보존할 경우 일반세균, 저온세균 및 종속영양 세균이 $10^{5}/g$ 수준정도 증가하였으며, 나머지 지표세균은 거의 변화가 없었다. $30^{\circ}C$에서 보존할 경우 $20^{\circ}C보다\;10^{2}/g$ 수준 더 증가하는 경향을 나타내었을 뿐이었다. 우유류는 저온 살균처리에 의해 일반세균, 저온 세균 및 종속영양세균이 $10^{\circ}C\;보존시\;10^{4}/ml$ 수준까지 증가하였을 뿐 대장장균군, 포도상구균, 분변성연쇄상구균 및 슈도모나스균은 전혀 검출도지 않았다. $20^{\circ}C와\;30^{\circ}C$에서는 빠른 속도로 균수가 증가한 후 일정한 상태를 유지하였다.

• ALGAE
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• 제34권1호
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• pp.1-5
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• 2019

Hydrurus foetidus is a cold-water golden alga (Chrysophyceae) found in fast-flowing rivers mainly during time of snowmelt. It has primarily been studied by scientists located near alpine or northern locations, but there are also observations both in south and north America, Russia, Japan, in the Hope Bay area (Antarctica) and Himalaya. If and where environmental conditions are appropriate, Hydrurus may be distributed "worldwide." More information is wanted from areas where its presence may be expected.

• 한국식품영양과학회지
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• 제28권5호
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• pp.1092-1098
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• 1999

Gamma irradiation was applied to pork for improving its hygienic quality and evaluating its possible genotoxicity. The effective dose of irradiation was 3 kGy in pork for the sterilization of all contaminated microorganisms tested. After 8 weeks of storage at 5oC, no growth of microorganisms except for psychrophile and total aerobic bacteria was observed in the more than 3 kGy irradiated pork. The genotoxicity of high dose irradiated pork(30 kGy) was evaluated by Salmonella typhimurium reversion assay, chromosomal aberration test and in vivo micronucleus assay. The results were negative in the bacterial reversion assay with S. typhimurium TA98, TA100, TA1535, TA1537. In chromosomal aberration tests with CHL cells and in vivo mouse micronucleus assay, no significant difference in the incidences of chromosomal aberration and micronuclei was seen between nonirradiated and 30 kGy irradiated porks. These results indicate that 30 kGy irradiated pork did not show any genotoxic effects under these experimental conditions.

• 미생물학회지
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• 제19권4호
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• pp.174-178
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• 1981

Psychrophilic yeast strains, HJ3011, HJ3023, and HJ3021, which were isolated from the Han River during winter season of December 1980 to February 1981 were identified as Candida sp., Candida nivalis, and Rhodotorula rubra respectively. The effect of temperature on growth was carried out in this study. Growth rate constants of strains HJ3011 and HJ3023 were the highest value at $15^{\circ}C\;and\;16{\sim}20^{\circ}C$ respectively, and both growth rates diminished gradually above $20^{\circ}C$ and were decreased to zero at $25^{\circ}C$. According to the results obtained in this experiment, above two strains of yeast were confirmed as psychrophile. On the other hand since the strain of HJ3021 exhibited the highest growth rate constant at $15^{\circ}C$ and could slightly grow above $25^{\circ}C$, this strain was defined as psychrotroph.

• Journal of Microbiology
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• 제41권1호
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• pp.22-27
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• 2003

A lipase from Aeromonas sp. LPB 4, a psychrotophile isolated from a sea sediment was purified and characterized. The lipase was purified 53.5 fold to a homogeneous state by acetone precipitation and QAE sephadex column chromatography and its molecular weight was determined to be 50 kDa by SDS-PAGE. The enzyme exhibited maximum activity at 10$^{\circ}C$ and was stable at temperatures lower than 50$^{\circ}C$. This lipase favored substrates containing medium carbon chain of acyl group, while too low and high carbon chain decreased its activity. The lipolytic activity of purified lipase was slightly increased by the addition of 0.1% detergent, but decreased by 1% of detergent. Butanol severely decreased the lipase activity while methanol increased the activity about 15%.

• Journal of Microbiology
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• 제38권3호
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• pp.132-136
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• 2000

We recently identified Leuconostoc gelidum, a typical psychrophile, as a microbial component from kimchi that has been laboratory-prepared and fermented at 20$^{\circ}C$ . However, it has been shown that the growth of leuconostocs in food products is highly influenced by fermenting temperature. To determine the distribution of L. gelidum species in kimchi fermented at a lower temperature , 8$^{\circ}C$, we characterized a total of 64 dextran-forming strains isolated from kimchi using a polyphsic method including 16S rDNA sequencing and DNA-DNA gybridization. We found that 80% of the isolated were L. gelidum, which has been found mainly at chill-stored meat products. We also found that L. gelidum could be a dominant Leuconostoc species in so-called KimJang Kimchi, which is traditionally prepared at lat fall to be preserved during winter in Korea. These results suggest that L. gelidum can be a predominant species in kimchi especially when fermented at low temperature.

• Bulletin of the Korean Chemical Society
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• 제30권11호
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• pp.2647-2650
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• 2009

Cold shock proteins (Csps) are a subgroup of the cold-induced proteins on reduction of the growth temperature below the physiological temperature. They preferentially bind to single-stranded nucleic acids to translational regulation via RNA chaperoning. Csp plays important role in cold adaptations for the psychrophilic microorganism. Recently, Cold shock protein from psychrophilic bacteria, Colwellia psychrerythraea (CpCsp) has been identified. Three dimensional structures of a number of Csps from various microorganisms have been solved by NMR spectroscopy or X-ray crystallography, but structures of psychrophilic Csps were not studied yet. Therefore, cloning and purification protocols for further structural study of psychrophilic Csp have been optimized in this study. CpCsp was expressed in E. coli with pET-11a vector system and purified by ion exchange, size exclusion, and reverse phase chromatography. Expression and purification of CpCsp in M9 minimal media was carried out and $^{15}N$-labeled proteins with high purity over 90% was obtained. Further study will be carried out to investigate the tertiary structure and dynamics of CpCsp.

• 한국식품조리과학회지
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• 제17권6호
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• pp.617-624
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• 2001

계육의 위생화를 위한 방사선 조사기술의 이용가능성을 검토할 목적으로 방사선 조사 계육을 대상으로 미생물학적 및 유전독성학적 안전성 평가를 실시하였다. 3kGy의 감마선 조사는 저온성 세균을 약 1.5 log cycle 정도 감소시킬 수 있었고, 일반세균도 검출한계 이하로 감소되었으며, 특히 7kGy이상의 조사로 모든 오염미생물은 완전히 사멸시킬 수 있었다. 또한 감마선 조사후 냉동저장의 병용은 육제품의 초기살균과 미생물의 생육억제에 매우 효과적임을 알 수 있었다. 유전독성학적 안전성 시험의 경우에는 감마선 조사 및 비조사 닭고기 현탁액의 S. typhimurium TA98, TA100, TA1535 및 TA1537에 대한 복귀변이 집락수를 조사한 결과, 대사활성계 도입 및 부재시 모두, 모든 시험균주에서 시험적용 농도인 0.I~8.3mg/plate의 범위에서 복귀변이 집락수의 농도 의존적인 증가 혹은 감소를 보이지 않아 감마선 조사 닭고기(10kGy)는 돌연변이원성이 없는 것으로 판단되었다. 또한 설치류 망상적혈구를 이용하여 감마선 조사된 닭고기의 염색체 이상 시험을 수행한 결과, 감마선 조사 닭고기는 시험적용 용량인 1250~2500mg/plate의 범위에서 소핵을 가진 망상 적혈구의 출현율이 음성대조군과 유의한 차이를 나타내지 않아 소핵을 유발하지 않음을 확인하여 유전독성학적 측면에서의 안전성이 확인되었다.