• Title, Summary, Keyword: 세균

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Distribution of Indicator Organisms and Influence of Storage Temperature and Period in Commercial Animal Foods (시판 동물성 식품의 오염지표세균 분포 및 저장온도, 기간별 오염지표세균의 변화)

  • 이용욱;박석기
    • Journal of Food Hygiene and Safety
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    • v.13 no.4
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    • pp.430-440
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    • 1998
  • The average number of total viable counts for the commercial pork tested was 19/g, coliform 1.8/g, psychrophilic bacteria 15/g, heterotrophic bacteria 12/g, fecal streptococcus 6.2/100 g, Pseudomonas aeruginosa 13/100 g and none of heat-resistant bacteria and Staphylococcus was detected. That for the commercial beef tested was 130/g, coliform 5.2/g, psychrophile 140/g, heterotroph 28/g, Staphylococcus 1.2/g, fecal streptococcus 9.5/100 g, Pseud. aeruginosa 1.9/100 g and heat-resistant bacteria was not detected. That for the commercial chicken tested was 8800/g, coliform 53/g, psychrophile 4600/g, heterotroph 4700/g, fecal streptococcus 9.9/100 g, Pseudo aeruginosa 2.5/100 g. That for milk was 4700/ml, psychrophile 120/ml, heterotroph 420/ml and the others were not detected. That for the commercial cheese was 3.2/g, psychrophile 2.3/g, heterotroph 1.6/g, Staphylococcus l/g, fecal streptococcus 9.1/g. That for fermented milk was $10^{7}/ml$, heatresistant bacteria $10^{6}/ml$, fecal streptococcus 2400/100 ml, lactobacillus $3.2{\times}10^{15}/ml$, in accordance with lactic acid bacteria and the others were not detected. There was not detected any indicator organisms from ham, sausage, butter, eggs and quails in the commercial fooods tested. SPC, coliform, psychrophile and heterotroph in commercial meats stored at $10^{\circ}C$ were increased rapidly as time goes on but heat-resistant bacteria, staphylococcus, fecal streptococcus and Pseudo aeruginosa were constant. At $20^{\circ}C$, SPC, coliform, psychrophile, heterotroph and fecal streptococcus were the highest at 7 days and heat-resistant bacteria, staphylococcus and Pseudo aeruginosa were increased a little. At $30^{\circ}C$, all indicators were increased rapidly for 3 and 7 days and then decreased rapidly. All indicator organisms were increased at the level of 10/g for 14 days in meat products stored at $10^{\circ}C$, but SPC, psychrophile and heterotroph in meat products stored at $20^{\circ}C$ were increased at the level of $lO^5/g$. It showed that the indicators in meat products stored at $30^{\circ}C$ had a tendency to increase at the level of $10^{2}/g$ relative to those stored at $20^{\circ}C$. SPC, psychrophile and heterotroph in milk stored at $10^{\circ}C$ increased up to the level of $10^4/ml$, but coliform, staphylococcus, fecal streptococcus and Pseudo aeruginosa were not detected. As stored at $20^{\circ}C$ and $30^{\circ}C$, they were increased rapidly for 1 or 3 days and then constant for a long time.

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Bacterial Community of Free-living and Aggregated Bacteria at Thawing Period in Lake Baikal (해빙기 바이칼호에서 부유세균과 Aggregates에 부착한 세균의 군집구조)

  • 홍선희;김옥선;전선옥;유재준;안태석
    • Korean Journal of Microbiology
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    • v.38 no.3
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    • pp.192-197
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    • 2002
  • Fluorescent in situ hybridization (FISH) with rRNA-targeted oligonucleotide probes was used to compare the community structures of free-living and aggregated bacteria at thawing period in Lake Baikal. Targeted groups were Eubacteria, $\alpha$-, $\beta$-, $\gamma$- proteobacteria groups, Cytophaga-Flavobacterium group and Planctomycetales. Total bacterial numbers of free-living bacteria were ranged from $0.2{\times}10^6\cells{\cdot}ml^-1$ to $3.2{\times}10^6\cells{\cdot}ml^-1$, which were decreasing with depth, while the aggregated bacterial numbers were dramatically increasing from $0.4{\times}10^4 to 3.3{\times}10^4 \cells{\cdot}ml^-1$ with depth. The ratios of EUB probe binding cells to DAPI counts were ranged from 52.3 to 74.1% in free-living bacteria, and from 39.6 to 66.7% in the aggregated bacteria, respectively. Community structures of the aggregated bacteria were very different from each free-living bacteria at every depth. At 25 m depth, where the chlorophyll a concentration was highest, both structures were quite different from those of surface layers, rendering the fact that the community structures might be affected by phytoplankton. The vertical profile of community structure of aggregated bacteria is particular. The proportion of $\beta$-proteobacteria group was increasing with depth and it was 51.8% at 100 m, but the dominant group was $\gamma$-pro-teobacteria group at 250 m. Taken together, the biodiversity and succession of aggregated bacteria are quite different from free-living bacteria.

Identification of differentially expressed proteins in the bacterial biofilm (세균성 바이오필름-특이 발현 단백질의 규명)

  • Kang, Chi-Dug;Choi, Jeam-Il
    • Journal of Periodontal and Implant Science
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    • v.35 no.2
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    • pp.271-275
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    • 2005
  • 본 연구는 치주낭에 biofilm형태로 부착되어 질환을 유발시키고 항생제 빚 항균제에 저항을 일으키는 세균 독성요소를 규명하기 위해 시행된 기초연구이다. 치주질환의 주 병원균의 하나인 Porphyromonas gingivalis 381 biofilm의 세포외막에 특이하게 발현되는 단백질을 규명하기 위한 기초적인 자료를 얻기 위해 시행하였다. Porphyromonas gingivalis 381을 통상적인 세균 배양용 broth를 사용하여 혐기성 세균 배양기로 24시간 배양한 것을 대조군으로 하고, tissue culture plate를 이용하여 혐기성 배양조건 하에서24시간동안 biofilm을 형성하여 실험군으로 설정하였다. 세균을 수획하여 세포외막을 분리하고 isotonic isoelectric focusing을 시행한 결과 주로 약 20-30 kilodaltons에 해당하는 수종의 세균세포막 단백질이biofilm으로 배양한 세균에서 더 상승적으로 발현됨이 관찰되었고, 상이한 수종의 단백질도 planktonic culture broth로 배양한 세균에서 다 상승적으로 발현됨을 관찰할 수 있었다. 이것은 세균의 배양조건과 환경에 따라 그 외막 단백질이 서로 다르게 발현됨을 입증하는 기초적인 자료로서 향후 단백질의 동정과 성격을 규명하는 근간 실험으로 추진할 계획이다.

Evaluation of Bacteriological Safety in Deep Confined Aquifer (심층피압지하수에서 세균군집의 분석에 의한 분변성 오염 평가)

  • 조장천;김상종
    • Korean Journal of Microbiology
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    • v.35 no.1
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    • pp.47-52
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    • 1999
  • The study on the bacterial distribution was performed to evaluate the bacteriological safety in 4 deep confined aquifers drilled for drinking. All the investigated aquifers were oligotrophic, howevec bacterial densities and activities and the number of indicator bacteria in C-2 boreholes were much higher than those in other boreholes. Fecal pollution was observed in 3 boreholcs except C-1 borehole. The ratio of gram positive bacteria of the C-2 borehole was much lower than those 01 another boreholes. The numbers of total colifonns, fecal coliforms, and fecal Slreptococcus in the C-2 boreholes were 61, 33, 55 CFU (250 ml)$^{-1}$

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Microbiological Evaluation of Foods and Kitchen Environments in Childcare Center and Kindergarten Foodservice Operations (보육시설과 유치원 급식의 식품 및 환경 미생물의 오염도 평가)

  • Seol, Hye-Rin;Park, Hyoung-Su;Park, Ki-Hwan;Park, Ae-Kyung;Ryu, Kyung
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.38 no.2
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    • pp.252-260
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    • 2009
  • Whereas the numbers of childcare centers and kindergartens are increasing rapidly, systematic management to control the food safety of foodservice operation is not yet well established. Samples from 12 centers in Seoul and Gyeonggi Province were collected to assess the microbiological quality of 32 raw materials, 24 cooked foods, 76 food-contact surfaces (knives, cutting boards, dish towels and gloves), 17 employees' hands and 12 air-borne bacteria. The microbiological analyses were performed for aerobic plate counts (APC), Enterobacteriaceae, E. coli and 7 pathogens (B. cereus, C. jejuni, C. perfringens, L. monocytogenes, Salmonella spp., S. aureus, and V. parahaemolyticus). Among raw materials, E. coli ($1.39{\sim}2.08\;\log\;CFU/g$) were detected in 4 out of 6 meats and 7.46 log CFU/g of APC in tofu. High enterobacteriaceae levels of 4.23, 5.14 and 4.19 log CFU/g were found in cucumber salad, steamed spinach with seasonings and steamed bean sprout with seasonings, respectively. No pathogens were found in all samples except for C. perfringens detected from raw spinach and raw lotus root. Only APC and enterobacteriaceae were found in food-contact surfaces. Two of the 23 knives and three of the 24 kitchen boards showed over 500 CFU/$100\;cm^2$ of APC; also, APC levels (5.03 to 5.44 log CFU/g) were detected in 4 of the 12 dish towels. Only one glove showed Enterobacteriaceae (2.44 log CFU/glove) contamination. Enterobacteriaceae were found in 2 employees' hands ($2.37{\sim}4.44\;\log\;CFU$/hand) among the 16 employees. The contamination levels of air-borne bacteria were shown unacceptable in two (2.25 and 2.30 log CFU/petri-film/15 min) out of the 12 kitchen areas. These results suggest that the microbiological hazards in some foods and environments are not well controlled and thus a guideline should be provided to ensure the food safety in childcare center and kindergarten foodservice operations.

Effect of Salinity on the Bacterial Community in the Sewage Treatment System (하수 처리 과정에서 염분이 세균 군집에 미치는 영향)

  • 서미애;홍선희;김동주;박경미;안태석
    • Korean Journal of Microbiology
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    • v.37 no.2
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    • pp.124-129
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    • 2001
  • For elucidating the effect of salinity to the effect of wastewater treatment, the heterotrophic bacterial numbers, total bacterial numbers, and the bacterial community structure by FISH method were analyzed. The total bacterial numbers were not significantly changed by the salinity. But the heterotrophic bacterial numbers and bacterial community structures were drastically changed by the increase of salinity. In case of 1% salinity, the heterotrophic bacterial numbers and structure were slightly changed comparing to those of contol. In case of 2% and higher salinities, the numbers of heterotrophic bacteria and the proportions of Eubacteria, Proteobacteria $\alpha$-group, $\rho$-group and Cytophaga-Flavobacterium groups were deceasing. By these results, the salinity stress to bacterial community in waste water treatment was unveiled, and for sustaining the waste water treatment system, the salinity should be lower than 1%.

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Distribution of bacterial biomass in the water column of Soyang lake (소양호 수중 생태계에서의 세균 생체물질량의 분포)

  • 김명운;강찬수;김상종
    • Korean Journal of Microbiology
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    • v.27 no.2
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    • pp.130-138
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    • 1989
  • Microbiological parameters such as bacterial biovolume and biomass in Soyang Reservoir was statistically analyzed with the physico-chemical enviromental factors. Analysis of correlation and multiple regression showed that temperature affects most of microbiological parameters. Variations of total bacterial number, total bacterial biovolume and saprophyte number were highly correlatd with the concentrations of chlorophyll a and pheophytin a. Bacterial production by the $^{3}H$-thymidine incorporation rate was largely affected by Seston. It suggests that microbiological factors such as bacterial biovolume and bacterial biomass were controled by the concentration of seston and distribution of phytoplankton which acts as carbon and energy source for the bacterial community in the water column of Soyang Reservoir.

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