• Title/Summary/Keyword: Microbiological evaluation

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Evaluation of Korean Water Quality Standards and Suggestion of Additional Water Parameters (국내 농업용수 수질기준의 적정성 평가 및 추가수질항목 제안)

  • An, Youn-Joo;Lee, Woo-Mi;Yoon, Chun-Gyeong
    • Korean Journal of Ecology and Environment
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    • v.39 no.3 s.117
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    • pp.285-295
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    • 2006
  • Korean water quality standards for the protection of agricultural water uses were originally derived based on management of public water resource. They were not prepared to protect crop plants from contaminants, and therefore required water parameters in agricultural uses were excluded in current water quality standards. Korean water standards in river and lake have five levels, and level IV is correspondent to agricultural water uses. Currently, there is no Korean guidelines to protect crop plants from contaminants contained in agricultural water. In Canada, agricultural water guidelines are provided to protect crops from contaminants. In this study, agricultural water quality standards in Korea were compared with them in developed countries to evaluate the adequacy of Korean water quality standards for the protection of agricultural water uses. Additional water quality parameters in agricultural uses were also proposed. Suggested parameters include electric conductivity, sodium, chloride, boron, copper, iron, zinc, and microbiological quality, They are the required parameters to protect crop plants as well as human health. Current water quality standards in agricultural uses was not considered to be appropriate in terms of crop protection. Additional water parameters should be included in agricultural water quality standards.

Quality Evaluation of Conventional Salted Cabbages (시중 절임배추의 품질 평가)

  • Kim, Jin-Hee;Park, Kun-Young;Choi, Hae-Sun;Yang, Ji-Young
    • The Korean Journal of Food And Nutrition
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    • v.23 no.4
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    • pp.659-663
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    • 2010
  • This research aimed to investigate the quality of conventional salted cabbages. Here, we studied the general characteristics and microbiological aspects of purchased salted cabbage samples from 15 companies. The purchased salted cabbages used a sun-dried salt, but two samples used a mixture of sun-dried salt and processed salt. There were 4 times of washing, 3 steps of washing after automatic washing, and 3 steps of washing after bubble washing as washing methods for the salted cabbages and ground water was used as the washing water. Also, three samples received HACCP certification. The salt contained in the purchased salted cabbages ranged from 0.5% to 2.0%, representing low salted cabbages. The pH of the purchased salted cabbages ranged from 5.32 to 6.47, and hardness ranged from 1,997 g to 3,665 g. Rewashing was necessary before using some salted cabbages due to foreign materials such as insects, soil, etc. Total bacterial counts of the purchased salted cabbages ranged from 3.36 log to 6.06 log and coliform bacteria ranged from below 1 log to 6.05 log, whereas other pathogens were not detected.

Development of New Manufacturing Process for Changran-Jeotgal 3. Improvement of Seasoning Process and Quality Estimation (창란젓갈 제조의 신기술 개 발 3. 조미공정의 개량 및 품질평가)

  • LEE Won-Dong;LEE Jae-Jin;CHANG Dong-Suck;YOON Ji-Hye;LEE Myung-Suk
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.34 no.2
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    • pp.119-124
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    • 2001
  • In Conventional process, sugaring and seasoning step were combined during seasoning process of Changran-Jeotgal. While, in the case of Improved process, sugaring and seasoning step were separated and agitation was employed in order to control moisture content and improve taste. The addition of $20\%$ of corn syrup and agitation with 10 rpm for 4 hours at $20^{\circ}C$ were carried out to optimize the seasoning process in Changran-Jeotgal. From above results, quality estimation of Changran-Jeotgal manufacturing process, such as chemical and microbiological changes, there were little difference for salinity, pH, VBN value, crude fat and crude protein between Improved process and Conventional one, However water activity of Changran-Jeotgal produced by the Improved process was lower with 0.82 than that of Conventional one with 0.90. And the sensory evaluation showed that Improved process produced more favorable products; By regional groups, Seoul residents favored them more than Busan ones and by age, teen-aged like them best.

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Improvement of Validity and Efficiency for Detection of Cryptosporidium Ocysts and Giardia Cysts in Environmental Water Samples (환경수 중 크립토스포리디움 오시스트 및 지아디아 시스트 검출의 정확도 및 회수율 향상을 위한 연구)

  • 이목영;조은주;김도연;변승헌;이의광;오세종;안승구
    • Korean Journal of Microbiology
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    • v.39 no.1
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    • pp.27-35
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    • 2003
  • No currently available methods to monitor pathogenic protozoa, Cryptosporidium and Giardia in environmental water come close to acceptable sensitivity, specificity and reproducibility, and so it has to be accompanied by thorough quality control and performance evaluation to credibly predict the distribution of them. We collected surface water samples from the Han River and spiked our prepared (oo)cysts, determined Matrix Spike recoveries using USEPA Method 1623 and considered what factors influence MS recovery and validity. As a result, average 46% of spiked oocysts and 60% of spike cysts were recovered, but repetitive sampling and statistical approach seemed to be necessary to determine the environmental pollution level of two protozoa as their variation coefficients was so much as 35oio and 26%. And MS recoveries with two acid dissociations during immunomagnetic separation were improved more 10% than that with one dissociations and the use of spiked suspension enumerated by flow cytometry instead of manual preparation enhanced the validity and reliability in spiking tests. Because fluorescence characteristics of (oo)cysts stained on well slides with FITC-labeled monoclonal antibodies and DAPI was not always same, well Elides from spiked field samples were helpful to evaluate the performance of staining. We found many (oo)cyst-like objects with typical fluorescence, not (co)cysts, from the Han River water samples, and then it was concluded that nuclei staining by DAPI (4',6-diamidino-2-phenylindole) and examination by Differential Interference Contrast Microscope should be critical for valid identification.

Biological Hazard Analysis of Angelica gigas Nakai on Production and Marketing Steps (당귀의 재배 및 유통과정 중 생물적 위해요소 분석)

  • Park, Kyeong-Hun;Kim, Byeong-Seok;Lee, Jeong-Ju;Yun, Hye-Jeong;Kim, Se-Ri;Kim, Won-Il;Yun, Jong-Chul;Ryu, Kyoung-Yul
    • Korean Journal of Soil Science and Fertilizer
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    • v.45 no.6
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    • pp.1216-1221
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    • 2012
  • This study is aimed to investigate microbiological contamination of Angelica gigas Nakai. A total of 111 samples including root, soil, and irrigation water were collected from farms and market to detect aerobic bacteria, Bacillus cereus, coliform, Escherichia coli, Listeria monocytogenes,. Salmonella spp., and Staphylococcus aureus. The contaminations of aerobic bacteria, coliform, and Bacillus cereus in the root during cultivation were found 6.71 log CFU $g^{-1}$, 4.13 log CFU $g^{-1}$, and 3.54 log CFU $g^{-1}$, respectively. The contamination of coliform and B. cereus were detected in all steps from harvesting to processing, with the highest count recorded from the cutting step. In marketing, the contaminations of aerobic bacterial, coliform, and B. cereus were 5.5~6.0 log CFU $g^{-1}$, 2.4~2.6 log CFU $g^{-1}$, and 3.5~4.0 log CFU $g^{-1}$, respectively. Listeria monocytogenes, Salmonella spp, and Staphylococcus aureus were not detected in any of samples. This result indicated that hygienic soil management and post harvest management should be performed to reduce the contamination of hazard microorganisms and to produce safe agro-products.

Evaluation and Improvement of Bioassay for Residual Antibiotics in Foods (식품 내의 잔류 항생제에 대한 미생물학적 간이검사법의 평가 및 개선)

  • Park, Min-Hee;Kim, Tae-Woon;Jo, Nam-Uk;Jeong, Ji-Yoon;Lee, Soon-Ho;Lee, Jong-Ok;Kim, Hae-Yeong
    • Microbiology and Biotechnology Letters
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    • v.36 no.4
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    • pp.360-365
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    • 2008
  • For the screening of residual antibiotics in foods, bioassays and microbiological inhibitor tests are commonly applied. These methods are tested by the various susceptibility of bacteria against different kinds of antibiotics. However, the sensitivity of bioassay is generally insufficient to detect some residual antibiotics at level of interest. This study was performed to investigate the detection limit of variable antibiotics of the bioassay and to improve the sensitivity to some antibiotics. The sensitivity of bioassay using Bacillus megaterium ATCC 9885, B. subtilis ATCC 6633, B. cereus ATCC 11778 and Geobacillus stearothermophilus ATCC 10149 was low in the detection of macrolides, quinolones, chloramphenicol, and monensin. On the contrary, Micrococcus luteus ATCC 9341 showed high sensitivity to macrolides and Escherichia coli ATCC 11303 was highly sensitive to quinolones and aminoglycosides. Consequently, both strains would be useful to improve sensitivity of bioassay with a wide detection range.

Combined Effect of Cold Plasma and UV-C Against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on Fresh-cut Lettuce (양상추에 인위접종된 Escherichia coli O157:H7, Salmonella Typhimurium과 Listeria monocytogenes에 대한 저온 플라즈마와 UV-C의 살균 효과)

  • Seong, Ji-Yeong;Park, Mi-Jung;Kwon, Ki-Hyun;Oh, Se-Wook
    • Journal of Food Hygiene and Safety
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    • v.32 no.1
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    • pp.64-69
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    • 2017
  • This study was conducted to investigate the effect of cold plasma combined with UV-C irradiation against Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes on lettuce. E. coli O157:H7, S. Typhimurium, and L. monocytogenes, corresponding to approximately 5.82, 5.09, 5.65 log CFU/g, were inoculated on lettuce, respectively. Then, the lettuce was treated with cold plasma, UV-C and combination (cold plasma + UV-C), respectively. The treated lettuce was stored for 9 days at $4^{\circ}C$ for microbiological analysis and sensory evaluation. Cold plasma reduced the populations of E. coli O157:H7, S. Typhimurium, and L. monocytogenes by 0.26, 0.65, and 0.93 log CFU/g, respectively. Each microorganism were reduced by 0.87, 0.88, and 1.14 log CFU/g after UV-C treatment. And, the combined treatment that was treated by cold plasma after UV-C treatment reduced the populations of inoculated microorganisms by 1.44, 2.70, 1.62 log CFU/g, respectively. The all treatment significantly (p < 0.05) reduced the populations of all inoculated bacteria compared to untreated lettuce. UV-C combined with cold plasma was the most effective for reducing the pathogenic bacteria on lettuce, by showing log-reductions of ${\geq}2.0\;log\;CFU/g$. All treatment was not significantly different until 6 day storage compared to control group in terms of appearance, texture and overall acceptability. Therefore, the combined treatment will be an effective intervention method to control the bacteria on lettuce.

Radio-sensitivity of Contaminated Pathogens in Marinated Beef Rib (Galbi) Treated with ${\gamma}-Irradiation$ and Its Sensory Properties (시판 양념갈비에 오염된 병원성 미생물의 감마선 감수성 및 감마선 조사된 갈비의 관능적 품질특성)

  • Lee, Na-Young;Cho, Cheo-Hoon;Kang, Ho-Jin;Kim, Dong-Soo;Byun, Myung-Woo
    • Korean Journal of Food Science and Technology
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    • v.36 no.1
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    • pp.168-173
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    • 2004
  • Radio-sensitivity of pathogens in commercial marinated beef ribs, Galbi, and effect of irradiation on microbiological safety and sensory properties of marinated beef rib were investigated. Commercial raw marinated beef ribs were highly contaminated by pathogenic microorganisms including Bacillus cereus, Salmonella typhimurium, Escherichia coli, and Staphylococcus aureus, ranged from $10^{3}\;to\;10^{4}\;CFU/g$. Gamma irradiation reduced pathogen count during storage. No viable cells of pathogens were observed in sample irradiated at 7.5 kGy except for Bacillus cereus. Radio-sensitivity of inoculated pathogens in marinated beef ribs and commercial one showed $D_{10}$ value of 0.54-0.60 and 2.15-2.98, respectively, In sensory evaluation irradiated sample showed highest color and overall acceptance among treatments (p<0.05). Results indicate low dose (2.5-5.0 kGy) irradiation is effective for ensuring safety of marinated beef ribs without decreasing sensory quality.

Functional evaluation of sourdough containing lactic acid bacteria isolated from sliced radish kimchi (깍두기로부터 분리된 유산균으로 제조한 사워도우의 기능성 평가)

  • Lim, Eun-Seo;Kim, Young-Mog;Lee, Eun-Woo
    • Korean Journal of Microbiology
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    • v.53 no.3
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    • pp.180-192
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    • 2017
  • The purpose of this study is to investigate the antioxidative and antimicrobial activities of sourdough fermented with the lactic acid bacteria (LAB) isolated from sliced radish kimchi. According to 16S rRNA gene sequence analysis, the isolated lactic acid bacteria were categorized as Leuconostoc dextranicum SRK03, Lactobacillus brevis SRK15, Pediococcus halophilus SRK22, Lactobacillus acidophilus SRK30, Lactobacillus plantarum SRK38, Leuconostoc citreum SRK 42, and Lactobacillus delbrueckii SRK60 with sequence similarity of 99%. After fermentation with L. dextranicum SRK03, L. acidophilus SRK30, L. plantarum SRK38 or L. delbrueckii SRK60 and Saccharomyces cerevisiae KCTC 7246 at $30^{\circ}C$ for 24 h LAB and yeast in sourdough were present at levels of $10^9$ and $10^7CFU/g$, respectively. In particular, the titratable acidity and ethanol and exopolysaccharide contents of sourdough fermented with L. dextranicum SRK03 were also significantly (P < 0.05) higher than those of sourdough fermented with L. acidophilus SRK30, L. plantarum SRK38, or L. delbrueckii SRK60. The sourdough fermented with L. dextranicum SRK03 and L. acidophilus SRK30 showed not only good DPPH radical-scavenging capacity but anti-lipid peroxidation activity. In addition, the viable counts of Bacillus cereus ATCC 11778 and Staphylococcus aureus ATCC 6538 in sourdough during storage for 5 days at $25^{\circ}C$ were significantly (P < 0.05) lower than those of pathogenic bacteria in the control group due to the organic acids and bacteriocin produced by L. acidophilus SRK30 strain.

A Microbiological Analysis and Hazard Factor Evaluation of Food Utensils and Fixtures of Food Service Operations in Schools (학교 집단급식소 내 식기류 및 집기류의 미생물학적 분석 및 위해요인 평가)

  • Park, Sung-Jun;Hong, Sung-Ho;Lee, Anne Ha-Young;Kim, Cheol-Ju;Kim, Su-Jin;Kim, Sung-Kyoon;Ko, Gwang-Pyo
    • Journal of Environmental Health Sciences
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    • v.37 no.5
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    • pp.376-386
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    • 2011
  • Objectives: The aim of this study was to evaluate the microbial hazards posed by food utensils and fixtures in food service operations at selected middle and high schools located in Seoul, Korea. Methods: We collected 200 samples of utensils and fixtures including cups, spoons/chopsticks, food trays and tables from five different schools in Seoul. Target microorganisms of this study were divided into two groups: total bacterial count and total coliform as indicators of microbial contamination and Bacillus cereus and Staphylococcus aureus as pathogens of food poisoning. We used selective media to quantify microbial concentration and 16S rRNA PCR assay for qualitative analysis. In addition, intensive interviews with nutritionists were conducted and observations were made to identify factors that may affect microbial contamination. Logistic regression analysis was employed to examine the relationship between the microbial concentration and operation characteristics of each operation. Results: The level of microbial concentration in school B and C were significantly lower than in school A, D and E (p<0.05). Some samples from school A, D and E showed over 3.4 log CFU/100 $cm^2$ (total bacterial count) and 1.0 log CFU/100 $cm^2$ (total coliform), which requires immediate hygienic action. The number of customers per staff member, periodicity of hygiene education for staff and daily operation time of sterilizers were also found to be important factors related with the microbial contamination of food service operations. Conclusions: These results suggested that not only a HACCP (Hazard Analysis and Critical Control Point) approach, but also efforts to assess internal risk factors within operations be needed to reduce the microbial contamination of food utensils and fixtures. This study is expected to provide preliminary data for assessing microbial hazards in food service operations.