• Title/Summary/Keyword: Bacteria

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Lactic held Bacteria for the Preservation of Fruit and Vegetables (과실 및 채소류의 저장에 있어서 Lactic Acid Bacteria의 이용)

  • 김건희;배은경
    • Food Science and Preservation
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    • v.6 no.2
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    • pp.245-254
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    • 1999
  • Traditionally, lactic acid bacteria(LAB) is microorganism that has been used for food fermentation. Bacteriocinogenic culture and by-products of lactic acid bacteria have the antimicrobial effect. The antimicrobial effect of lactic acid bacteria enable to extend the shelf life of many foods through fermentation processes. Therefore, a lot of investigation of antimicrobial compounds from LAB have been studied on the effect of foods preservation of fish, meat, dairy product, refreserated nonfermentive food and so on. However a little research on the effects of LAB in fruit and vegetables preservation has been reported. In this study, effectiveness of LAB as a quality preservative in fruit and vegetables storage were reviewed.

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Interactions between marine bacteria and red tide organisms in Korean waters

  • Seong, Kyeong Ah;Jeong, Hae Jin
    • ALGAE
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    • v.28 no.4
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    • pp.297-305
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    • 2013
  • There is increasing interest in the relationships between marine bacteria and red tide organisms. Some bacteria are known to kill red tide organisms, and may be responsible for accelerating the termination of red tides. Thus, certain algicidal bacteria have been proposed for the control of red tides. Meanwhile, many red tide organisms are known to feed on marine bacteria. The roles of marine bacteria and red tide organisms are therefore reversible. In Korean waters, the killing of red tide organisms by algicidal bacteria, and also the feeding of red tide organisms on marine bacteria have been extensively investigated. The findings of such studies may influence the conventional view of red tide dynamics, and also planktonic food webs. Here, we review the species and concentrations of algicidal bacteria that kill red tide organisms in Korean waters, as well as the ingestion rate and grazing impact of red tide organisms on marine bacteria. Furthermore, we offer an insight into the ecological roles of these 2 components in marine planktonic food webs.

Evaluation of Microbiological Contamination of Water Purifiers at Two Universities in Chungcheong Region

  • Jin Young Yun
    • Biomedical Science Letters
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    • v.29 no.4
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    • pp.256-262
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    • 2023
  • The purpose of this study is to investigate microbial contamination in water purifiers from two universities (A and B) in Chungcheong region and to evaluate about the harmfulness of the isolated bacteria to the human. The degree of microbiological contamination of six water purifiers at university A was investigated three times from July 2018 to September 2019, and nine water purifiers at university B were investigated in 2023. The isolated bacteria were biochemically identified using an API kit and Vitek-2 system, and then the bacteria were identified to the species level using MALDI-TOF MS. In addition, the possibility of human infection of the isolated bacteria was evaluated through a literature search. In July 2018 and September 2019, the number of bacteria isolated inside the faucet was below the acceptable standard for hot water, but exceed for cold water in all water purifiers. In January and September 2019, bacteria exceeding the acceptable standards were isolated nine times from the cold water of six water purifies (a total of 12 water purifiers). Bacteria identified by MALDI-TOF MS included anaerobic bacteria (Clostridium novyi, Clostridium themopalmarium etc.), Gram-positive bacilli (Microbacterium testaceum, Arthrobacter woluwensis etc.), and Gramnegative bacilli (Acinetobacter nosocomialis, Comamonas kerstersii etc.), which are difficult identify by biochemical methods. In conclusion, bacteria exceeding the acceptable standard were isolated from the cold water of most of the water purifiers. Most of the isolated bacteria were low-pathogenic bacteria from natural environment, but opportunistic bacteria that can cause infection in humans were also isolated from some water purifiers.

A Test of Two Models for the Bacteria Flux across the Sediment/Water Interface in an Effluent-dominated Stream (하수처리 방류 소하천내 퇴적물로부터의 박테리아 유출 플럭스모델 비교)

  • Ahn, Jong-Ho
    • Journal of Korean Society of Water and Wastewater
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    • v.24 no.2
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    • pp.165-172
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    • 2010
  • Treated sewage could enable growth by providing key nutrients or seeding the sediments with enterococci strains that can grow in the environment. This study is to test the hypothesis that the flux of bacteria into the water column is rate-limited by the transfer of bacteria across the sediment/water interface. Two conceptual models are derived for the transfer of bacteria to the water column from the sediment/water interface: convective diffusion of isolated bacteria and resuspension of particle-associated bacteria. The model predictions are directly tested together with field measurements of bacteria and sediment in an effluent-dominated stream where high concentrations of enterococci in this stream originate primarily from growth of the bacteria in stream sediments. The results reveal that high concentrations of enterococci in this stream are transported primarily by resuspension of particle-associated bacteria accumulated at the sediment/water interface, either in the form of bacterial aggregates or in the form of inorganic particles.

A Novel Optimization Algorithm Inspired by Bacteria Behavior Patterns

  • Jung, Sung-Hoon;Kim, Tae-Geon
    • Journal of the Korean Institute of Intelligent Systems
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    • v.18 no.3
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    • pp.392-400
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    • 2008
  • This paper proposes a novel optimization algorithm inspired by bacteria behavior patterns for foraging. Most bacteria can trace attractant chemical molecules for foraging. This tracing capability of bacteria called chemotaxis might be optimized for foraging because it has been evolved for few millenniums. From this observation, we developed a new optimization algorithm based on the chemotaxis of bacteria in this paper. We first define behavior and decision rules based on the behavior patterns of bacteria and then devise an optimization algorithm with these behavior and decision rules. Generally bacteria have a quorum sensing mechanism that makes it possible to effectively forage, but we leave its implementation as a further work for simplicity. Thereby, we call our algorithm a simple bacteria cooperative optimization (BCO) algorithm. Our simple BCO is tested with four function optimization problems on various' parameters of the algorithm. It was found from experiments that the simple BCO can be a good framework for optimization.

Hygienic Superiority of Kimchi (김치의 위생학적 우수성)

  • Kim, Yong-Suk;Shin, Dong-Hwa
    • Journal of Food Hygiene and Safety
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    • v.23 no.2
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    • pp.91-97
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    • 2008
  • Kimchi is a representative traditional food in Korea and a type of vegetable product that is the unique complex lactic acid fermentation in the world. It can be considered as a unique fermented food generated by various flavors, which are not included in raw materials, that can be generated by mixing and fermenting various spices and seasonings, such as red pepper powder, garlic, ginger, and salted fish, added to Chinese cabbages. Functionalities in Kimchi have been approved through several studies and the probiotic function that is mainly based on lactic acid bacteria including their physical functions in its contents has also verified. Studies on the verification of the safety of Kimchi including its physiological functions have been conducted. In particular, the function of lactic acid bacteria, which is a caused of the fermentation of Kimchi. Although the lactic acid bacteria contributed to the fermentation of Kimchi is generated from raw and sub-materials, the lactic acid bacteria attached on Chinese cabbages has a major role in the process in which the fermentation temperature and dominant bacteria are also related to the process. The salt used in a salt pickling process inhibits the growth of the putrefactive and food poisoning bacteria included in the fermentation process of Kimchi and of other bacteria except for such lactic acid bacteria due to the lactic acid and several antimicrobial substances generated in the fermentation process, such as bacteriocin and hydrogen peroxide. In addition, the carbon dioxide gas caused by heterolactic acid bacteria contributes to the inhibition of aerobic bacteria. Furthermore, special ingredients included in sub-materials, such as garlic, ginger, and red pepper powder, contribute to the inhibition of putrefactive and food poisoning bacteria. The induction of the change in the intestinal bacteria as taking Kimchi have already verified. In conclusion, Kimchi has been approved as a safety food due to the fact that the inhibition of food poisoning bacteria occurs in the fermentation process of Kimchi and the extinction of such bacteria.

Changes of Index Microorganisms and Lactic Acid Bacteria of Korean Fermented Vegetables (Kimchi) during the Ripening and Fermentation-Part 1 (김치의 숙성 및 발효중 오염지표미생물과 유산균의 변화-제1보)

  • Kim, Jong-Gyu;Yoon, Joon-Sik
    • Journal of Environmental Health Sciences
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    • v.31 no.1
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    • pp.79-85
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    • 2005
  • This study was undertaken to investigate the changes of index microorganisms and lactic acid bacteria of traditional Korean fermented vegetables (kimchi) during the ripening and fermentation period. A type of kimchi, baechoo-kimchi, was prepared and stored at $10^{\circ}C$ for 8 days. The numbers of the total aerobic bacteria, psychrotrophilic bacteria, coliform bacteria, and Escherichia coli in the kimchi and also in raw materials of the kimchi (Chinese cabbage, green onion, ginger, garlic, and red pepper) were counted using appropriate media. The highest number of aerobic bacteria was detected from ginger, then red pepper, then garlic, then Chinese cabbage, and lowest number from green onion. The highest number of psychrotrophilic bacteria was detected from red pepper, then Chinese cabbage, then garlic, then ginger, and the lowest number from green onion. Coliforms and E. coli were not detected from all of the raw materials of kimchi. Total aerobic bacteria and lactic acid bacteria of the kimchi showed gradually increasing during ripening and fermentation. The number of psychrotrophilic bacteria showed a similar level in the kimchi. Coliform bacteria were detected at the 3rd, 4th, and 5th day of the kimchi fermentation period, although they were not detected from the raw materials of the kimchi. However, the bacteria were not detected in the kimchi after 6 days. E. coli was not detected in all kimchi samples. The pH value of the kimchi gradually decreased, and acidity increased over fermentation period. This study indicates that there was contamination of coliform bacteria during the process of kimchi preparation, and lactic acid bacteria proliferated in the kimchi during fermentation inhibited the growth of coliforms. More research is needed to evaluate the inhibitory effects of each raw materials of kimchi.

Possibility of cementation of soft soil using Bacteria (Bacteria를 이용한 연약한 흙의 고결화 가능성)

  • Kim, Dae-Hyeon;Kim, Ho-Chul;Park, Kyoung-Ho
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09a
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    • pp.379-391
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    • 2010
  • In order to understand the mechanism of cementation of soft soils treated with bacteria, three types of specimens(untreated, normal bacteria concentration treated, and high bacteria concentration treated) were made. Scanning Electron Microscope(SEM), EDX and X-ray diffraction(XRD) analyses were performed on the soft silt and loose sand specimens. Compared with the untreated specimen, a clearer cementation between particles was observed in the high bacteria concentration treated specimen. Based on the scanning electron microscope(SEM) EDX analyses, more calcium carbonate was observed in the specimen treated with high bacteria concentration than other specimens. On the basis of the preliminary results, it appears that microbial cementation can occur in the soft soil. Further study on the cementation of soils using bacteria is necessary to validate this result.

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Isolation and Characterization of Biofouling Bacteria in Ultra-high Purity Water Used in the Semiconductor Manufacturing Process

  • Kim, In-Seop;Lee, Kye-Joon
    • Journal of Microbiology and Biotechnology
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    • v.10 no.4
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    • pp.554-558
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    • 2000
  • Bacteria were isolated and identified from an advanced high-purity water system that supplies ultra-high purity water (UHPW) for 16-megabyte DRAM semiconductor manufacturing. Scanning electron microscopic and microbiological observations revealed that the primary source of the bacteria isolated from the UHPW was detached cells from biofilms developed on the pipe wall through which the UHPW, a man-made and extremely nutrient poor environment, was passing. About 63-65% of the bacteria isolated from the UHPW and the pipe wall were Gram-positive, whereas only 10% of the bacteria isolated from the feed water were Gram-positive. The of Gram-positive bacteria and seven genera of Gram-negative bacteria. Strains of the UHPW bacteria effectively adhered to and formed a biofilm on the surface of polyvinyl chloride (PVC) pipe.

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The Antibacterial Activity of Garlic Juice Against Pathogenic Bacteria and Lactic Acid Bacteria. (병원성 세균과 젖산균에 대한 마늘의 항균작용)

  • 정건섭;강승연;김지연
    • Microbiology and Biotechnology Letters
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    • v.31 no.1
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    • pp.32-35
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    • 2003
  • This study was carried out to determine the inhibitory effect of garlic juice against Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella typhimurium, Shigella flexneri. Staphylococcus aureus, Streptococcus mutans, Virio. parahaemolyticus which are food pathogenic bacteria and Lactobacillus acidophilus, Lactobacillus brevis, Lactobacillus casei, Lactobacillus plantarum, Lactococcus. lactis, Leuconostoc mesenteroides which are lactic acid bacteria. An aqueous extract of garlic was bacteriocidal against Gram-positive and Gram-negative bacteria in all concentrations (0.1∼2.5(w/v)%) tested in this experiment. Especially 0.5(w/v)% garlic juice inactivated completely E. coli, S. typhimurium, S. flexineri, V. parahaemolyticus and 1.0(w/v)% garlic juice perfectly reduced P. aeruginosa, S. mutans. Generally, the experiment result indicate that garlic juice restrains the growth of the pathogenic bacteria better than the lactic acid bacteria. Therefore, garlic has potential for the preservation of processed foods.