• Title, Summary, Keyword: food spoilage microorganisms

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Antimicrobial Effect of Indigofera kirilowii Extracts on Food-borne Pathogens (산두근 추출물의 식중독성 미생물에 대한 항균효과)

  • 배지현
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.33 no.7
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    • pp.1106-1111
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    • 2004
  • This study was performed to investigate the antimicrobial effect of the Indigofera kirilowii extracts against food-borne pathogens. The Indigofera kirilowii was extracted with methanol at room temperature, and fractionation of the methanol extract from Indigofera kirilowii was carried out by using petroleum ether, chloroform, ethyl acetate, and methanol, respectively. The antimicrobial activity of the Indigofera kirilowii extracts was determined using a paper disc method against food-borne pathogens and food spoilage bacteria. The ethyl acetate extract of Indigo/era kirilowii showed the highest antimicrobial activity against Staphylococcus aureus and Shigella dysenteriae. The water extract of Indigofera kirilowii showed relatively low antimicrobial activity against microorganisms used in this experiment. The synergistic effect has been found in combined extracts of Indigofera kirilowii and Pulsatilla koreana as compared to each extract alone. The growth inhibition curve was determined using ethyl acetate extracts of Indigofera kirilowii against S. aureus and S. dysenteriae. The ethyl acetate extract of Indigofera kirilowii showed strong antimicrobial activity against S. aureus at the concentration of 4,000 ppm. The 4,000 ppm of ethyl acetate extract from Indigofera kirilowii retarded the growth of S. aureus more than 24 hours and S. dysenteriae up to 48 hours. This study showed the possibility of using ethyl acetate extract of Indigofera kirilowii as a material of food preservative.

Quorum-Sensing Mechanisms in Bacterial Communities and Their Potential Applications (세균의 의사 소통(Quorum-Sensing) 기구와 그 잠재적 응용성)

  • Yoon, Sung-Sik
    • Food Science of Animal Resources
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    • v.26 no.3
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    • pp.402-409
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    • 2006
  • Although microorganisms are, in fact, the most diverse and abundant type of organism on Earth, the ecological functions of microbial populations remains poorly understood. A variety of bacteria including marine Vibrios encounter numerous ecological challenges, such as UV light, predation, competition, and seasonal variations in seawater including pH, salinity, nutrient levels, temperature and so forth. In order to survive and proliferate under variable conditions, they have to develop elaborate means of communication to meet the challenges to which they are exposed. In bacteria, a range of biological functions have recently been found to be regulated by a population density-dependent cell-cell signaling mechanism known as quorum-sensing (QS). In other words, bacterial cells sense population density by monitoring the presence of self-produced extracellular autoinducers (AI). N-acylhomoserine lactone (AHL)-dependent quorum-sensing was first discovered in two luminescent marine bacteria, Vibrio fischeri and Vibrio harveyi. The LuxI/R system of V. fischeriis the paradigm of Gram-negative quorum-sensing systems. At high population density, the accumulated signalstrigger the expression of target genes and thereby initiate a new set of biological activities. Several QS systems have been identified so far. Among them, an AHL-dependent QS system has been found to control biofilm formation in several bacterial species, including Pseudomonas aeruginosa, Aeromonas hydrophila, Burkholderia cepacia, and Serratia liquefaciens. Bacterial biofilm is a structured community of bacterial cells enclosed in a self-produced polymeric matrix that adheres to an inert or living surface. Extracellular signal molecules have been implicated in biofilm formation. Agrobacterium tumefaciens strain NT1(traR, tra::lacZ749) and Chromobacterium violaceum strain CV026 are used as biosensors to detect AHL signals. Quorum sensing in lactic acid bacteria involves peptides that are directly sensed by membrane-located histidine kinases, after which the signal is transmitted to an intracellular regulator. In the nisin autoregulation process in Lactococcus lactis, the NisK protein acts as the sensor for nisin, and NisR protein as the response regulator activatingthe transcription of target genes. For control over growth and survival in bacterial communities, various strategies need to be developed by which receptors of the signal molecules are interfered with or the synthesis and release of the molecules is controlled. However, much is still unknown about the metabolic processes involved in such signal transduction and whether or not various foods and food ingredients may affect communication between spoilage or pathogenic bacteria. In five to ten years, we will be able to discover new signal molecules, some of which may have applications in food preservation to inhibit the growth of pathogens on foods.

The Distribution of Microflora in the Viscera of Sardine, Sardinops melanosticta by the storage Temperature (저장온도에 따른 정어리 내장 미생물상의 변화에 대하여)

  • CHO Hak-Rae;CHANG Dong-Suck;LEE Myung-Suk;HUR Sung-Ho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.23 no.1
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    • pp.7-11
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    • 1990
  • As the putrefaction of fish is greatly relied on the microorganisms inhabited in the viscera of them, we investigated the microfloral changes in the viscera of sardine, Sardinops melanosticta, which has been caught a lot in adjacent sea of Korea but showed rapid spoilage, after storages with various temperature. The following results were obtained. Viable cell counts at $25^{\circ}C$ of the viscera of sardine were $1.6\times10^5/g$ at the fresh sample, $1.5\times10^5/g$ at the frozen sample, $2.9\times10^8/g$ at the spoiled samples. The most predominant microbial genera from the fresh sardine were Moraxella spp.($31.4\%$) and Pseudomonas spp.($28.6\%$), but Enterobacteriaceae($83.1\%$) was in spoiled sample. While Moraxella spp.($46.2\%$) and Flavobacterium-Cytophaga($21.0\%$) were predominant in the frozen sample and Enterobacteriacear($69.6\%$) was in the thawed-spoiled sample. The rates of proteolytic enzyme producing bacteria were $20\%$ in the fresh sample, $22\%$ in the frozen sample but the rates were increased to $52\%,\;29\%$ in the spoiled sample and the thawed-spoiled sample respectively.

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Characterization of Bacteriocin-Like Substances Produced by Bacillus subtilis MJP1 (Bacillus subtilis MJP1이 생산하는 Bacteriocin-Like Substances)

  • Yang, Eun-Ju;Chang, Hae-Choon
    • Microbiology and Biotechnology Letters
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    • v.35 no.4
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    • pp.339-346
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    • 2007
  • The MJP1 bacterial strain, which possesses antifungal activity, was isolated from meju and identified as Bacillus subtilis based on its morphological and biochemical properties, as well as its 16S rRNA sequence. Antimicrobial activity was found against various species of Gram-positive bacteria, yeasts, and molds, including food-spoilage microorganisms. The antifungal activity was found to be stable after heat and proteolytic enzyme treatment, and in the pH range of $6.0{\sim}10.0$. The antibacterial activity was stable in the pH range of $6.0{\sim}10.0$, but about 50% of the activity was lost after 24 hr at $30^{\circ}C$. The antibacterial compound was also inactivated by proteolytic enzyme treatment, indicating its proteinaceous nature. The apparent molecular masses of the partially purified antifungal and antibacterial compounds, as indicated by using the direct detection method in Tricine-SDS-PAGE, were approximately 2.4 kDa and 4.5 kDa, respectively. These studies suggest that B. subtilis MJP1 produces two bacteriocin-like substances with antifungal and antibacterial activities.

Inhibition of Foodborne Pathogens and Spoilage Bacteria and Their Structural Changes by Ethanol Extract of Schizandra chinensis Baillon (오미자 에탄올 추출물에 의한 식품위해성 세균의 증식 억제 및 세포구조 변화)

  • Kim, Se-Ryoung;Kim, Mee-Ra
    • Journal of the East Asian Society of Dietary Life
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    • v.22 no.1
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    • pp.109-119
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    • 2012
  • This study analyzed the antibacterial activity of the ethanol extract of Schizandra chinensis Baillon against food pathogenic microorganisms to determine its capabilities as a natural antimicrobial agent. A paper disc diffusion test, minimum inhibitory concentration (MIC) determination, and time-kill assay showed that the ethanol extract strongly inhibits the growth of Listeria monocytogenes, Bacillus cereus, Escherichia coli O157:H7, and Pseudomonas aeruginosa. Release of cytoplasmic ${\beta}$-galactosidase was detected in E. coli, E. coli O157:H7, S. aureus, and P. aeruginosa treated with the ethanol extract. An increase of outer membrane permeability caused by the ethanol extract was also observed. An outward flow of cell constituents was detected in the Gram negative strains treated with the ethanol extract. These results imply that the inner and outer membranes of cells were partially destroyed and cell constituents were released by the treatment of the S. chinensis Baillon ethanol extract. The results of this study indicate that ethanol extract of S. chinensis Baillon evidences a fairly good antibacterial effect.

Effect of High Pressure Processing on Freshness of Meat Products (육류가공품의 고압처리가 신선도에 미치는 영향 평가)

  • Hwang, Seong-Hee
    • Journal of Food Hygiene and Safety
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    • v.33 no.4
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    • pp.272-279
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    • 2018
  • The high pressure processing (HPP) is a technology which can preserve the quality of foods, such as the fresh taste, incense, texture, vitamin content, and so on, by minimizing the heating process. It does so by applying an instantaneous and uniform pressure that is the same as the water pressure that is 60 km deep in the sea. HPP is a technology that can inhibit food poisoning and spoilage caused by microorganisms and is currently an actively studied area. In this study, we investigated the effects of a high pressure treatment (0, 4, 6 min) on sliced ham, which is a typical meat product, at 600 MP a were tested for their effect on freshness. Moisture contents varied from 48 to 69%, salinity varied from 1.07 to 1.11%, and the pH decreased from 6.4~6.5 to 6.1~5.15. However, there was no difference between the control and treatment groups. General bacteria stored at $20^{\circ}C$ after hyper-pressure treatment were found to have no significant microorganisms in all groups until 4 weeks. but exceeded $10^5$ in control group and HPP 6 min treatment group from 5 weeks, At week 7, it was found to exceed $10^6$. The results indicate it was not possible to ingest food in the 4-and 6 minute treatment groups. Coliform was not observed in all groups despite observing for a total of 7 weeks at $20^{\circ}C$ weight test. VBN, a method used to determine the protein freshness of meat, showed a VBN value of less than 1 mg% until the fourth week and a value of 1 to 2 mg% after 5 weeks. The TBA was used as an index of the degree of fat acidosis in the meat tissues. The results showed it was below 0.18 mgMA / kg until the end of 7 weeks; this value was within the range for fresh meat, and there was no difference in treatment group. In this experiment, deformation of the packaging material did not occur and no swelling occurred due to the generation of gas. It is believed that the basic preservation effect was achieved only by blocking with the air due to the close contact of the packaging material.

Antimicrobial Effects of a Bacteriocin Mixture from Lactic Acid Bacteria against Foodborne Pathogens (복합 박테리오신의 항균활성 및 축산식품 저장성 증진 효과)

  • 한경식;오세종;문용일
    • Food Science of Animal Resources
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    • v.22 no.2
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    • pp.164-171
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    • 2002
  • The purpose of this study was to evaluate inhibitory activity of a bacteriocin mixture from lactic acid bacteria(LAB) against foodborne pathogens. Each bacteriocin solutions were prepared by growing nine strains of bacteriocin producers in MRS broth for 18~24 h followed by centrifugation(8000$\times$g, 20 min, 4$^{\circ}C$). Bacteriocins were purified from ammonium sulfate precipitation and were resuspended in 50 mM phosphate buffer(pH 7.0). Nine bacteriocins were mixed together and then allowed to freeze at -2$0^{\circ}C$. The mixture of nine bacteriocins showed enhanced inhibitory activity compared to each of bacteriocins and inhibited the Gram negative pathogens including Escherichia coli 0157:H7, Klebsiella pneumoniae, Pseudomonas chlororaphis and Shigella sonnei. The mixture of bacteriocin solutions was significantly lower than controls when a freeze-dried bacteriocin mixture was added to frank sausage, Mozzarella cheese and pork loin. With addition of bacteriocin mixture, total mesophilic bacteria in pork loin were constant over storage period, whereas total mesophilic bacteria in Mozzarella cheese and frank sausang slightly increased. Total viable cells of control group increased during storage without bacteriocin treatment. Volatile base nitrogen content of pork loin during storage also increased significantly without bacteriocin treatment. The bacteriocin mixture was capable of inhibiting pathogenic and spoilage microorganisms and extending the shelf-life of cheese and meat products during storage.

Antifungal and Antioxidant Activities of Extracts from Leaves and Flowers of Camellia japonica L. (동백나무 잎과 꽃 추출물의 항미생물 활성 및 항산화 효과)

  • Lee, Sook-Young;Hwang, Eun-Ju;Kim, Gi-Hae;Choi, Young-Bok;Lim, Chae-Young;Kim, Sun-Min
    • Korean Journal of Medicinal Crop Science
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    • v.13 no.3
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    • pp.93-100
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    • 2005
  • This research was performed to investigate the possibilities of industrial usage of camellia (Camellia japonica L.) by examining the antioxidant and antimicrobial effects of methanol extract with different sections. Content of total phenolics, DPPH radical scavenging activities and antibacterial activity of young leaf, mature leaf, flower bud, flower, bark, and seed of camellia were compared in vitro experimental models. Total phenolics was contained the higher in young leaf (74.62 mg), flower bud (65.02 mg) and flower (62.42 mg) but less than 20.95 mg per 100 g of dry weight in other parts of Camellia japonica L. And effects of antioxidant measured by DPPH radical scavenger activity ($RC_{50}$, reduce concentration 50%), was shown higher $7.16{\sim}18.14\;{\mu}g/m{\ell}$ in methanol extract of young leaf, flower bud and flower than $61.23\;{\mu}g/m{\ell}$ of BHT as a chemical oxidant. Also, the antimicrobial activity of Camellia japonica L. extracts determined using a paper disc method against food-borne pathogen and food spoilage bacteria, the young leaves extracts showed the most active antimicrobial activity against 7 kinds of harmful microorganisms. Flower bud extracts showed the highest antibacterial activity against P. aeruginosa and Enterobacter spp. C1036. In addition, the minimum inhibitory concentration (MIC) of young leaf extract against B. subtillis,S. fradiae,S. aureus,E. coli,P. aeruginosa, Enterobacter spp. C1036, and S. typhimurium were revealed 1 to 15 ${\mu}g/m{\ell}$. As a result, antimicrobial activity of camellia extracts was shown higher gram positive bacteria than gram negative bacteria.

Antioxidative and Antimicrobial Activities of Euphorbia jolkini Extracts (암대극(Euphorbia jolkini Boiss) 추출물의 항산화 및 항균활성)

  • Kim, Ji-Young;Lee, Jung-A;Yoon, Weon-Jong;Oh, Dae-Ju;Jung, Yong-Hwan;Lee, Wook-Jae;Park, Soo-Yeong
    • Korean Journal of Food Science and Technology
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    • v.38 no.5
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    • pp.699-706
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    • 2006
  • The antioxidative and antimicrobial activities of Euphorbia jolkini extracts were investigated. Total polyphenohc compounds extracted were approximately as follows: 162.08 mg/g from ethanol, 12.64 mg/g from n-hexane, 48.11 mg/g from dichloromethane, 544.08 mg/g from ethyl acetate, 176.42 mg/g from butanol, and 30.00 mg/g from water. The ethylacetate fraction of this extraction showed the highest antioxidative activity $(IC_{50})$: DPPH radical scavenging capacity was measured at $8.38\;{\mu}g/mL$, xanthine oxidase inhibitory activity was $466.01\;{\mu}g/mL$, superoxide radical scavenging capacity was $11.39\;{\mu}g/mL$, and nitric oxide scavenging capacity was $332.11\;{\mu}g/mL$. Antimicrobial activities were determined by paper disc method and minimum inhibitory concentration of E. jolkini extracts against food-borne pathogens and spoilage bacteria. The growth inhibition curves of E. jolkini extracts against Bacillus cereus, Listeria monocytogenes, and Escherichia coli were also determined. These results suggest that the ethylacetate fraction of E. jolkini has strong antimicrobial activity against the all species of microorganisms as well as strong antioxidant activity.