• Journal of Microbiology and Biotechnology
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• 제26권5호
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• pp.953-958
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• 2016

Chitosan-based film-forming gel is regarded as a promising vehicle for topical delivery of antimicrobial agents to skin wounds, since it protects from microbial infection and the cationic polymer itself possesses antibacterial activity. In this study, possible synergistic interaction against common skin pathogens between the cationic polymer and tyrothricin (TRC), a cyclic polypeptide antibiotic, was investigated, by determining the concentration to inhibit 90% of bacterial isolates (MIC). The addition of the polysaccharide to TRC dramatically reduced the MIC values of TRC by 1/33 and 1/4 against both methicillin-resistant and methicillin-susceptible Staphylococcus aureus, respectively. The synergism of TRC and chitosan combination against both strains was demonstrated by the checkerboard method, with a fractional inhibitory concentration index below 0.5. Moreover, co-treatment of TRC and chitosan exhibited antibacterial activity against Pseudomonas aeruginosa, due to the antibacterial activity of chitosan, whereas TRC itself did not inhibit the gram-negative bacterial growth. These findings suggested that the use of chitosan-based film for topical delivery of TRC could be an alternative to improve TRC antimicrobial activity against strains that are abundant in skin wounds.

• 한국식품조리과학회지
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• 제18권3호
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• pp.309-318
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• 2002

The purposes of this study were to estimate the microbial and physicochemical quality of vegetable dishes without heat treatment such as sengchae, a traditional Korean vegetable dish, and to suggest a safer method of preparation. Platycodon sengchae and vegetable salad were monitored from the ingredient to final product before serving while storing at different temperature (4, 10$^{\circ}C$) and period (1, 2, 4, 7 days) at foodservice establishments. The results showed that the storage temperature pH, Aw, moisture content, and microbial loads are the important factors affecting the quality of vegetable dishes without heat treatment, and a thorough hygienic management from the purchase to the preparation of the dishes is needed to secure the quality of prepared foods in the foodservice establishments.

• Natural Product Sciences
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• 제22권3호
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• pp.216-219
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• 2016

The microbial transformation of anthranilic acid (1) by the marine-mudflat-derived fungus Thielavia sp. produced an antibacterial polycyclic quinazoline alkaloid, thielaviazoline (2). The stereostructure of the metabolite was assigned based on detailed spectroscopic data analyses including comparison of the NMR ($^1H$ and $^{13}C$) data with those of reported compound (2). Compound 2 displayed in vitro antimicrobial activity against methicillin-resistant and multidrug-resistant Staphylococcus aureus (MRSA and MDRSA), with minimum inhibitory concentrations (MICs) of 6.25 and $12.5{\mu}g/mL$, respectively. Compound 2 also showed potent radical-scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) with an $IC_{50}$ of $11{\mu}M$, which was more active than the positive control, L-ascorbic acid ($IC_{50}$, $20.0{\mu}M$).

• Asian-Australasian Journal of Animal Sciences
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• 제32권11호
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• pp.1763-1775
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• 2019

Objective: The influence of konjac gel level on fermentation process and product qualities were assessed to evaluate the feasibility of using it as fat analog in Northeastern Thai fermented sausage (Sai Krok E-san). Methods: Five treatments of fermented sausages were formulated by replacing pork backfat with 0%, 7.5%, 22.5%, and 30% konjac gel. The changes in lactic acid bacteria (LAB) and important physicochemical properties of samples were assessed during 3 days of fermentation. After the end of fermentation at day 3, water activity ($a_w$), instrumental texture, color, microbial counts, and sensory evaluation were compared. The best product formulation using konjac for replacing pork back fat were selected and used to compare proximate composition and energy value with control sample (30% pork backfat). Results: An increase in konjac gel resulted in higher values of LAB, total acidity, and proteolysis index with lower pH and lipid oxidation during 3 days of product fermentation (p<0.05). It was noted that larger weight loss and product shrinkage during fermentation was observed with higher levels of konjac gel (p<0.05). The resulting sausage at day 3 with 15% to 30% konjac gel exhibited higher hardness, cohesiveness, gumminess, springiness, and chewiness than control (p<0.05). The external color of samples with 22.5% to 30% konjac gel were redder than others (p<0.05). Mold, Salmonella spp., Staphylococcus aureus, and Escherichia coli in all finished products were lower than detectable levels. Product with 15% konjac gel had the highest scores of sourness linking and overall acceptability (p<0.05). Conclusion: The product with 15% of konjac gel was the optimum formulation for replacing pork backfat. It had higher sensorial scores of sourness and overall acceptability than control with less negative impact on external appearance (product shrinkage) and weight loss. Moreover, it provided 46% fat reduction and 32% energy reduction than control.

• Journal of Microbiology and Biotechnology
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• 제15권5호
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• pp.919-923
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• 2005

A bacterium capable of poly(${\gamma}$-glutamic acid) production was isolated from nonpasteurized soy sauce. It was judged to be a variety of Bacillus subtilis and designated as B. subtilis C1. B. subtilis C1 produced ${\gamma}$-PGA in the absence of exogenous glutamic acid; therefore, it is a de novo PGA­producing bacterium. The product produced by B. subtilis C1 was characterized by amino acid analysis to be composed of solely glutamic acid. However, the $H^1-NMR$ spectra showed chemical shifts of glycerol protons in addition to those of authentic ${\gamma}$-PGA, indicating that the product is in fact a bioconjugate of ${\gamma}$-PGA. The finding is unique, because the microbial production of ${\gamma}$-PGA bioconjugate has never been reported before. The molecular mass of the product was over 10,000 kDa as determined by GPC, and $97\%$ of the product was D-glutamate, indicating that L-glutamate was converted to its D-form counterpart by B. subtilis C1.

• 한국균학회지
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• 제31권1호
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• pp.44-49
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• 2003

Pythium ultimum에 의하여 발생하는 오이 모잘록병의 생물학적 방제의 효율을 연구하기 위하여 여러 미생물 제제인 Trichoderma harzianum, Streptomyces sp., Bacillus sp.,(그린바이오텍, 경기도 파주)에 톱밥, 쌀겨 등이 첨가되었다. 감자한천배지에 첨가한 톱밥 자체만으로도 P. ultimum 균사의 생육이 저해되었다. Green-all T(Trichoderma harzianum), Green-all S(Streptomyces), Green-all G(Bacillus)제제들은 오이 모잘록병의 발생을 현저히 감소시켰다. 그러나, 종자를 파종하고 병원균을 접종한 실험에 있어서 톱밥, 쌀겨 등을 Green-all T, Green-all S 제제에 첨가한 것은 입모율에 있어서 미생물 제제 단독처리에 비하여 생물학적 방제의 효과가 현저히 증가하지는 못하였다. 대조적으로, Green-all G 제제는 아미노닥터를 첨가하여 주면, 단독 처리시의 42% 이병율에서 2% 이병율로 크게 감소하여, 오이모잘록병에 대한 오이묘에 대한 생물학적 방제효과 실험에서 Green-all T 제제에 톱밥을 첨가하면, 발병도(disease index)가 56으로 5로 감소하여, P. ultimum의 생물학적 방제 효과가 톱밥이 첨가되지 않는 것에 비하여 더욱 증가되었다. 이는 유기물 첨가에 의하여 생물하걱 방제 효과가 증진될 수 있음을 가르쳐 주는 것이라 하겠다.

• 한국포장학회지
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• 제18권1_2호
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• pp.33-38
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• 2012

흑미를 첨가하여 제조한 기능성 찐빵에 변형기체포장으로 적용하여 저장성에 미치는 영향을 살펴보았다. 흑미 첨가 찐빵은 미생물적으로 매우 민감하여서 쉽게 부패될 수 있는 특성을 가지고 있으며, 이를 억제할 수 있는 변형기체 포장이 저장성 향상과 유통기한 연장에 기여할 수 있는 것으로 확인되었다. 미생물적 품질과 관능적 품질에 근거하여 각 포장조건 별 저장수명은 함기 포장에서는 5일 미만, 질소 포장에서는 5일, 이산화탄소 60%/질소 40% 포장에서는 8일, 이산화탄소 100% 포장에서는 15일로 설정할 수 있었다. 하지만 이산화탄소 포함 변형기체 조건에서도 노화에 의한 texture 변화는 계속 진행되므로, 이러한 저장수명 연장에의 변형기체 포장의 적용은 찐빵의 재가열 등의 상황에서 이루어져야 할 것으로 판단된다.

• Ocean and Polar Research
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• 제35권1호
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• pp.39-50
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• 2013

Biomass and community composition of microphytobentos in tidal flats were studied by HPLC analysis and also investigated to examine the relationship between microphytobenthic pigments and Adenosine-5' triphosphate (ATP) as an index of total microbial biomass in intertidal environments (muddy and sandy sediment) of Gyeonggi Bay, west coast of Korea. Microphytobenthic pigments and ATP concentration in muddy sediment were the highest at the surface while the biomass of microphytobenthos in sandy sediment was the highest at the sub-surface (0.75 cm sediment depth). The detected pigments of microphytobenthos were chlorophyll a, b (euglenophytes), $c_3$, peridinin (dinoflagellates), fucoxanthin (diatom or chrysophytes), diadinoxanthin, alloxanthin (cryptophytes), diatoxanthin, zeaxanthin (cyanobacteria), ${\beta}$-carotein, and pheophytin a (the degraded product of chlorophyll a). Among the pigments which were detected, the concentration of fucoxanthin was the highest, indicating that diatoms dominated in the microphytobenthic community of the tidal flats. There was little significant correlation between OC (Organic Carbon) and ATP in both sediments. However, a positive correlation between chlorophyll a concentration and ATP concentration was found in sandy sediment, suggesting that microbial biomass could be affected by labile OC derived from microphytobenthos. These results provide information that may help us understand the relationship between microphytobenthos and microbial biomass in different intertidal sediment environments.

• 한국식품위생안전성학회지
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• 제31권3호
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• pp.201-209
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• 2016

실내 공기질 관리의 중요성이 대두되면서 쾌적한 실내 환경에 도움을 주는 공기청정 기능과 습도 조절 기능을 동시에 갖춘 제습기와 공기청정기가 각광받고 있다. 하지만 오랜 기간 동안 공기정화제품을 사용하게 될 시에는 필터가 오염되어 본연의 기능을 상실하게 되는 것으로 알려져 있지만 이에 대한 구체적인 연구나 보고는 드문 편이다. 이에 본 연구에서는 가정과 사무실 등에서 사용한 공기정화제품을 수거하여 주요 부위별 미생물 오염도 및 주요 오염 미생물들을 분석하였다. 그 결과, 4 종류의 공기정화제품에서 오염도가 높은 부위는 필터부위, 물이 직접 닿는 부위 및 공기가 외부로부터 직접적으로 들어오는 입구부위 등에서 미생물학적 오염도가 가장 높았다. 하지만 공기정화제품은 사용하는 환경과 조건에 따라서 미생물학적 오염도 및 오염 미생물의 성상은 각각 다르게 나타났다. 하지만 이들 공기정화제품들에는 공통적으로 Staphylococcus sp., Micrococcus sp. 그리고 Bacillus sp.의 세균과 Cladosporium sp. 및 Penicillium sp.의 진균이 공통적으로 오염되어 있는 우점종인 것으로 분석되었다.

• Preventive Nutrition and Food Science
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• 제10권2호
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• pp.122-129
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• 2005

Chlorine dioxide $(ClO_2)$ treatment was evaluated for microbial growth inhibition and its effects on the quality of vacuum-packaged chicken breasts. Chicken breast samples were treated with 3, 50, and 100 ppm of $ClO_2$ solution, respectively. After $ClO_2$ treatment, chicken breast samples were individually vacuum-packaged and stored at $4^{\circ}C$, a typical storage temperature for meat and meat product, for 7 days. The vacuum-packaged chicken breasts treated with $ClO_2$ had significantly lower total bacteria, yeast and mold, total coliform, and Salmonella spp. were significantly reduced by $ClO_2$ treatment. $D_{10}-values$ of total bacteria count, yeast and mold, total coliform, and Salmonella spp. in vacuum-packaged chicken breasts was 93, 83, 85, and 50 ppm, respectively. The pH of vacuum-packaged chicken breasts decreased with increasing $ClO_2$ concentration. Thiobarbituric acid reacted substance (TBARS) values of vacuum-packaged chicken breasts increased during storage, regardless of $ClO_2$ concentration. $ClO_2$ treatment caused negligible changes in Hunter L, a, and b values in the vacuum-packaged chicken breasts. Sensory evaluation of the vacuum-packaged chicken breasts showed that there were no significant changes among the samples treated with various $ClO_2$ concentration. These results indicate that $ClO_2$ treatment could be useful in improving the microbial safety and quality of meat products.