The objective of this study was to evaluate the changes in the physicochemical and microbiological characteristics of pork loin meat through microwave treatment. The microwave treatment was divided into two groups: continuing microwave treatment (CW) and holding microwave treatment (HW). The microwave treatment resulted in a whiter color (L value) and affected the a, b value. The initial pH was 5.51~5.74, but it increased to 6.32~6.51 when the pork loin samples were stored for three days. During storage for 14 days, the pH changes were not significantly different (p>0.05). The thiobarbituric-acid values of all the pork loin samples increased along with the storage period, and decreased with increasing microwave dose. The volatile basic nitrogen (VBN) content of the control was higher than those of the other samples, and the VBN content decreased along with the microwave dose. The total plate counts of the pork loin samples decreased with increasing microwave dose. The study results indicated that T2 (100 W, HW) is most effective for the safety of pork loin meat without decreasing the meat’s physicochemical and microbiological characteristics.

The effect of phytoncide solution treatment on the browning and quality of fresh-cut iceberg lettuce during storage was studied. The treatments were applied as four solutions adjusted at 10℃: distilled water (DW) as the control; edible ethanol (EE); 1% (v/v) phytoncide essential oil from pine needle diluted with distilled water (DP); and 1% (v/v) phytoncide essential oil diluted with edible ethanol (EP). Fresh-cut lettuce was dipped in each solution for 60 sec, was rinsed with distilled water, was packaged with an OPP film bag, and was then stored at 4℃ for 12 days. The EP group had a significantly high level of total soluble solids, titratable acidity, and carbon dioxide, and low total bacteria counts, pH, and oxygen. The sensory score of color in the EP group recorded a high value, but the EE and EP groups recorded low scores in aroma and taste during the storage period. Alcohol and phytoncide were vaporized by opening the package for two hours, and the score of the aroma and taste of EP showed no differences from those of the other groups. Based on the above results, it was determined that the phytoncide essential oil diluted in edible alcohol with 1% solution inhibited the browning of and microbial growth in fresh-cut lettuce, and will be a useful natural compound in maintaining the quality of fresh-cut produce.

Fibers of microbial polyesters, poly(3-hydroxy butyrate) (PHB) and poly(3-hydroxy butyrate-co-3-hydroxy valerate) (HB-co-HV) were prepared by electrospinning method. The obtained fibers were evaluated by differential scanning calorimetry, scanning electron microscopy, and oil absorption. The formation of fibers was strongly dependent on a concentration of solution. At a low concentration, the fibers contained beads which is from aggregation of polymer due to short evaporation time. The fine fibers with 2-5 mm diameter were obtained at 20 wt% concentration. The contact angle measurement showed that the fiber had higher water contact angle than the film due to the lotus-like effect. Oil absorbency showed that the fiber had higher than the film. Specially, the HB-co-HV fiber which was spinned from 20 wt% absorbed 65% oil which is much higher than that of a normal polypropylene-based oil paper.

Red-ripe ‘Betatiny’ jujube-shaped cherry tomato fruits via stem maintenance or stem removal were stored at 20℃ for 12 days. Their quality and microbial safety parameters like their respiration rate, weight loss, soluble solids content (SSC), titratable acidity (TA), firmness, hue value, aerobic microflora, coliform, yeast and mold count, and decay were evaluated during their storage. The jujube-shaped cherry tomato fruits whose stems were removed lost less weight than the fruits whose stems were maintained during their 12 days of storage. The stem removal lowered the respiration more significantly than the stem maintenance, and the formation of novel tissues at the stem scar that resulted from the stem removal was observed morphologically. The SSC, TA and hue value of the skin color decreased after eight storage days, but showed no difference between the stem maintenance and removal. The stem had higher microbial counts like aerobic microflora, coliform, and yeast and mold counts. The stem maintenance showed a short shelf-life because molds grew on the attached stem after five storage days. The shelf-life of the jujube-shaped cherry tomato fruits whose stems were removed was about eight days, but that of the fruits whose stems were maintained and that were stored at 20℃ was only about six days.

The effects of NaCl concentration on bio-hydrogen production and microbial community by dark-fermentation were evaluated. The examined NaCl concentration was varied from 0 to 5%. When NaCl concentration ranged from 0 to 3%, the hydrogen production was insignificantly affected. 4% or more NaCl concentration decreased accumulated hydrogen production and the lag time was longer. In addition, the metabolite pathway of the bacteria were shifted from butyrate to acetate by microbial community changes with high concentration of NaCl. FISH analysis was achieved to analyze the microbial community after the dark-fermentation performance. Hydrogen producing bacteria, Clostridium sp. Cluster I and Cluster XI, was dominated with 0 ~ 3% of NaCl, while Eubacteria, general bacteria, was dominated with 4 ~ 5% of NaCl. Therefore, the growth and hydrogen production of the hydrogen producing bacteria were inhibited with over 4% of NaCl.

In this study, we isolated microorganisms from dried persimmon in Sangju and obtained 15 strains of microorganisms as the basic research to prevent the quality changes during drying and storage of dried persimmon. Contaminated microorganisms were separated using seven species of medium. Viable cell counts of dried persimmon from Sangju was 5.18×102∼1.68×107 CFU/g. Green mold K2-1 accounted for the highest percentage in the contaminated dried persimmons and identified as a major causative microorganism. Light violet and creamy yeasts were the second largest contaminated microorganisms. Green mold K2-1 strain was identified as Penicillium sp. and fungus K-1 and K-3 were identified as Caldosporium sp. and Aspergillus sp.

This study was attempted to evaluate the change of microbial community in inoculums, lag, and stationary phase using the community level physiological profiles (CLPP) base on C-substrate utilization. It was to ascertain the characterizing microbial community over time in the enrichment step of microbial fuel cells. Microbial fuel cell is a device that converts chemical energy to electricity with aid of the catalytic reaction of microorganisms using C-substrate included wastewater. Microbial fuel cells enriched by a mixture of anaerobic digestive sludge of the sewage treatment plant and livestock wastewater were used. The current after enrichment was generated about 0.84 ± 0.06 mA. Microbial community in inoculums, lag and stationary phase used amine group, phosphorylated chemical group, and carboxylic acid group (some exclusion). However, phenolic compound did not use by microorganisms in lag and stationary phase. It means that there are not the microorganisms capable of decompose the phenol in microbial fuel cell enriched by livestock wastewater. In case of substrates of amino acid and carbohydrates group, these C-substrates were only used by microorganisms in the stationary phase. It may be that electrochemically active microorganisms (EAM) which we want to know should utilize the better these C-substrates than that of lag phase. This study showed that the electrochemically active bacteria that can be distinguished by electron changes of C-substrate utilization over time could be separated.

본 연구에서는 크루즈선에서 발생하는 오 폐수의 고도처리를 위하여 SBR공정에 유효미생물을 주입하는 변법을 이용하여 실험실 규모의 실험을 수행하였다. 질소 인의 고도 처리 효율과 크루즈선이라는 특수 환경과의 접목성을 검토한 결과 SBR공정에 유효미생물을 주입하는 변법은 선박환경에 매우 적합한 것으로 평가되었다. 또한 기존의 활성슬러지에 유효미생물의 주입함으로써 슬러지 팽화 등의 문제를 해결할 수 있어 슬러지의 안정성을 확보할 수 있었으며, 미생물 관찰 결과 고도처리에 유리한 미생물종의 출현으로 질소 인의 처리 효율이 높아지는 것을 확인할 수 있었다. 이로 인해 총질소와 인의 제거 효율은 74%, 75%로 나타났으며 이러한 결과로 미루어 강화되어가는 해양오염기준을 충만족시킬 수 있을 공정으로 판단된다.

The aim of this study was to investigate the growth of aerobic bacteria in fresh-cut salad during short-term temperature abuse (4∼30℃temperature for 1, 2, and 3 h) for 72 h and to develop predictive models for the growth of total viable cells (TVC) based on Predictive food microbiology (PFM). The tool that was used, Pathogen Modeling program (PMP 7.0), predicts the growth of Aeromonas hydrophila (broth Culture, aerobic) at pH 5.6, NaCl 2.5%, and sodium nitrite 150 ppm for 72 h. Linear models through linear regression analysis; DMFit program were created based on the results obtained at 5, 10, 20, and 30℃ for 72 h (r2 >0.9). Secondary models for the growth rate and lag time, as a function of storage temperature, were developed using the polynomial model. The initial contamination level of fresh-cut salad was 5.6 log CFU/mL of TVC during 72 h storage, and the growth rate of TVC was shown to be 0.020∼1.083 CFU/mL/h (r2 >0.9). Also, the growth tendency of TVC was similar to that of PMP (grow rate: 0.017∼0.235 CFU/mL/h; r2=0.994∼1.000). The predicted shelf life with PMP was 24.1∼626.5 h, and the estimated shelf life of the fresh-cut salads with short-term temperature abuse was 15.6∼31.1 h. The predicted shelf life was more than two times the observed one. This result indicates a ‘fail safe’ model. It can be taken to a ludicrous extreme by adopting a model that always predicts that a pathogenic microorganism will grow even under conditions so strict as to be actually impossible.

This study was carried out to research microorganisms having the antifungal activity against ginseng Alternaria blight pathogen Alternaria panax and ginseng anthracnose pathogen Colletotrichum gloeosporioides. Eleven Bacillus strains. were isolated from Korean traditional soybean paste and Kimchi. Among the 11 isolates, DJ5, KC1, KC2 and KC4 showing antagonistic activity on the mycelial growth of A. panax and C. gloeosporioides in pairing culture were finally selected as the antagonistic microorganisms. Based on 16s rRNA sequence and phylogenetic tree analysis, they were identified as Bacillus spp.. The selected microorganisms were investigated antagonistic activity by measured leaf-segment colonization in pot test. When Bacillus sp. were injected after A. panax treatment, KC1, KC2 and KC4 showed similar effect to chemical pesticides treated control. To measure preventive effect of Bacillus sp, antagonistic microorganisms were injected and C. gloeosporioides was treated in pot. When measuring the effectiveness for the prevention of Anthracnose, All Bacillus spp. showed approximately 83~90 % degree of superior preventive effect. In general, The four Bacillus spp. isolated from Korean traditional fermented foods showed therapeutic effect of Alternaria blight and preventive effect of Anthracnose.

The aim of this study was to determine the effect of effective microorganisms (EM) on growth, yield and fruit nutrient contents of two cultivars (‘Muhanjilju’ and ‘Daetong’) of hot pepper. The number of injection of EM cultivated are 6 times from the pepper plant seedlings until harvested in both cultivars. Stem girth was highest in the treatment of Lactobacillus plantarum whereas lowest in no EM control. In ‘Muhanjilju’, the number of branches was highest (79.3) in the treatment of Bacillus subtilis whereas in ‘Daetong’ was highest (119.0) as treated with Lactobacillus plantarum. Yield of the red hot pepper fruits that sum of two varieties was highest in the treatment of Rhodopseudomonas capsulatas (53.1kg FW per 10a). Regardless of EM treatments, average yield was 8% higher in ‘Daetong’ than is ‘Muhanjilju’ (33.8kg vs 31.2kg per 10a). The incidence of antracnose was lowest by the Rhodopseudomonas capsulatas treatment, which led to the highest yield. As for the effect on fruit mineral nutrients, total N and phosphorus concentrations were highest in the treatment of Lactobacillus plantarum and Bacillus subtilis in both varieties, respectively. The highest content of total carotenoids was obtained from the treatment of Lactobacillus plantarum in both varieties.

토양 및 지하수 등의 혐기성환경에 서식하는 황산염환원박테리아의 활동으로 생성되는 맥키나와이트가 용존산소에 의해 산화 및 용해되는 특성을 관찰하였다. 오염지역에 산화지하수 유입에 의한 용존산소량 증가로 인해 안정화된 핵종들(예: 환원우라늄)이 산화 및 용해되는 상황에서 일반적으로 같이 공존하는 황화광물의 역할을 알아보고자 하였다. '디설퍼비브리오 디설프리칸스(Desulfovibrio desulfuricans)'라는 황산염환원박테리아가 만든 맥키나와이트를 '과산화수소수'와 '아질산나트륨'으로 산화시키면서 발생되는 광물 용해 현상을 약 2주 동안 관찰하였다. 산화제의 종류에 따라 시료의 광물학적 산화 및 용해 반응 특성은 달랐으나, μm 크기의 황화광물 입자들에 의한 용존산소의 소모와 그에 따른 황산염 농도의 증가로 인해 산화수가 초기에 안정화되었다. 이와 같은 결과로부터 알 수 있는 사실은, 황산염환원미생물에 의해 다량 만들어지는 황화광물이 지하수의 산소를 소모시켜 환원 환경의 교란을 예방할 뿐만 아니라 버퍼물질로써 환원/침전된 핵종들의 장기 안정화에 상당한 기여를 할 것으로 예상된다.

본 연구에서는 유용미생물로 알려진 광합성세균(Photosynthetic bacterium), 바실러스균(Bacillus subtilis), 유산균(Lactobacillus plantarum)을 분화용 시클라멘(Cyclamen persicum Mill. ‘Rose with Eye’)에 2주 간격으로 7회 관주 처리하여 생육 및 화색에 미치는 영향을 알아보았다. 그 결과를 요약하면 다음과 같았다. 생육에서는 유용미생물 처리구는 고온피해를 적게 받거나 빠르게 회복하였으며 꽃수 또한 유용미생물 처리구에서 높았다. 시클라멘의 화색도 무처리구에 비해 유용미생물 처리구의 화색이 더욱 선명한 것을 볼 수 있었다. 배양토 화학적 특성 분석 시 미생물 처리구가 무처리구와 다른 결과를 보이는 것으로 P2O5, K, Ca, Mg, Na, NO3-N 등이 시클라멘 흡수 시 미생물제 관주처리가 영향을 준 것으로 판단되었다. 그러나 미생물의 종류별로 다소 다른 차이를 보였으며 농도 처리구에 따라 식물체 부위별 효과가 달라 적합한 미생물 종류와 농도를 찾는 실험이 계속되어야 할 것으로 판단되었다. 또한 여러 방법으로 다양한 화훼류에도 접목할 수 있을 것으로 기대된다.

We isolated and characterized novel duck feather-degrading bacteria producing keratinase. Twelve strains were isolated from soil and faces at poultry farm, and decayed feathers. They were identified as Bacillus methylotrophicus, Pseudomonas geniculata, Pseudomonas hibiscicola, Exiquobacterium profundum, Bacillus pumilus, Bacillus amyloliquefaciens, Chryseobacterium indologenes, Bacillus thuringiensis, Thermomonas koreensis, respectively, by phenotypic characters and 16S rRNA gene analysis. Generally, the level of keratinase production was not proportional to feather degradation rate. The highest keratinolytic activity was observed in the culture inoculated with Chryseobacterium indologenes D27. Although all strains did not degrade human hair, strains tested effectively degraded chicken feather(53.8-91.4%), wool(40.4-93.0%) and human nail (51.0-82.9%). These results suggest that strains isolated could be not only used to improve the nutritional value of recalcitrant feather waste but also is a potential candidate for biotechnological processes of keratin hydrolysis.

This study was carried out to investigate the physiochemical and microbiological changes of dandelion during fermentation. Thirty and fifty percentage raw sugar groups (SFE30 and SFE50) were introduced into dandelions and fermented for 120 days at 15-20℃. This study was conducted to investigate the utilization of sucrose on lactic acid bacteria from dandelions and their effect on the pH, titratable acidity, microorganism and formation of organic acids in dandelions during fermentation. The number of lactic acid bacteria increased remarkably up to 15 days of fermentation and then decreased rapidly thereafter. The maximum number of lactic acid bacteria, 7.9 log CFU/mL was reached at pH 4.17 and the pH of dandelion showed a slight decrease during fermentation and decreased steadily up to 90 days to reach an optimum pH of 4.0. The titratable acidity of dandelions fermented increased during fermentation. The concentration of organic acid, amino acid and free sugar in SFE30 was higher than both SFE50 and DWE. The results of dandelions fermented were remarkably retarded in the 50% raw sugar group compared to the 30% raw sugar group.

With the rapid growth of fresh-cut produce market, the South Korean fresh-cut industry is facing the challenge of ensuring food safety. As the estimation of the microbial numbers in fresh-cut produce processing lines (tools, and equipment) using the conventional microbiological techniques takes days, so there is a need for faster and easier monitoring methods. This study was conducted to investigate the use of ATP bioluminescence assay to measure the degree of microbial contamination from three actual fresh-cut processing lines. The samples collected from frech-cut vegetables, and fresh-cut fruits processing plants were tested for the estimation of the bacterial number, using the ATP bioluminescence and microbiological methods. The result of former was transferred to log RLU/100 cm2, and that of the latter was transferred to log CFU/100 cm2. A positive linear correlation between the ATP bioluminescence assay value and aerobic-plate count was found for fresh-cut processing lines, with a correlation coefficient of 0.8772 (n=50). The results of this study indicate that ATP bioluminescence assay can be used to monitor microbial contamination in fresh-cut produce processing plants, and can help improve the hygiene therein.