• Korean Journal of Poultry Science
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• v.33 no.1
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• pp.33-39
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• 2006

This study was conducted to investigate the feeding effect of $bio-silverlite^{(R)}$ on growth performance, organ phenomenon and cecum microflora in broiler chicks. The $bio-silverlite^{(R)}$ was made by an ion exchange between illite and $silver(Ag^+)$. There were four treatment groups: negative control group(non-treatment), antibiotic supplement group (positive control), 0.5% $bio-silverlite^{(R)}$ supplment group and 1.5% $bio-silverlite^{(R)}$ supplement group. Total 200 birds was assigned for this five replication tests, allocating 10 birds into each treatment. Experimental diets were formulated on isocalories and isonitrogen for the whole experimental period. Body weight gain was higher in antibiotic supplementation (+C) and $bio-silverlite^{(R)}$ supplement groups(S 0.5% and 51.5%) than the negative control group(-C), and feed efficiency was significantly enhanced with increase of the level of $bio-silverlite^{(R)}$ supplement. The length of small intestine was longer in +C than in -C and $bio-silverlite^{(R)}$ supplement groups (P<0.05), and the weight of small intestine was proportional to the level of $bio-silverlite^{(R)}$ supplement. Crop weight was lower in $bio-silverlite^{(R)}$ supplement group than in -C and +C groups (P<0.05), and the cecum weight was heavier in $bio-silverlite^{(R)}$ supplementation group. Intestinal villi height was longer in 51.5% group at 3 weeks and 6 weeks of age than in -C and +C groups. With the respect of the formation of intestinal microflora, TBC and CBC was not affected by age and feed additive. However, the number of LAB was slightly higher in $bio-silverlite^{(R)}$ supplement group than in -C and +C groups.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.3
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• pp.181-194
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• 2002

Parasitism is a one-sided relationship between two organisms in which one benefits at the expense of the other. Parasitic dinoflagellates, particularly species of Amoebophrya, have long been thought to be a potential biological agent for controlling harmful algal bloom(HAB). Amoebophrya infections have been reported for over 40 species representing more than 24 dinoflagellate genera including a few toxic species. Parasitic dinoflagellates Amoebophrya spp. have a relatively simple life cycle consisting of an infective dispersal stage (dinospore), an intracellular growth stage(trophont), and an extracellular reproductive stage(vermiform). Biology of dinospores such as infectivity, survival, and ability to successfully infect host cells differs among dinoflagellate host-parasite systems. There are growing reports that Amoebophrya spp.(previously, collectively known as Amoebophrya ceratii) exhibit the strong host specificity and would be a species complex composed of several host-specific taxa, based on the marked differences in host-parasite biology, cross infection, and molecular genetic data. Dinoflagellates become reproductively incompetent and are eventually killed by the parasite once infected. During the infection cycle of the parasite, the infected host exhibits ecophysiologically different patterns from those of uninfected host in various ways. Photosynthetic performance in autotrophic dinoflagellates can be significantly altered following infection by parasitic dinoflagellate Amoebophrya, with the magnitude of the effects over the infection cycle of the parasite depending on the site of infection. Parasitism by the parasitic dinoflagellate Amoebophrya could have significant impacts on host behavior such as diel vertical migration. Parasitic dinoflagellates may not only stimulate rapid cycling of dissolved organic materials and/or trace metals but also would repackage the relatively large sized host biomass into a number of smaller dinospores, thereby leading to better retention of host's material and energy within the microbial loop. To better understand the roles of parasites in plankton ecology and harmful algal dynamics, further research on a variety of dinoflagellate host-parasite systems is needed.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.436-447
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• 2004

Wetland plants have evolved specialized adaptations to survive in the low-oxygen conditions associated with prolonged flooding. The development of internal gas space by means of aerenchyma is crucial for wetland plants to transport $O_2$ from the atmosphere into the roots and rhizome. The formation of tissue with high porosity depends on the species and environmental condition, which can control the depth of root penetration and the duration of root tolerance in the flooded sediments. The oxygen in the internal gas space of plants can be delivered from the atmosphere to the root and rhizome by both passive molecular diffusion and convective throughflow. The release of $O_2$ from the roots supplies oxygen demand for root respiration, microbial respiration, and chemical oxidation processes and stimulates aerobic decomposition of organic matter. Another essential mechanism of wetland plants is downward water movement across the root zone induced by water uptake. Natural and constructed wetlands sediments have low hydraulic conductivity due to the relatively fine particle sizes in the litter layer and, therefore, negligible water movement. Under such condition, the water uptake by wetland plants creates a water potential difference in the rhizosphere which acts as a driving force to draw water and dissolved solutes into the sediments. A large number of anatomical, morphological and physiological studies have been conducted to investigate the specialized adaptations of wetland plants that enable them to tolerate water saturated environment and to support their biochemical activities. Despite this, there is little knowledge regarding how the combined effects of wetland plants influence the biogeochemistry of wetland sediments. A further investigation of how the Presence of plants and their growth cycle affects the biogeochemistry of sediments will be of particular importance to understand the role of wetland in the ecological environment.

• Microbiology and Biotechnology Letters
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• v.43 no.1
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• pp.38-44
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• 2015

This study was conducted to investigate the effects of electrolyzed water (EW) and hot-air-drying with ultraviolet light (UV) to reduce coliform bacteria of Undaria pinnatifida (UP). The UP was washed in the order of 15% EW, tap water (TW), and distilled water (DW) under following conditions: 15% EW for 10 min (washing: 1 time), TW for 1 min, and DW for 10 min (washing: 5 times). Viable cells, coliform, and mold counts were at 10²-10³ CFU/g in untreated samples. After EW treatment, viable cells, coliform, and molds were not detected in whole samples or on the surface of UP. But, after hot-air-drying at 48°C for 48 h, the number of viable cells, coliform, and molds were 10¹-10⁵ CFU/g. After hot-air-drying at 48°C for 48 h with UV (12-48 h), viable cells, coliform, and molds were not detected in whole samples or on the surface of UP. In respect of color value, there were no significant changes. In sensory evaluation, the UP with hot-air-drying with UV (12 h) had the highest score in overall preference among UV treatment groups. These results suggest that the treatments at 15% EW for 10 min and hot-air-drying at 48°C for 48 h with UV (12 h) were effective to reduce coliform bacteria of the dried Undaria pinnatifida.

• Journal of Food Hygiene and Safety
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• v.31 no.1
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• pp.42-50
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• 2016

The effects of freezing and thawing conditions on microbiological quality and microstructure change of inoculated (Listeria monocytogenes and Campylobacter jejuni) and non-inoculated chicken breasts were investigated. Chicken breasts were frozen with air blast freezing (-20, -70, and $-150^{\circ}C$), ethanol ($-70^{\circ}C$) and liquid nitrogen ($-196^{\circ}C$) immersion freezing. There were no significant differences on the populations of L. monocytogenes inoculated with chicken breasts under different freezing conditions. However, air blast freezing ($-20^{\circ}C$) resulted in significant reductions for total aerobic bacteria and C. jejuni compared to the control and other freezing treatments. The frozen samples were thawed with (hot or cold) air blast, water immersion, and high pressure thawing at $4^{\circ}C$ and $25^{\circ}C$. the populations of total aerobic bacteria, and yeast and mold in the frozen chicken breast increased by 5.78 and 4.05 log CFU/g after water immersion thawing ($25^{\circ}C$) treatment. After five freeze-thaw cycles, the populations of total aerobic bacteria, yeast and mold, and C. jejuni were reduced by 0.29~1.40 log cycles, while there were no significant differences (P > 0.05) in the populations of L. monocytogenes depending on the freeze-thaw cycles. In addition, the histological examination of chicken breasts showed an increase in spacing between the muscle fiber and torn muscle fiber bundles as the number of freeze-thaw cycles increased. These results indicate that freezing and thawing processes could affect in the levels of microbial contamination and the histological change of chicken breasts.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.9 no.2
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• pp.162-168
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• 2006

Purpose: Microbial colonization of the intestine begins just after birth and development of the normal flora is a gradual process. The first bacteria colonizing the intestine in newborns are Staphylococcus, Enterobacteriaceae and Streptococcus. For several days after birth, the number of Bifidobacterium spp. increase. The aim of this study was to investigate the changes of microflora for seven days postnatally in neonatal stool. Methods: Fifteen neonates (breast : formula : mixed feeding 1 : 8 : 6, vaginal delivery : cesarean section 3 : 12) who were born at the Kangdong Sacred Heart Hospital, Hallym University were enrolled. First meconium and stools of postnatal 1-, 3-, and 7-day were innoculated. Blood agar plates for total aerobes, trypton bile X-glucuronide agar for E. coli, phenylethyl alcohol agar for gram positive anaerobes, MRS agar for Lactobacillus spp., bifidobacterium selective agar for Bifidobacterium spp. and cefoxitin-cycloserine-fructose agar for Clostridium difficile were used in the general incubator ($CO_2$ free incubator), $CO_2$ incubator or the anaerobic chamber for 48 or 72 hours at $37^{\circ}C$ and then colony forming units were counted. Results: No microflora was identified in the first meconium. Total aerobes, E. coli, and gram positive anaerobes were significantly increased with advancing postnatal days. In only one baby, Lactobacillus acidophilus was detected $2{\times}10^5CFU/g$ in the seven-day stool. Bifidobacterium spp. was detected in two babies. Clostridium difficile was not detected during the seven days. There were no significant differences in the bowel flora depending on the delivery pattern and feeding method. Conclusion: This study shows many changes in the intestinal normal flora in neonatal stool during seven days postnatally. If these findings are confirmed with larger studies, the data may be preliminary findings to support use of probiotics in neonates.

• Food Science of Animal Resources
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• v.23 no.4
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• pp.342-349
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• 2003

Escherichia coli O157：H7, Staphylococcus aureus and Salmonella enteritidis are food borne pathogens involved in food poisoning in numerous countries. This study aimed to obtain knowledges on the survival of Esc coli O157：H7, Sta aureus and Sal. enteritidis in the yoghurt added with water extract of Omija(Schizandra chinensis). The growth inhibition of Schizandra chinensis extract on the food borne pathogens were measured by total microbial count and effect of growth inhibition was correspondent to the concentration of Schizandra chinensis extract. The highest growth inhibition effect of Schizandra chinensis extract was shown on the Sta aureus followed by Sal. enteritidis and Esc. coli O157：H7. The number of surviving Esc. coli O157：H7 cell(3.55${\times}$10$\^$5/ CFU/mL) was decreased to 1.00${\times}$10$^1$∼3.00${\times}$10$^1$ CFU/mL after 24 hours incubation by the addition of 0.4∼l.0％ of Schizandra chinensis extract in the yoghurt. And also the viable cell counts of surviving Sta. aureus cells (initial inoculum 1.24${\times}$10$\^$5/ CFU/mL) were decreased gradually to 4.00${\times}$10$^2$∼8.50${\times}$10$^2$ CFU/mL after 48 hours of incubation, but the viable cells of Sal. enteritidis were not detected after 24 hours of incubation. Growth of the food borne pathogens was strongly inhibited by the addition and incubation of Schizandra chinensis extract for 48 hours in the yoghurt.

• Food Science and Preservation
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• v.19 no.5
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• pp.774-782
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• 2012

Baechu kimchi without cuttlefish (control), baechu kimchi with cuttlefish (CK), cuttlefish baechu kimchi with yogurt (CK+Y), and cuttlefish baechu kimchi with vitamin C (CK+VC) were prepared, and the fermentation characteristics of the prepared kimchi samples were investigated during 28 days of fermentation at $4^{\circ}C$. The levels of moisture, crude lipid, and crude ash did not differ much among the samples, but the crude protein levels of CK, CK+Y, and CK+VC were greater than that of the control. The pH values of CK+Y and CK+VC slowly decreased compared with those of the control and CK during fermentation. The acidity increased sharply until 21 days then gradually increased thereafter. The total microbial counts achieved maximum levels at 21 days, and the kimchi to which yogurt and vitamin C were added showed values lower than that of the control. The number of Leuconostoc sp. in CK+Y and CK+VC was higher than that in the control. In our sensory evaluations, cuttlefish kimchi with yogurt or vitamin C scored highest in terms of texture, sour taste, ripened taste, and overall acceptability.

• Food Science and Preservation
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• v.21 no.4
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• pp.512-519
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• 2014

This study was carried to investigate the physicochemical and microbiological characteristics of seasonal salted-Kimchi cabbage order to provide basic data for optimal salting and storage condition of seasonal Kimchi cabbage. Generally, fall season samples had slightly higher pH and acidity value than the other seasonal salted Kimchi cabbage. The soluble solids content of spring, summer, fall and winter samples were 5.95%, 6.18%, 6.29% and 7.76%, respectively. The salt content of all the seasonal salted Kimchi cabbage samples were insignificant. The number of microbial bacteria in the summer samples were generally much more significant than spring and winter samples. There was no significant difference in the color of seasonal salted Kimchi cabbage. As for the texture properties, the firmest samples in the surface rupture test were the spring samples (force: 4.92 kg), and the hardest samples in the puncture test were the summer samples (force: 11.71 kg). In the correlation analysis of the quality characteristics of seasonal samples, the soluble solids content and hardness of the seasonal salted Kimchi cabbage was significantly correlated at 1% significance level. Also, in the principal component analysis, F1 and F2 were shown to explain 27.28% and 35.59% of the total variance (62.87%), respectively. The hierarchical cluster analysis of the quality characteristics of seasonal samples, the samples were divided into three groups: spring cabbage group, summer cabbage group and fall and winter cabbage group.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.7
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• pp.935-939
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• 2006

Raw oyster (Crassostrea gigas) was inoculated with Vibrio parahaemolyticus and Escherichia coli, treated with high hydrostatic pressure and evaluated for microbial counts. Cell death of V. parahaemolyticus (Vp) increased with the increase of applied pressure. Vp starting inoculum of $3.8{\times}10^5\;CFU/mL$ was totally eliminated after exposure to 200 MPa for 10 min at $22^{\circ}C$ Viable cell of Vp decreased with the increase in treatment time and dropped below the detection limit with treament of 25 min at $22^{\circ}C/150\;MPa$. The number of Vp by treatment of $0^{\circ}C$ and $10^{\circ}C$ for 20 and 25 mon at 100 MPa, respectively. For E. coli, there was an initial lag up to 250 MPa gollowed by a rapid decline. Treatment at 325 MPa/$22^{\circ}C$ for 15 min caused 5-log reduction, while that at 375 MPa resulted in total reduction of starting inoculum of $4.0{\times}10^7\;CFU/mL$. Lower treatment temperature showed higher killing effect of E. coli at the same treatment pressure and time. Viable cell of E. coli decreased with the increase in treatment time, and 4-log reduction was achieved with treatment of 5 min at $10^{\circ}C$/350 MPa and then total reduction was achieved after treatment of 15 mon. Higher pressure, lower temperature and longer time were more effective in sterilizing V. parahaemolyticus and E. coli.