• Food Science of Animal Resources
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• v.27 no.1
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• pp.80-86
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• 2007

This experiment was conducted to investigate the changes of pork meat quality characteristics exposed to ozone gas for 5, 10, and 15 min and then vacuum packaged during storage for 0, 5, 10, 15, and 20 day at $4^{\circ}C$. The ozone gas exposed groups of pork loin cuts (OZM) had slightly higher pH value compared to the control at day 0 and 5 (p<0.01). The 15 min exposure of ozone gas groups showed significantly (p<0.01) higher TBARS value than that of control at the day 15 and 20. However, there was no significant difference in all groups at day 0,5, and 10. The CIE $L^*$ and $b^*$ values of OZM showed no significant difference between control and ozone gas treated groups during storage. The loin cut color of ozone gas exposure for 15 min had significantly lower CIE $a^*$ values than the other groups at day 0,5, and 15 (p<0.01). The aerobic plate count and coliform bacteria count of pork loin cuts exposed ozone gas significantly (p<0.01) was reduced at day 0 by about $0.45-1.04\;log_{10}CFU/g$ and $0.26-0.30\;log_{10}CFU/g$, respectively. As ozone gas exposure time extended, the aerobic plate count and coliform bacteria count of OZM were increased at day 0, 5, and 10 (p<0.01). However, there were no significant differences observed among groups at day 20 in the counts of aerobic and coliform bacteria. In conclusion, the meat cuts exposed to ozone gas for 5 and 10 min before packing may be a reasonable packing method regarding the effects of ozone level on meat oxidation, color change and microbial reduction.

• Food Science of Animal Resources
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• v.28 no.1
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• pp.51-58
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• 2008

This study was performed to evaluate the physico-chemical properties of fermented sausages containing probiotic starter cultures (LK-30 plus, Lactobacillus plantarum 155 and 167, and Pediococcus damnosus L12) with reduced fat levels, and to determine the optimum condition for the manufacture of these products. Although low-fat fermented sausages were reduced fat content at the amount of 90% and the ripening time by 1-2 weeks, as compared to regular-fat counterpart, they became harder and had many winkles outside due to the extreme drying. In addition, fat level in fermented sausages affected the composition and shear force values. During ripening, pH, lightness and yellowness values tended to decrease, however, microbial counts of inoculated lactic acid bacteria were increased up to $10^8-10^9cfu/g$ within 3 days and remained constant thereafter. Low-fat fermented sausages had higher microbial counts than regular-fat ones. Although the inoculated probiotic starter cultures alone had the functional properties, such as cholesterol reduction, anti-high blood pressure and antimicrobial activity, they did not have distinctive characteristics in the fermented sausages. Based on these results, the low-fat fermented sausages were successfully manufactured, but a little bit increased fat level and improved functional properties in the fermented sausages would be required to have better quality as compared to regular-fat counterparts.

• Food Science of Animal Resources
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• v.28 no.4
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• pp.437-444
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• 2008

Microbial reduction, physicochemical property, and sensory evaluation of irradiated beef patty were investigated. The microbial counts of refrigerated beef patty were reduced to below the number of 3 logs after irradiation at 3 kGy. But no viable microorganism was detected in frozen beef patty irradiated at 3 kGy. Food additives such as nitrite, salt, phosphate and ascorbic acid did not affect on the inactivation of microorganism by irradiation. The irradiation effect on the water holding capacity was not significant, but frozen irradiated beef patty showed higher water holding capacity than refrigerated beef patty. The drip loss of irradiated beef patty did not show significant differences according to irradiation doses. Considering the influence of food additives, the irradiated beef patty mixed with salt and phosphate showed lower drip loss than that without food additives. In refrigerated beef patty, TBARS values were increased with increase of irradiation doses and showed lower values in the beer patty mixed with food additives than that without food additives. The redness of refrigerated beef patty showed highest values at 3 kGy of irradiation and then decreased with increasing irradiation doses, while in the frozen beef patty did not show distinct tendency according to the irradiation doses or food additives. In sensory evaluation, the irradiated beef patty showed unpleasant smell as compared with the non irradiated beef patty, but showed some-what higher score in smell at the sample contained ascorbic acid regardless of irradiation doses.

• Korean Chemical Engineering Research
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• v.52 no.5
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• pp.581-586
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• 2014

Main objects for wastewater treatment operation are to maintain effluent water quality and minimize operation cost. However, the optimal operation is difficult because of the change of influent flow rate and concentrations, the nonlinear dynamics of microbiology growth rate and other environmental factors. Therefore, many wastewater treatment plants are operated for much more redundant oxygen or chemical dosing than the necessary. In this study, the optimal control scheme for dissolved oxygen (DO) is suggested to prevent over-aeration and the reduction of the electric cost in plant operation while maintaining the dissolved oxygen (DO) concentration for the metabolism of microorganisms in oxic reactor. The oxygen uptake rate (OUR) is real-time measured for the identification of influent characterization and the identification of microorganisms' oxygen requirement in oxic reactor. Optimal DO set-point needed for the micro-organism is suggested based on real-time measurement of oxygen uptake of micro-organism and the control of air blower. Therefore, both stable effluent quality and minimization of electric cost are satisfied with a suggested optimal set-point decision system by providing the necessary oxygen supply requirement to the micro-organisms coping with the variations of influent loading.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.253-259
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• 2012

Disposal of high amount of coal combustion by-products, such as fly ash and bottom ash, is of a great concern to the country, due to the huge treatment cost and land requirement. On the other hand, those coal-ash wastes are considered to have desirable characteristics that may improve physical, chemical, and biological properties of soils. Especially, compared with fly ash, bottom ash has a larger particle size, porous surface area, and usable amount of micronutrients. In the present study, we examined bottom as a soil amendment for mitigating $CO_2$ emission and enhancing carbon sequestration in soils fertilized with organic matter (hairy vetch, green barely, and oil cake fertilizer). Through laboratory incubation, $CO_2$ released from the soil was quantitatively and periodically monitored with an enforced-aeration and high-temperature respirometer. We observed that amendment of bottom ash led to a marked reduction in $CO_2$ emission rate and cumulative amount of $CO_2$ released, which was generally proportional to the amount of bottom ash applied. We also found that the temporal patterns of $CO_2$ emission and C sequestration effects were partially dependent on the relative of proportion labile carbon and C/N ratio of the organic matter. Our results strongly suggest that amendment of bottom ash has potential benefits for fixing labile carbon as more stable soil organic matter, unless the bottom ash contains toxic levels of heavy metals or other contaminants.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4665-4674
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• 2014

The aim of this study was to confirm the feasibility of the electro-coagulation process as a pre-treatment for the membrane separation of anaerobic digestion effluents to minimize membrane fouling. The reduction of membrane fouling was evaluated according to the number of electrodes (immersed surface area of electrodes), current density and contact time. In the case of the small surface area of electrodes, the increased electric field strength resulted in a soluble COD increase due to the destruction of the microbial flocs and/or cells, whereas large changes in the soluble COD were not observed in the case of the high surface area of electrodes. On the other hand, the T-P concentration decreased as a result of the precipitation of aluminum ions and phosphates. The membrane permeation flux increased and the fouling resistance (Rc+Rf) decreased with increasing electric current density. Although the particle size of the anaerobic digestion effluent increased slightly, it was not related directly to the reduced fouling phenomena. The main mechanism for the enhanced flux was attributed to the inorganic particulate produced during electrocoagulation, such as $AlPO_4$, which acted as a dynamic membrane deposited on the membrane surface.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.12
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• pp.1743-1749
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• 2011

The microbial reduction and quality characteristics of salted Chinese cabbage using electrolyzed water were investigated. The electrolyzed water was used to control the microbes in the processes of primary washing, salting, and secondary washing. The total bacteria, lactic acid bacteria, coliform, pH, salinity, vitamin C, and total sugar were analyzed. After primary washing by electrolyzed water, the total bacteria populations were reduced to 2.78 log cfu/g, and the coliform populations were similarly reduced. After secondary washing by electrolyzed water, the total bacteria population of Chinese cabbage was reduced to a maximum of 1.5 log cfu/g. The salinity of Chinese cabbage and salting solutions increased rapidly over three hours, and then increased slowly. The sterilization effect of electrolyzed salting water could not last beyond 3 hours, because the OHCl concentration of electrolyzed water was reduced by over 90% at the third hours of the salting process. Vitamin C was reduced and total sugar did not change regardless of treatments during the salting process. Consequently, electrolyzed water was effective to remove microbes from salted Chinese cabbages.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.5 no.4
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• pp.31-44
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• 1985

The application of anaerobic attached microbial films in the expanded bed process has recently been examined at high temperatures ($55^{\circ}C$) and with particulate matter. Extrapolation of the kinetics suggested that waste activated sludge (WAS) could be efficiently digested at hydraulic retention times as short as six hours in the expanded bed process. This would represent a 99 percent digester reactor volume reduction and would introduce interesting solids management alternatives if such a high rate process were developed. This paper presents a summary of a 1.5 year study of the feasibility of such a process. Three continuously fed $55^{\circ}C$ laboratory reactor systems were used to define the kinetics and the site of reactions-control completely mixed reactors were compared to the expanded beds (AAFEB) with and without a hydrolysis unit preceding the attached film unit. Well defined laboratory-generated WAS was compared to actual WAS from a domestic sewage treatment facility. Sixty percent of the biodegradable organics were converted in an AAFEB at a 15-hour hydraulic retention time without hydrolysis, whereas greater than 95 perccent of the biodegradable organics were stabilized in a two-stage system consisting of a 3-day HRT hydrolysis reactor followed by a 15-hour HRT AAFEB. The limitations of this high rate process and its potential application are discussed.

• Journal of Animal Science and Technology
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• v.62 no.5
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• pp.682-691
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• 2020

Careful cleaning and disinfection of pigpens is essential to prevent disease spread and avoid the resultant economic losses. Hygiene in pigpens is generally evaluated by visual monitoring supplemented with bacteriological monitoring, which includes counting the total aerobic bacteria (TAB) and/or fecal indicator bacteria (FIB). However, these methods present drawbacks such as time and labor requirements. As adenosine triphosphate (ATP) is ubiquitous in all living organisms including microorganisms, this study aimed to directly compare the results of microbial assessment and ATP quantification, and to suggest possible detailed application methods of the ATP test for hygiene evaluation in pigpens of a farrowing unit. Before and after standard cleaning procedures, samples were collected from the floor corner, floor center, and feeding trough of four pigpens at different time points. No FIB were detected and both the TAB and ATP levels were significantly decreased in the floor center area after cleaning. FIB were continuously detected after cleaning and disinfection of the floor corners, and there was no significant ATP level reduction. The feeding trough did not show any significant difference in these values before and after cleaning, indicating insufficient cleaning of this area. The levels of TAB and ATP after cleaning were significantly correlated and the average ATP value was significantly lower in the absence of FIB than in their presence. In the absence of standard references, a more thorough hygiene management could be achieved evenly by supplementing cleaning or disinfection based on the lowest ATP results obtained at the cleanest test site, which in the present study was the floor center. Overall, these results indicate that the on-farm ATP test can be used to determine the cleanliness status, in addition to visual inspection, as an alternative to laboratory culture-based testing for the presence of microorganisms.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.1
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• pp.105-110
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• 1985

A incubation study was conducted to find out the effects of rice straw and gypsum as soil ameriolite on urease, nitrate and nitrite reductase activities in newly reclaimed saline sandy soil. The results obtained were summarized as follows: 1. Very low urease activities were observed in saline soil if contrast to high productive paddy soil. Urease activities were lower at 5 days than that of 25 and 50 days after incubation. Remarkably high urease activities were obtained by the application of rice straw and gypsum. 2. Comparing with NPK treatment, application of rice straw and gypsum were enhanced the activities of nitrate and nitraite reductase. 3. Positive correlation (r=0.5501 p=0.05) was obtained between urease activities and ammonium nitrogen concentration in soil. 4. Cyclic oxidation and reduction of nitrate and nitrite in soil were obtained in terms of first order microbial kinetics reaction in case of application of rice straw and gypsum, respectively. 5. Positive correlation (r=0.6296 p=0.05) was obtained between the activitie of nitrite reductase and nitrate reductase in soil.