• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.55 no.5
• /
• pp.541-548
• /
• 2022

Biofloc technology (BFT) systems provides an additional protein source for fish by converting waste in microbial flocs. Therefore, we aimed to determine the difference in the protein levels of the diet of Far Eastern catfish Silurus asotus reared in BFT and FW systems. We applied a two-way (six protein levels × two aquaculture systems) ANOVA design. We formulated six experimental diets to contain different protein levels (CPs)- 20%, 25%, 30%, 35%, 40% and 45%-referred to as the CP20, CP25, CP30, CP35, CP40 and CP45 diets, respectively. We randomly distributed 900 fish into 36 (18 each for BFT and FW), 300 L tanks (25 fish/tank) with three replications of each diet for 4 weeks. The weight gain (WG) and specific growth rate (SGR) considerably improved as the dietary protein level increased in the formulated diets. The BFT fish showed higher growth performance with any experimental diet than the FW fish. The growth performance of the fish fed the BFT-CP35 diet was higher than that of the fish fed the FW-CP45 diet. In conclusion, the cultivation of Far Eastern catfish (S. asotus) in BFTs can be carried out under reduced dietary protein levels.

• Journal of Life Science
• /
• v.17 no.9 s.89
• /
• pp.1284-1289
• /
• 2007

The Biological Activated Carbon (BAC) process in the water treatments represents a kind of biofiltration process which capabilities of bacteria to remove organic matters are maximized. It enables to eliminate organic matters and effectively reduce microbial regrowth potentials. As attached bacteria employ natural organic matter as a substrate, they are significantly dependent on indigenous microorganisms. In this study, characteristics of bacterial community by culturable and unculturable Methods have been conducted in a pilot plant using SAC in water treatment process at the downstream of the Nakdong River. Based on the results, HPC and bacterial- production for coal-based activated carbon material were $1.20{\sim}56.2{\times}l0^7$ cfu/g and $1.2{\sim}3.7\;mgC/m^{3}h$, respectively, in the SAC process. The highest level of attached bacteria biomass and organic carbon removal efficiency was found in the coal-based activated carbon. The genera Pseudomonas, Flavobacterium, Alcaligenes, Acilzetobacter, and Spingomonas were identified for each activated carbon material. Pseudomonas vesicularis was the dominant species in the coconut- and coal-based materials, where as Pseudomonas cepacia was the dominant species in the wood-based material. The Scanning Electron Microscope (SEM) observation of the activated carbon surface also found the widespread distribution of rod form and coccus. The community of attached bacteria was investigated by performing Fluorescent in situ hybridization (FISH) analysis. a group was dominant in coal, wood and coccunt-based materials, ${\alpha},\;{\beta}\;and\;{\gamma}$ group ranged from 27.0 ${\sim}$ 43.0%, 7.1 ${\sim}$ 22.0%, 11.3 ${\sim}$ 28.6%, respectively. These results suggest that a group bacterial community appears to be regulated removal efficiency of organic material in water treatment process.

• Journal of Food Hygiene and Safety
• /
• v.34 no.6
• /
• pp.583-590
• /
• 2019

As the consumption of fresh fruits and vegetables increases, food poisoning caused by foodborne pathogen contamination is not decreasing. To prevent the contamination of produce, a quick and easy, low-cost, environmentally-safe disinfection method that does not affect produce freshness or quality is needed. This study demonstrates a new-concept, circulating-water disinfection system that purifies water by using newly developed 'LED-PS (photosensitizer)-induced ROS generation unit'. Using various types of LED-PS induced ROS generation units, we investigated the conditions for reducing the density of various pathogenic bacteria by more than 3 log CFU / mL in 1 hour. The major operational factors affecting the density reduction of the LED-PS-induced ROS generation unit were analyzed. Depending on bacteria species, the density reduction rate was varied. The effect of the units on reducing the density of Bacillus cereus and Pectobacterium carotovorum subsp. carotovorum was high, but the effect on foodborne bacteria such as Escherichia coli was relatively low. In this circulating water disinfection system, the density reduction effect tended to increase as the flow rate increased and the initial bacterial density decreased. As the amount of PS absorbed beads increased, the density reduction effect increased exponentially in some bacteria. Model 3280, a double cylindrical unit connecting two single cylindrical units, could completely sterilize more than 3 log CFU/mL of B. cereus and P. carotovorum subsp. carotovorum in 30 minutes of LED irradiation.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.33 no.5
• /
• pp.1-11
• /
• 2001

In the past, abundant and clean water was available for paper mills'use. However, the growth of population and industry made water less available nowadays. Also, environmental regulation limits wastewater discharge, which affects mill operation cost. Therefore, paper mills are under pressure to use more recycled water and mill system closure. As a result, chemical and physical parameters of water are changing and new environment if being created for microorganisms in paper mill system as well. The more soluble or suspended organic materials are increased as more water is recycled and less or scarce dissolved oxygen is available, depending on the degree of recycled water usage. Microorganism flora ill paper mill system will be a1so shifted according to the environmental change of mill system. Anaerobic bacteria, including sulfate reducing bacteria (SRB), will be dominant in the system as very low or almost no oxygen available in the system. Nevertheless, it is common in domestic paper mills that employ the same and old biocides as a means of microbial control, and microbiological control is often less recognized or even neglected. The right biocide selection for increased reductive environment of mills is critical for operation and estimated loss from paper quality defects such as sheet break, holes due to microbiological cause is tremendous compared to the microbiological control cost. It is imperative to investigate and diagnosis the environmental change of mills for right control of cumbersome microorganisms. Several useful diagnosis tools, including new technology employing OFM(Optical Fouling Monitor) in situ, are illustrated.

• Food Science and Preservation
• /
• v.14 no.2
• /
• pp.142-147
• /
• 2007

We optimized braising time to improve the storage quality of braised kidney beans. The beans were prepared with different heating times between 25 and 50 min. and then stored at $10^{\circ}C$ for 20 day. Physical, chemical, microbiological, and organoleptic quality indices were monitored throughout storage. Longer braising times yielded products with lower concentrated brine coverage. Bis resulted in higher soluble contents and slightly lower water activities. Excessive heating time exposed the kidney beans to air and caused rapid microbial growth on the surfaces of the beans, which negatively affected product quality. The longest heating time of 50 min. also resulted in a large increase in product hardness. A braising time of 30 min. was best for preservation, as good sensory quality was mainatained.

• Korean Journal of Food Science and Technology
• /
• v.36 no.2
• /
• pp.239-245
• /
• 2004

Storage quality of minimally processed onion as influenced by hot-water dipping was investigated to examine feasibility of mild heat treatment as efficient post-processing method. fresh onions were peeled, trimmed, and dipped in hot water at various temperatures ($50-80^{\circ}C$) for 1 min. Heat-treated onions were cooled, de-watered, packaged in low density polyethylene (LDPE) film pouches ($63\;{\mu}m\;thickness$), and stored at $10^{\circ}C$. Samples treated at higher temperatures ($70-80^{\circ}C$) showed significant increases in flesh weight loss and discoloration during storage as compared to others. Hot-water dipping remarkably reduced initial microbial load of prepeeled onions, with over 1 log cycle decrease in aerobic bacterial count. After 7 days storage, no significant differences in viable aerobe count were observed among treated and untreated samples, with both showing $10^{6}-10^{7}\;CFU/g$. For sensory attributes including discoloration, wilting, decay, and visual quality, onions treated with hot-water dipping at $60^{\circ}C$ scored highest. Results suggested hot-water dipping at specific condition as practical post-processing treatment could effectively prolong shelf life of minimally processed onion.

• Asian Journal of Turfgrass Science
• /
• v.23 no.2
• /
• pp.219-228
• /
• 2009

The construction procedures and artificial turf maintenance program on golf course definitely influence on the distortion of its environment. Soil microbial communities in soil profile were affected directly by those practises on turf areas. In Jeju island, the environmental impact assessment has been required to apply the first quality class granular activated carbon(GAC), which has a high absorbent character to agricultural chemicals, on the soil profiles of golf green system to reduce the pesticide leaching to ground water. This research was carried out to analyze the changes of microbial communities and chemical properties on soil profiles where GAC had been applied at the construction stage at two golf courses in Jeju. The changes of soil microbial population and chemical properties associated with construction methods of soil profile and agrochemical management program were analyzed by monthly at the surface and sub-soil profiles during April through October, 2007. The total numbers of bacteria and fungi, soil moisture content, soil physio-chemical properties were measured on greens and fairways of the both golf courses with different GAC treatment on the green and fairway soil profiles. The results showed that GAC had positive effects on the water holding capacity, pH and EC, however, it did not improved the holding capacity of available nutrients ${NO_3}^-,{NH_4}^+$, and phosphorus by its sorption phenomenon. In microbial count test, the total numbers of bacteria and fungi showed a great variation during sampling dates. That may directly relate to the agrochemical application, however, the ratio of total bacterial number versus total fungus number showed a constant value on a sub-soil of 15~30cm depth. Thus, the construction method of GAC in soil profile, and application of fertilizer and pesticide, both impacted on the changes of microbial population. It's means that the construction method of soil profile and turf management using agro-materials might greatly affect on the turfgrass culture and the environment of golf course.

• Food Science of Animal Resources
• /
• v.35 no.2
• /
• pp.216-224
• /
• 2015

The objective of present study was to evaluate the effects of the application of chitosan and chitosan/whey protein on the chemical, microbial and organoleptic properties of Göbek Kashar cheese during ripening time (on 3^rd, 30^th, 60^th and 90^th d). Difference in microbiological and chemical changes between samples was found to be significant (p<0.05) during ripening period. Cheese samples with edible coating had statistically lower mould counts compared to the uncoated samples. Furthermore the highest and lowest mould counts were determined in control (4.20 Log CFU/g) and other samples (<1 Log CFU/g) at 60^th and 90^th d of storage. All samples exhibited higher levels of water soluble nitrogen and ripening index at the end of storage process. At the end of 90 day storage period, no signicant dierences in salt and fat values were observed among the cheeses studied. The edible coatings had a beneficial effect on the sensory quality of cheese samples. In the result of sensory analysis, while cheese C and the chitosan coated cheese samples were more preferred by the panellists, the chitosan/whey protein film-coated cheese samples received the lowest scores. This study shows coating suggests could be used to improve the quality of cheese during ripening time.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.11 no.1
• /
• pp.53-59
• /
• 1991

This experiment was conducted to investigate the effects of propionic acid and wilting on fermentation quality of Italian ryegrass silage. Grass material was wilted for a day before ensiling and propionic acid(0. 0, 0. 2. 0. 5 and 0.8 7~ of fresh matter) was applicated at ensiling time. Chemical composition, fermentation acids, pH, microbial population and distribution of the nitrogen contents were evaluated. The results obtained are summarized as follows: 1. The contents of dry matter and water soluble carbohydrate in the silage were increased by wilting, and crude fibre, NDF and ADF were decreased with increasing propionic acid levels. 2. The pH values of the silage increased by increasing DM content, but decreased with increasing propionic acid levels. Lactic acid content lowed in wilted silage, and acetic acid and butyric acid formation were decreased with increasing propionic acid levels. 3. Total nitrogen content in the silage was i n ~ r e a s e d ( ~ < . 05) by addition of propionic acid and wilting, and was the highest in the prewilting-0.8 Q propionic acid applicated silage. The production of NHBN was decreased with propionic acid and was the lowest in the 0.8 % treated silage. 4. The number of total bacteria and yeasts were estimated $10^6~10^7$, $10^2~10^3$ respectively. Moulds number were decreased with increasing propionic acid levels.

• Food Science of Animal Resources
• /
• v.40 no.5
• /
• pp.844-851
• /
• 2020

The objective of this study was to compare effects of two different aging methods on physical, chemical, and microbial traits of pork loin: Dry and wet-aged meat was hung in the cooler at 8±1℃ and 85±2.1% humidity for 14 days, while wet-aged meat was immersed in a 3.5% salt solution of brine in vacuum pouches. On day 7, pH and moisture content were higher in dry-aged loins than in wet-aged, while drip loss and total plate counts (p<0.05) were lower on day 14. As aging continued, the pH and drip loss of dry-aged loins decreased, while their total plate counts and water holding capacity (WHC) increased (p<0.05). After 7 and 14 days of aging, redness in dry-aged loins was higher than that in wet -aged muscles (p<0.05). On day 14 of aging, hardness, chewiness, and adhesiveness were lower in dry-aged pork loin as compared to those in wet-aged samples (p<0.05). Consequently, the results suggested that dry and wet aging methods differently affects meat quality traits of pork loin.