• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.2
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• pp.147-155
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• 2008

A series of experiments were conducted to find standard test organisms and to develop test protocols for sediment toxicity tests using indigenous amphipods inhabited in Korean coastal environments. The indigenous amphipods Mandibulophoxus mai and Monocorophium acherusicum were well associated with various sediment substrates from sand to mud. The tolerance limits to various physico-chemical factors affecting bioassay results such as temperature, salinity and total ammonium as well as the sensitivities to contaminants in water and sediments were investigated using M. mai and M. acherusicum in the present study. These amphipods were tolerable to the adequate ranges of salinity ($10{\sim}30\;psu$), temperature ($10{\sim}25^{\circ}C$) and ammonia (<50 ppm). They have relevant sensitivities to the reference toxicants, dissolved cadmium as well as other metals and organic pollutants, when compared to the standard test species used in other countries. Field-sediment toxicity tests revealed that M. mai would be more sensitive to sediment-associated pollutants than M. acherusicum, while the sensitivity of M. acherusicum was comparable to those of other sediment test species in other countries. Overall results of this first attempt to develop an amphipod sediment toxicity test protocol in Korea indicated that M. mai and M. acherusicum should be applicable in the toxicity assessment of contaminated sediments, following the further evaluation encompassing various ecological and toxicological evaluation and the standardization of test method.

• Journal of Food Hygiene and Safety
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• v.38 no.3
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• pp.123-130
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• 2023

Salmonella spp. are prevalent foodborne pathogens that are infective at relatively low concentrations, thus posing a serious health threat, especially to young children and the elderly. In several countries, the management and regulation of Salmonella spp. in food, including seafood, adhere to a negative detection standard. The risk of infection is particularly high when seafood is consumed raw, which underscores the importance of timely detection of pathogenic microorganisms, such as Salmonella. Accordingly, this study aimed to develop a combined pre-treatment and detection method that includes pre-culture and DNA extraction in order to detect five species of Salmonella at concentrations below 10 CFU/mL in seafood. The effectiveness of the proposed method was assessed in terms of the composition of the enrichment (pre-culture) medium, minimum incubation time, and minimum cell concentration for pathogen detection. Furthermore, a practical DNA extraction method capable of effectively handling high salt conditions was tested and found to be successful. Through polymerase chain reaction, Salmonella spp. Were detected and positively identified in shellfish samples at cell concentrations below 10 CFU/g. Thus, the proposed method, combining sample pre-treatment and cell culture with DNA extraction, was shown to be an effective strategy for detecting low cellular concentrations of harmful bacteria. The proposed methodology is suitable as an economical and practical in situ pre-treatment for effective detection of Salmonella spp. in seafood.

• Journal of Practical Agriculture & Fisheries Research
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• v.3 no.1
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• pp.116-131
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• 2001

Experiments were conducted to determine effects of whole and processed corns on in situ disappearance rates of nutrients in the rumen and in vitro degradability of dry matter by rumen microorganisms. Whole corn(WC) was processed into four different types; ground corn(GC), cracked corn(CC), flaked corn(FC), and soaked corn(SC). In the in situ experiment, the rate of ruminal DM disappearance after 48 hour incubation was highest in GC(76.1%) and lowest in WC and SC(12% ; P<0.01). The rate of ruminal CP disappearance after 48 hour incubation was highest in GC and CC(48 and 38%, respectively; P<0.01). The rate of ruminal OM disappearance after 48 hour incubation was highest in GC(76.14%) and lowest in WC and SC(11.82 and 12.26%, respectively; P<0.01). In the in vitro experiment, the two-stage incubation technique was used to measure digestibilities of whole and processed corns. The digestibility of DM was higher in GC, CC and FC(86.95, 85.84 and 82.29%, respectively) than in WC(15.36%; P<0.01).

• Korean Journal of Food Science and Technology
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• v.53 no.1
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• pp.1-11
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• 2021

In this review, recent foodborne outbreaks caused by viruses in the Republic of Korea (2010-2019) were analyzed. The human norovirus was found to be the major foodborne virus causing an average of 94.9% of the viral outbreaks. Reverse-transcription polymerase chain reaction (PCR) with electrophoresis has been widely used to detect viruses, but several rapid detection methods, including real-time PCR, multiplex PCR, and quantum dot assay, have also been suggested. For norovirus inactivation studies, surrogates such as murine norovirus and feline calicivirus have been widely used to identify the reduction rate owing to the limitations in laboratory cultivation. Conversely, direct cell infection studies have been conducted for other foodborne viruses such as adenovirus, astrovirus, rotavirus, and hepatitis A or E virus. Moreover, virucidal mechanisms using various physical and chemical treatments have been revealed. These recent studies suggest that rapid in situ detection and effective control are valuable for ensuring food safety against viral infections.

• Food Science and Preservation
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• v.19 no.1
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• pp.62-66
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• 2012

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 $cm^2$, and that of the latter was transferred to log CFU/100 $cm^2$. 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.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.1
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• pp.18-27
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• 2020

The correct distinction of carbapenem-resistant Enterobacteriaceae (CRE) and ccarbapenemase producing Enterobacteriaceae (CPE) and the rapid detection of CPE are important for instituting the correct treatment and management of clinical infections. Screening protocols are mainly based on cultures of rectal swab specimens on selective media followed by phenotypic tests to confirm a carbapenem-hydrolyzing activity, the rapid carbapenem inactivation method, lateral flow immunoassay, the matrix-assisted laser desorption ionization-time-of-flight test and molecular methods. The CPE is accurate for detection, and is essential for the clinical treatment and prevention of infections. A variety of phenotypic methods and gene-based methods are available for the rapid detection of carbapenemases, and these are expected to be routinely used in clinical microbiology laboratories. Therefore, to control the spread of carbapenemase, many laboratories around the world will need to use reliable, fast, high efficiency, simple and low cost methods. Optimal effects in patient applications would require rapid testing of CRE to provide reproducible support for antimicrobial management interventions or the treatment by various types of clinicians. For the optimal test method, it is necessary to combine complementary test methods to discriminate between various resistant bacterial species and to discover the genetic diversity of various types of carbapenemase for arriving at the best infection control strategy.

• Microbiology and Biotechnology Letters
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• v.38 no.4
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• pp.373-378
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• 2010

Studies on standardization and quality upgrade of nuruk which is a basic component in brewing are required to increase the quality level of Korean traditional rice wines and to develop the technology for practical use of it. It is important to isolate best strains, to improve the properties and effectively preserve them for brewing industry. In this study, 16 commercial nuruk samples were obtained from the commercial markets located in Chungcheong areas in Korea. 174 fungal strains were isolated from the samples on DG18 medium using a dilution plating method and then screened for enzyme activity and acid production. The active strains were identified based on the morphological characteristics and ITS sequence analysis. Out of 174 strains, 12 strains showed high amylase activity. Especially, Rhizopus sp. CN084, CN174, Aspergillus sp. CN161 and Mycocladus sp. CN042 showed high saccharogenic power and dextrinogenic enzyme activity on cooked wheat bran medium. On the other hand, Aspergillus sp. CN010, CN161, Rhizopus sp. CN105, CN168 and Rhizomucor sp. CN088 produced high acid production on the same medium. Our results showed that the active strains may be used as microbial sources for nuruk starter with good quality in brewing.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.8
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• pp.598-606
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• 2013

This study was performed to determine whether biomineralization microbes were actively present underneath landfill cover soil producing biocalcification. From this, various types of microbes were observed. Among them, two species were dominantly found; Bacillus megaterium and Alkaliphilus metalliredigens that were known as biominerlization bacteria. With those microbes, $CO_2$ was more highly consumed than without bacteria. In response, the calcium carbonate mineral was produced at 30% (wt) greater than that of the control. At the same time, TG-DTA was successfully used for quantification of $CO_2$ consumed forming calcium carbonate minerals resulting from biocalcification. It was decided that the presence of solidified sewage sludge cake utilized as a cover soil in the landfill could efficiently contribute to possible media adaptably and naturally sequestering $CO_2$ producing from the landfill.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.2
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• pp.121-128
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• 2008

As an aquatic ecotoxicity test method, a bioassay using the inhibition of sporualtion of the green macroalga, Ulva pertusa, has been developed. Optimal test conditions determined for photon irradiance, pH, salinity and temperature were $100\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, $7{\sim}9$, $25{\sim}35\;psu$ and $15{\sim}20^{\circ}C$, respectively. The validity of the test endpoint was evaluated by assessing the toxicity of four metals (Cd, Cu, Pb, Zn) and elutriates of sewage or waste sludge collected from 9 different locations. When the metals were assayed, the $EC_{50}$ values indicated the following toxicity rankings: Cu ($0.062\;mg{\cdot}L^{-1}$) > Cd ($0.208\;mg{\cdot}L^{-1}$) > Pb ($0.718\;mg{\cdot}L^{-1}$) > Zn ($0.776\;mg{\cdot}L^{-1}$). When compared with other commonly used bioassays of metal pollution listed on US ECOTOX database, the sporualtion test proved to be the most sensitive. Ulva sporulation was significantly inhibited in all elutriates with the greatest and least effects observed in elutriates of sludge from industrial waste ($EC_{50}=6.78%$) and filtration bed ($EC_{50}=15.0%$), respectively. The results of the Spearman rank correlation analysis for $EC_{50}$ data versus the concentrations of toxicants in the sludge presented a significant correlation between toxicity and four heavy metals(Cd, Cu, Pb, Zn). The method described here is sensitive to toxicants, simple to use, easy to interpret and economical. It is also easy to procure samples and maintain cultures. The present method would therefore probably make a useful assessment of aquatic toxicity of a wide range of toxicants. In addition, the genus Ulva has a wide geographical distribution and species have similar reproductive processes, so the test method would have a potential application worldwide.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.11
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• pp.1719-1723
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• 2010

The purpose of this study was to verify feasibility of using a ATP Luminometer, real-time hygiene monitoring tool for food contact surfaces in foodservices. For this, 54 cutting boards, 70 knives, 21 rubber gloves in 4 institutional foodservices were studied. ATP (RLU: relatively light unit) values by ATP Luminometer were compared with APC (CFU: colony forming unit) of swabbing culture method using aerobic count plates of 3M petrifilm. ATP ranged from 0 RLU/$cm^2$ to 64693 RLU/$cm^2$ on knives, from 0.1 RLU/$cm^2$ to 6743.6 RLU/$cm^2$ on cutting boards and from 31 RLU/$cm^2$ to 465635 RLU/$cm^2$ on the rubber gloves. APC ranged from 0 CFU/$cm^2$ to 166667 CFU/$cm^2$ on knives, from 0 CFU/$cm^2$ to 1000 CFU/$cm^2$ on cutting boards and from 0 CFU/$cm^2$ to 730000 CFU/$cm^2$ on the rubber gloves. To express the degree of association between ATP and APC, a linear regression was performed. There were significant positive correlations found between log RLU and log CFU on the knives (r=0.84, p<0.001), the cutting boards (r=0.79, p<0.001), the rubber gloves (r=0.78, p<0.001). Results of this study showed the possibility that ATP bioluminescence technique can be used as the monitoring tool for surface hygiene in foodservices.