• Korean Journal of Ecology and Environment
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• v.39 no.1 s.115
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• pp.110-118
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• 2006

The Namyang Stream in Hwaong polder was planned for several water uses including recreation, where people can contact the water and consume some amount during the recreational activity. A human health risk was assessed from exposure to E. coli in the Namyang Stream, which receives partially treated wastewater from watershed. The QUAL2E model was applied to simulate stream water quality, and this model was calibrated and verified with field monitoring data. The calibration result showed a high correlation coefficient of greater than 0.9. The mean concentration of E. coli in the Namyang Stream from the QUAL2E output was in the range of 5,000 ${\sim}$ 8,000 MPN 100 mL^{-1}$, which exceeded national and international guidelines. The Beta-Poisson was used to estimate the microbial risk of pathogens ingestion and the Monte-Carlo analysis (10,000 trials) was used to estimate the risk characterization of uncertainty. The Microbial risk assessment showed that the risk ranged from 7.9 ${\times}\;10^{-6}\;to\;9.4\;{\times}10^{-6}$. Based on USEPA guidelines, the range of $10^{-6}\;to\;10^{-8}$ was considered reasonable levels of risk for communicable disease transmission from environmental exposure, and the risk above $10^{-4}$ was considered to be in the danger of infection. Therefore, water quality of the Namyang Stream might not be in the danger of infection although it exceeded national and international guidelines. However, it was in the range of communicable disease transmission, and thorough wastewater collection and treatment at the source is recommended to secure safe recreation water quality.

• Journal of Microbiology and Biotechnology
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• v.30 no.9
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• pp.1335-1342
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• 2020

The identification of bacterial pathogens to humans is critical for environmental microbial risk assessment. However, current methods for identifying pathogens in environmental samples are limited in their ability to detect highly diverse bacterial communities and accurately differentiate pathogens from commensal bacteria. In the present study, we suggest an improved approach using a combination of identification results obtained from multiple databases, including the multilocus sequence typing (MLST) database, virulence factor database (VFDB), and pathosystems resource integration center (PATRIC) databases to resolve current challenges. By integrating the identification results from multiple databases, potential bacterial pathogens in metagenomes were identified and classified into eight different groups. Based on the distribution of genes in each group, we proposed an equation to calculate the metagenomic pathogen identification index (MPII) of each metagenome based on the weighted abundance of identified sequences in each database. We found that the accuracy of pathogen identification was improved by using combinations of multiple databases compared to that of individual databases. When the approach was applied to environmental metagenomes, metagenomes associated with activated sludge were estimated with higher MPII than other environments (i.e., drinking water, ocean water, ocean sediment, and freshwater sediment). The calculated MPII values were statistically distinguishable among different environments (p < 0.05). These results demonstrate that the suggested approach allows more for more accurate identification of the pathogens associated with metagenomes.

• Journal of Food Hygiene and Safety
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• v.34 no.6
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• pp.551-556
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• 2019

Recently, due to the fact that the mineral content in the wash water of the GAP-certified melon exceeds the GAP wash water standards, there are cases where the certification cannot be maintained. Therefore, agricultural industry demand requesting relaxation of the inorganic elements standard for water quality has been increasing, taking into account the consumption characteristics of Korean melon, which is eaten after removing the peel. This study was conducted to evaluate the human risks of four inorganic materials (fluorine, arsenic, iron and manganese) based on the water quality data of 142 samples of groundwater that was used for washing GAP-certified Korean melon in Seongju area from 2017 to 2019. As a result, the HQ of four minerals in Koreans who consumed groundwater used for washing GAP-certified Korean melons in the Seongju area was below 0.10 on average. In particular, in the case of iron and manganese which are esthetic influence substances, the average HQ was 0.00. The overexposure group showed 0.01, which was lower than the HQ (average 0.01, overexposure group 0.03) of the group that consumed Korean melon. Based on all the results, even if the groundwater of the Seongju area is used to wash GAP-certified Korean melon, the impact from these four inorganic materials, including iron and manganese, for Korean population consuming Korean melon will be minimal.

• Korean Journal of Environmental Biology
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• v.30 no.1
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• pp.71-76
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• 2012

Spills of $M/V$ Hebei Spirit on $7^{th}$ December 2007 caused a seriously damage to the ecosystem of Korean coast. Of these, microbial communities (i.e., attached benthic micro-algae) were reported to be sentive to the environmental change so it can be used for ecological risk assessment. Our experiment was designed to examine the ecological risk assessments for oil pollutant using benthic attached algal community on the artificial substrates of acrylic plates. Field monitoring in the culture system was conducted in Jangmok Bay. The abundances of attached micro-algae on artificial substrates gradually increased with increasing of sampling times. Among them, diatoms were the most important colonizer of coastal water, with the genera $Cylindrotheca$ and $Navicular$ most abundant. In particular, developed the culture system has correctly measured qualitative and quantitative abundance of attached micro-algae because same acrylic plates as artificial substrates were used. Thus, this culture system may be directly applied to the ecological risk experiments of microbial community structure from oil pollutants.

• Journal of Food Hygiene and Safety
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• v.24 no.3
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• pp.226-231
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• 2009

The aim of this study was to determine exposure assessment of pathogenic bacteria in edible ices by using the monitoring data from the previous study. According to the results of exposure assessment of edible ices contaminated with S. aureus, the contamination level of S. aureus in raw materials was higher than other foodborne pathogens, and the contamination level of S. aureus in mixed samples increased much before sterilization. The most significant reduction in contamination level was observed in mixed samples after sterilization, thus, the contamination levels in frozen final products was less than that of raw materials. Overall, the possibility for the infection of foodborne bacteria from the intake of edible ices per person per day was ranged from minimum $5.89{\times}10^{-7}$ to maximum $5.01{\tims}10^{-5}$. For more realistic estimates, consumption of edible ices and dose-response model must be studied further.

• Journal of Ecology and Environment
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• v.47 no.2
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• pp.14-26
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• 2023

Background: An important consideration for the risk assessment of transgenic plants is their overwintering potential in a natural ecosystem, which allows the survival of the seed bank and may lead to seed reproduction. Here, we investigated the overwintering of sunflower (Helianthus annuus L.) seeds in the laboratory (temperatures: -5, -1, 5, and 10℃) and in the field (burial depth: 0, 5, 15, and 30 cm) as a case study to examine the invasiveness of transgenic crops. Results: Sunflower seeds germinated when incubated at 5℃ and 10℃ for 2, 4, 6, and 12 weeks but not when incubated at -5℃ or -1℃. However, the seeds incubated at -5℃ or -1℃ germinated when they were transferred to the optimal germination temperature (25℃). Up to 16.5% and 15.0% of seeds were dormant when cultured at sub-zero temperatures in a Petri dish containing filter paper and soil, respectively. In the field trial, soil temperature, moisture, and microbial communities differed significantly between soil depths. Germination-related microorganisms were more distributed on the soil surface. Seeds buried on the surface decayed rapidly from 4 weeks after burial, whereas those buried at depths of 15 cm and 30 cm germinated even 16 weeks after burial. No dormancy was detected for seeds buried at any depth. Conclusions: Although sunflower seeds did not overwinter in situ in this study, we cannot exclude the possibility that these seeds lie dormant at sub-zero temperatures and then germinate at optimal temperatures in nature.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.5
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• pp.694-698
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• 2020

The consumption of Gwamegi, a semi-dried saury Cololabis saira, and its vegetable sides has increased owing to its availability online. Therefore, this study investigated the microbial contamination levels in Gwamegi and its accompanying vegetable sides bought online by measuring total viable bacteria, coliforms, Escherichia coli, Staphylococcus aureus and fungi. The total viable bacteria ranged from 3-5 log CFU/g. The fungi in Gwamegi and garlic were 3.4 and 3.9 log CFU/g, respectively. The positive rate of bacterial contamination was 100% (2-3 log CFU/g) in Gwamegi, cabbage Brassica rapa subsp. pekinensis, and green chili Capsicum annuum, whereas the contamination positive rate was 80% and 60% (< 2 log CFU/g) in chives Allium ascalonicum L. and garlic A. sativum L., respectively. The positive rates of E. coli were 0%, 20%, 60%, and 40% in Gwamegi, green chili, cabbage, and chives, respectively. The contamination levels of E. coli were 1-2 log CFU/g. S. aureus was detected at < 1 log CFU/g in all raw materials. The data on microbial contamination levels may be used for microbial risk assessment of Gwamegi and vegetables for controlling the level of microbial contamination and securing microbiological safety.

• Food Science of Animal Resources
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• v.38 no.5
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• pp.1043-1054
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• 2018

Salmonellosis caused by chicken consumption has been a critical issue in food safety worldwide, including in Korea. The probability of illness from consumption of chicken was simulated in study, based on the recipe of Dakgalbi, a commonly eaten chicken dish in Korea. Additionally, the processing stage at slaughterhouses to decrease Salmonella concentration in broilers was modeled to explore its effect on the likelihood of illness. A Monte Carlo simulation model was created using @RISK. Prevalence of Salmonella in chickens at the retail stage was found to be predominantly important in determining the probability of illness. Other than the prevalence, cooking temperature was found to have the largest impact on the probability of illness. The results also demonstrated that, although chlorination is a powerful tool for decreasing the Salmonella concentration in chicken, this effect did not last long and was negated by the following stages. This study analyzes the effects of variables of the retail-to-table pathway on the likelihood of salmonellosis in broiler consumption, and also evaluates the processing step used to decrease the contamination level of Salmonella in broilers at slaughterhouses. According to the results, we suggest that methods to decrease the contamination level of Salmonella such as chlorination had little effect on decreasing the probability of illness. Overall, these results suggest that preventing contamination of broiler with Salmonella must be a top priority and that methods to reduce the concentration of Salmonella in broilers at slaughterhouses hardly contribute to safe consumption of Salmonella-contaminated chicken.

• Journal of Food Hygiene and Safety
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• v.27 no.3
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• pp.312-316
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• 2012

This study was to present the proper probability distribution models that based on the data for surveys of food cold storage temperatures as the input variables to the further MRA (Microbial risk assessment). The temperature was measured by directly visiting 7 food plants. The overall mean temperature for food cold storages in the survey was $2.55{\pm}3.55^{\circ}C$, with 2.5% of above $10^{\circ}C$, $-3.2^{\circ}C$ and $14.9^{\circ}C$ as a minimum and maximum. Temperature distributions by space-locations was $0.80{\pm}1.69^{\circ}C$, $0.59{\pm}1.68^{\circ}C$, and $0.65{\pm}1.46^{\circ}C$ as an upper (2.4~4 m), middle (1.5~2.4 m), and lower (0.7~1.5 m), respectively. Probability distributions were also created using @RISK program based on the measured temperature data. Statistical ranking was determined by the goodness of fit (GOF) to determine the proper probability distribution model. This result showed that the LogLogistic (-4.189, 5.9098, 3.2565) distribution models was found to be the most appropriate for relative MRA conduction.

• Journal of Food Hygiene and Safety
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• v.34 no.2
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• pp.199-204
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• 2019

This study aimed to generate a probability distribution model based on temperature data of frozen food storage facility as input variables for microbial risk assessment (MRA). We visited 8 food-handling businesses to collect temperature data from their cold storage warehouses. The overall mean temperature inside the storage facilities was $-20.48{\pm}3.08^{\circ}C$, with 20.4% of the facilities having above $-18^{\circ}C$, with minimum and maximum temperature values of -10.3 and $-25.80^{\circ}C$ respectively. Temperature distributions by space locations of natural and forced convection were $-22.57{\pm}0.84$ and $-17.81{\pm}1.47^{\circ}C$, $-22.49{\pm}1.05$ and $-17.94{\pm}1.44^{\circ}C$, and $-22.68{\pm}1.03$ and $-18.08{\pm}1.42^{\circ}C$ in the upper (2.4~4 m), middle (1.5~2.4 m), and lower (0.7~1.5 m) shelves, respectively. Probability distributions from the temperature data were obtained using the program @RISK. Statistical ranking was determined using goodness of fit to determine the probability distribution model. Our results show that a log-normal distribution [5.9731, 3.3483, shift (-26.4281)] is most appropriate for relative MRA conduction.