• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.162-167
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• 2015

매년 여름철 피서지 1순위로 손꼽히는 해수욕장은 해양레포츠의 발달과 관광사업의 촉진으로 수많은 관광객들이 방문하고 있다. 하지만 우리나라 대부분의 해수욕장에서는 건전한 해수욕을 위한 수질안전지표 설정이 매우 미흡한 편이며 오염수준 또한 심각하다. 이에 강원도 강릉시 경포해수욕장을 대상지역으로 2012년 7월 17일부터 9월 4일까지 매주 화요일 오전에 채취한 시료로부터 병원성 수질지표인 장구균과 대장균, 총대장균군의 오염도를 분석하였다. 시료는 경포해수욕장 오리바위 배후부터 연안방향을 따라 200m 간격으로 3지점과 이안방향을 따라 백사장(dry beach), 포말대(swash zone), 유영층(swimming zone)의 3지점에서 총 9개를 채취하였다. 기온, 강우, 장소 등의 해안 환경 변화에 따른 병원균 증식 유리조건 및 인자들간의 상관성을 분석한 결과 백사장에서는 총대장균군, 포말대에서는 장구균, 유영층에서는 대장균의 농도가 가장 높았다. 또한 주간 누적 강우량과 평균 기온에 따라 시료채취 지점마다의 상관성에서는 백사장은 강우량과 정비례, 기온과는 반비례, 포말대와 유영층은 강우량과 반비례, 기온과는 정비례의 관계를 보였다. 백사장과 해수층인 포말대, 백사장과 유영층 각각은 반비례 관계를 보였지만 미비한 수준이었으며 포말대와 유영층간의 상관성은 약 90%의 매우 높은 수치를 띄었다. 본 연구는 건전한 수계 레크레이션 문화의 수질 안전지표 설정을 위해 해수욕장의 대표 관광명소 중 하나인 경포해수욕장을 대상으로 병원성 수질 지표들의 증식 유리 조건 및 확산특성 예측에 목적이 있다. 나아가 본 과정은 해변을 찾는 관광객들의 수질 안전 정보 제공 및 체계적인 가이드라인 제시로도 가치 있을 것으로 기대된다.

• The Microorganisms and Industry
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• v.39 no.1
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• pp.2-4
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• 2013

• Microbiology and Biotechnology Letters
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• v.43 no.3
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• pp.259-266
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• 2015

Observed trends in climate change, globalization and an aging population have an effect on public health conditions in Korea, prompting a reevaluation of current environmental regulations. In this study, we evaluated the performance of the total coliform (TC) standard, which is the only microbiological standard in the current regulation regime for hot spring water, by estimating correlation with the presence/absence of Legionella, a non-fecal opportunistic pathogen with heat-tolerance. Microbiological data in 7 studies that surveyed Legionella in hot spring waters were subjected to meta-analyses with the odds ratio (OR) as the effect size. The presence/absence of Legionella was significantly correlated to TC levels [OR = 3.1(1.5–6.4, 95% CI), p = 0.002]. Due to there being no direct explanation as to the reason for the occurrence of TC, mesophilic fecal bacteria, being coupled with Legionella presence, the mechanism of the correlation between the two kinds of bacteria was further investigated. Legionella presence was more prevalent with a high heterotrophic plate count [HPC; 4.0(2.2–7.2); p < 0.001] and water temperature [4.3(1.4–13.6), p = 0.011] when the temperature range was <40℃. However, it was reverse-correlated with water temperature when the temperature was >50℃ [0.2(0.1–0.4), p < 0.001]. Therefore, bacterial standing crops in hot spring waters appear to be determined by water temperature in general, and this forces TC and Legionella levels be correlated. In accordance with this relationship, HPC rather than TC reflect the levels of non-fecal contamination better. Therefore, employing HPC as the sole microbiological standard, or adding HPC into the current standard of hot spring water assessment, is suggested as a proactive measure to prevent health issues arising from contamination.

• Journal of Food Hygiene and Safety
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• v.26 no.2
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• pp.154-159
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• 2011

Inadequate food handling and poor hand hygiene playa major role in the occurrence of foodborne diseases. The objective of this study was to find out if the level of microbial contamination on the hands of food preparers varies by time during their working period. This study focused on the contamination of aerobic plate count, total and fecal coliforms, Escherichia coli, Staphylococcus aureus, and Salmonella spp. Sampling from left hand and right hand of twenty food preparers was done with glove-juice method at every two hours during their work. Microbiological testing was conducted according to the Food Code of Korea. The microbiological load on the hands was changed over time. Samples taken from their hands before work and at 8 hours showed higher levels of bacteria than those taken at 2, 4, and 6 hours during work and/or after work (p < 0.05). The contamination levels of microorganisms were consistently higher in right hand than in left hand. Poor hand hygiene practices were indicated by the positive results for total and fecal coli forms, E. coli, S. aureus, and Salmonella spp. on the hands of some food preparers. This study indicates food preparers' hands can be a vehicle of pathogen during their work. The results of this study emphasize the importance of hand hygiene education and training targeting the food preparers.

• Journal of Korean Society on Water Environment
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• v.25 no.1
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• pp.136-141
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• 2009

Inactivation rates between enterococci and total coliforms were compared in order to find the suitability of enterococci as an indicator microorganism under various experiment conditions - freshwater and/or seawater, indoor and/or outdoor conditions. In case of indoor laboratory experiments, inactivation rates of enterococci ($k_D$: 0.050~0.082) were faster than those of total coliforms ($k_D$: 0.034~0.045) in freshwater matrix. In seawater matrix, however, survival rate of enterococci was longer than that of total coliforms at two out of three experiments in indoor condition. When incubated in outdoor conditions, enterococci were inactivated significantly more rapidly than total coliforms both in freshwater and seawater matrices. With these results, enterococci appear to be less suitable than total coliforms in terms of inactivation rates.

• Korean Journal of Microbiology
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• v.49 no.4
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• pp.424-428
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• 2013

To identify risk factors for Legionella contamination, water quality variables routinely measured in examination of natural and city waters were meta-analyzed for significance of correlation to Legionella incidences. For evaluation of abundance of Escherichia coli as a risk factor, which is currently used as an indicator of Legionella contamination in an official guideline in Korea, odds ratio (OR) of above-cutoff total coliform counts for Legionella presence/absence was used as the effect size in the meta-analysis. The OR was estimated as 1.05 (0.36-3.12, 95% CI), and the probability of having identical odds reached 0.92. Also, ORs from individual studies showed significant heterogeneity (P=0.008), which contributed to 63% of total variance of the ORs. In the case of heterotrophic plate count (HPC), the OR for Legionella presence/absence was 2.72 (2.04-3.63) with highly significant deviation from identical odds (P<0.0001). ORs from different studies were seemingly homogeneous ($Q_{df=8}$=12.7, P=0.12). Turbidity and concentrations of chlorine, iron ion and cupper ion were other routine variables that could be considered as risk factors. However, statistical measures from different studies were not uniform enough to develop an appropriate effect size while the number of studies reporting the variables was also small (3-5). In conclusion, HPC appeared to be appropriate as indicator of Legionella contamination, rather than fecal bacteria contamination. HPC may imply abundance of habitats (amoebas and biofilms) of Legionella in water. This result warrants further studies for standardizing protocols and cutoff values to infer Legionella risks from HPC.

• Clean Technology
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• v.26 no.1
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• pp.39-54
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• 2020

This study analyzed the groundwater quality according to the depth and geological features in Gyeongsangnam-do area using groundwater quality monitoring network data to grasp the groundwater quality characteristics and to provide basic data for policy making on efficient groundwater management. Five hundred and three data sets were acquired from background water quality exclusive monitoring network in soil groundwater information system for five years (2013 ~ 2017). Except for the total coliforms and tracer items such as mercury, phenol, and others, the parameters of water quality were significant or very significant, depending on depth and geological features. As the depth got deeper, the average value of pH and electrical conductivity increased; water temperature, dissolved oxygen, oxide reduction potential, arsenic, total coliforms, and turbidity decreased; and total unfit rate for drinking water standards was lower. It was found that the sum of the positive and negative ions was the highest in the clastic sedimentary rock and the lowest in metamorphic rock. The total unfit rate for drinking water standards was the highest for metamorphic rocks, followed by clastic sedimentary rock and unconsolidated sediments and, finally, intrusive igneous rock with the lowest penetration. The Na-Cl water type, which indicated the possibility of contamination by external pollutants, appeared only at some points in shallow depths and in clastic sedimentary rocks.

• Journal of Food Hygiene and Safety
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• v.32 no.5
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• pp.396-403
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• 2017

The purpose of this study was to investigate water quality for irrigation water used in Napa cabbage cultivation. The water samples were analyzed for physiochemical and microbiological quality for a total of 111 samples including surface water (n = 75) and groundwater (n = 36) collected from five different regions where Napa cabbage is massively grown. As a conclusion, the levels of fecal indicators for surface water were higher than those for groundwater. The numbers of coliform from surface water and groundwater were 1.96-4.96 and 0-3.98 log MPN/100 mL, respectively. Enterococci were detected in 95% (72/75) of surface water samples and 22% (8/36) of groundwater samples. Besides, 97% (73/75) of surface water samples were observed being contaminated with Escherichia coli, and 22% (8/36) of groundwater sample was positive for E. coli. In the case of surface water, E. coli and coliform correlate to T-P, and enterococci showed relevance to the suspended solid (SS) and biochemical oxygen demand (BOD). In groundwater, fecal indicator bacteria showed relevance to the SS and chemical oxygen demand (COD). These results could be provided as fundamental date for establishing microbial standard of water used in leafy vegetables cultivation.

• Journal of Life Science
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• v.18 no.3
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• pp.395-402
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• 2008

Level of microbial contamination was examined in four fish farms of Jeju east coast for sanitary indication of bacterial contamination such as heterotrophic bacteria, Escherichia coli O157:H7, Salmonella spp., Vibrio parahaemolyticus, Staphylococcus aureus, Bacillus cereus and total coliforms. The samples were collected and investigated from June to October in 2007. Bacterial species of S. aureus, B. cereus and Salmonella spp. were frequently detected from the seawater of above fish farms. Salmonella spp., S. aureus, B. cereus were detected in the range of $0{\sim}4.3{\times}l0^3,\;0{\sim}2.7{\times}l0^4,\;0{\sim}7.6{\times}l0^3$ CFU/ml, respectively, from the fish feed used in all four selected farms. Additionally, Salmonella spp., S. aureus, B. cereus were detected in oliver flounder (Paralichthys olivaceus) of these farms, however total coliforms and E. coli O157:H7 were not detected during our experimental period. For the production of microbiologically safe and healthy oliver flounder, proper quality control of feed, sanitation programs, and continuous monitoring of microorganism are essential practices, which required to include in the farm management system.

• Food Science and Preservation
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• v.30 no.3
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• pp.459-471
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• 2023

The Bayesian network (BN) model was applied to analyze the characteristic variables that affect compliance with safety inspections of farmed eel during the production stage, using the data from 30,063 cases of eel aquafarm safety inspection in the Integrated Food Safety Information Network (IFSIN) from 2012 to 2021. The dataset for establishing the BN model included 77 non-conforming cases. Relevant HACCP data, geographic information about the aquafarms, and environmental data were collected and mapped to the IFSIN data to derive explanatory variables for nonconformity. Aquafarm HACCP certification, detection history of harmful substances during the last 5 y, history of nonconformity during the last 5 y, and the suitability of the aquatic environment as determined by the levels of total coliform bacteria and total organic carbon were selected as the explanatory variables. The highest achievable eel aquafarm noncompliance rate by manipulating the derived explanatory variables was 24.5%, which was 94 times higher than the overall farmed eel noncompliance rate reported in IFSIN between 2017 and 2021. The established BN model was validated using the IFSIN eel aquafarm inspection results conducted between January and August 2022. The noncompliance rate in the validation set was 0.22% (15 nonconformances out of 6,785 cases). The precision of BN model prediction was 0.1579, which was 71.4 times higher than the non-compliance rate of the validation set.