• 한국환경보건학회지
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• 제40권2호
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• pp.88-97
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• 2014

Objectives: The aim of this study was to evaluate the occurrence of microbiological contamination of kitchen utensils and environments of food service operations at university located in Seoul, Korea. Methods: We collected swab samples from the surfaces of knives, chopping boards, floors, and drains, as well as drinking water and airborne bacteria samples from 20 food service operations. Three bacterial indicators and five food poisoning bacteria were measured quantitatively and qualitatively, respectively. We used selective culture media and the PCR assay targeting 16S rRNA gene for the microbiological analysis. Results: We detected bacterial indicators on knives or chopping boards in eight different food service operations and, three food service operations (I, M, and O) showed more than 3 log colony forming units $(CFU)/100cm^2$ on their knives, significantly higher than the others. The levels of bacterial indicators on the floors and drains in the cooking areas were much higher than those on the cooking utensils. S. aureus was detected on 10 floors and 8 drains. Culturable bacteria were identified in 5 drinking water samples, and food service operation B ($431.1CFU/m^3$) and C ($551.2CFU/m^3$) showed more than $400CFU/m^3$ of total airborne bacteria. Conclusions: These results suggest that some of food service operations in this study may require additional investigation to secure the microbial safety of cooking environments. In addition, further actions including hygiene education for employees and proper guidelines to maintain clean cooking environments should be prepared.

• 한국환경보건학회지
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• 제19권1호
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• pp.30-36
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• 1993

A survey was conducted to measure concentration of airborne microbe in a hospital using RSC air sampler during October~November 1991.The result was as follows: 1) In an agar strip GK-A media for total counts of microbial particles. The highest count were 1384 CFU/m$^3$ in the main lobby, followed by 912 CFU/m$^3$, in the obstetric room, 688 CFU/m$^3$ in 1CU. By gram staining, the distribution for organisms in the air were shown 74.1% in gram possitive cocci followed by 16.8%, in gram possitive bacilli 6.7% in gram negative bacilli and 4.7% in yeast, but low organism was detected in recovery room with 194 CFU/m$^3$. 2) In agar strip S media for Staphylococci the count at the main lobby was detected in the recovery room with 92 CFU/m$^3$, Tests of coagulase were negative Staphylococci with 78%, and positive Staphylococci with 22%. The Staphylococci were highly resistance to penicillin, ampicillin and sensitive to amikacin, cefazolin, gentamycin and chloramphenicol. 3) In agar strip C media for coliform bacteria the colony counts at the main lobby was 139 CFU/m$^3$ and treatment room was 190 CFU/m$^3$, most frequently isolated microorganisms were non fermentative bacilli. 4) In agar strip HS media for yeast and molds. Most frequently colony counts 17~76 CFU/m$^3$, 0.5% lactophenol cotton blue stains were shown unidentified 77.2%, 8.1%, in Penicillium 8.1% in Aspergillus, and 3.8% in mucor.

• 한국입자에어로졸학회지
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• 제19권1호
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• pp.1-11
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• 2023

Respiratory face masks are protective facepieces that are designed to filter inhaled air. They are easy-to-use devices that can protect the wearer against various hazardous particles in the air. Respiratory face masks also prevent the spread of viruses and bacteria-containing droplets that are released from the coughing or sneezing of the infected people. During the COVID-19 pandemic, various types of face masks have circulated on the market. Their ability to filter sub-micron particles, which are the sizes of harmful particulate matter and airborne viruses, needs to be investigated. Their breathability, the easiness of breath through the mask, also needs to be considered. In this study, wwe evaluated the performance of filters used for different types of face masks certified by different standards including Korean (KF94, KF80, KF-AD), USA (N95), and Chinese (KN95) standards. We also tested the filters of nanofiber masks and surgical masks for which there are no standards for filtration test. The N95 mask filters showed the highest quality factor for capturing virus-sized particles. The other types of mask filters have acceptable performance except for nanofiber mask filters whose performance is very low.

• 한국환경보건학회지
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• 제36권4호
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• pp.306-312
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• 2010

This field study was performed to evaluate the efficiency of a plasma ion-operated air cleaner in temporal reduction of airborne pollutants emitted from a pig housing facility. In the case of gaseous pollutants, the plasma ion air cleaner was not effective in reducing levels of ammonia, hydrogen sulfide, nitrogen dioxide, or sulfur dioxide (p>0.05). In the case of particulate pollutants, however, the air cleaner was effective in reducing levels of particulate matter ($PM_{2.5}$ and $PM_1$) by 79(${\pm}6.1$) and 78(${\pm}3.0$)%, respectively. Unlike the case of these fine particle fractions, the reduction of total suspended particles (TSP) and $PM_{10}$ following treatment was almost negligible. In the case of biological pollutants, the mean reduction efficiencies for airborne bacteria and fungi were relatively low at 22(${\pm}6.6$) and 25(${\pm}8.7$)%, respectively. Taken together, these results indicate that in terms of air pollutants released from this pig housing facility, the plasma ion air cleaner was primarily effective in reducing levels of $PM_{2.5}$ and $PM_1$.

• Advances in environmental research
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• 제2권1호
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• pp.61-80
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• 2013

Quantification of viable forms of microbial community (bacteria and fungi) using culture-dependent methods was done in order to characterize the indoor air quality (IAQ). Role of those factors, which may influence the concentration of viable counts of bacteria and fungi, like ventilation, occupancy, outdoor concentration and environmental parameters (temperature and relative humidity) were also determined. Volumetric-infiltration sampling technique was employed to collect air samples both inside and outside the schools. As regard of measurements of airborne viable culturable microflora of schools during one academic year, the level of TVMCs in school buildings was ranged between 803-5368 cfu/$m^3$. Viable counts of bacteria (VBCs) were constituted 63.7% of the mean total viable microbial counts where as viable counts of fungi (VFCs) formed 36.3% of the total. Mean a total viable microbial count (TVMCs) in three schools was 2491 cfu/$m^3$. Outdoor level of TVMCs was varied from 736-5855 cfu/$m^3$. Maximum and minimum VBCs were 3678-286 cfu/m3 respectively. Culturable fungal counts were ranged from 268-2089 cfu/$m^3$ in three schools. Significant positive correlation (p < 0.01) was indicated that indoor concentration of viable community reliant upon outdoor concentration. Temperature seemed to have a large effect (p < 0.05, p < 0.01) on the concentration of viable culturable microbial community rather than relative humidity. Consistent with the analysis and findings, the concentration of viable cultural counts of bacteria and fungi found indoors, were of several orders of magnitude, depending upon the potential of local, spatial and temporal factors, IO ratio appeared as a crucial indicator to identify the source of microbial contaminants.

• Journal of Animal Science and Technology
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• 제64권3호
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• pp.539-563
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• 2022

Nine pig farms were evaluated for the welfare quality in Korea using animal- and environment-based parameters (particularly air quality parameters) during the winter of 2013. The Welfare Quality^® (WQ^®) protocol consists of 12 criteria within four principles. The WQ^® protocol classifies farms into four categories ranging from 'excellent' to 'not classified'. Each of these criteria has specific measures for calculating scores. Calculations for the welfare scores were conducted online using the calculation model in the WQ^® protocol. Environment-based parameters like microclimate (i.e., temperature, relative humidity, air speed, and particulate matter), bacteria (total airborne bacteria, airborne total coliform, and airborne total Escherichia coli), concentration of gases (carbon dioxide, ammonia, and hydrogen sulfide) were measured to investigate the relationship between animal- and environment-based parameters. Correlations between the results of animal- and environment-based parameters were estimated using spearman correlation coefficient. The overall assessments found that five out of nine farms were 'acceptable', and four farms were 'enhanced'; no farm was 'not classified'. The average score for the four principles across the nine farms, in decreasing order, were 'good feeding' (63.13 points) > 'good housing' (59.26 points) > 'good health' (33.47 points) > 'appropriate behaviors' (25.48 points). In the result of the environment aspect, the relative humidity of farms 2 (93.4%), 3 (100%), and 9 (98%) was much higher than the recommended maximum relative humidity of 80%, and four out of the nine farms had ammonia concentrations greater than 40 ppm. Ammonia had negative correlations with 'positive social behaviors' and positive emotional states: content, enjoying, sociable, playful, lively, happy and it had positive correlations with negative emotional states: aimless, distressed. The concentration of carbon dioxide had negative correlations with positive emotional states; calm, sociable, playful, happy and it had a positive correlation with negative emotional state; aimless. Our results indicate that the control of the environment for growing pigs can help improve their welfare, particularly via good air quality (carbon dioxide, ammonia, hydrogen sulfide).

• 한국식품영양과학회지
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• 제42권3호
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• pp.457-463
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• 2013

Dressing 가공공정에 대한 HACCP(Hazard Analysis Critical Control Point) 시스템 구축을 위하여 위해요소 분석을 실시하였다. 위해요소 분석은 주원료, 용수, 미생물 평가, 작업장별 공중 낙하균과 종업원에 대한 병원성 미생물 검사를 하였다. 충청북도 진천 소재의 SJ 회사에서 2012년 4월 1일부터 30일까지 30일 동안 수행하였다. 그 결과 원료의 미생물은 5회 동안 검출되지 않았으며, 작업장 I과 작업장 II, 포장실, 세척용수, 검사실에서 사용된 용수의 총균수는 $3.0{\times}10^1$ CFU/mL 이하로 검출되었다. 드레싱 생산과정 중 열처리 및 혼합 과정에서 총균수는 평균 $3{\times}10$ CFU/mL가 검출되었으나 대장균과 진균류, 병원성 미생물은 검출되지 않았다. 공중 낙하균(총균수와 진균류)은 각각의 작업장에서 법적 허용치 이하로 검출되었다. 작업자들의 총균수 미생물 평가에서 모두 양성반응이었으나 대장균과 황색포도상구균은 검출되지 않았다. 결론적으로 위생관리 기준은 HACCP 시스템을 위한 미생물의 한계기준과 일반세균과 병원성 미생물과 같은 위해요소를 예방 및 감소시키기 위하여 설정하여야 한다.

• 한국산업보건학회지
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• 제33권4호
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• pp.395-402
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• 2023

Objectives: Microbial contamination of face masks used by healthcare professionals can vary depending on the degree of exposure to bioaerosols in various healthcare environments. However, research on this topic is limited. Therefore, we analyzed microbial contamination of N95 respirators used in hospital offices, wards, and outpatient settings. Methods: Samples isolated from N95 respirators worn for 2, 4, and 6 hours were incubated at a temperature of 35-37℃ or 25-28℃ for 24 hours or for 3-7 days, and colony-forming units were counted in chocolate agar, tryptic soy agar, and Sabouraud dextrose agar plates. Total indoor airborne bacteria were also measured in the healthcare environments. Finally, microbial species were identified using Gram staining with a microscopic speculum. Results: The three types of environments did not deviate from the maintenance of standard indoor air quality. There was no difference between the microbial species identified in the healthcare environment and mask contamination. However, the number of bacteria in the masks worn in each environment differed, and the degree of contamination increased with mask-wearing time (p<0.05). Conclusions: Therefore, care must be taken to avoid recontamination of masks due to improper use and exposure to biological hazards in healthcare environments. In conclusion, scientific evidence is necessary for safe mask-wearing times. Based on the results of this study, we hope to conduct further research to establish guidelines for the safe use of face masks during respiratory disease epidemics.

• 한국환경보건학회지
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• 제39권5호
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• pp.456-464
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• 2013

Objectives: The aim of this study was to investigate the microbial contamination levels in elevators in apartment buildings and to provide information on such microbial contamination. Methods: A total of 144 samples, including from the exterior buttons, interior buttons, elevator handrails, walls, ventilators and airborne bacteria were collected in the morning and afternoon from July to August 2013 for six different elevators. The samples were used to detect sanitary indicator bacteria (total bacteria, coliform, and Escherichia coli), pathogenic bacteria (E. coli O157, L. monocytogenes, Salmonella spp., B. cereus, S. aureus) and fungi. Results: Contamination levels of total bacteria were 0.3-3.8 and 0.0-2.4 log CFU/100 $cm^2$ in the morning and afternoon, respectively. In the case of coliform bacteria, the levels were 0.0-3.7 log CFU/100 $cm^2$ in the morning and 0.0-0.3 log CFU/100 $cm^2$ in the afternoon. However, E. coli was not detected among all samples. Bacillus cereus, pathogenic bacteria, was only detected in 13 (11%) among 144 samples. E. coli O157, L. monocytogenes, Salmonella spp. and S. aureus were not detected among all samples. Comparing the samples collected in the morning and afternoon, we could confirm that the samples in the afternoon were cleaner. Conclusions: This study indicates that the samples in the afternoon were cleaner because these samples were collected following routine cleaning. Also, the levels of contamination in the elevators were low and the sanitary conditions were comparatively well-managed. Therefore it is deemed necessary for elevators be cleaned regularly to provide good conditions for people using elevators.

• 한국건설순환자원학회논문집
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• 제10권1호
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• pp.117-123
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• 2022

현대인은 대부분의 시간을 실내에서 보내고 있기 때문에 실내 공기질에 대한 관심이 높아지는 추세이다. 실내 공기의 주요 오염원으로는 인간의 활동, 건축자재, 생활용품, 외부로부터 오염된 대기의 유입 등을 들 수 있다. 실내 공기질 관리법에서는 실내공기 오염물질로 미세먼지, 총 부유세균, 곰팡이, 이산화탄소 등 17종을 규정하고 있다. 현대인의 실내 환경은 세균과 곰팡이균의 생육환경이 흡사하기 때문에 일상생활에서 세균과 곰팡이에 항상 노출된다. 특히 많은 사람이 모이는 다중이용시설의 경우에는 세균감염의 위험이 더 크다고 할 수 있다. 한편 솔잎은 예전부터 항균효과가 뛰어난 것으로 알려져 있으며, 한약재, 식용 등 쓰임새가 다양하다. 그 외에 의약, 식품 및 염색제 관련 산업에서는 적극적으로 활용하고 있으며, 최근에는 건축자재로 이용하기 위한 시도도 이루어지고 있는 실정이다. 솔잎의 항균효과에 관한 연구는 상당히 많이 이루어지고 있으며, 다양한 항균 성분을 가지고 있다. 따라서 본 연구는 솔잎 추출물의 항세균, 항곰팡이 효과를 확인하였으며, 이를 토대로 솔잎 추출물을 혼입한 시멘트 경화체를 제작해 솔잎 추출물의 혼입 비율별 세균과 곰팡이에 대한 항균 활성 효과를 연구하였다. 솔잎 추출물은 황색포도상구균과 대장균에 대해 항세균 효과를 나타났으며, 검정 곰팡이에 대해 생육환경을 저해하는 것이 나타났다. 솔잎 추출물을 혼입한 시멘트 경화체는 황색포도상구균과 대장균에 대해서 항균 활성 효과를 나타냈다. 그러나 검정 곰팡이에 대해서 항균 활성 효과를 나타내지 않았다. 결과적으로, 솔잎추출물을 혼입한 시멘트 경화체는 병원균 억제에는 효과적이지만 곰팡이에 대해서는 효과가 없는 것으로 판단되며, 솔잎추출물을 항균재료 사용하기 위해서는 곰팡이의 생육을 저해하는 요인에 대한 추가적인 연구가 필요할 것으로 판단된다.