• Journal of Environmental Health Sciences
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• v.40 no.6
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• pp.469-476
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• 2014

Objectives: The purpose of this study was to identify the stains causing infections in dental clinics by analyzing bacterial contamination, as well as to suggest improvements for infection control in dental clinics. Methods: In this study, a questionnaire survey of 47 dental hospitals and clinics located in Gyeonggi-do and Incheon, South Korea was administered from June 2013 to September 2013 and used to investigate the practice rates of infection control by dental hygienists and to analyze the bacterial contamination levels in dental offices. Results: In the studied institutions, the bacterial contamination levels of water lines were $20.9{\times}10^3$ colony forming units (CFU)/mL for three-way syringes, $12.7{\times}10^3CFU/mL$ for high-speed handpieces and $9.8{\times}10^3CFU/mL$ for gargling water. The bacterial contamination levels of surfaces were $44.9{\times}10^3CFU/mL$ in cuspidors, higher than in unit chairs ($2.9{\times}10^3CFU/mL$) and light handles ($6.7{\times}10^3CFU/mL$). The mean bacterial cell count of water lines and surfaces was relatively high in all establishments founded 11 years ago or more, and the mean bacterial cell count of waterline handpieces was $6.27{\times}10^3CFU/mL$ in establishments founded between one and five years ago, $11.16{\times}10^3CFU/mL$ six to ten years ago and $20.04{\times}10^3CFU/mL$ 11 years ago or more, which suggests that earlier foundation is associated with higher bacterial contamination levels with a statistical difference (p<0.01). Similarly, the mean bacterial cell count of cuspidors using water from water lines was also $70.16{\times}10^3CFU/mL$ in at least 11-year-old establishments, statistically significantly higher among in one- to five-year-old ($4.61{\times}10^3CFU/mL$) and six- to ten-year-old clinics ($47.89{\times}10^3CFU/mL$) (p<0.05). Conclusion: This study may be utilized to improve the bacterial contamination levels in dental offices by controlling the characteristics and environmental factors of dental offices that affect the microbial contamination of waterlines and surfaces in such institutions.

• Fisheries and Aquatic Sciences
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• v.18 no.3
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• pp.235-240
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• 2015

Seasonal variation in the prevalence of norovirus in oysters Crassostrea gigas was investigated and compared to levels of Escherichia coli, a fecal indicator in oysters. Oysters were collected from Iwon-myeon, Taean-gun, Korea, a primary production area for European Union export of oysters between 2013 and 2014. We observed seasonality in the prevalence of norovirus in oysters, with a higher prevalence and viral load detected during winter months. Oysters taken from production areas that complied with the European Union standard for raw consumption (< 230 MPN/100 g of E. coli) had 22.1% of the samples test positive for norovirus (15/68 samples). However, norovirus was not detected in any of the samples (0%, 0/4 samples) that were collected from production sites that exceeded the standard fecal contamination level for raw consumption (> 230 MPN/100 g of E. coli). These results indicated that there is a negative correlation between the prevalence of norovirus and high levels of E. coli in oysters. Therefore, our results suggest that current food safety guidelines using only a bacterial fecal contamination indicator, E. coli, may not adequately assess shellfish production areas for viral and bacterial contamination.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.245-245
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• 2017

Heavy metal pollution of agricultural soils affects land productivity and has impact on the quality of surrounding ecosystem. Soil microbial community parameters are used as reliable indices for assessing quality of agricultural lands under metal stress. This study investigated bacterial community structure of polluted and undisturbed paddy soils to elucidate soil factors that are related to alteration of bacterial communities under conditions of metal pollution. No obvious differences in the richness or diversity of bacterial communities were observed between samples from polluted and control areas. The bacterial communities of three locations were distinct from one another, and each location possessed distinctive set of bacterial phylotypes. The abundances of several phyla and genera differed significantly between study locations. Variation of bacterial community was mostly related to soil general properties at phylum level while at finer taxonomic levels concentrations of arsenic and lead were significant factors. According to results of bacterial community functional prediction, the soil bacterial communities of metal polluted locations were characterized by more abundant DNA replication and repair, translation, transcription and nucleotide metabolism pathway enzymes while amino acid and lipid metabolism as well as xenobiotic biodegradation potential was reduced.Our results suggest that the soil microbial communities had adapted to the elevated metal concentrations in the polluted soils as evidenced by changes in relative abundances of particular groups of microorganisms at different taxonomic resolution levels, and by altered functional potential of the microbial communities.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.1150-1158
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• 2009

Since equipment currently being used in the department of radiological technology comes into contact with patients carrying diseases, there inevitably will be the existence of pathogenic bacteria. Therefore, in order to increase the importance of using disinfectant in hospital infection precaution and the recognition of hospital infection management, comparisons were made by measuring the bacterial contamination levels in radiology room within the department of radiological technology and comparing the measurements with post disinfection levels. Disinfecting the rooms from detected bacteria was conducted with water, tissue cleaner, or 70% alcohol. When measuring bacterial contamination levels in radiology rooms, a variety of bacteria was detected. When disinfecting the interior of radiology rooms the effectiveness of destroying bacteria and preventing hospital infection was greatest when using 70% alcohol compared to water, tissue cleaner and ventilation. Therefore, there needs to be a development of a better antiseptic for destroying bacteria because there is a possibility for hospital medical equipment to be constantly contaminated. Efforts need to be made to prevent hospital infections and patient secondary infection by disinfecting and sterilizing equipment.

• Food Science and Preservation
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• v.20 no.3
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• pp.323-329
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• 2013

Strawberries are among the leading ready-to-eat agricultural products that have superior taste and nutrition. Thus, consumer concerns about the safety of eating strawberries are growing. To evaluate the contamination levels of strawberries according to their cultivation methods (nutriculture, pesticide-free culture and organic farming) and parts [fruit (flesh), stalk (pedunle) and leaf (calyx)], 1,020 parts of strawberry samples were collected at 12 farms in Nonsan-si and quantitatively or qualitatively examined for the indicators of food safety and food poisoning bacteria. The total aerobic bacteria count in the whole samples was 2.3~6.8 ${\log}_{10}$ CFU/g, and coliform bacteria were detected in 14.2% of the whole samples with a contamination level range of 2.1~4.5 log CFU/g. E. coli were detected in 0.9% of the whole samples with a contamination level range of 2.1~2.8 log CFU/g. The analysis of the bacterial levels according to the cultivation methods showed that the total aerobic bacteria and coliform counts were higher in the strawberries that were grown via organic farming than in those that were grown via nutriculture and pesticide-free culture. However, the E. coli counts of the strawberries that were grown via organic farming and via pesticide-free culture were similar and differed from that of the strawberries that were grown via nutriculture. The analysis of the contamination levels according to the parts of the strawberries showed that the total aerobic bacteria, coliform and E. coli counts of the fruits, stalks and leaves of the strawberries did not significantly differ. Staphylococcus aureus was detected in two organically grown strawberries, but Salmonella spp., Listeria monocytogenes and E. coli O157:H7 were not detected in the whole samples. These results show that the bacterial contamination levels of the strawberries differed based on their cultivation methods. Thus, a suitable method of reducing the bacterial contamination levels of strawberries according to their farming methods is needed.

• Journal of Nutrition and Health
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• v.4 no.3
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• pp.13-25
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• 1971

During a period from October 1st to November 15th in 1971, We made a survey on hygienic status of kitchen utensils used at 270 college student's home in 9 districts of Seoul city. The results obtained could be summarized as follows. In bacteriological study on the kitchen utensils 20.7% of them revealed contaminations with general bacterial counts of over 100/m1 and 20.0% of them with coliform bacteria. It was probable that degrees of bacterial contamination of the kitchen utensils were chiefly attributable to levels of education of housewives and living standard of individual household. Factors that were presumed to be directly responsible for the contamination were sources and storage of water and methods of washing the utensils. One of the major sources of contamination was derived from the use of a piece of cloth (Hangjoo) to wipe up the utensils after soashing. Hygienic treatment of Hangjoo in urgently needed. Otherwise, it is desirable not to used the Hangjoo and leave the utensils dry after washing them with boiling water.

• Reproductive and Developmental Biology
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• v.37 no.4
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• pp.213-217
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• 2013

The objective of this study was to investigate the effect of bacterial contamination on elapsed time after preservation on boar semen. Known numbers of Escherichia coli (E. coli) were inoculated to freshly ejaculated semen and sperm parameters such as viability, motility, agglutination, acrosome integrity and hypo-osmotic swelling test were performed during 7 days of liquid preservation. Semen samples were prepared using antibiotic free BTS extender and 4 different levels of E. coli were treated to semen with following concentrations; 3,000, 5,000, 7,000, 10,000 CFU/ml of sperms. Semen samples were preserved at $17^{\circ}C$ for 7 days in semen storage until analyzed. Aliquots were subjected to measure the sperm viability, motility and agglutination using computer assisted sperm analysis (CASA) system, acrosome integrity was performed using chlortetracycline (CTC) staining method and hypo-osmotic swelling test was performed using hypotonic solution from day 1 (day of semen collection) to 7. Detrimental effects on sperm motility and viability were observed 3 days after preservation at the level of 5,000 CFU/ml (p<0.05). Percentage of sperm abnormality was higher (p<0.05) in over 5,000 CFU/ml groups. Sperm agglutination rate was also significantly higher (p<0.05) in groups of 5,000 and 7,000 CFU/ml. The rate of acrosome reacted sperm was higher as preservation time goes in all the samples but the pattern was clearly higher among E. coli contaminated groups (p<0.05). The sperm membrane integrity in terms of hypo-osmotic test, E. coli affects little compared to other sperm parameters. The deleterious effects observed due to the bacterial contamination in semen suggest that importance of hygiene protocol to minimize the bacterial contamination during semen collection and processing.

• International Journal of Oral Biology
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• v.39 no.3
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• pp.137-143
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• 2014

Dental professionals are repeatedly exposed to many microorganisms present in both blood and saliva. Thus, dental professionals are at a greater risk of acquiring and spreading infections, and the implementation of infections control guidelines is necessary. Cellular phones have become a necessary device for communicating in hospitals. Cellular phones contaminated with bacteria may serve as a fomite in the transmission of pathogens by the hands of medical personnel. Nevertheless, studies about rate and levels of bacterial contamination of cellular phones have been extremely limited with regards to dental personnel. The purpose of this study was to identify bacterial flora on the cellular phones of dentists by a molecular biological method using the 16S rRNA cloning and sequencing method. We acquired total 200 clones from dentists' cell phones and identified the bacterial species. Pseudomonas (34.6%), Lactobacillus (18.5%), Azomonas (11.5%), and Janthinobacterium (6%) were the dominant genera on dentists' cell phones. The oral bacteria identified were Anaerococcus lactolyticus, Gibbsiella dentisursi, Lactobacills leiae, Streptococcus mitis, Streptococcus oligofermentans, and Streptococcus sanguinis. Pathogenic bacteria and opportunistic pathogens such as Carnobacterium funditum, Raoultella planticola, Shigella flexneri, Lactobacillus iners, Staphylococcus aureus, and Staphylococcus epidermidis were also identified.

• The Journal of Advanced Prosthodontics
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• v.14 no.5
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• pp.273-284
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• 2022

PURPOSE. Computer-aided design and manufacturing (CAD-CAM) of implant abutments has been shown to result in surface contamination from site-specific milling and fabrication processes. If not removed, these contaminants can have a potentially adverse effect and may trigger inflammatory responses of the peri-implant tissues. The aim of the present study was to evaluate the bacterial disinfection and cleaning efficacy of ultrasonic reprocessing in approved disinfectants to reduce the microbial load of CAD-CAM abutments. MATERIALS AND METHODS. Four different types of custom implant abutments (total N = 32) with eight specimens in each test group (type I to IV) were CAD-CAM manufactured. In two separate contamination experiments, specimens were contaminated with heparinized sheep blood alone and with heparinized sheep blood and the test bacterium Enterococcus faecium. Abutments in the test group were processed according to a three-stage ultrasonic protocol and assessed qualitatively and quantitatively by determination of residual protein. Ultrasonicated specimens contaminated with sheep blood and E. faecium were additionally eluted and the dilutions were incubated on agar plates for seven days. The determined bacterial counts were expressed as colony-forming units (CFU). RESULTS. Ultrasonic reprocessing resulted in a substantial decrease in residual bacterial protein to less than 80 ㎍ and a reduction in microbiota of more than 7 log levels of CFU for all abutment types, exceeding the effect required for disinfection. CONCLUSION. A three-stage ultrasonic cleaning and disinfection protocol results in effective bacterial decontamination. The procedure is reproducible and complies with the standardized reprocessing and disinfection specifications for one- or two-piece CAD-CAM implant abutments.

• Food Science and Preservation
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• v.18 no.1
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• pp.7-12
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• 2011

Paprika is a major export of Korea, but biosafety is important if exports are to grow. To date, few paprika biosafety data are available. We evaluated microbiological contamination of paprika, and determined bacterial levels with respect to storage temperature. Mean counts of total aerobic bacteria were $2.3{\pm}0.3\;log_{10}\;CFU/g$, but coliforms were not isolated. Staphylococcus aureus, Salmonella spp., Listeria spp., and Escherichia coli O157 were also not detected. When bacterial contamination of paprika stored at room temperature or $4^{\circ}C$ for 20 days was evaluated, the numbers of total aerobic bacteria peaked at 14-16 days at room temperature (4 times more than those of $4^{\circ}C$). However, aerobic bacteria grew slowly at $4^{\circ}C$. Coliforms were also detected twice at room temperature, but not upon storage at $4^{\circ}C$. The results indicate that the paprika exported from Korea is relatively biosafe. However, food hygiene issues must be addressed to reduce contamination during storage and distribution.