• Food Engineering Progress
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• v.13 no.4
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• pp.352-359
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• 2009

Lactic acid bacteria was isolated for the production of probiotic animal feed supplemented with garlic and its antimicrobial properties were investigated. A total of 112 strains of lactic acid bacteria which grew on the medium containing garlic extract were isolated from kimchi, jeotgal, and jangachi. Among them 14 strains were tested for acidand bile salt-resistance as well as antimicrobial activities against animal pathogenic bacteria such as Salmonella choleraesuis, Escherichia coli, Staphylococcus aureus, and Shigella flexneri. Of these strains, a strain P'GW50-2 from pickled scallion with most desirable properties was selected and identified as Lactobacillus plantarum TJ-LP-002. Antimicrobial activity of L. plantarum TJ-LP-002 showed relatively wide range of inhibition spectrum against Gram negative bacteria such as Aeromicrobium hydrophila, E. coli, Pseudomonas, Salmonella, Shigella, and some Gram positive bacteria such as Bacillus cereus, Staphylococcus aureus, Clostridium perfringens, and Propionibacterium.

• Journal of dental hygiene science
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• v.19 no.2
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• pp.107-112
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• 2019

Background: Good oral health is important for systemic body health and quality of life. Spray oral cleansers are increasingly preferred because of their convenience of carrying and the ease of oral hygiene management. In addition, many kinds of oral cleanser products containing various ingredients with antibacterial, washing, and moisturizing effects are being manufactured. However, concerns about the safety and side effects of oral sprays are increasing, and there is very little information regarding the use and care of oral sprays is available to consumers. This study aimed to investigate the effects of oral spray on oral bacteria and tissue to elucidate the factors that need to be considered when using oral sprays. Methods: The effects of oral spray on the growth of dental plaque bacteria was assessed using disk diffusion assays. Cytotoxicity and morphological changes in oral epithelial cells were observed by microscopy. The effects of oral spray on dental plaque growth were also confirmed on specimens from permanent incisors of bovines by Coomassie staining. Results: The pH of spray products, such as Perioe Dental Cooling, Cool Sense, and Dentrix, were 3.65, 3.61, and 6.15, respectively. All tested spray products showed strong toxicity to dental plaque bacteria and oral epithelial cells. Compared with those on the control, dental plaque bacteria deposits on the enamel surface increased following the use of oral spray. Conclusion: Three types of oral spray, namely Perioe Dental Cooling, Cool Sense, and Dentrix, strongly inhibited the growth of dental plaque bacteria and oral epithelial cells. The oral spray ingredient enhanced dental plaque growth on the enamel surface. Users should be informed of precautions when using oral sprays and the need for oral hygiene after its use.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.3
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• pp.191-204
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• 2019

The 20-kHz ultrasonic irradiation was applied to investigate bacterial inactivation and antibiotic susceptibility changes over time. Applied intensities of ultrasound power were varied at 27.7 W and 39.1 W by changing the amplitude 20 to 40 to three bacteria species (Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus). By 15-min irradiation, E. coli, a gram-negative bacterium, showed 1.2- to 1.6-log removals, while the gram-positive bacteria, Enterococcus faecalis and Staphylococcus aureus, showed below 0.5-log removal efficiencies. Antibiotic susceptibility of penicillin-family showed a dramatic increase at E. coli, but for other antibiotic families showed no significant changes in susceptibility. Gram-positive bacteria showed no significant differences in their antibiotic susceptibilities after ultrasound irradiation. Bacterial re-survival and antibiotic susceptibility changes were measured by incubating the ultrasound-irradiated samples. After 24-hour incubation, it was found that all of three bacteria were repropagated to the 2- to 3-log greater than the initial points, and antibiotic inhibition zones were reduced compared to ones of the initial points, meaning that antibiotic resistances were also recovered. Pearson correlations between bacterial inactivation and antibiotic susceptibility showed negative relation for gram-negative bacteria, E. coli., and no significant relations between bacterial re-survival and its inhibition zone. As a preliminary study, further researches are necessary to find practical and effective conditions to achieve bacteria inactivation.

• The Korean Journal of Food And Nutrition
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• v.9 no.4
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• pp.484-489
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• 1996

The influence of acetic acid (AA) dips on aerobic plate counts (APC), gram-negative bacterial counts (GNC), pH, and sensory tests of pork hams was studied during storage at 4$^{\circ}C$. Pork hams were treated by dipping in 0.5~3.0%(v/v) AA for 0~3 min. Treatments of 1.0~3.0% AA for 3 min completely (P<0.05) inhibited the GNC for 12 days of storage. Treatments of 3.0% AA for 3 min completely (P<0.05) inhibited the APC for 12 days of storage. Treatments with 1.0~3.0% AA for 0~3 min prolonged the microbiological shelf-life to 12 days of storage. Sensory evaluations of pork hams treated with acetic acid were liked less than the fresh controls due to acidic odor and whitness.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.6
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• pp.910-916
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• 2022

The purpose of this study is to evaluate the effect of underwater non-thermal dielectric barrier discharge plasma (DBD plasma) on the sterilization of three types of pathogenic bacteria that cause diseases in freshwater fish and the reduction of a tetracycline antibiotics. This experiment was conducted in the DBD plasma generator, and the voltages used to generate plasma were 11.6 kV and 23.1 kV. The measurement intervals were 0, 1, 5, 10 and 15 min. As a result of DBD plasma treatment, Aeromonas hydrophila, Edwardsiella tarda and Pseudomonas fluorescens were removed 93-99% after 5 min at 23.1 kV, and the tetracycline antibiotics were reduced 70-95% after 15 min at 23.1 kV. In this study, as a result of treating the effluent with DBD plasma at a fish farm where the medicinal bath was conducted with oxytetracycline-HCl (OTC-HCl) products, OTC-HCl decreased by 62% after 10 min at 23.1 kV.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.6
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• pp.493-502
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• 2009

The concentrations of outdoor airborne bacteria measured in Seoul, Korea for one year (Jan. 2008~Dec. 2008) ranged from $500CFU/m^3$ to $7,500CFU/m^3$. In monthly concentration distribution, the level of outdoor airborne bacteria was highest in September and October and lowest in March. In seasonal concentration distribution, the order of level of outdoor airborne bacteria was autumn>winter>spring>summer. In regional concentration distribution, the highest level of outdoor airborne bacteria was generally found in the forest, followed by general area and traffic site. In distribution characteristics according to particle size, outdoor airborne bacteria showed 31% for >$7.0{\mu}m$ (stage 1), 21% for $4.7{\sim}7.0{\mu}m$(stage 2), 15% for $3.3{\sim}4.7{\mu}m$(stage 3), 19% for $2.1{\sim}3.3{\mu}m$(stage 4), 10% for $1.1{\sim}2.1{\mu}m$(stage 5), and 4% for $0.65{\sim}1.1{\mu}m$(stage 6) and its mean respirable fraction was 48%. In concentration distribution by yellow dust, the mean levels of outdoor airborne bacteria were 803 $(\pm479)CFU/m^3$ for period of yellow dust and 691 $(\pm1,134)CFU/m^3$ for period of non-yellow dust. Although the level of outdoor airborne bacteria was higher in period of yellow dust than period of non-yellow dust, there was no significant difference between period of yellow dust and non-yellow dust (p>0.05). In correlation analysis between outdoor airborne bacteria and atmospheric factors (temperature and relative humidity), there was no significant correlation between outdoor airborne bacteria and atmospheric factors. The predominant airborne bacteria were identified to the Bacillus-derived species.

• Journal of the Mineralogical Society of Korea
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• v.24 no.4
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• pp.279-287
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• 2011

In order to identify if bacteria surviving in soils and groundwater can change the oxidation/reduction potential of groundwater, Eh values of solution that contained bacteria were measured for 2 weeks. The Eh values of the solution reacted with sulfate-reducing bacteria decreased from -120 mV to -500 mV in 5 days, and $Desulfuricans$ was superior to $Vulgaris$ in reducing the solution. The Eh value was relatively higher for the solution containing $Shewanella$, iron-reducing bacteria, showing -400 mV. During the Eh decrease by the metal-reducing bacteria, a sulfide mineral such as mackinawite (FeS) started precipitating through the microbial reducing process for sulfate and ferric iron. These results show that the ORP of natrual groundwater may be sensitive to the geomicrobial respiration. In addition, a subsurface environment where groundwater is highly reduced and sulfide minerals are largely biogenerated may be a good place to retard the migration of oxidized radionu-clides by making them precipitated as reduced forms.

• Korean Journal of Microbiology
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• v.37 no.1
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• pp.61-65
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• 2001

Epifluorescence microscopy was used to observe epiphytic bacteria directly on plant leaf surfaces as well as indirectly in the leaf liberating solution by staining with fluorochromes of 4',6-diamidino-2-phenylindole (DAPI) and acridine orange(AO). Epiphytic bacteria could not be well observed on the leaf surface by staining with AO due to an intrusive orange or red background fluorescence. However, DAPI gave us clear epifluorescent images of the bacteria on the leaf. On the contrary, epiphytic bacteria in the liberating leaf solution were well observed on filters stained by both types of fluorochrome, although DAPI showed better fluorescent images than AO and not necessarily required a washing step of the filters stained. The optimum conditions of the DAPI stains were 5 $\mu$g/ml for 5 min both for leaves and for filters of the liberating solution. It was confirmed that a critical step in the epifluorescence microscopy of leaf surfaces was to minimize release of water from the leaf. For this, the stained leaf samples were put on a filter paper, kept in a dry oven at $70^{\circ}C$ for 2 min instead of air-drying, and then immediately observed by epifluorescence microscopy. The established technique was applied to enumerate epiphytic bacteria on oak tree leaf surfaces.

• Journal of Microbiology and Biotechnology
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• v.27 no.1
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• pp.67-71
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• 2017

This study examined the antimicrobial activity of flaxseed meal extract (FME) against Staphylococcus aureus and Escherichia coli O157:H7 inoculated on red mustard. With the treatment of 0.7% FME for 3 min, the reduction levels of S. aureus and E. coli O157:H7 populations were 1.23 and 1.83 log CFU/g, respectively. In addition, the combined treatment of 0.7% FME at $50^{\circ}C$ for 3 min reduced the populations of the pathogenic bacteria by 2.28 and 2.41 log CFU/g, respectively. The color and the vitamin C content were not significantly different between treatments. Thus, FME can be used as a novel antimicrobial agent in fresh-cut vegetables.

• Biomedical Science Letters
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• v.7 no.1
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• pp.27-30
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• 2001

We have examined if lactic acid bacteria could suppress the toxic effect of bisphenol A. Lactobacillus casei YA-70 was chosen as representative. Thirty rats were divided into two groups (immature and mature) according to the weight. Each group was divided again into the control group (only alcohol treatment), bisphenol A treated group, and bisphenol A plus Lactobacillus casei YA-70 treated group. When 500 ppm of bisphenol A was fed everyday, 83% of immature group and 50% of mature group died within 3 weeks. Their internal organs, mainly livers and lungs, were changed in color and severely damaged. In the intestine of 5 ppm-fed group tumor-like nodules were observed. However, their number and size were markedly decreased when Lactobacillus casei YA-70 was supplemented in diet. This study strongly indicates that Lactobacillus casei YA-70 might play an important role to suppress the toxic effect of endocrine disruptor.