• Food Science of Animal Resources
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• v.44 no.2
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• pp.372-389
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• 2024

This study investigated the efficacy of ultraviolet-C (UV-C) irradiation in enhancing the quality of raw bovine milk by targeting microbial populations and lipid peroxidation, both of which are key factors in milk spoilage. We categorized the raw milk samples into three groups based on initial bacterial load: low (<3 Log 10 CFU/mL), medium (3-4 Log 10 CFU/mL), and high (>4 Log 10 CFU/mL). Using a 144 W thin-film UV-C reactor, we treated the milk with a flow rate of 3 L/min. We measured the bacterial count including standard plate count, coliform count, coagulase-negative staphylococci count, and lactic acid bacteria count and lipid peroxidation (via thiobarbituric acid reactive substances assay) pre- and post-treatment. Our results show that UV-C treatment significantly reduced bacterial counts, with the most notable reductions observed in high and medium initial load samples (>4 and 3-4 Log 10 CFU/mL, respectively). The treatment was particularly effective against coliforms, showing higher reduction efficiency compared to coagulase-negative staphylococci and lactic acid bacteria. Notably, lipid peroxidation in UV-C treated milk was significantly lower than in pasteurized or untreated milk, even after 72 hours. These findings demonstrate the potential of UV-C irradiation as a pre-treatment method for raw milk, offering substantial reduction in microbial content and prevention of lipid peroxidation, thereby enhancing milk quality.

• Journal of Environmental Health Sciences
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• v.29 no.1
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• pp.1-7
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• 2003

This study was carried out to investigate the airborne microbial pollution in hospital environment. Using a mechanical air sampler, microbiological samples were taken from intensive care unit, general ward room, patients wailing room and outdoor of 20 hospitals in Seoul, Korea. The concentration of airborne bacteria and fungi ranged 97-410 cfu/㎥ and 37-77 cfu/㎥, respectively and patients waiting room had highest bacterial count. 10 genera of molds were identified and the most frequently recovered molds were Aspergillus, followed by Penicillium, Alternaria and Cladosporium. Among Staphylococcus species, S. haemolyticus and S. epidermidis were predominant and 47% of Staphylococcus species were isolated from intensive rare unit.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.696-701
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• 2013

Flounder Verasper moseri Jordan et Gilberu sikhae is one of the traditional Korean fermented food. Microbiological, chemical, and biogenic amine analyses were carried out to evaluate the quality of commercial flounder sikhae and establish standardization. The quality characteristics were analyzed in terms the salinity, volatile basic nitrogen, pH, amino-N, TBA value, biogenic amine, viable cell count, and lactic acid bacteria. Quality evaluation of commercial flounder sikhae revaled an average pH of 4.84, volatile basic nitrogen of 43.47 mg/100 g, amino-N of 213.04 mg/100 g, salinity of 5.77 %, viable cell count of $10^6-10^7CFU/g$, viable lactic acid bacteria count of $10^6-10^7CFU/g$ and biogenic amine level of 0.70-47.34 mg/kg.

• Journal of the East Asian Society of Dietary Life
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• v.10 no.5
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• pp.419-424
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• 2000

To develop a functional Kimchi utilizing onion, 5 different Kimchi with onion used as a major ingredient were formulated. The changes in pH. titratable acidity, reducing sugar. total bacterial count, and the number of lactic acid bacteria in the process of fermentation were studied A. onion Kimchi Control. B : onion Kimchi added with oyster, C : onion Kimchi added with salted shrimp, D : onion Kimchi added with oyster, cucumber, and a bit of radish, E : onion Kimchi added with salted shrimp, cucumber, and a bit of radish. pH of onion Kimchi decreased during storage, but titratable acidity increased. The pH values of onion Kimchi were not significantly different among groups, the changes in pH during fermentation were the lowest in A, and changes in B and D were lower than those of C and E. Salt concentration tended to decrease during the fermentation process, and the changes in salt concentration were lower in D and E than in B and C. Reducing sugar content maximized at 4 days of fermentation and decreased after 12 days. The number of lactic acid bacteria increased during first 4 days of fermentation and decreased after 12 days. Total lactic acid bacterial count were the most lowest in A.

• Korean Journal of Microbiology
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• v.28 no.1
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• pp.76-82
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• 1990

In samples taken from mouth of the Nakdong River, mercury-resistant bacteria grown on the media supplemented with over 20 ppm of mercuric chlorice were below 0.3% of all aerobic heterotrophs. Among them, seven strains grown over 100 ppm of mercuric chloride were isolated and all were identified as Pseudomonas. The toxic effect of mercury on the growth of the most resistant strain N14 was influenced by the organic compounds and concentration. The growth and physiological activity to N14 strain were affected by toxic mercury in the early stage: The viable count and glucose turn over rate of N14 strain dropped to the lowest level as soon as the bacteria came into contact with mercury. During the extended lag period, however, bacteria accommodated to the stress and the viable count and glucose turnover rate increased. After the lag period, bacteria began to proliferate and their growth reached similar level to that of control. In crude extracts of N14 strain grown in nutrient browth containing. $10{\mu}M$ $HgCl_{2}$, a mercuric ion dependent oxidation of NADPH was demonstrated. Therefore the mechanism of mercury-resistance of the N14 strain involved the elimination of the mercury from growth media. In the N14 strain which a wide range of resistance to antibiotics was observed in, four multiple plasmids were detected. As a result, the supposition that N14 strain has a plasmid-encoded enzyme system may be quite within the realms of possobility.

• The Plant Pathology Journal
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• v.34 no.5
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• pp.403-411
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• 2018

This study takes strawberry-fruits as the test material and discusses the effect of Burkholderia contaminans B-1 on preventing postharvest diseases and inducing resistance-related substances in strawberry-fruits. Soaking and wound inoculating is performed to analyze the inhibitory effects of different treatment solutions on the gray mold of postharvest strawberry-fruits. The count of antagonistic bacteria colonies in the wound is found, and the dynamic growth of antagonistic bacteria and the pathogenic fungus is observed by electron microscopy. The results indicated that, either by soaking/wound-inoculating, the fermentation and suspension of antagonistic bacteria significantly reduced the incidence of postharvest diseases of strawberry-fruits. With wound inoculation, the inhibition rate of antagonist fermentation and suspension ($1{\times}10^{10}cfu/ml$) respectively reached 77.4% and 66.7%. It also led to a significant increase in the activity of resistance-related enzymes, i.e., phenylalanine ammonia lyase (PAL), 4-coumarate coenzyme A ligase (4CL), cinnamate-4-hydroxylase (C4H) and chalcone isomerase (CHI). On 1 d and 2 d post-treatment, the activity of 4CL was respectively 3.78 and 6.1 times of the control, and on 5 d, the activity of PAL was increased by 4.47 times the control. The treatment of antagonistic bacteria delayed the peaking of cinnamyl-alcohol dehydrogenase (CAD) activity and promoted the accumulation of lignin and total phenols. The antagonistic bacteria could be well colonized in the wounds. On 4-5 d post-inoculation, the count of colonies was $10^8$ times of that upon inoculation. Electronmicroscopy indicated that the antagonistic bacteria delayed the germination of pathogenic spores in the wounds, and inhibited further elongations of the mycelia.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.365-365
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• 2017

Yogurt is a food produced by bacterial fermentation of milk and the bacteria used to make it are known as "yogurt cultures". Most of them belong to probiotics such as Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus bacteria. Domestic fermented milk market is increasing and about 30 companies are producing yogurt. The purpose of this study was to analyze the quality characteristics of domestic commercial semisolid type yogurt. We collected 20 types of commercial yogurt at local markets. Physicochemical properties including pH, sugar content, acidity, viscosity and microbial characteristics of lactic acid bacteria counts were measured. The yogurt showed pH 4.5, 7.4~18.1% of sugar contents, 0.6~1.3% of total acids and 282~748 cP of viscosities. In the microorganism populations, lactic acid bacteria count were 6.5~11.5 Log CFU/mL and anaerobic lactic acid bacteria count were 7.2 ~ 11.1 Log CFU/mL. The quality characteristics were different depending on the constituents of the sample and the microorganisms used. These results are related to the quality characteristics of yogurts which are useful information about identifying new trends in domestic fermented milk industry.

• The Korean Journal of Food And Nutrition
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• v.34 no.6
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• pp.604-611
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• 2021

In this study, we investigated the effects of adding oat and lactic acid bacteria on the quality and functionality of yogurt. Yogurt was fermented with various lactic acid bacteria,; Lactobacillus acidophilus (LA), Lactobacillus delbrueckii sub. bulgaricus (LB), and Streptococcus thermophilussei (ST) and quality properties, β-glucan content, antioxidant activity were estimated. The quality of control and oat added yogurt (OY) showed significant differences depending on the type of strain and combination. The addition of oats significantly accelerated the lactic acid bacteria production, decreased the pH, and increased the titratable acidity and count of the viable cells compared to the control. Acid production was highest in ST, with the complex strains containing ST and LALBST showing high quality characteristics. The viscosity of oat yogurt was higher than that of the control group, and LALBST was also significantly higher than that of the control group. The β-glucan content of OY was 0.14-0.2%, and the organic acid content and antioxidant activity were also significantly increased by the addition of oats. As a result, it is thought that the addition of oats and a combination of lactic acid bacteria can be used for improving the quality and functionality of yogurt.

• The Korean Journal of Food And Nutrition
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• v.3 no.1
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• pp.13-22
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• 1990

Nangmyun-broth was collected as samples from 25 common restaurants in Bucheon to examine it's sanitary condition. The main course of bacterial contamination was persuited for it's sanitary improvement. Bacterial count in summer sample was not greatly different from that in winter, resulting in total count 1.7$\times$10i1m1, lactic acid bacteria 8.7$\times$106/ml, coliform group 1 2$\times$105/ml, Staphylococcus aureus 6.5$\times$102/ml. Bacterial contamination occurred remarkably with the use of storage barrel in which remnent Nangmyun-broth was still resting, because the remnant Nangmyun-broth contained high level of bacteria Good santary condition in Nangmyun-broth was obtained by the use of clean barrel which had been washed with tap water or sterilizied with steam before filling fresh Nangmyun -broth for cold storage. The growth of Escherichia coli and Staphylococcus aureus was inhibited in the presence of acetic acid(0.01~0.05%) or mustart(0.1~0.5%)

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.4
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• pp.444-451
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• 2001

The purpose of this study was to evaluate the rate of adherence of bacteria on various denture relining materials and to find out the effects of chitosan, when it was added to denture relining materials. Denture relining materials such as Tokuso rebase normal $set^{(R)}$, Mild $rebaron^{(R)}$, $Kooliner^{TM}$, and New $truliner^{TM}$ were used in this study. The adherence of Streptococcus mutans was studied on the surfaces in the denture relining materials with chitosan and in those without chitosan. When chitosan was added to M17 broth and MRS broth, the viable cell count of Streptococcus mutans was reduced. The viable cell count of Streptococcus mutans on the specimens decreased in the following order : Mild rebaron, Tokuso rebase normal set, and Newtruliner and Kooliner. The deture relining materials with chitosan showed a lower rate of adherence of Streptococcus mutans than those without chitosan.