• Korean Journal of Microbiology
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• v.38 no.3
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• pp.180-185
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• 2002

The direct viable count (DVC) and plate count (PC) methods was used to measure the number of bacteria in potable groundwater samples collected from bottled water from the market, mineral water, and edible groundwater near the urban areas and the stock farming congested areas. As a result, the number of living bacteria by DVC was comprised 30~80% of the total direct count (TDC), whereas the number of living bacteria by PC was around l~30% of DVC. Such results show that viable but non-culturable (VBNC) bacteria exist in the potable groundwater with high percentages. On the other hand, upon measuring the value from the conventional nutrient broth (NB), $10^-2$ fold diluted nutrient broth (DNB), and R2A broth, the values from the DNB and R2A showed 2~50 times higher than the conventional NB medium. These results indicate that oligotrophic bacterial groups which can multiply in the low nutrient broth abundantly exist in the oligotrophic environment like potable groundwater.

• Human Ecology Research
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• v.59 no.2
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• pp.275-286
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• 2021

In this study, we produced kimchi with cooked Dioscorea batatas yam based on the its outstanding nutritional value, biological activity, and pharmacological action. Sliced kimchi cabbage, processed white radish kimchi (kkakdugi), and whole kimchi cabbage were prepared with 3% Dioscorea batatas, and the physicochemical and bioactivity characteristics were analyzed. In three kinds of Dioscorea batatas. The pH of the kimchi decreased and its acidity increased as the storage period was extended. The period of the maximum total viable cell count of the sliced cabbage and the processed white radish kimchi (kkakdugi) was 14 days, while the period for whole kimchi cabbage was 21 days. The period of maximum lactic acid bacteria count was 14 days for all three kinds. For physiological activities, polyphenol and flavonoid contents and DPPH elimination were highest immediately after production of the kimchi. Also, anthocyanin content increased as the storage period extended. The pH, acidity, total viable cell count, lactic acid bacteria count, and physiological activities were shown to be different according to the type of kimchi and the storage period.

• Journal of Environmental Health Sciences
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• v.19 no.2
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• pp.34-39
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• 1993

One hundred and eighty-seven water samples were collected from 23 of spring water, 2 of ground water, 1 of tap water in Pusan area and 3 of natural mineral waters. Total coliform group, fecal coliform, viable cell count and microflora were investigated to evaluate water quality of drinking water. The results were as follows: range and geometric mean value of total coliform and fecal coliform MPN's of spring water were 0~1,500/100 ml, 85/100 ml and 0~460/100 ml, 24/100 ml but coliform group was not detected in the samples of tap water and natural mineral water. Viable cell count of spring water, ground water and tap water were lower as 100 cell than the criteria for drinking water but that of natural mineral water was higher as 6.5X 10$^2$~7.4X 10$^3$ /ml. Predominant speces among the 219 strains isolated from the samples were 19.6% Aeromonas spp., 19.2% Enterobacteriaceae, 16% Acinetobacter spp. Especially, spring water and vessels were contaminated by Hafnia spp. and Providencia Spp, inhabitant of the oral cavity.

• The Korean Journal of Food And Nutrition
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• v.21 no.1
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• pp.51-55
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• 2008

Colour and texture are the most difficult quality aspects of Kimchi to maintain during storage. Therefore, this study investigated how to maintain superior quality Kimchi during fermentation without changes in color and texture. By examining differences between samples covered with vinyl(A group) and not covered with vinyl(B group) and assessing pH, total acidity, total viable cell count, total lactic acid bacteria cell count and sensory characteristics. The results are indicated that pH, total acidity, total viable cell and total lactic acid bacteria were similar between group A and B. Group A showed higher sensory score for colour, taste, texture and acceptability than group B(p<0.001). Covering the Kimchi with vinyl appeared to have a similar effect as when Kimchi is kept in a Kimchi-pot under stones or the outer leaves of vegetables making it possible to maintain good color and texture during storage. In conclusion, even though, it is not practical to use Kimchi-pots within urban settings today, vinyl coverings may offer the same effects.

• Journal of Microbiology and Biotechnology
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• v.6 no.5
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• pp.340-346
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• 1996

In order to find out if staphylococci occur in significant numbers in Korean fermented fish products, a total of 40 different fermented fish products were collected from different markets in Korea and analyzed for their physico-chemical and microbiological states. The pH, salt concentration and water activity of the products were measured and the total viable cell count and the number of Staphylococcus grown on mannitol salt agar were determined. The identification of the strains of Staphylococcus were made by API Staph Strip and MIS identification kits, and the physiological properties of the identified strains were further characterized by different conventional methods. The pH, salt content and water activity of fermented fish samples varied widely from 4.8 to 7.1, 7.4-28.7$%$ and 0.77-0.84, repectively, depending on the type of product. The total viable cell count varied from $10^4-10^9$ cfu/ml, and most of the samples had $10^5-10^6$ cfu/ml No correlation was found between the viable cell count and the pH, NaCl concentration and water activity of the samples. Among the 35 colonies identified as Staphylococcus strains by the identification kits, S. xylosus was the most frequently occurring strain marking 17, and S. warneri was 8, S. epidermidis 4 and S. cohnii 2. S. hominis, S. saprophyticus, S. haemolyticus and S. aureus were also identified once each. In some samples (K-3, P-6, K-8, G-5 and G-10), 2-3 different species of Staphylococcus were found. Considering the region of sampling, among the 10 samples from Kunsan 5 were identified as S. warneri, while in the other regions S. xylosus was predominant. Although the physiological characteristics of the identified strains were generally consistent with those in Bergey's Manual, some discrepances were also observed. All the strains were highly salt tolerant, growing in the media containing over 18$%$ NaCl. All the strains except S. aureus (G-11) showed negative in hemolysis activity, plasma coagulation and DNase tests. All the strains including S. aureus (G-11) showed negative in enterotoxin test.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.4
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• pp.531-538
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• 2003

To elucidate the physicochemical change of Panicm miliaceum powders caused by irradiation and identify detection of irradiation, viscosity, TBA value, Hunter color and total viable count were measured after irradiation of Panicum miliaceum powder. Panicum miliaceum powders from Korea and China were irradiated at 0, 2.5, 5, 7.5, 10, 15 kGy using a $Co^{60}$ irradiator and stored for 9 months at $0^{\circ}C$ and $20^{\circ}C$. All samples resulted in decrease for viscosity and specific parameter values by increasing dosage at 50 rpm after irradiation. These values showed dose-dependent relationship (above $r^2$＝0.92) between non-irradiated and irradiated samples during storage. These results suggest that the detection of irradiated Panicum miliaceum at various doses is possible by using viscometric method during storage. Total viable count, TBA value and Hunter color were determined as assistant indices for the samples viscosity measured. Total viable count, TBA values showed dose-dependent relationship (2.5 ~15 kGy). The difference in viscosity along with total viable count, TBA values between non-irradiated samples little or some changed with the lapse of post-irradiation time, but was still distinguishable each other more than 6 months at $0^{\circ}C$ and $20^{\circ}C$ for Panicum miliaceum powders from Korea and China.

• Korean Journal of Food Science and Technology
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• v.35 no.2
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• pp.173-181
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• 2003

Physicochemical changes in corn starch caused by irradiation were investigated, and irradiated samples were identified. Viscosity, TBA value, Hunter color, and total viable count were measured after irradiation of corn starch. Corn starches from Korea and China were irradiated at 0, 2.5, 5, 7.5, 10, and 15 kGy using a $Co^{60}$ irradiator and stored for 9 months at $0^{\circ}C$ and $20^{\circ}C$. Viscosity and specific parameter values decreased in all samples with increasing irradiation dosage at 50 rpm, showing a dose-dependent relationship $(above\;R^2=0.80)$ between non-irradiated and irradiated samples during storage. These results suggest that detection of irradiated corn starches is possible using viscometric method during storage. Total viable count, TBA value, and Hunter color were determined as supplemental indices for measuring viscosities of samples. Total viable count and TBA values showed dose-dependent relationship $(2.5{\sim}15 kGy)$. Differences in viscosity and total viable count, and TBA values among non-irradiated samples showed little changes with the lapse of post-irradiation time, but were still distinguishable for more than 6 months at $0^{\circ}C$ and $20^{\circ}C$ for corn starches from korea and China.

• Advances in environmental research
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• v.2 no.1
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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.

• Korean Journal of Microbiology
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• v.39 no.3
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• pp.181-186
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• 2003

This study was performed to analyze quantitatively the number of living bacteria in forest soil samples collected from Mt. Keryong using improved direct viable count (DVC) and plate count (PC) methods. The number of living bacteria by DVC comprised 18～44% of the total direct count (TDC), whereas the number of living bacteria by PC was less than 1% of TDC. These results showed that viable but non-culturable (VBNC) bacteria existed in the soil with high percentages. Besides, DVC was proved to make it possible to make a quantitative detection of the VBNC bacteria. On the other hand, upon measuring the value from the conventional nutrient broth (NB) and $10^{-2}$ folded diluted nutrient broth (DNB), the values from the DNB showed 5 to 10 times higher than those from the conventional NB medium. These results indicate that oligotrophic bacterial groups, which could multiply in the low nutrient broth, abundantly exist in the soil ecosystem. It would also be possible to apply this kind of method to other substrate to make a quantitative detection of soil bacterial groups.

• Food Science of Animal Resources
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• v.42 no.1
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• pp.153-174
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• 2022

This trial was conducted to evaluate the effect of overwrap, vacuum, and modified atmosphere packaging (MAP) on poultry breast fillets' microbiological, biochemical shelf life and sensory attributes. The fillets were divided into 4 groups, and each of the treatments was replicated 3 times with 60 breast fillets. The first group was a control group with overwrap packaging; the second group was vacuum packed (VP); the third and fourth groups were MAP-1: 0% O₂, 40% CO₂, 60% N₂, and MAP-2: 20% O₂, 40% CO₂, 40% N₂. The microbiological and biochemical analyses were performed for the total viable count, coliform count, Pseudomonas count, Salmonella count, total volatile basic nitrogen (TVB-N), pH, cooking loss, color, lipid oxidation, tenderness, and sensory analysis. The data were analysed through two-way ANOVA by Minitab (Minitab 17.3.1). Meat treated with understudy MAP compositions and vacuum packaging reduced total viable count, Pseudomonas count, and total coliform count than control (p<0.05). TVB-N remained below the recommended limit throughout storage except aerobic packaging (p<0.05). Cooking loss (%) was lowered and showed non-significant results (p>0.05) between vacuum packaging and both MAP concentrations. The meat stored in MAP-2 was characterised by higher (p<0.05) visual scores. Whilst MAP-1 showed higher (p<0.05) L^* values and overall acceptability. Sample packaged under aerobic packaging showed significant (p<0.05) results for b^* and thiobarbituric acid reactive substances (TBARS). Meat stored in aerobic packaging showed higher (p<0.05) shear force values. The outcome of this trial may help to promote the application of understudy MAP compositions and rapid detection of microbes by biochemical analysis under local conditions.