• Journal of Animal Science and Technology
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• v.46 no.4
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• pp.667-676
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• 2004

Yogurt was prepared from skim milk added with 1, 2, 4 or 6% of rice- or skim milk powders and commercial lactic acid bacterial starters. Changes in pH, titratable acidity, viable cell counts, viscosity, organic acid contents and carbohydrates during fermentation were monitored and its sensory evaluation was also performed. The optimum level of additives such as rice- and skim milk powders for yogurt manufacture was selected. Fermentation properties of yogurt added with rice and skim milk powders were studied. The control yogurt reached pH 4.5 after 10 hours of fermentation, whereas the samples added with 4 or 6% rice powders reached pH 4.5 in 6 hours and those added with skim milk powder reached in 8 hours. After 4 hours of fermentation, the control yogurt reached a titratable acidity at 1.0 %, whereas other samples exceeded 1.0%. After 4 hours of fermentation, the viable cell counts in the samples added with 4% rice powders were the highest. At the level of 4% rice powders, the curd viscosity decreased. Except for the sample added with 6% skim milk powders, all the samples produced higher lactic acid during fermentation, and galactose level in yogurt was the highest when added with 4% rice powder or 6% skim milk powder. In overall sensory evaluation using 5 parameters, the sensory scores of all the yogurts were not significantly different. However, the sample added with 4% skim milk powders was the best for color and overall acceptability. The sample added with 4% rice powders was the best for the flavor and texture. From this experiment, the optimun level of additives such as rice or skim milk powders was selected to be 4%.

• Journal of Food Hygiene and Safety
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• v.31 no.4
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• pp.258-263
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• 2016

The risks of sanitary indicative bacteria, heavy metals and chlorinated derivatives in 94 cases of sanitary wet towels used in food services (39 from sanitary wet towel treatment business, 55 from food services) were assessed in the present study. Lead was detected in the range of N.D.~0.41 mg/kg (75 cases were not detected), N.D.~0.25 mg/kg of arsenic (93 cases were not detected), N.D.~0.01 mg/kg of cadmium (7 cases were lower than limit of quantitation; 87 cases were not detected), 0.003 mg/kg ~ 0.09 mg/kg of mercury. And chromium (VI) was not detected from all samples. The level of lead was the highest among the tested heavy metals, and the highest concentration of lead was 0.41 mg/kg. However, it was only 2.1% of legal limit (less than 20 mg/kg). The average moisture content of the samples was 61.9% (50.0% ~ 77.0%) and it showed no relevance to the detection of bacterial counts. Escherichia coli was not detected. Bacterial counts were detected 43 cases and among them, 24 cases were exceeded the legal limit. It was verified that the packaging conditions of sanitary wet towel (whether it is packed by a piece or not and sealed or not) are critical factors to cause the germ contamination and cross contamination in the wet towels. The chlorinated derivatives (chlorites and chlorates) were detected in 17 (19.3%) out of 88 cases. The results would be used as preliminary information to establish the programs of "Safety education for manufacturers and public policy of safety".

• Journal of the East Asian Society of Dietary Life
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• v.19 no.6
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• pp.967-974
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• 2009

The effects of Opuntia ficus-indica var. saboten powder on the growth of lactic acid bacteria (LAB) were investigated in order to explore the possibility of manufacturing fermented milk containing the powder. Differences in pH, acidity, LAB counts, viscosity, and sensory evaluation were measured. Also the effects of dietary supplementation on the growth of piglets were evaluated by feeding fermented milks containing 0.1%, 0.2%, 0.5%, and 1.0% Opuntia ficus-indica var. saboten powder. Levels of pH, titratable acidity, viable LAB counts and viscosity were significantly different by the addition of the powder. When fermented milks containg 0.1%, 0.2%, 0.5% and 1.0% Opuntia ficus-indica var. saboten powder were kept at $4^{\circ}C$ for 30 days, viable LAB counts remained high after 30 days of storage. The effects of dietary supplementation of 0.2% Opuntia ficus-indica var. saboten fermented milk were investigated by examining piglet growth rate and fecal ammonia gas release. The piglets were fed 100g/herd of the fermented milk for 14 days. Average daily body weight gain was significantly (p<0.05) improved (110%) with dietary supplementation of the fermented milk, compared to a control group. More over, fecal ammonia gas emissions were reduced by dietary supplementation of the Opuntia ficus-indica var. saboten fermented milk. Sensory evaluation results showed that the samples containing 0.1% and 0.2% Opuntia ficus-indica var. saboten powder had the most parameters similar to those of the control.

• Korean Journal of Agricultural Science
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• v.19 no.1
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• pp.40-50
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• 1992

This experiment was carried out to stimulate lactic starter culture for yoghurt manufacturing. A each of 1.5% of Bios 2000, CR starter medium, and Yeast extract were added to bulk medium, acidity, pH and changes in the number of lactic acid bacteria were investigated at, intervals of two hours for Lactobacillus bulgaricus and four hours for Streptococus thermophilus and Lactobacillus casei. The results obtained were summarized as follows. 1. The acidity of control arrived at 0.99% after 16 hours of incubation during the incubation of Lactobacillus bulgaricus. Whereas that of CR starter medium reached 1.00% at 12 hours of incubation. Yeast extract, 1.12% at 12 hours, and Bios 2000 reached 0.97% at 10 hours respectively, Thus, Bios 2000 showed the fastest rate of acid production. 2. When the acidity of experiment medium peaked on optimum levels. pH of control was 4.03 in 16 hours of incubation during the incubation of Lactobacillus bulgaricus. Whereas that of Bios 2000 reached 4.10 of Yeast extract reached 3.97 at 12 hours, and of CR starter medium reached 4.05 at 12 hours. 3. Lactic acid bacterial counts were $3.1{\times}10^{10}/ml$ after 16 hours of incubation during the incubation of lactobacillus bulgaricus, Whereas those of Bios 2000 reached $2.1{\times}10^{10}/ml$ at 10 hours, with the fastest stimulation of growth, The counts in CR starter medium were at $2.9{\times}10^{10}/ml$ at 12 hours, and Yeast extract were $3.8{\times}10^{10}/ml$ at 12 hours. 4. The acidity of control, CR starter medium, and Yeast extract reached 0.92% at 44 hours, and 0.96% at 32 hours, and 0.90% at 32 hours respectively, Also, that of Bios 2,000 reached 0.97% at 32 hours, which exhibited the highest, among the treatments. 5. The pH of control was 4.27 at 44 hours. that of CR starter medium was 4.33 at 40 hours and that of Yeast extract was 4.25 at 32 hours during the incubation in Streptococcus thermophilus. Besides, pH of Bios 2000 is lowest as 4.18 at 32 hours. 6. Lactic acid bacterial counts in control, CR starter medium, and Yeast extract during the incubation of Streptococcus thermophilus were $9.8{\times}10^{9}/ml$ at 44 hours,$9.5{\times}10^{8}/ml$ at 40 hours, and $9.6{\times}10^{8}/ml$ at 32 hours. And, the highest number was $2.0{\times}10^{9}/ml$ for Bios 2000 at 32 hours. 7. The acidity of control during the incubation of Lactobacillus casei reached 0.92% at 40 hours, and those of CR starter medium and Yeast extract were 0.95% at 40 hours, and 1.01% at 36 hours respectively. Also, Bios 2000 had the highest acidity as 0.94% at 32 hours. 8. The pH of control, CR starter medium and Yeast extract during the incubation Lactobacillus casei was 4.27 at 40 hours. 4.21 at 40 hours, and 4.15 at 36 hours respectively. Also, Bios 2000 showed the lowest pH, as 4.23, at 32 hours. 9. Lactic acid bacterial counts in control, CR starter medium and Yeast extract during the incubation of Lactobacillus casei were $9.4{\times}10^{7}/ml$ at 40 hours, $1.1{\times}10^{8}/ml$ at 40 hours, and $5.0{\times}10^{8}/ml$ at 36 hours respectively. And, the progress of 32 hours showed the highest number of lactic acid bacteria as$6.4{\times}10^{8}/ml$ in Bios 2000.

• Korean Journal of Microbiology
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• v.49 no.2
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• pp.137-145
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• 2013

This study was performed at 2 sites of Nak-Dong River to investigate the changes of nitrifiers depending on the presence and absence of organic pollutants (due to the effluents of domestic wastewater treatment plant, WWTP). Conventional chemical parameters such as T-N, $NH_4$-N, $NO_2$-N, $NO_3$-N were measured and the quantitative nitrifiers at the 2 sites were analyzed comparatively by fluorescent in situ hybridization (FISH) with NSO190 and NIT3, after checking the presence of gene amoA of ammonia oxidizing bacteria (AOB) and 16S rDNA signature sequence for Nitrobacter sp. that belongs to nitrite oxidizing bacteria (NOB). Also ${\alpha}{\cdot}{\beta}{\cdot}{\gamma}$-Proteobacteria were detected using FISH to get a glimpse of the general bacterial community structure of the sites. Based on the distribution structure of the ${\alpha}{\cdot}{\beta}{\cdot}{\gamma}$-Proteobacteria and the measurement of nitrogen in different phases, it could be said that the site 2 was more polluted with organics than site 1. Corresponding to the above conclusion, the average numbers of AOB and NOB detected by NSO160 and NIT3, respectively, at site 2 [AOB, $9.3{\times}10^5$; NOB, $1.6{\times}10^6$ (cells/ml)] was more than those at site 1 [AOB, $7.8{\times}10^5$; NOB, $0.8{\times}10^6$ (cells/ml)] and also their ratios to total counts were higher at site 2 (AOB, 27%; NOB, 34%) than those at site 1 (AOB, 18%; NOB, 23%). Thus, it could be concluded that the nitrification at site 2 was more active due to continuous loading of organics from the effluents of domestic WWTP, compared to site 1 located closed to raw drinking water supply and subsequently less polluted with organics.

• Food Science and Preservation
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• v.11 no.3
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• pp.394-399
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• 2004

The effects of gamma irradiation to improve the hygienic quality and microbiological shelf stability of whole baked egg were investigated by comparison with autoclaving process. The contamination levels of coliform, total aerobic bacteria and fungal group in a fresh egg were 10$^{5}$ CFU/g, 10$^{2}$ CFU/g and 10$^{1}$ CFU/g, respectively. After baking process, total aerobic bacteria and fungi were not exceeded to 10$^{1}$ CFU/g. Also, coliform was not detected under the aseptic process. However, cell counts of the baked egg after packaging reached to 10$^{4}$ CFU/g of total aerobic bacteria, 10$^{1}$ CFU/g of coliform, and 10$^{2}$ CFU/g of fungi. Therefore, it was assumed that microbial contamination of baked and packaged egg was mainly originated from an environmental uptake during packaging process. Microbiological shelf stability of the non sterilized control was about a week. Whereas, the baked eggs irradiated at more than 5 kGy were stable over 12 weeks at ambient condition as like those being autoclaved. Analytical texture profIle was stable within 10 kGy, but it became hardened in the sample treated with autoclaving. About 67$\%$ of panelists identified a sensory difference between non-irradiated and 10 kGy-irradiated sample. The baked egg irradiated at 10 kGy and autoclaved had lower acceptability than the control or samples irradiated lower than 5 kGy. Therefore, it was considered that optimal irradiation dose for radiation sterilization of baked and packaged egg was 5 kGy. At that point, it was recommended that appropriate microbiological shelf-life was 12 weeks at ambient condition.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.6
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• pp.885-891
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• 2011

We conducted this study to determine the optimum dose of gamma irradiation needed for the sterilization of milk porridge for patients. Milk porridge, known as Tarakjuk, was irradiated with gamma ray at doses of 0, 1, 3, 5, 7, or 10 kGy. The microbial contamination, $D_{10}$ values of isolated microbe spores, color, and viscosity were measured during storage at $35^{\circ}C$. The initial count of total aerobic bacteria was 2.60 log CFU/g in the non-irradiated milk porridge, but coliforms, spore-forming bacteria, yeast, and molds were not detected. The total counts of aerobic and spore-forming bacteria in the non-irradiated and 1 kGy irradiated milk porridge increased with storage period. These microbes were not detected in the milk porridge irradiated with 10 kGy. The $D_{10}$ values of isolated spores from milk porridge were 2.71 kGy (in milk porridge) and 2.21 kGy (in saline solution). All CIE color increased with gamma irradiation, but the sensory value of color did not significantly change. The viscosity of the milk porridge decreased with gamma irradiation and storage period, and the decrease in viscosity with storage period became smaller as the radiation doses increased. Sensory evaluation scores of the milk porridge were above normal (4.0) when irradiated with less than 5 kGy. These results indicate that gamma irradiation could be beneficial for preparing food with higher nutrient density and lower viscosity, especially for gastric tube-fed patients.

• Korean Journal of Food Science and Technology
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• v.41 no.5
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• pp.578-586
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• 2009

This study was conducted to determine the effects of alkaline electrolyzed water (AIEW), acidic electrolyzed water (AcEW), 1% citric acid, and 100 ppm sodium hypochlorite, either alone or in combination with citric acid, in reducing the populations of spoilage bacteria and foodborne pathogens (Listeria monocytogenes and Escherichia coli O157:H7) on lettuce at various exposure times (3, 5, and 10 min) with different dipping temperatures (1, 20, 40, and $50^{\circ}C$). In addition, the inhibitory effect of alkaline electrolyzed water combined with citric acid on the browning reaction during storage at $4^{\circ}C$ for 15 days was investigated. Compared to the untreated control, electrolyzed water more effectively reduced the number of total bacteria, mold, and yeast than 100 ppm sodium hypochlorite under the same treatment conditions. All treatments exposed for 5 min significantly reduced the numbers of total bacteria, yeast, and mold on head lettuce. The inactivation effect of each treatment on head lettuce was enhanced as the dipping temperature increased from 1 to $50^{\circ}C$, but there was no significantly difference at temperatures greater than $40^{\circ}C$ (p<0.05). The total counts of yeast and mold in head lettuce were completely eliminated when a combination of 1% citric acid and AlEW treatment was used at temperatures greater than $40^{\circ}C$. However, decreased reduction in L. monocytogenes (2.81 log CFU/g), and E. coli O157:H7 (2.93 log CFU/g) on head lettuce was observed under these treatment conditions. In addition, enhanced anti-browning effect was observed when the samples were subjected to both 1% citric acid and AlEW treatment at temperatures greater than $40^{\circ}C$ compared to when single treatments alone were used. Thus, this combined treatment might be considered a potentially beneficial sanitizing method for improving the quality and safety of head lettuce.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.1
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• pp.110-115
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• 2011

Shelf-life of brined baechu cabbage was extended by pasteurization at $65^{\circ}C$ for 30 min. Starters (Leu. citreum and Lab. plantarum) were added to the pasteurized brined cabbage to supply beneficial lactic acid bacteria during kimchi fermentation. Control kimchis made with baechu cabbage without pasteurization and no addition of the starters to the pasteurized cabbage kimchi were also prepared. The fermentation characteristics and health functionalities of DPPH free radical scavenging activities and in vitro anticancer effects in AGS human gastric cancer cells were compared. The pasteurized brined cabbage could not be fermented well and the functionalities were also low; however, the addition of starter(s), especially mixed starters of Leu. citreum and Lab. plantarum to the pasteurized brined cabbage, significantly increased the counts of lactic acid bacteria, hardness (texture) and overall acceptability in sensory evaluation. The free radical scavenging activities and the anticancer effects were also increased. The fermentation patterns of starter added kimchi prepared with pasteurized brined cabbage were similar to those of naturally fermented kimchi. It seemed that growth of lactic acid bacteria during kimchi fermentation contributed to increased taste and health functionality of kimchi.

• Korean Journal of Agricultural Science
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• v.14 no.2
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• pp.309-317
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• 1987

The raw milk produced in Korea was heated at $70^{\circ}C$, $75^{\circ}C$, $80^{\circ}C$, $85^{\circ}C$, $90^{\circ}C$, $95^{\circ}C$ and $100^{\circ}C/15sec.$. The changes in chemical composition and microbiological aspects of the milk were summarized as following results: 1. In high temperature pasteurized milks as the heat treatment increased, pH value decreased but protein, fat, lactose and ash did not show significant changes in their contents while casein nitrogen and non-protein nitrogen increased but non-casein nitrogen and filterable nitrogen decreased in their contents. 2. Calcium content of raw milk decreased from 119.79mg/100g to 111.86mg/100g at $75^{\circ}C$ and to 106.24mg/100g at $100^{\circ}C$. Vitamin C decreased from $1.37mg/100m{\ell}$ of raw milk to $1.15mg/100m{\ell}$ at $75^{\circ}C$ and $0.94mg/100m{\ell}$ at $100^{\circ}C$. Artificial digestibility increased as the heat treatment got higher. 3. Viable bacteria counts decreased from $9.0{\times}10^3/m{\ell}$ at $75^{\circ}C$ to $3.4{\times}10^2/m{\ell}$ at $100^{\circ}C$. Coliforms were not found at $70^{\circ}C$ and thermoduric bacteria, thermophiles, psychrotrophic bacteria, mould and yeast decreased rapidly as the heat treatment increased. 4. The results of Keeping quality test for high temperature pasteurized milk showed that the' milks preserved at $25^{\circ}C$ and $37^{\circ}C$ were clotted just after 1 day but the milk preserved at $4^{\circ}C$ showed good shelf life which did not have any deterioration in titratable acidity, microorganisms and com positions.