• Korean Journal of Microbiology
• /
• v.3 no.1
• /
• pp.7-10
• /
• 1965

Higher number in colony counts in coliforms, total aerobes, and anerobes was obtained from marketable soy-bean mash than front that in fermented tank. The ratio between coliform contamination and total viable cells was higher in red pepper mash than in soy-bean mash. E. coli, contaminated in soy-bean mash persisted longer at low temperature ($0^{\circ}C$-$^5{\circ}C$) than at room temperature and they vanished after seven days of storage at room temperature. At 30.deg.C and 35.deg.C, these organisms were more effected than at room temperature. E. coli cells, inoculated in red pepper mash, were not recovered at room temperature after five days incubation. Soy-bean mash, completely fermented at normal conditions, were detected to contain $10^8$- $10^9$ organisms per gram of sample. On the contrary, marketable soy-bean mash were found to have more than 10$^{9}$ per gram samples. Since samples were found to have more than $10^9$ aerobes and anaerobes per gram, contamination of coliforms seemed to be apparent.

• Journal of Microbiology and Biotechnology
• /
• v.24 no.2
• /
• pp.225-235
• /
• 2014

Total 121 lactic acid bacteria were isolated from homemade Inner Mongolia extra hard Hurood cheese. Seven of these strains, identified as Lactobacillus plantarum, were studied for probiotic characteristics. All seven strains survived at pH 3.0 for 3 h, or in the presence of oxgall at 0.3% or 0.6% for 4 h, but their viabilities were affected to different extents at pH 2.0 for 3 h. Strains C37 and C51 showed better adherence to Caco-2 cells, and higher hydrophobicity. The seven L. plantarum strains were different in in vitro free radical scavenging activities and cholesterol-reducing ability. In vivo evaluation of the influence of L. plantarum C37 on the intestinal flora in a mouse model showed strain C37 could increase the viable counts of lactobacilli in feces of mice and decrease the viable counts of enterococci. When L. plantarum C37 was used to prepare probiotic Hurood cheese, it was able to maintain high viable counts (>7.8 log CFU/g) during the whole storage period, but the composition of the cheese was not changed. These results indicate that L. plantarum C37 could be considered as a promising probiotic strain.

• Journal of Korean Society of Water and Wastewater
• /
• v.23 no.2
• /
• pp.199-205
• /
• 2009

It is very important to differentiate of DNA derived from live or dead bacteria within mixed microbial communities in aquatic environments. Ethidium monoazide (EMA) is a DNA intercalating agent and the treatment of EMA with strong visible light cleaves the genomic DNA of bacteria. In dead bacterial cells, EMA intercalates into the genomic DNA, induces the cleavage of DNA, and inhibits the PCR amplification. In this study, we developed the EMA-PCR and EMA real-time PCR to detect the DNA derived from viable Escherichia coli (E.coli) in mixed cultures of live and dead E.coli. The treatment of EMA, $50{\mu}g/mL$, and 650 W visible halogen light exposure for 2 minutes cleaved the genomic DNA derived from heat killed E.coli but did not those of live E.coli. EMA-PCR could detect the DNA from live E.coli in mixed culture samples of live and dead E.coli at various ratio and there was no DNA amplification in only dead E.coli cultures. Similar results were observed in EMA real-time PCR. Further studies are needed to develop various EMA-PCR methods to detect viable waterborne pathogens such as Helicobacter pylori, Giardia lamblia, and so on.

• Food Science of Animal Resources
• /
• v.30 no.1
• /
• pp.49-54
• /
• 2010

The aim of this research was to estimate the effect of temperature and develop predictive models for the growth of total viable cells (TVC) and Escherichia coli (EC) on chicken breast under aerobic and various temperature conditions. The primary models were determined by Baranyi model. The secondary models for the specific growth rate (SGR) and lag time (LT), as a function of storage temperature, were developed by the polynomial model. The initial contamination level of chicken breasts was around 4.3 Log CFU/g of TVC and 1.0 Log CFU/g of E. coli. During 216 h of storage, SGR of TVC showed 0.05, 0.15, and 0.54 Log CFU/g/h at 5, 15, and $25^{\circ}C$. Also, the growth tendency of EC was similar to those of TVC. As storage temperature increased, the values of SGR of microorganisms increased dramatically and the values of LT decreased inversely. The predicted growth models with experimental data were evaluated by $B_f$, $A_f$, RMSE, and $R^2$. These values indicated that these developed models were reliable to express the growth of TVC and EC on chicken breasts. The temperature changes of distribution and showcase in markets might affect the growth of microorganisms and spoilage of chicken breast mainly.

• KSBB Journal
• /
• v.15 no.3
• /
• pp.219-225
• /
• 2000

Both the production of high spore concentration and high insecticidal activity are required in the production of Bacillus thuringiensis to be used for the bacterial insecticide. In the production of high cell and spore concentrations of B. thuringiensis the continuous fed-batch culture(CFBC) and intermittent fed-batch culture(IFBC) were investigated at $28^{\circ}C$ by maintaining 40% dissolved oxygen concentration. When the final glucose concentration was 50 g/L the maximum viable cell number obtained using the CFBC with linear gradient feeding was $9.37{\times}109$ cells/mL and maximum spore concentration was $8.33{\times}109$ spores/mL which was approximately 84.4% yield of spore formation. When the final glucose concentration was 100 g/L the aximum viable cell and spore concentrations obtained using the IFBC with pH-statb were $1.38{\times}$1010 cells/mL and $1.35{\times}1010$ spores/mL respectively and the yield of spore formation was approximately 97.8%.

• Food Science of Animal Resources
• /
• v.20 no.1
• /
• pp.56-63
• /
• 2000

This study was investigated the effects of the addition of adlay with levels of 1%(T1), 2%(T2), 3%(T3) and 4% (T4) in skim milk substrate on the physicochemical and microbiological properties of yoghurt during fermentation and storage period at 4$\pm$1$^{\circ}C$. Adlay yoghurt were fermented with the mixed cultures of YC-380, ABT-4 and ABT-D. Titratable acidity and pH values of all treatments were increased and decreased significantly(p<0.05) with fermentation period, respectively and increased and decreased slightly during the storage period, respectively. There were increased and decreased in order of all treatments fermented with YC-380, ABT-4 and ABT-D. Viscosity of adlay yoghurt increased rapidly in order of T4, T3, T2 and T1 during fermentation and slowly in order of T1, T2, T3 and T4 during the storage period. There were increased in order of all treatments fermented with ABT-D, YC-380 and ABT-4. The counts of viable cells of lactic acid bacteria in all treatments were rapidly and slightly increased during fermentation and storage period, respectively. There were increased in order of fermented with ABT-D, ABT-4 and YC-380 in all treatments. The counts of E. coli were not found in adlay yoghurt. In all treatments, T1 showed slightly high compared to that of control. Based on the results of this experiment, the optimum level of addition of adlay were 1% (w/v) for production of acid production, pH, viscosity and the counts of viable cells of lactic acid bacteria.

• Food Science of Animal Resources
• /
• v.40 no.4
• /
• pp.541-550
• /
• 2020

The use of yeast assist kefir fermentation, but also can cause food spoilage if uncontrolled. Hence, in this study, the microbial composition of an existing commercial kefir starter was modified to produce a functional starter, where Lactobacillus acidophilus KCNU and Lactobacillus brevis Bmb6 were used to replace yeast in the original starter to produce non-yeast kefir-like fermented milk. The functional starter containing L. acidophilus KCNU and L. brevis Bmb6 demonstrated excellent stability with 10¹⁰ CFU/g of total viable cells throughout the 12 weeks low-temperature storage. The newly developed functional starter also displayed a similar fermentation efficacy as the yeast-containing control starter, by completing the milk fermentation within 12 h, with a comparable total number of viable cells (10⁸ CFU/mL) in the final products, as in control. Sensory evaluation revealed that the functional starter-fermented milk highly resembled the flavor of the control kefir, with enhanced sourness. Furthermore, oral administration of functional starter-fermented milk significantly improved the disease activity index score by preventing drastic weight-loss and further deterioration of disease symptoms in DSS-induced mice. Altogether, L. acidophilus KCNU and L. brevis Bmb6 have successfully replaced yeast in a commercial starter pack to produce a kefir-like fermented milk beverage with additional health benefits. The outcome of this study provides an insight that the specific role of yeast in the fermentation process could be replaced with suitable probiotic candidates.

• Korean Journal of Food Science and Technology
• /
• v.18 no.2
• /
• pp.124-129
• /
• 1986

Soy yogurt beverage (SYB) was preapred from soy protein isolate. The effort of stabilizers or pH adjustment on the sedimentation of SYB curd and the microbiological quality of SYB during storage were investigated. The curd in SYB precipitated significantly during the first 24 hours of storage and the sedimentation of curd could be reduced by the addition of proper amount of CMC or PGA. The sedimentation of curd was also retarded by adjustment of pH of SYB. When SYB prepared by Lactobacillus acidophilus was kept at $5^{\circ}C$ for 48 days, the number of viable cells was not changed and titratable acidity increased gradually. When SYB prepared by L. bulgaricus was kept at $5^{\circ}C$ for 48 days, the number of viable cells decreased slightly and titratable acidity increased gradually.

• YAKHAK HOEJI
• /
• v.38 no.3
• /
• pp.265-273
• /
• 1994

ln vitro and in vivo antibacterial activities of DWQ-013(1-cyclopropyl-6,8-difluoro-7-(3-methylthiomethylpyrrolidinyl)-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid), a new fluoroquinolone antibacterial agent, were compared with those of ciprofloxacin, sparfloxacin and ofloxacin against aerobic and anaerobic standard strains and clinical isolates. DWQ-013 had a broad spectrum and potent antibacterial activity against Gram-positive and Gram-negative bacteria. The antibacterial activity of DWQ-013 against Staphylococcus aureus was equal to that of sparfloxacin(SPFX) and superior to those of ciprofloxacin(CPFX). The antibacterial activity against Gram-negative bacteria was slightly lower than those of ciprofloxacin and sparfloxacin. MIC of DWQ-013 against Pseudomonas aeruginosa$(0.781{\sim}1.563\;{\mu}g/ml)$ was usually equal to that of sparfloxacin$(0.781\;{\mu}g/ml)$ and was inferior to that of ciprofloxacin$(0.098\;{\mu}g/ml)$. The number of viable cells was decreased rapidly after addition of DWQ-013 at concentration of $1{\sim}2$ folds of MIC.

• Korean journal of food and cookery science
• /
• v.31 no.2
• /
• pp.128-135
• /
• 2015

Blueberry juice extraction (JE), hot water extract (HE), and 50% ethanol extract (EE) were fermented with Lactobacillus plantarum CGKW3. We investigated the quality characteristics and antioxidative activities of yanggaeng prepared with different amounts of fermented blueberry extract (JE, HE, EE). The viable cells in fermented HE was higher (7.49 log CFU/mL) than JE (7.28 log CFU/mL) and EE (6.99 log CFU/mL), during the fermentation period. The viable cells and acidity in yanggaeng increased significantly with increasing levels of fermented blueberry extract (p<0.05). In terms of color, the lightness and yellowness decreased significantly, but redness increased with increasing levels of fermented blueberry extract. In the texture profile analysis, control showed the highest result in hardness. Cohesiveness did not show significant differences, according to amount of fermented blueberry extract. The springiness decreased with the increasing levels of fermented blueberry extract. Antioxidant activity, which was measured by DPPH and reducing power, was significantly higher than those of control; and it increased proportionally according to the amount of fermented blueberry extract. Anthocyanin contents were increased proportionally with the increasing levels of fermented blueberry extract. Sensory evaluation showed that the color, taste, flavor, texture, and overall acceptability of yanggaeng containing the JE, HE, and EE were higher than those of the control.