• Journal of Dairy Science and Biotechnology
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• v.34 no.1
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• pp.9-20
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• 2016

Various microflora, including lactic acid bacteria, are important and necessary components of various cheeses and have significant roles in cheese manufacturing and ripening. In general, the starter culture and secondary microflora could affect the physicochemical properties of various cheeses and could contribute to modifications during manufacturing and ripening. Therefore, during cheese manufacturing and ripening, microbial diversity may depend on continuous interactions among microflora and various environmental conditions. The microbial diversity of cheese is very complex and difficult to control using the classical microbiological techniques. However, recent culture-independent methods have been rapidly developed for microflora in cheese, which could be directly detected using DNA (and/or RNA) in combination with culture-dependent methods. Therefore, this review summarizes state-of-the-art molecular methods to analyze microbial communities in order to understand the properties that affect quality and ripening as well as the complex microbial diversity of various raw-milk, long-ripened cheeses.

• Food Science and Preservation
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• v.9 no.1
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• pp.19-27
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• 2002

The effect of gamma irradiation was investigated on the microbiological and physicochemical qualities of boiled-dried anchovies (large- and smallsized) packed in PVC film (0.06 ㎜) during storage at 15$\pm$1$\^{C}$ for 6 months. On the other hand, thermoluminescence characteristics of minerals extracted from the sample were analyzed to evaluate its possibility in detecting the irradiated anchovies. The samples were contaminated by microbial levels of 104∼106 CFU/g in total aerobic bacterial counts and negative in coliforms, which were different depending on the sample sizes. Gamma irradiation at 3 kGy was effective for improving the hygienic quality of both samples for 6 months, keeping the microbial population less than 20 CFU/g. Besides it was not detrimental to the quality attributes, such as instrumental color parameters L, a, b, ΔE), browning, TBA value, volatile basic nitrogen, trimethylamine-N and sensory properties(appearance, color, odor, tape, overall acceptability). However, storage conditions (time, temperature, packing) showed a critical factor nfluencing the quality changes of dried anchovies. Thermoluminscence analysis was prove to distinguish irradiated from non-irradiated anchovies by comparing both temperature at which glow curves appear and the curve intensity, that was possible even after 6 months at - 20$\^{C}$.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.116-123
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• 2004

This study was conducted to investigate the changes in physicochemical and microbiological properties during fermenting process of organic fertilizer which was made from the mixture of organic materials such as sesame oil cake, fish meal, blood meal, rice bran, ground bone meal, and natural minerals such as illite, crusted oyster shell and loess. They were mixed and fermented for 70 days. The sesame oil cake and rice bran, major ingredients for organic fertilizers, consisted of 7.6 and 2.6% total nitrogen, 3.6 and 4.6% $P_2O_5$, 1.4 and 2.2% $K_2O$, respectively. The ground bone meal included 29.2% $P_2O_5$ and illite included 3.8% $K_2O$. Temperature of organic fertilizer during the fermentation rapidly increased over $50^{\circ}C$ within 2 days after mixing and stabilized similar to outdoor temperature after 40 days. Moisture content decreased from 36.3 to 16.0% after 1 month. C/N ratio of organic fertilizer slightly increased until 30 days and thereafter, it slowly decreased, It resulted from the faster decrease of total nitrogen concentration compared with organic matter. Concentration of $NH_4-N$ in organic fertilizer rapidly increased from 1,504 to $5,530mg\;kg^{-1}$, the highest concentration after 10 days. Meantime, $NO_3-N$ concentration was low and constant about $150mg\;kg^{-1}$ over the whole fermenting period. This result seemed to be due to the high pH. The organic ferfilizer fermented for 70 days was composed of 2.7% N, 2.8% $P_2O_5$, 1.8% $K_2O$, and 35.9% organic matter. Total populations of aerobic bacteria, Bacillus sp. and actinomycetes, after fermenting process, were $12.5{\times}10^{10}$, $45.5{\times}10^{5}$ and $13.6{\times}10^{5}cfu\;g^{-1}$ respectively. Pseudomonas sp. was $71.9{\times}10^{7}cfu\;g^{-1}$ at first, but it rapidly decreased according to the rise of temperature. Yeasts played an important role in the early stage of fermentation and molds did in the late stage.

• Applied Biological Chemistry
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• v.46 no.3
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• pp.201-206
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• 2003

An apple wine was prepared by fermentation at $25^{\circ}C$ for 2 weeks using Saccha개myces cerevisiae KCCM 12224, followed by aging at $15^{\circ}C$ for 14 weeks, and its physicochemical and microbiological changes were investigated. The viable bacterial cell numbers, increased from $1.4{\times}10^3\;CFU/ml$ at the beginning of fermentation, to $2.8{\times}10^6\;CFU/ml$ after 2 weeks, but decreased to $1.0{\times}10^5\;CFU/ml$ after aging. The viable yeast cell numbers changed from $4.3{\times}10^4\;CFU/ml$ to $1.2{\times}10^7\;CFU/ml$ during the fermentation, and decreased to $1.2{\times}10^4\;CFU/ml$ after aging. Sugar content changed from $20.0^{\circ}Brix$ to $8.5{\circ}Brix$, and reducing sugar content was changed from 9.66% to 6.44%. Alcohol content and acidity increased to 7.0% and from 0.19% to 0.24%, respectively. No changes in acidity, pH, and sugar content were observed during the aging, but reducing sugar and solid contents decreased. When apple wine was fultered through $0.45\;{\mu}m$ nitrocellulose membrane followed by various ultrafiltration membranes with different molecular weight cut-off values, the initial flux $(121.2\;liter/m^2/h)$ and the average flux of Biomax 100k membrane were the highest among the membranes used. These membrane filtration treatments resulted in complete removal of microorganisms as well as decrease in turbidity and solid content without changes in other chemical properties. No changes in the physicochemical properties of the apple wine and no microorganisms were detected during the storage at $156{\circ}C$ for 6 weeks.

• Journal of the Korean Society of Food Culture
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• v.34 no.2
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• pp.224-232
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• 2019

This study evaluated the physicochemical and microbial quality characteristic of seasonal commercial kimchi for hygienic safety levels. The pH of seasonal commercial kimchi was 3.84-6.36 and the titratable acidity and salinity of the samples were 0.21-1.16 and 1.19-1.54%, respectively. The content of nitrate and nitrite in the commercial kimchi were lower in the spring and summer, which was affected by acidic condition of the kimchi depending on fermentation. Heavy metal contents in commercial kimchi are not an issue because they were detected only at very low levels. The total aerobic bacteria and coliforms counts ranged from 5.25 to 8.44 Log CFU/g and 0.00 to 5.08 Log CFU/g, respectively. The total aerobic bacteria and coliforms were detected more in summer than in the other seasons. E. coli was detected in three of the samples tested. Food-borne pathogens were not detected in any of the samples except for B. cereus. B. cereus was detected in the fall in more than 70% of samples. These results suggest that commercial kimchi distributed in the fall maintain the quality properties and the microbiological safety of kimchi compared to the other seasons. Therefore, further studies as an effective distribution system for the particular seasons will be needed to guarantee the hygienic safety levels of commercial kimchi required by the consumers.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.12
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• pp.2004-2011
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• 2013

This study was carried out to investigate the chemical and microbiological properties of Kimchi containing different amounts of squid and octopus during fermentation at $4^{\circ}C$ for 56 days. Kimchi were assigned to one the of the following 7 treatment groups: CK (control Kimchi; no addition), SK-5 (added 5% of squid), SK-10 (added 10% of squid), SK-20 (added 20% of squid), OK-5 (added 5% of octopus), OK-10 (added 10% of octopus), and OK-20 (added 20% of octopus). The quality characteristics of CK and other treatments were determined by measuring the pH, titratable acidity, reducing sugar, volatile basic nitrogen (VBN), and microbial analysis. During fermentation, Kimchi containing squid and octopus had higher pH and lower acidity values than the CK group (P<0.05). The titratable acidity was increased in all treatment groups, whereas the reducing sugar content decreased gradually during fermentation. The reducing sugar contents were highest in the CK group. The VBN value increased in all treatment groups with increasing storage period, and the CK group had lower VBN value than the other treatment groups containing squid and octopus. The numbers of total bacteria and lactic acid bacteria rapidly increased up to the second week, and this slowly increased thereafter.

• Journal of Animal Science and Technology
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• v.44 no.3
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• pp.361-368
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• 2002

The Korean frozen pork loins in vacuum packaged were obtained from three different Korean export companies and investigated for pH, proximate composition, cooking loss, physico-chemical and sensory characteristics. The frozen pork loins were stored at -20$^{\circ}C$ for 40 days. The results were as follows: The protein contents were relatively higher in the samples from the company II and the ash contents were relatively higher in the samples from the company I than those from the other companies. The samples from the company Ⅱ had highest pH and water-holding capacity, and cooking loss and shear force were lowest in the company II. The total plate counts and coliform bacteria for loins from 3 companies were in the range of 3.04${\sim}$3.75 log cfu/$cm^2$ or g and 0.37${\sim}$1.32 log cfu/$cm^2$ or g in average, respectively. The TBARS values were 0.35${\sim}$0.38 mg malonaldehyde/kg sample. There were no significant differences in sensory characteristics for raw and cooked loins from all companies.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.5
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• pp.660-665
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• 2008

The aim of this work was to investigate the microbiological and physicochemical properties of the rice sourdough for Jeungpyun prepared by mixed culture of Saccharomyces cerevisiae (S. cerevisiae) and Leuconostoc mesenteroides (L. mesenteroides) strains. The rice sourdough was fermented with S. cerevisiae and L. mesenteroides strains in rice dough for 24 hours at $30^{\circ}C$. Growth of L. mesenteroides strain was decreased after inoculation, however, it increased again after 18 hours of dough fermentation, and the growth of S. cerevisiae showed a typical growth pattern. Also, total aerobic microorganisms counts in rice sourdough were decreased due to the produced organic acids and ethanol during dough fermentation. These products led to a favorable fermentative quotient (FQ; molar ratio between lactic to acetic acid) value of $1.9{\sim}3.2$ and more stable fermentation for rice sourdough formation. The expansion ratio and viscosity were considerably increased by mixed cultivation of S. cerevisiae and L. mesenteroides strains. Addition of the brown rice at 10% (w/w) to dough preparation increased the relative expansion ratio to the highest value.

• Food Science of Animal Resources
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• v.30 no.2
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• pp.328-335
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• 2010

The aim of our study was to develop a new starter culture for fermented milk. Polymerase chain reaction screening of 103 acid-producing isolates from Kimchi identified 72 Lactobacillus strains. The ability of the strains to inhibit the growth of the food-borne human pathogens (Escherichia coli, Salmonella Enteritidis, Staphylococcus aureus) was measured, using a conventional paper disk method. Among the 72 strains, strain LHC52 displayed potent antagonistic activity. Use of 16S rDNA sequencing and the API 50CHL system identified the strain as Lactobacillus plantarum and it was designated L. plantarum LHC52. Biochemical analyses revealed especially high antibacterial activity against E. coli. Yogurt produced using L. plantarum LHC52 did not show different microbiological and physicochemical properties compared to conventionally-prepared yogurt, implicating L. plantarum LHC52 as a useful, potently antibacterial starter culture for yogurt preparation.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.5
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• pp.678-688
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• 2007

In this study, we investigated the effects of ripened tomato on the Baechukimchi fermentation, by measuring sensory, physicochemical, and microbiological properties during fermentation up to 28 days. The Baechukimchi, with various levels [0, 10, 20, 30%(w/v)] of ripened tomato, was fermented at $10^{\circ}C$. The product containing 20% ripened tomato showed the highest scores for overall acceptability, sour taste, texture, sour smell, and color. The intensity characteristic scores related to sour smell and sour taste were the highest in the control, and the texture score was highest in the 20% ripened tomato sample. During fermentation, total acidity increased while pH gradually decreased. The reducing sugar and total vitamin C contents of the experimental groups with added ripened tomato were higher than those of the control. Also, the time periods to reach maximum levels of lactic acid bacteria, by log numbers of cells and total viable cells, were more delayed in the experimental groups with added ripened tomato than in the control. Overall, the results indicate that a 20% addition of ripened tomato to Baechukimchi during fermentation can enhance sensory qualities and extended the palatable period of the product.