• Korean Journal of Food Science and Technology
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• v.23 no.6
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• pp.689-694
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• 1991

Jangsu, a Korean ancient non-alcoholic beverage made by lactic acid fermentation of cooked rice, was prepared and the microbial characteristics were investigated. The periodic removal of fermented product and the addition of newly made cooked rice and cold water as new substrate enhanced the growth of lactic acid forming bacteria but supressed the growth of proteolytic bacteria. The important microorganisms in jangsu were Lactobacillus, Lactococcus, Pediococccus and Leuconostoc species. Lactococcus thermophilus, Lactobacillus coryniformis and Leuconostoc mesenteroides were identified. The isolated strains were cultivated and used as starter culture of jangsu. Some useful strains were selected which were able to produce acceptable flavor and sufficient amount of acid lowering the pH to near 4.0.

• Food Science of Animal Resources
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• v.35 no.3
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• pp.406-412
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• 2015

The combined effects of electron-beam irradiation and ageing of beef were examined. The irradiated samples at dose of 0 or 2 kGy were kept and analyzed for the microbial growth, shear values, meat color, and nucleotide-related flavor compounds at different ageing temperatures (2, 10, or 25℃) for 8 d. The irradiation effect on inactivation of foodborne pathogens was also investigated. The population of Listeria monocytogenes and E. coli O157:H7 inoculated in beef samples decreased in proportion to the irradiation dose, showing D₁₀ values of 0.66 and 0.65 kGy respectively. The irradiated beef eye of round had lower number of total aerobic bacteria (TAB) than nonirradiated one during the storage, but the TAB increased with higher ageing temperature (p<0.05). Especially, TAB increased sharply in non-irradiated samples aged at 25℃ after 4 d (p<0.05). With increasing ageing temperature and ageing time, shear force values decreased (p<0.05). The color a* values of the irradiated beef were lower than those of the non-irradiated throughout the ageing period (p<0.05). As ageing time and temperature increased, the amounts of inosine monophosphate decreased and the hypoxanthine increased (p<0.05). Relatively high ageing temperature could be used at irradiated beef eye of round to shorten the ageing time.

• Food Science of Animal Resources
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• v.30 no.5
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• pp.780-786
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• 2010

This study compared the effects of autoclaving (AC; $121^{\circ}C$ for 15 min), gamma (GR), and electron beam irradiation (EB; 0-20 kGy) on the microbial, physicochemical, and sensory properties of ready-to-eat bulgogi during storage at $35^{\circ}C$ for 90 d. No viable cells were observed (p<0.05) upon AC, GR or EB at more than 15 kGy. However, adverse effects such as tenderization and deterioration of sensory properties were induced in bulgogi upon AC and high dose irradiation. Especially, the hardness and sensory qualities (texture and taste) of the AC-treated samples were extremely deteriorated (p<0.05). These results indicate that use of GR and EB (15 kGy) can ensure the microbial safety of bulgogi without compromising the hardness and sensory properties (texture, taste and flavor).

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.9
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• pp.1374-1383
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• 2003

The effect of applying edible coating and addition of antioxidants (butylated hydroxyanisole (BHA) plus butylated hydroxytoluene (BHT) in a 1:1 ratio) on pork patties were investigated prior to achieve desired physico-chemical, microbiological and sensory qualities. For this, five treatments were conducted as (i) control (neither coated nor antioxidants treated); (ii) coated without antioxidants treated; (iii) coated and antioxidants added in the batter mix only (100 ppm); (iv) coated and antioxidants added in meat mix (100 ppm) only; and (v) coated and antioxidants added both in the batter mix (50 ppm) and the meat mix (50 ppm). Addition of antioxidants both in the batter mix and the meat mix significantly (p<0.05) reduced the microbial loads and thiobarbituric acid (TBA) values. The TBA values significantly (p<0.05) increased up to day 14 and then progressively increased with the advancement of each interval of storage days up to 28 days. Total plate count significantly (p<0.05) increased with the increase in storage days.Coliform and Staphylococcus aureus were absent throughout the storage days in all samples. Staphylococcus aureus however, were present in the control group at day 14 and in enrobed (coated) patties (without antioxidants treated) at 28th day. Addition of antioxidants to batter mix and meat mix did not substantially enhance bacteriostatic activity. Application of coatings and antioxidants retarded the loss of firmness, flavor, changes in appearance and color, and also other sensory attributes. Control patties were better with respect to microbial quality and TBA values but had poorer sensory quality than coated patties.

• Korean Journal of Food Science and Technology
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• v.43 no.4
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• pp.407-412
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• 2011

Free and bound aroma compounds in green and fermented teas treated with microbial-fermentation were analyzed using headspace-solid phase microextraction gas chromatography (GC) and GC-mass spectrometry. Aldehydes and ketones in green tea decreased during microbial fermentation, whereas linalool and geraniol increased in the fermented tea. After enzyme treatment, (Z)-3-hexen-1-ol increased significantly following enzymatic hydrolysis of both green and fermented teas. In addition, benzaldehyde, 3-hexenyl acetate, and geraniol also increased in green tea with enzyme treatment. Bound aroma compounds in the green and fermented teas increased at different levels of added enzyme. We demonstrated the enhancement of both green and fermented teas by enzyme treatment, which can lead to improvement in the flavor qualities of green and fermented teas.

• Food Science of Animal Resources
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• v.33 no.2
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• pp.205-213
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• 2013

The objective of this study was to evaluate the quality characteristics of sun-dried Hanwoo beef jerky added with Salicornia herbacea (SH). Sliced Hanwoo beef shank were marinated and sun-dried at $28-30^{\circ}C$, relative humidity (RH) 30-35% for 3.5 h. The physicochemical and microbiological traits of the Hanwoo beef jerky were analyzed during the aerobically packaged storage at $25^{\circ}C$. The water activities of beef jerky with 0.5% and 1.0% SH were lower than those of the control at 0 d (p<0.05). The pH values of beef jerky with SH were significantly higher than those of the control (p<0.05). The beef jerky with SH and ascorbic acid showed significantly lower TBARS values than the control (p<0.05). The beef jerky with SH showed a significantly lower redness ($a^*$) than the control (p<0.05). Total plate count (TPC) of beef jerky with 1.0% SH was significantly lower than that of the control during the storage of 20 d (p<0.05). Yeast/mold was detected in the control and beef jerky with SH after storage periods of 10 and 20 d, but was not detected in jerky with ascorbic acid. With regard to the sensory properties, beef jerky with SH showed significantly greater flavor scores than the others (p<0.05). The result shows that SH powder can be used to increase the sensory quality and microbial safety of beef jerky.

• Food Science and Preservation
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• v.10 no.3
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• pp.278-283
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• 2003

Addition of ethanol and/or polylysine to kimchi was investigated to improve its microbial hygienic quality and to extend shelf-life. Ethanol was added to kimchi with several concentrations(0.3％, 0.6％, 0.9％) and stored at 10$^{\circ}C$. Addition of 0.6％ and 0.9％ ethanol showed apparent inhibitory effect on growth of microorganism, but any distinct difference was not found between those concentrations. Addition of ethanol was more effective on growth inhibition of coliform and lactic acid bacteria than others. Addition of 0.6％ and 0.9％ ethanol retarded apparently pH decrease and acidity increase. Although addition of 0.6％ ethanol in combination with 0.12％ polylysine showed good retardation of pH decrease and acidity increase, overall organoleptic quality was not good because of off-flavor and taste. Also, addition of 0.6％ ethanol showed good overall organoleptic quality.

• Journal of the FoodService Safety
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• v.3 no.1
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• pp.8-18
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• 2022

Dry-aging is one of the traditional aging processes, especially for beef. This aging process is being popular, because it produces unique brown/roasted flavor and texture that consumers prefer. However, as it is exposed to outside without packaging food safety concerns have been raised. The objective of this study was to investigate the presence of total aerobic bacteria (TAB) and pathogenic bacteria in manufacturing environment and suggest the safety management plan for the production of dry-aged meat. Surface samples from 66 environmental and 6 beef carcass samples were collected. According to the monitoring results, the contamination levels of TAB were in the order of shelves (5.4±1.1 Log CFU/cm²), cotton gloves (2.9±0.2 Log CFU/cm²), and door knobs (2.8±0.4 Log CFU/cm²) in the dry-aging room. In the door knobs, the level of mold was higher than that of yeast. These results indicate that the mold spores may be cross-contaminated with environmental factors inside the aging room. The risk factors that may occur during the manufacturing process were presented and possibility of risk was determined. From the aspect of microbiology, aging and trimming steps were determined as the critical control points. The temperature of the aging room should be maintained below 10℃ and the humidity below 75-85%. Based on the monitoring and the risk assessment of the dry-aging process, we prepared the safety management plan for the production of dry-aged meat, and it should be useful in improving the food safety of dry-aged meat.

• Food Science and Preservation
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• v.30 no.5
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• pp.729-742
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• 2023

The consumption of king oyster mushrooms has steadily increased owing to their unique flavor and delicate texture. This study extended the storage period of king oyster mushrooms (Pleurotus eryngii ) via gamma irradiation. Irradiated samples (0, 0.5, 1, 2, and 3 kGy) were stored at 4℃ with 80% relative humidity for up to 28 days, and the experiments were conducted every 7 day. Microbiological analysis revealed a dose-dependent reduction in total aerobic bacteria, Pseudomonas spp., and yeasts and molds, and gamma irradiation above 2 kGy effectively controlled microbial contamination for up to 28 days. At the 28th day of storage, the irradiated king oyster mushrooms exhibited delayed browning through the reduction of tyrosinase activity. Moreover, firmness reduction (%) was 80.59±1.89% for the non-irradiated group and 42.80±1.28, 34.57±1.13, 31.05±3.24, and 39.73±0.94% for the irradiated group (0.5, 1, 2, and 3 kGy), respectively. These results were supported by the scanning electron microscopy photos, which showed smaller pores in the irradiated group than in the non-irradiated group. This study demonstrated that 2 kGy of gamma irradiation effectively reduces microbial contamination and delays the browning and softening of king oyster mushrooms for up to 28 days.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.11
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• pp.1638-1648
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• 2016

This study was conducted to analyze the quality characteristics of kimchi in terms of garlic content (0~4.5%). Kimchi was made at $4^{\circ}C$ for 8 weeks, and pH, acidity, organic acid content, free sugar content, microbial counts, flavor pattern, and sensory characteristics were measured. The results show that kimchi containing garlic had a higher pH and lower acidity during fermentation than control kimchi without garlic. Principal component analysis enabled differentiation of the flavor pattern of kimchi according to fermentation period and garlic content. Addition of garlic to kimchi significantly decreased the numbers of total bacteria and lactic acid bacteria for 2 weeks after production. The numbers of total bacteria and lactic acid bacteria increased rapidly up to 2 weeks during fermentation and thereafter decreased gradually. Coliform counts were higher in the control than in kimchi containing garlic, whereas there was no detection after 4 weeks. Yeast and mold counts decreased significantly with increasing garlic content during the initial fermentation stage. Counts could not be detected in kimchi containing garlic. After 4 weeks, counts could not be detected in kimchi without garlic. Among kimchi with different garlic contents, fermentation was slower in kimchi with high garlic content; scores for off-odor and off-note taste were lower as well.