• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.10
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• pp.1456-1460
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• 2006

In order to determine the causes of sweetened adzuki ann spoilage, the characteristics of microorganism isolated from spoiled adzuki ann were investigated. The isolated microorganism was gram-positive, roil-shaped and shore-forming bacteria; its surface was smooth and glazed. From the results of the assimilation test of 46 different biochemicals by the Vitec 2 Compact test and comparison of the cellular wall composition of fatty acid by the data bank of Midi sherlock system, the microorganism was identified as Bacillus subtilis, D-value of the B. subtilis spore was 4.85 min at $115^{\circ}C$, 0.69 min at $121^{\circ}C$ and 0.48 min at $125^{\circ}C$; Z-value was 9.71. The Bacillus subtilis growth was not observed below water activity of 0.92 at $45^{\circ}C$. However, bacteria growth increased gradually as water activity increased above 0.93.

• Food Science and Biotechnology
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• v.16 no.6
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• pp.958-962
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• 2007

This study was conducted to determine the effects of microorganism inactivation using 3 ppm of aqueous ozone (AO), 1% citric acid, 1% lactic acid, and 1% acetic acid alone, as well as the combinations of AO and organic acid, for washing the raw materials of saengsik (carrot, cabbage, glutinous rice, barley) with or without agitation. The combination of AO and 1% of each organic acid significantly inactivated spoilage bacteria in both the vegetables and the grains (p<0.05). However, in the glutinous rice, no inhibitory effects were shown for total aerobic bacteria by using water, ozone, or the combination of AO with citric acid or lactic acid, without agitation. Microbial inactivation was enhanced with agitation in the grains, whereas dipping (no agitation) treatments showed better inhibitory effects in the vegetables than in the barley, suggesting that washing processes should take into account the type of food material.

• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.924-931
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• 2004

A bacteriocin-producing lactic acid bacterium, which strongly inhibited the Lactobacillus plantarum recognized as an important acid spoilage microorganism in kimchi fermentation, was isolated from kimchi. From morphological, physiological, sugar fermentation, biochemical tests, and l6S rDNA sequencing results, the isolate was identified as an Enterococcus sp. and designated as Enterococcus sp. K25. The bacteriocin produced by Enterococcus sp. K25 inhibited several Gram-positive bacteria, including Lb. plantarum, whereas it did not inhibit Gram-negative bacteria and yeasts. Optimal temperature and pH for the bacteriocin production were $25^\circ{C}$ and 5.5, respectively. Enterococcus sp. K25 was applied to kimchi manufacturing alone and together with other preservatives (i.e., chitosan and fumaric acid). In addition, growth of lactic acid bacteria, pH, and titratable acidity (TA) were measured during aging at $5^\circ{C}$ and $10^\circ{C}$. Inoculation of Enterococcus sp. K25 together with fumaric acid showed the most synergistic effect on extension of kimchi shelf-life. Compared to control (no addition), the treatment prolonged the kimchi shelf-life up to 6 days, whereupon the eight-point TA value recognized as the edible limit was reached.

• Journal of the Korean Applied Science and Technology
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• v.33 no.2
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• pp.255-263
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• 2016

Antimicrobial properties of Licorice(Glycyrrhizae radix L.) against food spoilage microorganism, Bacillus subtilis KCTC 1021 was investigated. Antibacterial activity of the essential oil was as equivalent as Potassium metabisulfite and myconazole. The licorice extracts was fractionated to hexane, chloroform, ethyl acetate, butanol and water fraction. Chloroform fraction showed the highest inhibitory effect on the Bacillus subtilis KCTC 1021. Chloroform fraction was further fractionated by silica gel column chromatography and thin layer chromatography(TLC). The antibacterial compound was isolated from their fractions and its chemical structures was identified as (R)-glabridin by ESI-MS, $^1H$-NMR and $^{13}C$-NMR.

• Journal of Food Hygiene and Safety
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• v.32 no.5
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• pp.363-370
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• 2017

In this study, we stored frozen shrimp (Litopenaeus vannamei) at $4^{\circ}C$ during 12 days and investigated the effect of chitosan coating with natural preservatives (0.05% carvacrol, 0.05% thymol) on the growth of microorganism (mesophilic bacteria, psychrophilic bacteria, Pseudomonas spp., $H_2S$ producing bacteria) and physiological characteristics (total volatile basic nitrogen and pH) and sensory evaluation (appearance, odor and general acceptance). Chitosan coating with natural antimicrobial compounds (0.05% carvacrol and 0.05% thymol) had inhibited the growth of all the target microorganism and showed the significant antimicrobial activity (p < 0.05) to mesophilic bacteria, psychrophilic bacteria and $H_2S$ producing bacteria until 12 day (the last day of this study). These treated groups had showed the significant difference (p < 0.05) in total volatile basic nitrogen and all the sensory characteristics but not in pH. Therefore, chitosan coating combined with natural antimicrobial compounds (0.05% carvacrol and 0.05% thymol) showed the effective antimicrobial activity on major spoilage microorganism on shrimp and could be used to elongate the shelf life of refrigerated shrimp.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.3
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• pp.413-417
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• 2003

To evaluate the antimicrobial activity of green tea against putrefactive microorganism in steamed bread, antibacterial activity of green tea extract against well-known strains of spoilage bacteria (Bacillus subtilis ATCC 6633, Bacillus pulmilus KCTC 3348 and Bacillus cereus IFO 12113) and mold (Aspergillus niger KCCM l1239) in bread was determined using the paper disk method. The green tea extract (GTE) showed the inhibition effects on the growth of all the strains of bacteria and mold at 1, 2, 3% levels. The activity of GTE was stable in the wide range of pH (4~9) and temperature (50~20$0^{\circ}C$). When green tea powder (GTP: 1, 3, 5%) was added to steamed bread increase of total bacterial and mold counts declined during storage at 25"C as the levels of GTP increased. By addition of 5% GTP, mold appeared 1 day late extending shelf life of steamed bread compared to control bread without GTP. Therefore, the levels of GTP added to steamed bread could be more than 5% for extended shelf life and wholesomeness of steamed bread.read.

• Food Science of Animal Resources
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• v.41 no.4
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• pp.701-714
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• 2021

In this study, the microbial community succession and the protein hydrolysis of donkey meat during refrigerated (4℃) storage were investigated. 16S rDNA sequencing method was used to analyze the bacteria community structure and succession in the level of genome. Meanwhile, the volatile base nitrogen (TVB-N) was measured to evaluate the degradation level of protein. After sorting out the sequencing results, 1,274,604 clean data were obtained, which were clustered into 2,064 into operational taxonomic units (OTUs), annotated to 32 phyla and 527 genus. With the prolonging of storage time, the composition of microorganism changed greatly. At the same time, the diversity and richness of microorganism decreased and then increased. During the whole storage period, Proteobacteria was the dominant phyla, and the Photobacterium, Pseudompnas, and Acinetobacter were the dominant genus. According to correlation analysis, it was found that the abundance of these dominant bacteria was significantly positively correlated with the variation of TVB-N. And Pseudomonas might play an important role in the production of TVB-N during refrigerated storage of donkey meat. The predicted metabolic pathways, based on PICRUSt analysis, indicated that amino metabolism in refrigerated donkey meat was the main metabolic pathways. This study provides insight into the process involved in refrigerated donkey meat spoilage, which provides a foundation for the development of antibacterial preservative for donkey meat.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.733-739
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• 1994

To extend the self-life of Dooboo (tofu), fish paste and Makkoli (Korean traditional rice wine) for which severe heat treatment are not expectable, main putrefactive microorganisms were isolated from each product and tested their growth inhibition by ethanol and water extracts of several edible plants. The ethanol extract of Phellodandron amurense Ruprs had the strong effect of growth inhibiting to all three isolates from Dooboo and Makkoli, and Eugenia caryophyllus, Pinus rigia Mill, Bletilla striata (Thunb) Reichb. Fill and Paeonia albiflora Pall were also same effect to isolates from fish paste. The ethanol extract was more effective inhibiting than water extract in all test microorganisms. The evident inhibition level of each extract was 2000 ppm of Pa ethanol for fish paste and 1000 ppm for Makkoli.

• The Korean Journal of Food And Nutrition
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• v.16 no.3
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• pp.180-186
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• 2003

In order to prediction of lethal effects on target microorganisms, this study was developed the program in the basis of Excel that was systemized with Visual Basic. This program was automatically calculated the lethal effects (L and Fo value) by using thermal characteristics (D and z value), kinetic model and mathematic model. For the selection of target microorganisms, we are selected two microorganisms because of spoilage increasing by acid production and decreasing quality of food, and heat resistance microorganisms. The target microorganisms were Bacillus cereus (D$_{121.1}$=0.0065 min, z=7.8$^{\circ}C$) and Bacillus subtilis (D$_{121.1}$=0.5 min, z =12$^{\circ}C$). The program was developed for the target microorganisms, and that was very useful for various microorganisms that direct introducing known D and z value.

• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.740-747
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• 2014

Antifungal properties of clove(Eugenia caryophyllata) against food spoilage microorganism, Penicillium rugullosum IFO 4683 was investigated. Antifungal activity of the essential oil was as equivalent as potassium metabisulfite and myconazole. The clove extracts was fractionated to hexane, chloroform, ethyl acetate, butanol and water fraction. Hexane fraction showed the highest inhibitory effect on the Penicillium rugullosum IFO 4683. Hexane fraction was further fractionated by silica gel column chromatography and thin layer chromatography(TLC). The antifungal compound was isolated from their fractions and their chemical structures were identified as eugenol, eugenol acetate and chavicol by EI-MS, $^1H$-NMR and $^{13}C$-NMR.