• Korean journal of food and cookery science
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• v.31 no.6
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• pp.725-732
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• 2015

This study was conducted to evaluate the effects of ethanol on the prolongation of the shelf-life of kimchi paste. Kimchi paste was prepared by adding 0.5~3.0% ethanol, and then stored at $4^{\circ}C$ for 35 days. The retardation of kimchi paste fermentation was evaluated by measuring chemical, microbial, and sensory characteristics. Titratable acidity and pH showed a slight difference, depending on the ethanol concentration. The titratable acidity showed the low content in kimchi paste with 3.0% ethanol during fermentation, whereas the pH showed a reverse tendency, indicating that fermentation was inhibited under a high ethanol concentration. The changes in the sugar-reduced contents were similar to that of the pH. The growth of microorganisms such as total aerobic bacteria, lactic acid bacteria, yeasts and molds in kimchi paste during fermentation were inhibited by ethanol, and the addition of 3.0% ethanol was most effective to inhibit the microbial growth. The number of coliform bacteria was decreased during fermentation of kimchi paste and not detected in any sample at 35 days, except for kimchi paste with 3.0% ethanol. In sensory evaluation, the addition of 0.5~1.5% ethanol in kimchi paste was showed no significant difference on sensory properties compared to the kimchi paste without ethanol (p<0.05). As a result, it is considered that the addition of 1.5% ethanol is the most appropriate to maintain the quality of kimchi paste, without the changing the flavor.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.3
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• pp.184-189
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• 2001

Surf clam, Mactra veneriformis, is a important shellfish produced in south-western coast of Korea. But it's ready to be contaminated and have sand in flesh because it mainly inhabit in silt at tHe inside of coastal area. We determined optimum conditions for the sand elimination and microbial depuration in the shellfish harvested from western coast of Korea. It was found that the most effective conditions of process water for the sand elimination were $23^{\circ}C$, $32.9-35.0\%_{\circ}$ salinity and pH $7.9\~9.0.\;A$ surf clam contained about 210 mg of sand whose $94\%$ was eliminated after 24 hours in natural sea water ($32.9\%_{\circ}$ , pH 7.9) controlled at $23^{\circ}C$. To eliminate both sand and microorganisms contaminated in surf clam, the process water should be run during at least 36 hours for the former and 24 hours for the latter at 150 L/minute/$m^3$of shellfish, when its volume was above 4,000 L/$m^3$ of shellfish in 2 tons of tank.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.1
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• pp.91-96
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• 1992

Twenty kinds of medicinal herbs were extracted by water and 95% ethanol and then antimicrobial activity of the extracts was investigated against various kinds of microorganisms. Water extracts of Gardeniae fructus (Gardenia jasminoides), Lycii fructus (Lycium chinense) and Schizandrae fructus (Schizandra chinensis) showed inhibitory effects on the growth of most of the bacteria. In the case of ethanol extracts, the 3 kinds of the samples such as Gardeniae fructus, Schizandrae fructus and Lithospermi radix (Lithospermum erythrorhizon) showed inhibitory effects on the growth of almost all bacteria. In particular, ethanol extract from Phellodendri cortex (Phellodendron amurense) showed the best inhibitory effect on the growth of S. aureus in the concentration of 0.01%. By the way, inhibitory effects of water extracts from these medicinal herbs were not so good on the growth of fungi but those of ethanol extracts were better and ethanol extracts of Phellodendri cortex showed best. Antimicrobial activity was variable according to the used extracting solvent. For example, inhibitory effets of ethanol ext-racts were $2{\sim}100$ times better than those of water extracts. Ethanol extract of Lithospermi radix was the most effective not only bactericidal effects but also sensory evaluation tests for tastes.

• Food Science and Preservation
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• v.10 no.4
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• pp.569-573
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• 2003

To determine the antimicrobial activity of methanol extracts form 'Formosa' plum against 4 kinds of pathogenic bacteria, the fermosa were got at different growth stages and were extracted using methanol, respectively. The Formosa methanol extracts treated with 5.0 mg/disc showed the highest antimicrobial activity against 4 kinds of pathogenic bacteria and those of Formosa 1-4(immature fruit), which thin out 10∼25 days before foal harvest, showed higher antimicrobial activity against gram positive and gram negative microorganisms than Formosa 5-6(mature fruit). Especially, the methanol extracts of Formosa 1 and 2 were exhibited the strongest growth inhibiting activities to these bacteria. The minimal inhibitory concentrations(MIC) of immature Fomosa methanol extracts was 320 $\mu\textrm{g}$/mL against Escherichia coli 0157:H7 and 160 $\mu\textrm{g}$/mL against Staphylococcus aureus respectively. The MIC of immature Formosa methanol extracts to Salmonella typhimurium and Listeria monocytogenes were 640 $\mu\textrm{g}$/mL. These results suggest that methanol extracs of immature formosa can be used as an effective natural antimicrobial agent in food.

• Food Science and Preservation
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• v.24 no.6
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• pp.827-833
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• 2017

This study was investigated the effects of various commercial sanitizers on microbial characteristics in fresh-cut iceberg lettuce during storage. For screening sanitizer, lettuce was cut and dipped in chlorine water ($0.2ml{\cdot}L^{-1}$), solution of organic acids such as ascorbic acid, citric acid, acetic acid, mixture of ascorbic acid and acetic acid (1-6%), and solutions of commercial sanitizers such as Formula 4$^{TM}$ (1,3,4%), Fresh produce wash$^{TM}$ (1,3,4%), Cleancol$^{TM}$ (1%), Chitochol$^{TM}$ (1%) and Natural Ca$^{TM}$ (0.1%) for 3 min, respectively. Washing lettuce with selected sanitizers resulted in reduction of aerobic bacteria of more than 2 log CFU/g. Initial pH of lettuce was related with the pH of sanitizers. pH ranged from 4.7 to 6.1 in Formula 4 (4%, pH 1.7) and Natural Ca (0.1%, pH 12.0), respectively. Chlorine water showed consistent and significant inhibition effect in all of microorganisms except total coliform. Over 3% of Formula 4 and Fresh produce wash were found to have high bactericidal activity among sanitizers. The sanitizers of chlorine water, Fresh produce wash, Chitochol and Natural Ca were effective in reducing yeast and mould populations. As coliform and E. coli, Formula 4 (4%) showed the highest bactericidal activity. The bactericidal effect of commercial sanitizers during storage varied with the kinds and concentrations of tested sanitizers. Although inhibition effect was not showed during storage, these results suggest that commercial sanitizers could be an alternative to chlorine for washing fresh-cut produce.

• Food Science and Preservation
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• v.23 no.7
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• pp.960-966
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• 2016

This study was conducted to explore the potential for use of atmospheric pressure dielectric barrier discharge plasma (atmospheric pressure DBD plasma) as a non-thermal sterilization technology for microorganisms in dried red pepper. The effects of key parameters such as power, exposure time and distance on the sterilization efficiency and the quality of red dried pepper by the atmospheric pressure DBD plasma treatment were investigated. The results revealed that the plasma treatment was very effective for sterilization of Staphylococcus aureus, with 15 min of treatment at 1.0 kW and 20 mm sterilizing 82.6% of the S. aureus. Increasing the power or exposure time and decreasing the exposure distance led to improved sterilization efficiency. The atmospheric pressure DBD plasma treatment showed no effect on the ASTA (American spice trade association) value or hardness of dried red pepper. Furthermore, no effects of atmospheric pressure DBD plasma treatment were observed on the sensory properties of dried red pepper. To assess the storage stability, the dried red pepper was treated with atmospheric pressure DBD plasma (1.5 kW power, 15 min exposure time and 10 mm exposure distance), then stored for 12 weeks at $25^{\circ}C$. Consequently, the ASTA value, hardness and capsaicin concentration of dried red pepper were maintained.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1511-1517
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• 1999

Effects of washing methods using electrolyzed acid water on lettuce(Lactuca sativa) and quality changes during storage were investigated. The multi-stage immersion treated 3 times in 2 min showed more effective than others to remove microorganisms. Total count of lettuce after immersion in electrolyzed acid water was decreased to 1/100-1/300 of $5.8\;{\times}\;l0^5CFU/g$ of non-immersed lettuce and $2.3\;{\times}\;l0^5CFU/g$ of tap water immersed lettuce. Also coliforms was significantly decreased to 1/3,000 of $3.1\;{\times}\;10^3CFU/g$ after electrolyzed acid water washing. However, microbial levels of electrolyzed acid water treated one became to be similar to those of non-treated lettuce after 3 days of storage at $10^{\circ}C$. The color values of L and b of lettuce treated with electrolyzed acid water were somewhat higher than those of others. Though chlorophyll content of lettuce just after immersion in electrolyzed acid water was 9% lower than those of non-treated one, the content was decreased to the same level of other treatments during storage. Decaying ratio showed the lowest value in lettuce immersed in electrolyzed acid water until 6 days of storage. The sensory tests for overall acceptability and appearance of lettuce immersed in electrolyzed acid water showed higher than those of others until $3{\sim}6$ days of storage.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.218-224
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• 2000

The antimicrobial activities of chitosan oligosaccharide(chitohexaose) and two types of chitosans M.W.(10,000 and M.W. 100,000) were examined against Escherichia coli O157 : H7(ATCC 43894), Staphylococcus aureus(ATCC 144458) and Candida albicans(KFRI 432). Chitosan with molecular weight of 10,000 showed the strongest antimicrobial activities to E. coil O157 : H7 and S. aureus, whereas chitohexaose acted most strongly against C. albicans. The most effective concentration of chitosan was measured to be 0.1 mg/mL for E. coil O157 : H7 and S. aureus, and that of chitohexaose to be 1 mg/mL for C. albicans. Antimicrobial activities of chitosans and chitohexaose were maintained for 60 min after their treatment. They were found to induce leakage of intracellular proteins and nucleic acids from treated microorganisms. The efflux determined by assaying the ${\beta}-galactosidase$ leaked from the lactose-induced E. coli O157 : H7 cells was observed to reach the highest level within 60 min after treatment with the antimicrobial agents and chitosan with 10,000 molecular weight gave the highest ${\beta}-galactosidase$ activity. Therefore, it is supposed that the antimicrobial activity of chitosan with its unique polycationic nature might be caused by its binding to anionic component(s) of the cell envelope and thereby inhibiting the membrane metabolism and/or leaking intracellular materials.

• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.1107-1113
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• 2000

Gamma irradiation technology was applied to develop salted and fermented shrimp with lower salt concentration, high sensory quality and storage stability. Shrimp was prepared with 15 and 20% of salt and fermented at $15^{\circ}C$ for 10 weeks. The sample was irradiated at 0, 5.0 and 10.0 kGy right before optimum stage of fermentation. Fermented shrimp with 30% of salt concentration was also prepared as a control. The proximate composition, salinity and Aw were not affected by gamma irradiation. However, pH of irradiated samples was lower than that of non-irradiated samples, probably because irradiation effectively suppressed excessive fermentation by controlling microorganisms. From the results of sensory analysis, it was concluded that fermented shrimp with 15% of salt and irradiated at 10 kGy before optimum fermentation, or 20% of salt and 5 kGy or above were the most effective in terms of sensory quality and storage stability.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.349-355
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• 2000

This study was conducted to enhance the storage stability of fermented shrimp with different salt contents using a high hydrostatic pressure. The effects of the magnitude of pressure and treatment time on the microorganisms of the fermented shrimp were investigated. The highest microbial counts with respect to the salt levels were observed at 18% salt, showing $3.4{\times}10^5\;CFU/g$ for general bacteria, $6.4{\times}10^4\;CFU/g$ for halophilic bacteria, $4.2{\times}10^5\;CFU/g$ for yeast and $3.0{\times}10^4\;CFU/g$ for halophilic yeast. The degree of sterilization increased with the magnitude of pressure and treatment time, and the sterilization could be analyzed by the first order reaction kinetics. The sterilization rate constants $(k_p)$ of the halophilic bacteria was lower than that of general bacteria. The $log(k_p)$ increased linearly with pressure and the slope of the regression line of the halophilic bacteria was greater than that of general bacteria, indicating that the sterilization of the halophilic bacteria was more dependent on the pressure. High hydrostatic pressure treatment was an effective non-thermal sterilization method for the salted and fermented shrimp, and the optimum treatment condition was for 10 min at 6,500 atm.