• Journal of the Korean Home Economics Association
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• v.23 no.2
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• pp.37-43
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• 1985

The effect of irradiation at dose of 3~10 kGy on the extension of the shelf-life of sliced dried squid and dried file and on its quality were investigated during nine months of storage at room temperature. The number of microorganisms, TBA value and TMA-N content were used as objective indices concerned to the sensory evaluation. In the number of initial microbial loading, total bacterial count of sliced dried squid and dried file fish were $2.7{\times}10^{8}\;and\;2.0{\times}10^{5}$, yeast and mold were $5.7{\times}10^{5}\;and\;6.2{\times}10^{5}$ and coliform group were $2.1{\times}10^{5}$ and above 10 per gram of the samples, respectively. The number of total bacteria was sterilized by 99% with irradiation of 3~10 kGy and irradiation of above 7 kGy was shown to be effective for the radurization of yeast, mold and coliform group. TBA value of irradiated groups were higher than storage time. The TMA-N content of nonirradiated group was markedly increased by microbial spoilage during storage, however above 8 kGy irradiated group were indicated about 10 mg% after nine months storage. In the sensory evaluation, the nonirradiated group was off favor after three months storage and was changed in color of dried fishes but 7~10 kGy irradiated group were maintained good qualit compared with those of fresh samples after nine months storage at room temperature.

• Food Science and Biotechnology
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• v.17 no.4
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• pp.850-856
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• 2008

White, red, and extruded ginsengs were studied against 8 strains of food-borne pathogens and/or food spoilage microorganisms. The ginseng powders were extracted with different extractants and screened for antimicrobial activity using the disc diffusion and broth dilution techniques. The results showed that the yield of extraction was higher with increase of aqueous solution content and temperature. Preliminary screening revealed that the red ginseng extracts were most active, that has been found to be highly effective against all tested microbe except Listeria monocytogenes. Moreover, Bacillus subtilis has shown highly susceptible, which the diameters of inhibition zone values of 28 extracts were between 7 and 14 mm. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) recorded for the different crude ginseng extracts against microorganism using ranged from 6.25 to 100 mg/mL, indicated that the methanol extract of ginseng were more effective than ethanol and water extracts. The 60% methanol extract of red ginseng had the greatest effects against B. subtilis with MIC and MBC values at 6.25 mg/mL.

• Journal of Food Hygiene and Safety
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• v.29 no.3
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• pp.189-194
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• 2014

This study was conducted to evaluate microorganism contamination of food utensils and service facilities in school and to prevent hazards by food poisoning occurrence. As a result, the highest number of microorganism growth plate ($12.3{\pm}2.6$) was detected in total bacteria test plate, and also observed $10.3{\pm}3.9$ growth plates in Staphylococcus aureus test plate and $9.5{\pm}3.9$ growth plates in E. coli and coliform bacteria test plate. But we could detect to the lowest number of growth plates ($1.5{\pm}1.0$) in Vibrio test plate. We also assessed that floors were appeared to the highest microorganism contamination rate in food utensils and service facilities. Therefore, $4.5{\pm}0.6$ growth plates was detected in pre-operation floor and $4.3{\pm}1.0$ growth plates in floor. And high level of microorganism contamination also observed in tables as $3.3{\pm}1.0$ growth plates in cooking table and $3.0{\pm}0.0$ growth plates in dining table. The level of microorganism contamination of food utensils such as kitchen knife, cutting board, and food tray were lower than that in food service facilities. We analysed microorganism contamination according to purpose of use in kitchen knifes and cutting boards. The microorganism contamination rate in fish kitchen knife ($2.0{\pm}0.8$) and fish cutting board ($1.3{\pm}1.5$) were slightly higher than that of others purpose of use. As a result of microorganism identification, various strains of microorganism were contaminated in food service facilities and some strains could detected more than two times. Especially, Staphylococcus aureus was repeatedly identified in cooking table, trench, and kitchen knife. Bacillus cereus was identified in kitchen knife, and then Pseudomonas fluorescens and Pseudomonas aeruginosa were also detected in food utensils and service facilities as known to food spoilage microorganisms. Klebsiella pneumoniae was detected four times repeat, which widely distribute natural environment as normal bacterial flora but sometimes cause acute pneumonia. These results suggest that food utensils and service facilities are contaminated with not only major food poisoning microorganisms such as Staphylococcus aureus, but also food spoilage microorganisms. Taken together, strict personal hygiene control and efficient food service facilities management will be needed to enhance food safety in school feeding and to improve student health.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 1993.12a
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• pp.6-9
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• 1993

According to changes in population, economic conditions, life-stile and eating habits, the frui ts and vegetables market wi 11 be shi fted from processed (i. e. , canned) to fresh. Undressed fresh produce, consisting of washed, disinfected and peeled fruits and vegetables that either sliced or grated, are currently increased in demand by retail and institutional market which use them as salad components or in ready-to use foods, Main attributes of minimally processed fruits and vegetables are convenience and fresh-like quality. Minimally processed Products readily deteriorate in quality, especially color and texture, as a result of endogeneous enzyme enhanced respiration and microorganisms which lead to reduced shelf Iife. According to changes in population, economic conditions, life-stile and eating habits, the frui ts and vegetables market wi 11 be shi fted from processed (i. e. , canned) to fresh. Undressed fresh produce, consisting of washed, disinfected and peeled fruits and vegetables that either sliced or grated, are currently increased in demand by retail and institutional market which use them as salad components or in ready-to use foods, Main attributes of minimally processed fruits and vegetables are convenience and fresh-like quality. Minimally processed Products readily deteriorate in quality, especially color and texture, as a result of endogeneous enzyme enhanced respiration and microorganisms which lead to reduced shelf Iife. Thus. to prevent these undesirable changes , val'ious techniques such as controlled atmosphere (CA) storage, modified atmosphere OIA) storage, including vacuum packaging have been receiving considerable attention, Although milch research has been done to find optimal conditions for whole intact frui ts and vegetables, only limi ted information is avai lable on fresh cut. and other minimally processed products. 81 iced frui ts exhibi t increas~d ethylene production and respiration compal'ed to whole f, 'uits during distribution in response to tissue damage. As a result, accelerated senescence and enzymatic browning OCCUI', Recent l'esearch on minimally processed fl'uits and vegetables has mainly focused on methods to inhibit browning, due to ban on use of sulfur dioxide, In order to retard or prevent these physiological changes, val'ious al ternatives, reducing agents. acidulants, chelating agents and inol'ganic sal ts have been evaluated for use on fresh cut fl'ui ts. Al though some agents were effective replacement for sulfur dioxide. consum$\textregistered$I'S demandless use of chemical on such products. Shel~ life of minimally processed products has been extended by inhibition of metabolic reactions associated with loss of quality and by inhibition of aerobic spoilage caused by wide variety of microorganisms. Appl ication of ~I.-\ packaging, including vacuum packaging, retards the rate of respiration, prevents growth of aerobic spoilage organisms, inhibits oxidation and color deterioration. Tissue softening is another major problem in minimally processed products because enzymes re 1 a ted to ce 11 wa 11 degrada t i on are not inactivated. Various treatments have been investigated for retardation of the softening of sliced products. Some studies have concentrated on the application of an active packaging system with ~I, l. packaging and calcium infi 1 tration as possible measures to retain firmness of processed products. In my opinion, one important step for production of minimally processed frui ts wi th favorabl e color of cut surface and firm texture is the selection of better cultivar. As the view, changing tendency of fresh color by apple cultivars and relationship between the tendency and PPO activity will be discussed in the seminar. In addition to the topic, research result on quality enhancement of fresh apple slices by heat shock treatment will be introduced.

• Food Science and Biotechnology
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• v.14 no.4
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• pp.461-465
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• 2005

To determine the cause of wet noodle spoilage, microorganisms isolated from wet noodles were identified and characterized. In addition, the growth inhibitory effects of organic acid mixture (OA: lactic acid 27.8%, acetic acid 12.0%, succinic acid 1.0%) and sodium dehydroacetate (SD) on the isolated strain were estimated in nutrient broth medium. The isolated strain was Gram-positive, rod shaped, motile, and spore forming. Based on physiological characteristics and the API 50 CHB-kit test results for the assimilation of 49 carbohydrates, the isolated strain was identified as Bacillus amyloliquefaciens (92.6%), which is able to degrade starch. Decimal reduction times (D-values) at 100, 105, and $110^{\circ}C$ for spores of B. amyloliquefaciens were 8.5, 5.1, and 2.5 min, respectively, and the z-value was $12.8^{\circ}C$. We estimated that B. amylo-liquefaciens isolated from spoiled wet noodles was a thermophilic species having high heat-resistance. Viable cell numbers in wet noodles and broth medium inoculated with B. amyloliquefaciens were decreased by 2-4 log cycles by combined treatment with 0.03 or 0.05% OA and 0.3% SD. These results revealed that OA combined with SD could be used as a potential agent to inhibit B. amyloliquefaciens in wet noodles.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.3
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• pp.494-499
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• 2004

This study was investigated the antimicrobial activity of clove extracts according to extraction solvents. The extracts were tested for their antimicrobial activity against several food spoilage microorganisms including Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa. The methanol extract showed stronger antimicrobial activities than water extract. However, petroleum ether extract did not show antimicrobial activity. The water extract of clove showed growth inhibition effect against Escherichia coli, Salmonella typhimurium and Staphylococcus aureus, whereas no effect against Bacillus subtilis. The methanol extract of clove extracts showed more sensitive antimicrobial activity in Gram (+) bacteria than in Gram (-) bacteria. The antimicrobial activities were increased with increasing concentration of the clove extract.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.949-958
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• 2000

Antimicrobial effects of 150 kinds of Korean and 82 kinds of Indonesian plants were investigated to develope natural food preservatives. Extracts of the plants with 70% ethanol were tested their antimicrobial effects against several food spoilage microorganisms, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger. Seventeen kinds of Korean and eighteen kinds of Indonesian plants were found relatively effective, of which Myristica fragrans and Melaleuca leucadendra were the most effective, respectively. The major fractions of the two plant extracts showing antimicrobial activity were further purified by solvent fractionation, silicagel column chromatography and preparative HPLC. The purified substances were identified as limonene and caprylic acid in M. fragrans, and ${\alpha}-terpineol$ in M. leucadendra, respectively.

• Korean Journal of Food Science and Technology
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• v.10 no.2
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• pp.224-230
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• 1978

Heat resistant putrefactive microorganisms causing spoilage of canned and processed foods were surveyed in the compost on mushroom growing bed, casing soil, raw mushrooms and canned products before sterilization at canneries located at 8 places including Buyo in Chung-Cheung-Do and monitored the total count and spore formers from the sample taken. The 9 strains of most severe heat resistant among the selected 140 spore formers were selected and determined D and Z value by TDT method. The most strong heat resistant strain was No. F-10, facultative thermophile, which was isolated from raw mushroom in Buyo area and it's Z value was $21.1^{\circ}F$ (M/15 phosphate buffer solution) and $D^{250}$ was 6.6 min.

• Korean Journal of Food Science and Technology
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• v.24 no.1
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• pp.92-96
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• 1992

Several coagulants was investigated for their effects on shelf-life of packed Tofu. The titratable acidity, amino nitrogen content in Tofu and the optical density of Tofu suspension were increased as the spoilage developed during storage. The number of microorganisms was increased to 13 million cells per gram after 1 day of storage at $30^{\circ}C$ in the Tofu prepared with $MgSO_{4}\;and\;CaCl_{2}$. But, the Tofu prepared from acetic acid was found to be more stable for storage. The quality of Tofu was maintained up to 12 days or 18 days at $30^{\circ}C\;or\;15^{\circ}C$, respectively. These results suggested that acetic acid was desirable as a coagulant of packed Tofu to extend its shelf life.

• Food Science and Preservation
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• v.13 no.2
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• pp.198-203
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• 2006

Prunus mume extract showed antimicrobial efface remarkably against the wide spectrum of putrefactive and food spoilage microorganisms above 250 ppm of concentration. Their thermal and pH stabilities were effective under the range of temperature $(40^{\circ}C{\sim}120^{\circ}C)$ and $pH(3{\sim}11)$. Prunus mume extract seemed to be a natural antimicrobial ideally with the view of their effectiveness and thermal & pH stabilities. In addition, their action modes suggested that their hydrophillic components would perturb the fucntions of microbial cell membranes synergistically.