• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.581-589
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• 1998

Effects of gamma irradiation on hygienic quality, extraction yields and physiological effectiveness in twenty-one kinds of Korean medicinal plants were investigated. Gamma irradiation at $5{\sim}10\;kGy$ eliminated the microorganisms contaminated in Korean medicinal plants. The total extraction yield in fifteen kinds of Korean medicinal plants increased by $5{\sim}25%$ at 10 kGy gamma irradiation. The physiological effectiveness such as antioxidation, anticomplement functions, nitrite scavenging and electron donating abilities of medicinal plants exposed to 10 kGy gamma irradiation were not different from that of the nonirradiated control.

• Preventive Nutrition and Food Science
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• v.2 no.2
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• pp.89-95
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• 1997

The comparative effects of gamma irradiation an ozone treatment on the microbiological and physicochemical qualities were investigated for the improvement of hygienic quality of aloe powder and bee pollen. Gamma irradiation at 7.5~10kGy could reduce total aerobic bacteria, molds and coliforms below detection levels, but ozone treatment up to 18 ppm for 8hr was not sufficient to eliminate the microorganisms from aloe powder and bee pollen. The physicochemical properties such as fatty acid an amino acid compositions, mineral content, TBA value, barbaloin and pigment contents were not significantly changed by gamma irradiation, whereas ozone treatment caused significant changes in fatty acid composition, lipid oxidation and destruction of barbaloin and natural pigments.

• Journal of Pharmaceutical Investigation
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• v.3 no.4
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• pp.5-15
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• 1973

An investigation was carried out on a basis of the bacteriological examination with a view to detecting the degree of bacterial contamination for the 77 samples collected from the locally-sold liquid specialties. It's test period was 50 days from July 10 to August 30, 1971. Specially, the survey has put emphasis on the population of general bacteria and the identification of coli-form group, staphylococcus species, streptococcus species, bacillus species, fungi, and yeast species from liquid samples. The results obtained are summarized as follows; (1) For the 77 samples tested, the contamination of general bacteria was found out as minimun 0, i,e., maximum, $12{\times}10^4$ and the total average $45{\times}10^2$ per milliliter. (2) Although streptococcus species could not be detected with the samples, the contamination of the coli-form and staphylococcus species means the strong suggestion of the possibility of pathogenic bacterial contamination. (3) Specially, the products which stay in the neutral pH range and use suspending agents need to care for the microbial contamination in the manufacturing crocess. (4) It is thought necessary to perform the microbiological quality control in the liquid preparations only at least. (5) As the microbial contamination degree in the liquid decreases according to the elapse of time, the microbiological quality control will have to be carried out immediately after the completion of the manufacturing process in order to know the accurate degree. (6) The author thinks that the main reason of the microbial contamination in the liquid is the contamination during the manufacturing process. (7) For the purpose of prevention of the microbial contamination in liquid, therefore, it is more important to make efforts for the rationalization of manufacturing process, the improvement of equipment and environment, the specific training of workers for hygienic knowledges, etc. rather than the use of preservatives for the preparations.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.7
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• pp.991-996
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• 2003

Determination of regional microbial contamination in the process of rice rolled in dried laver (Kimbab) and effects of gamma irradiation on the improvement of hygienic quality and shelf stability were investigated. Total aerobic bacterial distribution of raw materials of Kimbab were; 10$^{6}$ ∼10$^{7}$ CFU/g in dried laver, 10$^3$ CFU/g in cucumber and below 10 CFU/g in steamed rice, ham, fried egg, and salted radish. Total coliform bacteria were 10$^3$ CFU/g in dried laver and detected below detection limit (10 CFU/g) in other raw materials. And it was arithmetically calculated that the levels of total aerobic bacteria and coliform bacteria in Kimbab does not exceed 10$^{5}$ CFU/g and 10$^1$ CFU/g under the aseptic process, respectively. However, microbial contamination levels in just prepared Kimbab in a market were about 10$^{6}$ CFU/g of total aerobic and coliform bacteria. Therefore, it was considered that microbial contamination of Kimbab is mainly originated from environmental uptake during the preparation. The representative media for putrefying bacterial growth were steamed rice. Coliform bacteria were mainly increased in ham and fried egg during storage. The bacteria in dried laver were radio-resistant and survived at 3 kGy of gamma irradiation. Coliform bacteria on EMB agar plate were eliminated at the dose of 2 kGy. The sensory acceptability of 2 kGy irradiated Kimbab was stable and the Kimbab can be preserved for 24 hour at 15$^{\circ}C$. Therefore, it was considered that optimal irradiation dose for radicidation of Kimbab was 2 kGy.

• Korean Journal of Agricultural Science
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• v.45 no.2
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• pp.211-218
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• 2018

Different packaging methods and storage temperatures were tested to determine the storage stability of beef dry-aged for 21 days based on microbial, physicochemical, and sensory qualities. After completion of the dry aging, the dried surface of beef sirloin was trimmed off, and the beef was packaged using two different methods (oxygen-permeable wrap or vacuum packaging) and stored at different temperatures ($3{\pm}2^{\circ}C$ or $-23{\pm}2^{\circ}C$) for 0, 7, 14, or 21 days. Lipid oxidation and the sensory quality of the dry-aged beef were not affected by the packaging method and storage temperature during storage. No microbial growth was observed over the storage period in the vacuum-packaged dry-aged beef, regardless of the storage temperature. However, dry-aged beef in the oxygen-permeable wrap packaging showed microbial spoilage with 8.82 log CFU / g at day 7 of the refrigerated storage. The vacuum-packaged dry-aged beef showed the lowest values (p < 0.05) in $a^*$ and chroma at days 14 and 21 at $3^{\circ}C$, and days 7 and 14 at $-23^{\circ}C$, respectively. Therefore, it is recommended that dry-aged beef with wrap packaging stored in refrigerated conditions should be consumed as quickly as possible due to microbial growth. For long-term storage, dry-aged beef should be frozen because freezing can extend the color stability up to day 21 of storage without adverse effects on the hygienic or meat quality aspects of dry-aged beef.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.40-46
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• 1999

Microbiological quality of commercial white ginseng was examined, together with investigation on its water absorption pattern and radiosensitivity of molds isolated from the samples. Comparative effects of phosphine fumigation and gamma irradiation on microbial control and disinfestation of the samples packed in a commercial laminated film and stored for six months at ambient(20oC, 70% RH) and accelerated(40oC, 90% RH) conditions were studied. Commercial white ginseng was contaminated with coliforms by 103~104CFU/g and molds by 102~104CFU/g and thus decontamination process was required for hygienic quality and storage stability. Phosphine fumigation showed no sterilizing effects on microbes contaminated, while gamma irradiation at around 5kGy was effective for decontaminating microorganisms, showing D10 values of 0.48~0.60kGy for isolated molds. Even though the storage insects, Plodia interpuctella Hubner and Lasioderma serricorne(cigarette beetle) were easily destroyed by phosphine fumigation, gamma irradiation less than 5kGy was found effective for both purposes to improve biological quality of stored white ginseng, thereby extending the storage life of packed samples resulting from increased critical moisture content by about 1%(Aw 0.76).

• 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.

• Korean Journal of Environmental Biology
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• v.20 no.3
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• pp.189-196
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• 2002

The direct detection of intestinal pathogens and viruses often requires costly, tedious, and time-consuming procedures. These requirements developed a test to show that the water was contaminated with sewage-borne pathogens by assessing the hygienic quality of water based on indicator microorganisms whose presence indicates that pathogenic microorganisms may also be present. Various groups of microorganisms have been suggested and used as indicator microorganisms. Proposed and commonly used microbial indicators are total coliforms, fecal coliforms, fecal streptococci, Clostridium perfringens, heterotrophic plate count, bacteriophage, and so on. Unfortunately, most, if not all, of these indicators are not ideal because of the sensitivity and resistance to environment stresses and disinfection. However, the development of gene probes and PCR technology may give hope for the discovery of rapid and simple methods toy detecting small number of fecal pathogens in various environments.

• Journal of Food Hygiene and Safety
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• v.15 no.2
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• pp.61-67
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• 2000

Bacteriological quality evaluations were carried out for rice rolled in laver(Kimbab), Hamburger, Walnut cake and chinese noodle (Jajangmyun), which were on sale in April and May 1995, in May and July 1997 and in January 1999, at 20 different resting places on Kyung-Bu, Ho-Nam, Joong-Bu and Young-Dong Highway in Korea. Food poisoning bacteria were not detected. However numerous coliform bacteria were dectected saying that the sanitary condition of foods on sale at resting places of the highways was not hygienic. There exited 8.8$\times$10$^{4}$~6.6$\times$10$^{5}$ cells/g of coliform bacteria in all the Kimbab sold in 1995. As for Hamburger, 1.8$\times$10$^{2}$~4.7$\times$10$^{4}$ cells/g of coliform bacteria proliferated in all the samples. In 1997,E. coli was found in 16 cases and 21 cases respectively out of 22 Kimbab samples, Hamburger dealing at 7 resting places out of 14 were contaminated with 1.7$\times$10$^{2}$~1.9$\times$10$^{7}$ cells/g of coliform bacteria and Hamburgers dealing at 2 resting places were infected by 5. coli. In contrast to the Kimbab and Hamburger, all the 6 Walnut cake samples were free from the microbial pollution exhibitory that their hygienic condition was satisfactory. 3 samples out of 6 Jajangmyun were contaminated by 7.1$\times$10$^{2}$~2.0$\times$10$^{3}$ cells/g of coliform bacteria, but E. coli was not detected. Compared Kimbab sold in 1995 and 1997 with 1999, Kimbab sold in it can be said that hygienic control fur Kimbab should be performed more strictly during hot season than during cold season. Walnut cake was the safest against microbial contamination, followed by Jajangmyun, Hamburger and Kimbab in decreasing order, indicating that foods with mixed ingredients such as Kimbab and Hamburger were more susceptible to microbial infection, so that a more systematic safety control is needed for such foods during cooking, processing and distribution.

• Journal of the East Asian Society of Dietary Life
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• v.8 no.4
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• pp.430-440
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• 1998

Meat is a perishable product since it offers favorable conditions for microbial contamination and multiplication. Besides, undercooked and raw meat has been linked to outbreaks of hemorrhagic diarrhea due to the presence of microbial pathogens. Therefore, this study was conducted to find out the effect of the use of gamma-irradiation in order to improve preservation and eliminate this microorganisms. The Initial level of microbial contamination in pork was 1.1$\times$10$^3$ CFU/g (aerobic bacteria), 5.3$\times$10$^3$CFU/g (psychrophile), 3.1$\times$10$^3$ CFU/g (coliforms) and 3.2$\times$10$^3$ CFU/g(Listeria), All kinds of contaminated microorgnisms were sterilized by gamma irradiation at 3 kGy. The proximate composition of pork was not significantly changed by irradiation dose and storage period. The pH was slightly increased during storage period and titratable acidity decreased. However, no significant changes in pH and acidity were observed by gamma irradiation. There was no difference in total amino acid content regardless of irradiation dose and storage period. Glutamic acid was detected at high levels throughout the storage period. The major mineral compositions of pork were potassium, phosphorus, sodium, magnesium. No significant difference in the components of minerals were observed by gamma irradiation.