• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.537-543
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• 2020

The elderly population in the modern society is growing rapidly due to advance medical technology and minimally invasive surgery. Therefore, as the tendency to use medical device is increasing, pathogenic infection is a concern. Therefore, the first aim of modern medicine is infection prevention in medical place. Recently, patient implants are increasing using 3D printing. Hydroxyapatite is used as a representative material. And, there haven't had currently absorbed dose standard for sterilization of hydroxyapatite discs. Escherichia coli and Streptococcus mutans contaminated on the surface of hydroxyapatite discs were irradiated at each absorbed dose of 0, 0.5, 1.0, 3.0, 5.0 kGy using Gamma-ray of cobalt and Electron-beam of linear accelerator. Then, the number of bacteria was measured in the sample by the decimal dilution method. After sterilization, a non-parametric testing method was performed to compare the survival of Escherichia coli and Streptococcus mutans. As a result, Escherichia coli was sterilized at 1 kGy or more and Streptococcus mutans at 3 kGy or more on absorbed dose. It is considered possible to perform sterilization at a lower value than the recommended absorbed dose of radiation sterilization.

• Journal of Food Hygiene and Safety
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• v.18 no.1
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• pp.25-29
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• 2003

The p60 protein of Listeria spp. is a Listeria-Genus-specific, major extra-cellular protein, which is used as an indicator protein for the detection of these bacteria from contaminated foods. In this study, p60 protein were recombinantly produced in E. coli and were purified using amylose resin based column chromatography. Purified recombinant-p6O was used to generate monoclonal antibody against native p60. Antibody from hybridoma cell line, 1H4, specificically reacted with native p60 protein isolated from pathogenic Listeria spp. such as L. monocytogenes, L. ivanovii, L. welshimeri II, but did not or relatively weakly reacted with non-pathogenic Listeia species, L. innocua or other bacterial proteins. Antibody from 1H4 was produced using ascites fluid method and it may be useful to develop the Listeria-detection kits based on immunological method.

• Food Science of Animal Resources
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• v.34 no.6
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• pp.815-821
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• 2014

The effects of ultraviolet (UV) radiation were investigated with regards to the microbial growth inhibitory effect on the shelf life of Korean native cattle (Hanwoo) beef prior to refrigerated storage. The Hanwoo samples were exposed to UV radiation ($4.5mW/cm^2$) for 0, 5, 10, 15, and 20 min. The UV-irradiated beef that was exposed for 20 min showed significantly reduced mesophilic and psychrotrophic bacterial populations to the extent of approximately 3 log cycles, as compared to that of non-irradiated beef. About 2.5 Log CFU/g of mesophilic bacteria were different compared with UV-irradiated and non-irradiated meat. UV irradiation showed the most significant growth inhibition effects on mesophilic and psychrotrophic bacteria. Coliform and Gram-negative bacteria were also reduced by 1 log cycle. The population of L. monocytogenes, S. Typhimurium, and E. coli O157:H7 decreased significantly to 53.33, 39.68, and 45.76% after 10 min of UV irradiation. They decreased significantly to 84.64, 80.76, and 84.12%, respectively, after 20 min of UV irradiation. The results show that UV irradiation time and the inhibitory effect were proportional. These results verified that UV radiation prior to refrigeration can effectively reduce the number of pathogenic bacteria on the surface of meat and improve the meat's microbial safety.

• Korean Journal of Food Science and Technology
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• v.53 no.6
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• pp.799-808
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• 2021

This study was performed to investigate the extent of microbial contamination, the presence of enterotoxin genes, and the antibiotic susceptibility of Bacillus cereus in 58 red pepper plants and 43 environmental samples (soil, irrigation water, and gloves) associated with the plant cultivation. The detected counts of total aerobic bacteria, coliform bacteria, Escherichia coli, Bacillus cereus, and Staphylococcus aureus were lower in these samples, as compared to the regulations of standards for foods; moreover, pathogens, such as E. coli, E. coli O157:H7, Listeria monocytogenes, and Salmonella spp., were not detected. Genes encoding hemolysin BL enterotoxins (hblA, hblC, and hblD) as well as non-hemolytic enterotoxins (nheA, nheB, and nheC) were detected in 23 B. cereus specimens that were isolated from the test samples and had β-hemolytic activity. Interestingly, B. cereus is resistant to β-lactam and susceptible to non-β-lactam antibiotics. However, in this case, the isolated B. cereus specimens exhibited a shift from resistant to intermediate in response to cefotaxime and from susceptible to intermediate in case of rifampin, trimethoprim-sulfamethoxazole, vancomycin, clindamycin, and erythromycin. Therefore, the levels of B. cereus should be monitored to detect changes in antibiotic susceptibility and guarantee their safety.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.3
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• pp.243-249
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• 2017

Crabs are a popular seafood item. However, they can harbor many microorganisms, heavy metals, radioactivity, and benzo(a)pyrene, which are potential health risks to humans. The objective of this study was to assess the potential of swimming crabs for use in foods such as Ganjang-gejang, by measuring their sanitary biological and chemical properties. Viable microbial cell counts in swimming crab samples were $3.4{\times}10^2-6.7{\times}10^4CFU/g$, but no coliform, Escherichia coli, or pathogenic bacteria, such as Vibrio parahaemolyticus, Enterohemorrhagic E. coli, Listeria monocytogenes, Staphylococcus aureus, or Salmonella spp., were detected. Heavy metal concentrations in swimming crab samples were non-detectable to 0.112 mg/kg for total mercury, non-detectable to 0.435 mg/kg for lead, and 0.115-0.836 mg/kg for cadmium. Benzo(a)pyrene concentrations ranged from $0.025-0.060{\mu}g/kg$, and the volatile basic nitrogen content ranged from 8.7-15.6 mg/100 g. No radioactivity was detected in samples. These results suggest that swimming crabs are viable for use in seafood products.

• Korean Journal of Food Science and Technology
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• v.47 no.1
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• pp.81-86
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• 2015

Intense pulsed light (IPL), a nonthermal technology, has attracted increasing interest as a food processing technology. However, its efficacy in inactivating microorganisms has not been evaluated thoroughly. In this study, we investigated the influence of IPL treatment on the inactivation of Escherichia coli O157:H7 depending on light intensity, treatment time, and pulse number. Increased light intensity from 500 V to 1,000 V, raised the inactivation rate at room temperature. At 1000 V, the cell numbers were reduced by 7.1 log cycles within 120 s. In addition, increased pulse number or decreased distance between the light source and sample surface also led to an increase in the inactivation rate. IPL exposure caused a significant increase in the absorption at 260 nm of the suspending agent used in our experiments. This indicates that IPL-treated cells were damaged, consequently releasing intracellular materials. The growth of IPL-irradiated cells were delayed by about 5 h. The degree of damage to the cells after IPL treatment was confimed by transmission electron microscopy.

• Microbiology and Biotechnology Letters
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• v.43 no.3
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• pp.187-194
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• 2015

In this study, L. plantarum, when reacting with the culture media of potential pathogenic bacteria, exhibited an increase in growth rate and antimicrobial activity. In order to examine the characteristics and the nature of the reaction with the bacteria, this study carried out experiments involving culturing the test bacteria in M9 minimal media. Subsequently, the supernatant was incrassated by the decompression-drying method. Through colony forming unit assay, it was confirmed that L. plantarum had the function of growth inhibition to various bacteria. After culturing L. plantarum with bacterial media, the growth rate of L. plantarum was measured by absorbance (OD₆₀₀), the results showed that the growth rate (E. coli treatment group: OD₆₀₀ = 0.848, S. typhimurium treatment group: OD₆₀₀ = 0.848) increased, as compared with the non-treated control group (OD₆₀₀ = 0.48). In contrast, the concentrate itself did not induce the growth of L. plantarum. These results were observed as a universal phenomenon of the Lactobacillus species. Moreover, the increase in antimicrobial activity was observed in L. plantarum, which reacted with the culture media of E. coli and S. typhimurium, through a disc diffusion assay, and the result of growth inhibition against various bacteria was induced. Finally, based on the analysis results of the characteristics of bacteria culture media, which increased the growth rate of L. plantarum and antibacterial activity, the bacterial media had a tolerance for catabolic enzymes, pH 2−8 and heat. Therefore, this substance can be said to be a small molecule which is highly stable under various conditions.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.180-184
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• 2003

Several bacteria and yeasts were isolated from soil and characterized for the development of functional probiotics which can be used as a livestock feed additive. From the soil, the microbial strains which have acid/bovine resistance, antibiotics resistance and high stability, were isolated. Most strains selected were very tolerable against acids and very stable in a broad range of pH. Some strains could survive 100% at pH 2.5. The growth of the strains was not affected in the presence of bile acid, pathogenic E. coli and several antibiotics such as tetracycline, nisin, kanamycin, streptomycin, ampicillin. Acidogenic capability test showed that all the strains can produce acids. The hydrolytic activities were analysed for amylase, protease, lipase and cellulase to decompose various organic compounds. All the strains were found to be gram negative, round type, non-kinetic and the color is yellow or white.

• Journal of Animal Science and Technology
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• v.64 no.1
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• pp.166-182
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• 2022

Deer antler velvet is widely used in traditional medicine for its anti-aging, antioxidant, and immunity-enhancing effects. However, few studies have reported on the discovery of probiotic strains for deer antler fermentation to increase functional ingredient absorption. This study evaluated the ability of probiotic lactic acid bacteria to enhance the concentrations of bioactive molecules (e.g., sialic acid and gamma-aminobutyric acid [GABA]) in extracts of deer antler velvet. Seventeen strains of Lactobacillus spp. that were isolated from kimchi and infant feces, including L. sakei, L. rhamnosus, L. brevis, and L. plantarum, and those that improved the life span of Caenorhabditis elegans were selected for evaluation. Of the 17 strains, 2 (L. rhamnosus LFR20-004 and L. sakei LFR20-007) were selected based on data showing that these strains increased both the sialic acid and GABA contents of deer antler extract after fermentation for 2 d and significantly improved the life span of C. elegans. Co-fermentation with both strains further increased the concentrations of sialic acid, GABA, and metabolites such as short-chain fatty acids and amino acids. We evaluated the biological effects of the fermented antler velvet (FAV) on the antibacterial immune response in C. elegans by assessing worm survival after pathogen infection. The survival of the C. elegans conditioned with FAV for 24h was significantly higher compared with that of the control worm group fed only normal feed (non-pathogenic E. coli OP50) exposed to E. coli O157:H7, Salmonella typhi, and Listeria monocytogenes. To evaluate the protective effects of FAV on immune response, cyclophosphamide (Cy), an immune-suppressing agent was treated to in vitro and in vivo. We found that FAV significantly restored viability of mice splenocytes and immune promoting-related cytokines (interleukin [IL]-6, IL-10, inducible nitric oxide synthase [iNOS], interferon [IFN]-γ, and tumor necrosis factor [TNF]-α) were activated compared to non-fermented deer antlers. This finding indicated the protective effect of FAV against Cy-induced cell death and immunosuppressed mice. Taken together, our study suggests that immune-promoting antler velvet can be produced through fermentation using L. rhamnosus LFR20-004 and L. sakei LFR20-007.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.5
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• pp.557-566
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• 1996

An ecological study on pathogenic vibrios was done in the aquatic environments of southern coast of Korea during summer in 1995, to investigate the distribution and relationship between pathogenic vibrio and zooplankton. Furthermore, special emphasis was given to study on the efforts of zooplankton existence on the wintering of Vibrio cholerae in the aquatic region in Korea. During the study period, pathogenic vibrios were isolated from the samples such as V. parahaemolyticus, V. vulnificus, V. mimicus, and V. cholerae non O1, but V. cholerae O1 was not detected in any sample submitted in this study. Adsorption ratio of V. parahaemolyticus onto zooplankton was higher than that of E. coli. The efficiency of adsorption was found to be on the concentration of NaCl and other ions found in sea water. For example, adsorption ratio of V. parahaemolyticus were $75\%\;at\;5\%_{\circ}$ of NaCl solution and $55\%$ at same salinity of diluted sea water, but those were decreased as $20\%\;and\;7\%\;at\;15\%_{\circ}$ salinity of NaCl solution and diluted sea water, respectively. In addition, survival period of pathogenic vibrio was extended in the presence of live copepods at $25^{\circ}C$, but zooplankton existence has no significant effect on the survival rate at $5^{\circ}C$ in closed microcosm and also microalgae and dead copepods do not affect on the survival of V. parahaemolyticus. According to these experimental results, zooplankton has positive effects on the growth and survival rate of pathogenic vibrios in sea water during the summer season, but copepods have no significant effects on the growth and survival rate of them in winter season in Korea. Finally, authors suggest that V. cholerae is not able to over winter with zooplankton in adjacent sea water in Korea.