• Proceedings of the Korean Society for Food Science of Animal Resources Conference
• /
• 2004.05a
• /
• pp.89-119
• /
• 2004

This study was conducted to isolate lactobacilli having probiotic characteristics to be used as health adjuncts with fermented milk products. Acid tolerant strains were selected in Lactobacilli MRS broth adjusted to pH 4.0 from 80 healthy persons (infants, children and adults). And bile tolerant strains were examined in Lactobacilli MRS broth in which 1.0% bile salt was added. By estimation above characteristics, the strains No. 27, which was isolated from adult feces, was selected and identified as Lactobacillus salivarius subsp. salivarius based on carbohydrate fermentation and 16S rDNA sequencing. It was used as a probiotic strain in fermented milk products. The pH of fermented milk decreased from pH 6.7 to 5.0 and titratable acidity increased from 0.3% to 1.0% by L. salivarius subsp. salivarius (isolation strain 20, 35, and 37), when incubated for 36 h at $37^{\circ}C$. The number of viable cell counts of fermented milk was maximized at this incubation condition. The SDS-PAGE evidenced no significant change of casein but distinct changes of whey protein were observed by isolated L. salivarius subsp. salivarius for titratable acidity being incubated by $0.9{\sim}1.0%$ at $37^{\circ}C$. All of the strains produced 83.43 to 131.96 mM of lactic acid and 5.39 to 26.85 mM of isobutyric acid in fermented products. The in vitro culture experiment was performed to evaluate ability to reduce cholesterol levels and antimicrobial activity in the growth medium. The selected L. salivarius subsp. salivarius reduced $23{\sim}38%$ of cholesterol content in lactobacilli MRS broth during bacterial growth for 24 hours at $37^{\circ}C$. All of the isolated L. salivarius subsp. salivarius had an excellent antibacterial activity with $15{\sim}25$ mm of inhibition zone to E. coli KCTC1039, S. enteritidis KCCM3313, S. typhimurium M-15, and S. typhimurium KCCM40253 when its pH had not been adjusted. Also, all of the isolated L. salivarius subsp. salivarius had partial inhibition zone to E. coli KCTC1039, E. coli KCTC0115 and S. enteritidis KCCM3313 when it had been adjusted to pH 5.7. The selected strains were determined to have resistances of twelve antibiotic. Strains 27 and 35 among the L. salivarius subsp. salivarius showed the highest resistance to the antibiotics. Purified ${\alpha}$-galactosidase was obtained by DEAE-Sephadex A-50 ion exchange chromatography, Mono-Q ion exchange chromatography and HPLC column chromatography from L. salivarius subsp. salivarius 27. The specific activity of the purified enzyme was 8,994 units/mg protein, representing an 17.09 folds purification of the original cell crude extract. The molecular weight of enzyme was identified about 53,000 dalton by 12% SDS-PAGE. Optimal temperature and pH for activity of this enzyme were $40^{\circ}C$ and 7.0 respectively. The enzyme was found to be stable between 25 and $50^{\circ}C$. ${\alpha}$-galactosidase activity was lost rapidly below pH 5.0 and above pH 9.0. This enzyme was liberated galactose from melibiose, raffinose, and stachyose, and also the hydrolysis rate of substrate was compound by HPLC. These results indicated that some of the L. salivarius subsp. salivarius (strain 27 and 35) are considered as effective probiotic strains with a potential for industrial applications, but the further study is needed to establish their use as probiotics in vivo.

• Korean Journal of Poultry Science
• /
• v.37 no.3
• /
• pp.289-295
• /
• 2010

Because some zoonotic Salmonella can be transmitted to human through poultry products, threatening human public health, Salmonella infections in poultry are increasingly worldwide subject to control measures and programs. Given the fact that there are numerous opportunities for Salmonella to gain entry to extensive, integrated poultry operations including the hatching, handling, feeding, and processing facilities, the whole supply chain of poultry meat should be an object of Salmonella control programs as well as biosecurity of poultry farms. This article reviews Salmonella food poisoning caused by poultry source and critical need to control Salmonella in poultry productions, and describes practical strategies.

• The Journal of the Korean Society for Microbiology
• /
• v.19 no.1
• /
• pp.55-64
• /
• 1984

The clinical specimens used in this study were collected during the period from March 4, to December 30, 1983, from children's hospitals in Seoul area. They came from clinically apparent cases of diarrheal disease in hospitals. Many specimens were taken from rectal Swabs. During this period, 2166 stool cultures were streaked onto MacConkey plate and were them deposited in selenite broth. Colonies resembling pathogens on MacConkey medium were picked to KIA, Urea agar, malonate broth, ONPG broth, SIM. Reaction on those media cultures were identified biochemically with using API 20E test kit and confirmed serologically with commercially avabile Salmonella antisera(Difco) or Shigella antisera(Denka, Japan). The sensitivity of Salmonella and Shigella tested to ampicillin cephalosporin, chloramphenicol, colistin, gentamicin, tetracycline, streptomycin, nalidixic acid, neomycin, polymyxin B was performed by means of disc diffusion method recommended by Bauer-Kirby, using the discs prepared in BBL Laboratory. 1. There were 34 (1.6%) isolations of Salmonella cultures and 52(2.4%) isolations of Shigella from the 2,116 specimens. Only 53%of Salmonella were isolated by direct streaking on MacConkey plating media, by contrast, 80% of the Shigella were isolated directly. 2. Shigella flexneri types comprised 56% of the Shigellae isolate from 52 Shigellae identified 24% of Salmonella enteritidis ser typhimurium were identified. 3. Concerning to Salmonella and Shigella occurance according to month and sex, They shows relatively higher for the male than in case of female, and 2-3 age were shown the highest group. 4. October is the month with highest incidences. 5. In the sensitivity patterns of Shigellae, most of them were appeared to be resistant ampicillin, streptomycin, tetracycline, in case of Salmonella, 15% of them were resistant to chloramphenicol.

• Journal of Microbiology and Biotechnology
• /
• v.26 no.6
• /
• pp.1026-1034
• /
• 2016

In the current study, a total of 135 enterococci strains from different sources were screened for the presence of the enterocin-encoding genes entA, entP, entB, entL50A, and entL50B. The enterocin genes were present at different frequencies, with entA occurring the most frequently, followed by entP and entB; entL50A and L50B were not detected. The occurrence of single enterocin genes was higher than the occurrence of multiple enterocin gene combinations. The 80 isolates that harbor at least one enterocin-encoding gene (denoted "Gene⁺ strains") were screened for antimicrobial activity. A total of 82.5% of the Gene⁺ strains inhibited at least one of the indicator strains, and the isolates harboring multiple enterocin-encoding genes inhibited a larger number of indicator strains than isolates harboring a single gene. The indicator strains that exhibited growth inhibition included Listeria innocua strain CLIP 12612 (ATCC BAA-680), Listeria monocytogenes strain CDC 4555, Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, S. aureus ATCC 29213, S. aureus ATCC 6538, Salmonella enteritidis ATCC 13076, Salmonella typhimurium strain UK-1 (ATCC 68169), and Escherichia coli BAC 49LT ETEC. Inhibition due to either bacteriophage lysis or cytolysin activity was excluded. The growth inhibition of antilisterial Gene⁺ strains was further tested under different culture conditions. Among the culture media formulations, the MRS agar medium supplemented with 2% (w/v) yeast extract was the best solidified medium for enterocin production. Our findings extend the current knowledge of enterocin-producing enterococci, which may have potential applications as biopreservatives in the food industry due to their capability of controlling food spoilage pathogens.

• Korean Journal of Veterinary Research
• /
• v.44 no.4
• /
• pp.593-605
• /
• 2004

An egg has been considered as one of the most important food sources because of it's nutritional superiority and reasonable price. With the complexity of egg flow system from production to consumption in Korea, preventive measures for egg safety have been required. Therefore, our study was carried out to analyze hazards for the egg under farm level and develope preventive measures with a purpose of obtaining egg safety. To analyze biological hazards, microbial contamination of egg(normal, dirty and cracked), water, feed, manure and equipments associated with laying were investigated. One isolate of Salmonella enteritidis and S. bardo were detected from the manure and dirty egg shell respectively. The sanitary conditions in the farm were surveyed by questionaries. Confirmation of vaccination for purchasing chicks and establishment of sanitary guidances for water and type of water suppliers ought to be preceded. Feed supplier systems including feed tanks, feed pipes and hoppers were known that their contamination might give it a chance to infect individuals and egg content and shell. The safe and rapid disposal of dead chickens and rodent were reported as more crucial factors to prevent infectious disease and manage good sanitation. Egg selector and collecting belt should be kept properly not to be contaminated from egg fluids and feces. It should be also considered that regular gathering of eggs, removal of dirty or cracked ones, storage under refrigeration and the use of disposable egg tray were continuously fulfilled. Conclusively, Our results suggested that HACCP-based system for providing fresh and safe eggs to consumers should be applied to the farm.

• Korean Journal of Veterinary Research
• /
• v.26 no.1
• /
• pp.49-59
• /
• 1986

This paper deals with the distribution, reservoir and mode of spread of salmonella infection on 7 pig farms in Taegu, Gyeongbuk, Gyeongnam and Chungnam and a slaughter house in Teagu during the period from May 1984 to May 1985. Isolated salmonella were examined for serotypes and biotyping of S. typhimurium. The results obtained were summarised as follows; 1. Of total 7,995 samples from 7 pig farms and a slaughter house, 319 salmonella were isolated from 234 samples (2.9%) and their serovar strains were S. derby 77, S. infantis 41, S. enteritidis 20, S. typhimurium 18, S. bredeney 16, S. london 14, S. paratyphi B 9, S. anatum 8, S. montevideo 8, S. senftenberg 7, S. thompson 6, S. pullorum 4, S. paratyphi A 1 and untypable 70. 2. The incidence rate of diarrhea of piglets, weaned pigs and fattening pigs was 9.8%, 2.3% and 0.5%, respectively whereas the rate by salmonella infection was 4.2%, 1.2% and 11.3%, respectively. 3. The isolation rate of salmonella was higher in summer and autumn. 4. The isolation rate of salmonella varied from 1.1% to 4.5% in 7 pig farms, it was higher in sewages(4.4%), weaned pigs(3.7%), boars(3.7%) and other(3.7%) included soils, manure and wild rats according to samples. Three out of 7 pig farms were contaminated heavily with various serovars of salmonella. 5. The isolation rate of salmonella from pigs slaughtered was 8.1%, it was 13.6% in rectal contents and 1.6% in mensenteric lymph nodes. 6. Eighteen strains of S. typhimurium were classified into 3 different biovars(1, 10 and 10a) by the method of Brandis and were subdivided into 6 different full biovars(1a, 1d, 1dh, 3d, 26i and 26ei) by the method described by Duguid et al. Appearance of different biovars indicated the occurrence of different exotic infection sources on the farms.

• Microbiology and Biotechnology Letters
• /
• v.33 no.1
• /
• pp.35-40
• /
• 2005

This study was performed to investigate the antimicrobial effect of the Cutellaria baicalensis George extracts against food-borne pathogens. First, the Cutellaria baicalensis George was extracted with methanol at room temperatures, and fractionation of the methanol extracts from Cutellaria baicalensis George was carried out by using petroleum ether, chloroform, and ethyl acetate, and methanol respectively. The antimicrobial activity of the Cutellaria baicalensis George extracts was determined using a paper disc method against food-borne pathogens and food spoilage bacteria. The ethyl acetate extracts of Cutellaria baicalensis George showed the highest antimicrobial activity against Staphylococcus aureus and Shigella dysenteriae. The synergistic effect has been found in combined extracts of Cutellaria baicalensis George and Portulaca oleracea as compared to each extracts alone. Finally, the growth inhibition curve was determined using ethyl acetate extracts of Cutellaria baicalensis George against Staphylococcus aureus and Shigella dysenteriae. The ethyl acetate extract of Cutellaria baicalensis George showed strong antimicrobial activity against Staphylococcus aureus at the concentration of 4,000 ppm. The 4,000 ppm of ethyl acetate extract from Cutellaria baicalensis George retarded the growth of S. aureus more than 24 hours and Shigella dysenteriae up to 36 hours. The ethyl acetate extracts of Cutellaria baicalensis George has been shown the antimicrobial effect against Staphylococcus aureus and Shigella dysenteriae.

• Microbiology and Biotechnology Letters
• /
• v.32 no.3
• /
• pp.277-281
• /
• 2004

This study was performed to investigate the antimicrobial effect of the Fraxinus rhynchophylla extracts against food-borne pathogens. First, the Fraxinus rhynchophylla was extracted with methanol at room temperatures, and fractionation of the methanol extracts from Fraxinus rhynchophylla was carried out by using petroleum ether, chloroform, and ethyl acetate, and methanol respectively. The antimicrobial activity of the Fraxinus rhynchophylla extracts was determined using a paper disc method against food-borne pathogens and food spoilage bacteria. The ethyl acetate extracts of Fraxinus rhynchophylla showed the highest antimicrobial activity against Staphylococcus aureus and Shigella dysenteriae. The synergistic effect has been found in combined extracts of Fraxinus rhynchophylla and Portulaca aleracea as compared to each extracts alone. Finally, the growth inhibition curve was determined using ethyl acetate extracts of Fraxinus rhynchophylla against Staphylococcus aureus and Shigella dysenteriae. The ethyl acetate extract of Fraxinus rhynchophylla showed strong antimicrobial activity against Staphylococcus aureus at the concentration of 4,000 ppm. The 4,000 ppm of ethyl acetate extract from Fraxinus rhynchophylla retarded the growth of S. aureus more than 24 hours and Shigella dysenteriae up to 36 hours. The ethyl acetate extracts of Fraxinus rhynchophylla has been shown the antimicrobial effect against Staphylococcus aureus and Shigella dysenteriae.

• Korean Journal of Microbiology
• /
• v.37 no.1
• /
• pp.9-14
• /
• 2001

In order to investigate the pathogenicity and development of differential identification technique in the Yersinia species and other entericbacteria, we isolated 5 strains of Y.pseudotuberculosis from spring water sites in Seoul. The biochemical characteristics of isolated strains revealed that indole, VP($25^{\circ}C$, $37^{\circ}C$), $H_2S$, phenylalanine, lysine, arginine, ornithine, gas from glucose, lactose, sucrose, sorbitol, oxidase and motility($37^{\circ}C$) were all negative and urease, glucose, mannitol, salicin, catalase and motility($25^{\circ}C$) were all positive. To detect the causative agent of pseudotuberculosis(Y.pseudotuberculosis), we carried out a study using a PCR with inv primers complementary to the pathogenic region and found that all strains were positive, this revealed that strains from spring waters were pathogenic. Also 16S rDNA for total 5 strains of Y. pseudotuberculosis were amplified and a stretch of approximately 1,450 nucleotides were sequenced and analyzed. The 16S rDNA nucleotide sequence homologies among Yersinia species ranged 97.5% to 100% and between Y.pseudotuberculosis and other entericbacteria they ranged 93.0% to 95.1%. The Phylogenetic tree generated from the sequence analysis of the 16S rDNA gene showed 3 coherent clusters that could be separated into Y.pseudotuberculsis strains, some Yersinia species strains and other entericbacteria strains.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.1
• /
• pp.107-112
• /
• 2005

This study was performed to investigate the antimicrobial effect of the Hedyotis diffusa extracts against food-borne pathogens. First, the Hedyotis diffusa was extracted with methanol at room temperature and the fractionation of the methanol extracts was carried out by using petroleum ether, chloroform, and ethyl acetate, and methanol respectively. The antimicrobial activity of the Hedyotis diffusa extracts was determined by using a paper disc method against food-borne pathogens and food spoilage bacteria. The methanol extracts of Hedyotis diffusa showed the highest antimicrobial activity against Staphylococcus aureus and Shigella flexneri. Synergistic effect in inhibition was observed when Hedyotis diffusa extract was mixed Sophora subprostrata extract as compared to each extracts alone. Finally, the growth inhibition curves were determined by using ethyl acetate extracts of Hedyotis diffusa against Staphylococcus aureus and Salmonella Typhimurium. The methanol extract of Hedyotis diffusa had strong antimicrobial activity against Staphylococcus aureus at the concentration of 4,000 ppm. At this concentration, the growth of Staphylococcus aureus was retarded more than 36 hours and up to 24 hours for Salmonella Typhimurium. In conclusion, the methanol extracts of Hedyotis diffusa inhibit efficiently Staphylococcus aureus and Salmonella Typhimurium.