• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.8
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• pp.1227-1232
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• 2016

Electrolyzed activated water (EAW) has been reported to exhibit strong bactericidal effects on foodborne microorganisms. However, the disinfection efficacy of EAW is affected by factors such as water source and hardness. This study investigated bactericidal effects of EAW against three gram-positive (Bacillus cereus, Listeria monocytogenes, and Staphylococcus aureus) and three gram-negative (Cronobacter sakazakii, Escherichia coli O157:H7, and Salmonella Enteritidis) foodborne pathogens. Six strains were treated with EAW prepared at different water temperatures (4, 22, and $40^{\circ}C$) for 15 min, and D-values were generated. The results show that the lowest D-values for Lis. monocytogenes by EAW produced at $4^{\circ}C$ and $40^{\circ}C$ were 6.60 and 1.57 min, respectively. The lowest D-value for Sal. Enteritidis by EAW produced at $22^{\circ}C$ was 2.92 min. D-values of all strains treated by EAW produced at $40^{\circ}C$ decreased significantly compared to those treated by EAW produced at $4^{\circ}C$ (P<0.05). These results demonstrate that applying EAW produced at warm temperature is more effective for reducing foodborne pathogens for food safety.

• Korean Journal of Veterinary Service
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• v.35 no.2
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• pp.119-128
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• 2012

This study was performed to investigate the freshness and nutritive components of eggs from Incheon area. The eggs of 64 brands collected from 7 hypermarkets and 6 brands collected from farms were examined to test the Haugh unit (HU), egg yolk index and specific gravity. HU and specific gravity were higher in farm eggs than in hypermarket eggs (P<0.05), and there was no difference in the egg yolk index. Among hypermarket eggs, HU and egg yolk index were higher in the graded eggs than in non-graded eggs (P<0.05), and specific gravity was not different between them. HU and egg yolk index of the eggs collected in March were higher than those in August (P<0.05). To monitor the bacterial contamination, total coliforms, total bacterial counts (TBC) and Salmonella enteritidis were examined. Salmonella enteritidis and total coliforms were not detected from all eggs. TBC of farm eggs were less than $10^1$ CFU/mL in all samples and TBC of hypermarket eggs were less than $10^1$ CFU/mL in 187 samples, $10^1{\sim}10^2$ CFU/mL in 3 samples and $10^3{\sim}10^4$ CFU/mL in 2 samples, respectively. Antimicrobial residues were not detected from all eggs tested. The vitamin E contents in the vitamin E enriched eggs from 6 brands hypermarket were 1.98~22.96 mg/yolk100 g ($14.04{\pm}8.81$ mg/yolk100g), and those of 5 brands among them were higher than the average of ordinary eggs. In one brand egg, vitamin E content was lower than the average of ordinary eggs. The vitamin E contents of ordinary eggs were 1.75~16.36 mg/yolk100 g (average $5.57{\pm}2.76$ mg/yolk100 g) and there were no price differences between vitamin E enriched eggs and ordinary eggs. In the contents of vitamin E, docosahexaenoic acid (DHA) and cholesterol, there were no significant differences according to the price. These results suggests that egg production, distribution, and management system should be improved for supplying fresh eggs to consumers at reasonable prices.

• Food Science and Preservation
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• v.15 no.4
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• pp.568-575
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• 2008

The antimicrobial activities of raw garlic and garlic juice heated for 30 min at $65^{\circ}C,\;80^{\circ}C,\;and\;95^{\circ}C$ were investigated. Activities against food poisoning bacteria were measured. Raw garlic and garlic juice heated at $65^{\circ}C$ showed strong antimicrobial activities, but the antimicrobial activity of garlic juice heated at $80^{\circ}C$ was much less, and no antimicrobial activity was seen in garlic juice heated at $95^{\circ}C$. Raw garlic and garlic juice heated at $65^{\circ}C$ completely inhibited the growth of Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Salmonella typhymurium, and Salmonella enteritidis at levels below 0.2%(w/v) of garlic solids. The inhibitory effects of garlic juice heated at $80^{\circ}C$ were much lower, against all bacteria tested.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.10
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• pp.1472-1478
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• 2004

The effects of microorganisms inoculated in beef, pork and chicken on the production of various biogenic amines (BA) were examined. Acinetobacter haemolyticus, Aeromonas hydrophila subsp. hydrophila, Alcaligenes faecalis subsp. faecalis, Bacillus cereus, Bacillus subtilis, Enterobacter aerogenes, Enterobacter cloacae, Escherichia coli, Lactobacillus alimentarius, Lactobacillus curvatus, Leuconostoc mesenteroides subsp. Mesenteroides, Proteus mirabilis, Proteus vulgaris, Pseudomonas aerugina, Salmonella enteritidis and Salmonella typhimurium were inoculated into beef, pork and chicken and incubated for 24 h at optimum temperatures of each bacterium. In ground beef, total amount of amines (TAA) produced was highest in the sample inoculated with Bacillus cereus, followed by Enterobacter cloacae. In ground pork, TAA was highest in the sample inoculated with Alcaligenes faecalis, followed by Enterobacter cloacae, Proteus vulgaris and Bacillus cereus. TAA of chicken breast was highest in the sample inoculated with Alcaligenes faecalis, followed by Bacillus cereus and Lactobacillus alimentarius while in chicken leg was the sample inoculated with Proteus vulgaris, followed by Enterobacter aerogenes, Enterobacter cloacae and Alcaligenes faecalis. Among biogenic amines produced, cadaverine (CAD) was detected at the highest level, followed by putrescine (PUT) and tyramine (TYM), their order being reversed by the kind of microorganism in beef and pork. In chicken breast and leg, CAD level was still the highest but PUT, TYM or PHM was the second highest, depending upon the kind of microorganism inoculated. In total, Alcaligenes faecalis, Enterobacter cloacae and Bacillus cereus were ones that produced a larger amount of BAs regardless of meat sources from different species.

• Journal of Microbiology and Biotechnology
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• v.25 no.9
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• pp.1510-1518
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• 2015

In this work, we wanted to develop a probiotic from famous longevity villages in Korea. We visited eight longevity villages in Korea to collect fecal samples from healthy adults who were aged above 80 years and had regular bowel movements, and isolated lactic-acid-producing bacteria from the samples. Isolated colonies that appeared on MRS agar containing bromophenol blue were identified by means of 16S rRNA sequencing, and 102 of the isolates were identified as lactic-acid-producing bacteria (18 species). Lactobacillus fermentum was the most frequently found species. Eight isolates were selected on the basis of their ability to inhibit the growth of six intestinal pathogens (Escherichia coli O157:H7, Salmonella enterica subsp. enterica Typhimurium, Salmonella enterica subsp. enterica Enteritidis, Enterococcus faecalis, Staphylococcus aureus, and Listeria monocytogenes) and their susceptibility to 15 antimicrobial agents. Among these eight isolates, four Lactobacillus fermentum isolates were found not to produce any harmful enzymes or metabolites. Among them, Lactobacillus fermentum isolate no. 24 showed the strongest binding to intestinal epithelial cells, the highest immune-enhancing activity, anti-inflammation activity, and anti-oxidation activity as well as the highest survival rates in the presence of artificial gastric juice and bile solution. This isolate, designated Lactobacillus fermentum PL9988, has all the characteristics for a good probiotic.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1790-1797
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• 2002

Lactic acid bacteria were isolated from piglets and chicken and characterized. Lactic acid bacteria showing resistance to low pH and bile, adhesion to intestinal epithelium cells, and the inhibition of Escherichia coli and Salmonella spp. were identified as Lactobacillus acidophilus. L. acidophilus PF01 survived for 2 h in MRS broth adjusted to pH 2. L. acidophilus CF07 was less resistant than L. acidophilus PF01 to pH 2, but survived at pH 2.5 for 2 h. Both of isolates were able to grow in MRS broth containing 0.3% (w/v) bile, with L. acidophilus CF07 being more tolerant to bile than L. acidophilus PF01. L. acidophilus PF01 and CF07 adhered specifically to the duodenal and jejunal epithelium cells of piglet, and the cecal and duodenal epithelium cells of chicken, respectively. Both of isolates did not adhere to the epithelium cells of the various animal intestines from which they were isolated. When L. acidophilus was cultured with E. coli and Salmonella spp. in MRS broth, MRS broth containing 2% skim milk powder or modified tryptic soy broth at $37^{\circ}C$, L. acidophilus PF01 and CF07 inhibited the growths of E. coli K88 and K99, and S. enteritidis and S. typhimurium, respectively. Both of isolates were found to possess the essential characteristics of probiotic lactic acid bacteria for piglet and chicken.

• Food Science of Animal Resources
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• v.32 no.6
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• pp.706-712
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• 2012

The present study was aimed to produce a chicken polyclonal antibody against Cronobacter muytjensii and to develop an immunoassay for its detection. Purification of anti-C. muytjensii IgY from egg yolk was accomplished using various methods such as water dilution and salt precipitation. As a result, sodium dodecyl sulfate-polyacrylamide gel electrophoresis produced two bands around 30 and 66 kDa, corresponding to a light and a heavy chain, respectively. Indirect competitive enzyme-linked immunosorbent assay (IC-ELISA) was performed to determine the effectiveness of the chicken IgY against C. muytjensii. The optimum conditions for detecting C. muytjensii by indirect ELISA and checkerboard titration of the antigen revealed an optimum average absorbance at the concentration of 18 ${\mu}g/mL$, having ca. $10^8$ coated cells per well. The anti-C. muytjensii IgY antibody had high specificity for C. muytjensii and low cross-reactivity with other tested pathogens. In this assay, no cross-reactivity was observed with the other genera of pathogenic bacteria including Escherichia coli O157:H7, Salmonella Typhimurium, Staphylococcus aureus, Bacillus cereus, Enterobacter aerogenes, Salmonella Enteritidis and Listeria monocytogenes. In addition, detection of C. muytjensii in infant formula powder showed a low matrix effect on the detection curve of IC-ELISA for C. muytjensii, with similar detection limit of $10^5$ CFU/mL as shown in standard curve. These findings demonstrate that the developed method is able to detect C. muytjensii in infant formula powder. Due to the stable antibody supply without sacrificing animals, this IgY can have wide applications for the rapid and accurate detection of C. muytjensii in dairy foods samples.

• Food Science and Preservation
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• v.6 no.3
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• pp.345-359
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• 1999

The antimicrobial and antioxidative effects of Opuntia ficus-indica vur. saboten (OP) extract with different solvents and extraction methods were investigated. In general, antimicrobial activity of OP was higher in extracts by reflux than in extracts by shake. However, no significant difference in antimicrobial activity was observed between methanol, ethanol and water extract. The antimicrobial activity was significant against all microbes tested, especially against Pseudomonas aeruginosa by shake extract and against Escherichia coli O-157 by reflux extract. A severe morphological change with destruction of outer layer was observed in Salmonella enteritidis treated with water extract. Though OP extract in hydrogen activity was lower than 0.1% BHT, the activity of OP extract showed very high effectivenss than the activity of control. OP extract showed a similar extent of antioxidative activity with BHT.

• Journal of Microbiology and Biotechnology
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• v.26 no.6
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• pp.1026-1034
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• 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 Agricultural Science
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• v.21 no.2
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• pp.122-132
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• 1994

Bacteriostatic activity of secretory immumoglobulin A (SIgA) in human and bovine colostrums on enterotoxigenic type Salmonella was tested in the tissue culture medium. SIgA was used in $0.1{\sim}5.0mg/m{\ell}$ concentration with or without the addition of egg lysozyme tested for theirs bacteriostatic activites. 1. Bovine SIgA rich fraction with a large amount of $IgG_1$-dimer could be prepared from bovine colostrum of Holstein cows by anion exchange chromatography using DEAE-Sephadex A-50 and gel filtration on Sephadex G-200 and Sepharose 6B. 2. Human SIgA appeared to be the most bacteriostatic effect for all varieties of Salmonella in a range of $0.5{\sim}1.0mg/m{\ell}$ Bovine SIgA showed a marked bacteriostatic effect increased by increasing the concentration. Bovine IgG had not show bacteriostatic effect against both enterotoxigenic type Salmonella. Egg lysozyme as well as bovine SIgA also showed a marked bacteriostatic effect increased by increasing the concentration. 3. When the growth inhibition of human SIgA was tested by adding egg lysozyme with time interval, egg lysozyme showed bacteriostatic effect as compared with control. But human SIgA and adding with lysozyme showed slight the bacteriostatic effect. 4. When the growth inhibition of bovine SIgA was tested by adding egg lysozyme with time interval, all treatment against S. enteritidis showed bacteriostatic effect as compared with control In the case of S. typhinwrium, egg lysozyme showed a marked bacteriostatic effect as compared with control.