• Journal of Food Hygiene and Safety
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• v.29 no.1
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• pp.1-5
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• 2014

Many community gardens in large cities worldwide grow vegetables; however, no information regarding the levels of sanitary indicator bacteria and prevalence of foodborne pathogens in vegetables grown in urban community gardens is available. To evaluate the microbiological quality of vegetables from urban community gardens in Korea, 530 samples (nine types of vegetable, including Chinese cabbage, lettuce, radish leaves, spinach, mustard leaves, crown daisy, leek, Korean cabbage, and chicory) were collected at 11 urban community gardens in Seoul, Korea from September through October 2012. The levels of total aerobic bacteria, Escherichia coli, total coliforms, Salmonella spp. Listeria monocytogenes, and E. coli O157:H7 were evaluated quantitatively and/or qualitatively. The mean numbers of total aerobic bacteria and coliforms were 6.3 log CFU/g (range 3.8-8.1 log CFU/g) and 4.3 log CFU/g (range 2.1-6.4 log CFU/g), respectively. Total coliforms were detected on 67% of whole vegetables. Chicory showed the highest number of total aerobic bacteria and coliforms, whereas the lowest number of coliforms was detected on leeks. E. coli was detected on 2.3% of whole vegetables, including lettuce, radish leaves, mustard leaves, and chicory; however, foodborne pathogenic bacteria were not detected on any of the vegetable samples using this highly sensitive and validated procedure. Based on these findings, the presence of coliforms and E. coli demonstrates that opportunity for improvement of microbiological safety exists throughout the produce production chain, although no major foodborne pathogens were present in vegetables grown in urban community gardens.

• Food Science and Preservation
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• v.7 no.3
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• pp.326-330
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• 2000

Antimicrobial activities of marinex and preservative characteristics of soybean curds soaked in diluted marinex were investigated. One hundred ml of marinex showed antimicrobial activities against Streptococcus mutans, Bacillus subtilis, Pseudomonas aeruginosa, Salmonella typhimurium, Escherichia coli and Escherichia coli O-157 on a paper disc test. The growth of the microorganisms were inhibited with 200${\mu}{\ell}/m{\ell}$ of culture media. pH of soybean curd treated with marinex decreased to 1 day and then slowly increased as storage time increase, which was higher than control after 1 day of storage and lower after that time. Little difference was observed between control and marinex treated soybean curd in color. Hardness and chewiness of the treated sample were higher than those of the control. The numbers of E. coli and bacteria of the treated sample were lower than those of control during storage. The inhibition of the growth of E. coli and bacteria was dose dependent.

• Journal of Biosystems Engineering
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• v.33 no.2
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• pp.136-141
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• 2008

Fecal contaminations on poultry carcasses, not easily discemable by human eyes, are potential harbor sites of pathogenic Escherichia Coli (E. coli O157:H7). Development of sensitive detection methods for fecal contamination is essential to ensure safe production of poultry products. Fluorescence has been shown to be very sensitive in detecting fecal and other biological substances that can harbor pathogens. In this study, fluorescence excitation-emission spectra of poultry fecal matter were compared with spectra for poultry skin and meat. Results indicated that the combinations of fluorescence intensities at the wavelength of 520 nm, 579 nm, 625 nm, and 635 nm with 411 nm excitation showed above 97% accuracy for differentiation of the contaminants from poultry tissues. Excitation and emission bands determined could be used for constructing a real-time fluorescence imaging device for detection of harmful residues on poultry carcasses.

• Bulletin of the Korean Chemical Society
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• v.33 no.8
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• pp.2592-2596
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• 2012

Cysteine capped silver nanoparticles (Cys-AgNPs) have been synthesized by employing electrochemically active biofilm (EAB), $AgNO_3$ as precursor and sodium acetate as electron donor in aqueous solution at $30^{\circ}C$. Cys-AgNPs of 5-10 nm were synthesized and characterized by UV-Vis, FT-IR, XRD and TEM. Capping of the silver nanoparticles with cysteine provides stability to nanoparticles by a thiolate bond between the amino acid and the nanoparticle surface and hydrogen bonding among the Cys-AgNPs. In addition, the antibacterial effects of as-synthesized Cys-AgNPs have been tested against two pathogenic bacteria Escherichia coli (O157:H7) and Pseudomonas aeruginosa (PAO1). The results demonstrate that the as-synthesized Cys-AgNPs can proficiently inhibit the growth and multiplication of E. coli and P. aeruginosa.

• Biomedical Science Letters
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• v.16 no.1
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• pp.10-18
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• 2010

The present study was set to develop comprehensive system for assessing the safety of drinking water using PCR-reverse blot hybridization assay (REBA). The REBA developed in this study can detect waterborne pathogens such as Shigella spp., Salmonella spp., Citrobacter spp., Enterobacter spp., Klebsiella spp., Yersinia spp., Mycobacterium spp., Listeria spp. at the genus level, and Escherichia coli, Citrobacter freundii, Klebsiella pneumoniae, Pseudomonas aeruginosa, Yersinia enterocolitica, Y. pseudotuberculosis, Mycobacterium avium complex, M. marinum, Enterococcus faecalis, and Staphylococcus aureus at the species level, and E. coli O157:H7 at the strain level.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1368-1371
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• 2008

In this study, 50 rump samples of raw beef obtained from local Korean supermarkets were analyzed to survey microbial distributions. As results, mesophilic microorganisms ranged from $(1.4{\pm}0.01){\times}10^2$ to $(1.6{\pm}0.05){\times}10^5\;CFU/g$, and total coliforms ranged from 0 to $(1.3{\pm}0.04){\times}10^4\;CFU/g$. Major foodborne pathogens, including Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella spp., were not found among the samples. However, Staphylococcus aureus was isolated with 4% frequency. Other isolated microorganisms included Enterobacter amnigenus (4%), Enterobacter cloacae (24%), E. coli (24%), Listeria innocua (8%), Staphylococcus saprophyticus (56%), Staphylococcus xylosus (10%), and Staphylococcus warneri (8%).

• Korean journal of food and cookery science
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• v.16 no.1
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• pp.40-46
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• 2000

The sensitivity of various pathogenic bacteria(Listeria monocytogenes, Staphylococcus aureus, Aeromonas hydrophila, Escherichia coli O157:H7 and Salmonella typhimurium) to the pine needle and green tea extracts was tested. Water extract of pine needle(PNW), 70% ethanol extract of pine needle(PNE), water extract of green tea(GTW) and 70% ethanol extract of green tea(GTE) were prepared for the test of antibacterial activty. Tryptic soy broth(TSB) containing 0∼2%(w/v) of pine needle and green tea extracts were inoculated with 10$\^$5/∼10$\^$6/ cells/ml of each bacterium and incubated at 35$\^{C}$ for 24 hours. The standard plate count method was used to measure the inhibitory effect of the extracts. Minimum inhibitory concentration(MIC) and minimum bactericidal concentration(MBC) were derived from the survival curves of pathogenic bacteria. Antibacterial activities of the pine needle and green tea extracts were compared with that of sodium benzoate, a preservative, by clear zone test. L. monocytogenes, S. aureus and A. hydrophila were completely inhibited at 0.4∼1.6% level while E. coli and S. typhimurium were very resistant to the pine needle extracts. Green tea extracts completely inhibited all strains tested at 0.2∼1.0% level and bactercidal to all strains except L. monocytogenes at 0.5∼2.0% level. Antibacterial activities of pine needle and green tea extracts were stronger than that of sodium benzoate. The order of antibacterial activities of pine needle and green tea extracts to the pathogenic bacteria was GTE > GTW > PNE > PNW. This result suggests that green tea extracts can be used as an effective natural antibacterial agent in food.

• Journal of Food Hygiene and Safety
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• v.27 no.3
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• pp.209-214
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• 2012

The purpose of this study was to evaluate microbiological contamination of fresh-cut produce salads and raw cabbage toward climate change. Total aerobic bacteria, coliform and Escherichia coli were monitored to get the contamination levels and E. coli O157:H7, Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes and Salmonella spp. to detect pathogens with risk of foodborne disease from samples. Collection of 360 samples (180 fresh-cut produce salads and 180 raw cabbage), including 60 samples from each area after setting 3 areas depending on annual temperature and annual rainfall. As a result, total aerobic bacteria and coliform group were different was performed areas in raw cabbage but there was no difference between areas in fresh-cut produce salads. In addition foodborne pathogens including E. coli were not isolated from fresh-cut produce salads.

• Food Science and Biotechnology
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• v.16 no.4
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• pp.615-620
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• 2007

Commercially packed kimchi products from 6 different manufacturers, which are exported overseas as well as sold domestically, were analyzed to determine their microorganism distributions and presence of pathogenic bacteria. All samples showed decreasing pH levels (from 5.7-6.2 to 3.9-4.3) and increasing titratable acidities (from 0.3-0.4 to 0.8-1.2%) during 15 days of storage at $4^{\circ}C$. Total bacterial counts ranged from $2.1{\times}10^5-1.9{\times}10^6\;CFU/mL$ in the initial kimchi samples, and then increased to $1.1{\times}10^8-1.8{\times}10^9\;CFU/mL$. The coliform numbers decreased from approximately $2.5{\times}10^2-1.7{\times}10^4\;CFU/mL$ to zero. Major foodborne pathogens such as Salmonella spp., Staphylococcus aureus, Escherichia coli O157:H7, Listeria monocytogenes, Bacillus cereus, Yersinia enterocolitica, and Shigella spp. were not detected in any of the samples. However, 2 out of the 6 samples carried E. coli, emphasizing the need for improved hygiene practice. Interestingly, Hafnia alvei, belonging to the Enterobacteriaceae family, was isolated in all of the samples. Further study is needed on this newly reported bacterium in kimchi.

• Biomedical Science Letters
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• v.27 no.4
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• pp.323-328
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• 2021

Naegleria fowleri is a free-living amoeba causing primary amoebic encephalitis. In this study, we analyzed how the N-aceytlglucosamine (GlcNAc) and D-galactose affected the interaction between Naegleria fowleri and methicillin-resistant Staphylococcus aureus (MRSA) or Escherichia coli O157:H7, and the interaction with bacteria when monosaccharides were treated with N. fowleri for a longer pre-incubation time. When GlcNAc was treated with N. fowleri for 1 hr, the E. coli association was almost the same as that of the control not treated with GlcNAc until the concentration of GlcNAc was 25 mM. However, the E. coli association was reduced by approximately 91% with 100 mM GlcNAc. E. coli invasion into N. fowleri showed statistical significance only in the group treated with 100 mM GlcNAc. The interaction when treated with galactose showed a very different pattern in the 50 mM galactose group than when treated with GlcNAc. In the MRSA interaction, a statistically significant decrease in association (76.3% by GlcNAc and 88.7% by galactose) and invasion (3.6% by GlcNAc and 9.3% by galactose) was shown by the concentration of two 100 mM monosaccharides. The group treated with monosaccharides at the same time showed almost no difference in all interactions from the group treated with monosaccharides at the same time. Taken together, it suggested that the effect of monosaccharides on the interaction of several Gram-negative or positive bacteria and the evidence that the interaction could be enhanced by longer pre-incubation time.