• Korean journal of food and cookery science
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• v.21 no.3 s.87
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• pp.319-325
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• 2005

This study was performed to investigate the antimicrobial effect of the Forsythiae Fructus extracts against food-borne pathogens. First, Forsythiae Fructus was extracted with methanol at room temperature and the methanol extracts were fractionated by using petroleum ether, chloroform, ethyl acetate, and methanol. The antimicrobial activity of the Forsythiae Fructus extracts was determined by using a paper disc method against food-borne pathogens and food spoilage bacteria. The methanol extracts of Forsythiae Fructus showed the highest antimicrobial activity against Salmonella paratryphimurium and Salmonella typhimurium. A synergistic effect in inhibition was observed when Forsythiae Fructus extract was mixed with Ulmus davidiana Japonica extract as compared to each extract alone. Finally, the growth inhibition curves were determined by using ethyl acetate extracts of Forsythiae Fructus against Shigella flexneri and Salmonella paratyphimurium. The aqueous extract of Forsythiae Fructus had strong antimicrobial activity against Staphylococcus epidermidis at the concentration of 10,000 ppm. At this concentration, the growth of Shigella fexneri was retarded for more than 24 hours and for up to 12 hours for Staphylococcus epidermidis. In conclusion, the methanol extracts of Forsythiae Fructus efficiently inhibited Staphylococcus epidermidis and Shigella flexneri.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.3
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• pp.389-394
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• 2005

This study was performed to investigate the antimicrobial activity of the Rubia akane Nakai extract against food-borne pathogens. First, the Rubia akane Nakai was extracted with methanol at room temperature and the fractionation of the methanol extract was carried out by using petroleum ether, chloroform, and ethyl acetate, and methanol. The antimicrobial activity of the Rubia akane Nakai extract was determined by using a paper disc method against food-borne pathogens and food spoilage bacteria. The methanol extract of Rubia akane Nakai showed the highest antimicrobial activity against Bacillus cereus and Pseudomonas aeruginosa. Synergistic antimicrobial effect was observed when Rubia akane Nakai extract was mixed with Viscum album var. coloratum extract as compared to each extract alone. Finally, the growth inhibition curves were determined by using methanol extract of Rubia akane Nakai against Bacillus cereus and Pseudomonas aeruginosa. The methanol extract of Rubia akane Nakai had strong antimicrobial activity against Pseudomonas aeruginosa at the concentration of 4,000 ppm. At this concentration, the growth of Pseudomonas aeruginosa was retarded more than 72 hours and up to 48 hours for Bacillus cereus. From these results, it was concluded that the methanol extract of Rubia akane Nakai inhibited effectively Bacillus cereus and Pseudomonas aeruginosa.

• Journal of Microbiology and Biotechnology
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• v.26 no.9
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• pp.1505-1516
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• 2016

The detection of food pathogens is an important aspect of food safety. A range of detection systems and new analytical materials have been developed to achieve fast, sensitive, and accurate monitoring of target pathogens. In this review, we summarize the characteristics of selected nanomaterials and their applications in food, and place focus on the monitoring of biological and chemical contaminants in food. The unique optical and electrical properties of nanomaterials, such as gold nanoparticles, nanorods, quantum dots, carbon nanotubes, graphenes, nanopores, and polydiacetylene nanovesicles, are closely associated with their dimensions, which are comparable in scale to those of targeted biomolecules. Furthermore, their optical and electrical properties are highly dependent on local environments, which make them promising materials for sensor development. The specificity and selectivity of analytical nanomaterials for target contaminants can be achieved by combining them with various biological entities, such as antibodies, oligonucleotides, aptamers, membrane proteins, and biological ligands. Examples of nanomaterial-based analytical systems are presented together with their limitations and associated developmental issues.

• Food Science and Biotechnology
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• v.18 no.1
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• pp.89-94
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• 2009

Frequent outbreaks of foodborne illness have been increasing the awareness of food safety. Conventional methods for pathogen detection and identification are labor-intensive and take days to complete. Some immunological, rapid assays are developed, but these assays still require prolonged enrichment steps. Recently developed biosensors have shown potential for the rapid detection of foodborne pathogens. In this study, an impedimetric biosensor was developed for rapid detection of Salmonella entritidis in food sample. To develop the biosensor, an interdigitated microelectrode (IME) was fabricated by using a semiconductor fabrication process. Anti-Salmonella antibodies were immobilized based on neutravidin-biotin binding on the surface of the IME to form an active sensing layer. To evaluate the effect of electrode gap on sensitivity of the sensor, 3 types of sensors with different electrode gap sizes (2, 5, and $10{\mu}m$) were fabricated and tested. The impedimetric biosensor could detect $10^3\;CFU/mL$ of Salmonella in pork meat extract with an incubation time of 5 min. This method may provide a simple, rapid, and sensitive method to detect foodborne pathogens.

• Preventive Nutrition and Food Science
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• v.15 no.3
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• pp.233-238
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• 2010

The aim of this study was to determine microbiological contamination of fresh-red pepper and packaged-red pepper powder commercially available in South Korea. Thirty-seven fresh-red peppers were collected from 5 farms and 31 packaged-red pepper powders were purchased from retail markets in South Korea. Foodborne pathogens (Escherichia coli, Salmonella spp., Listeria monocytogenes, Staphylococcus aureus and Bacillus cereus), total viable counts, Enterobacteriaceae, coliforms, yeast and mold, and Aspergillus flavus were determined. Detection percentage of contamination of Bacillus cereus in fresh-red pepper was 8.1%, which was lower than the 39% of detection rate in packaged-red pepper powder. The contamination level of Bacillus cereus was 1～3 log CFU/g in packaged-red pepper powder. Escherichia coli was detected in 5.4% of fresh-red pepper samples and was not detected in packaged-red pepper powder. Enterobacteriaceae and coliforms were detected in both of fresh-red pepper and packaged-red pepper powders. Foodborne pathogens, except Bacillus cereus and Escherichia coli, were not detected.

• Food Engineering Progress
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• v.21 no.3
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• pp.191-200
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• 2017

There have been great efforts to develop a rapid and sensitive detection method to monitor the presence of pathogenic bacteria in food. While a number of methods have been reported for bacterial detection with a detection limit to a single digit, most of them are suitable only for the bacteria in pure culture or buffered solution. On the other hand, foods are composed of highly complicated matrices containing carbohydrate, fat, protein, fibers, and many other components whose composition varies from one food to the other. Furthermore, many components in food interfere with the downstream detection process, which significantly affect the sensitivity and selectivity of the detection. Therefore, isolating and concentrating the target pathogenic bacteria from food matrices are of importance to enhance the detection power of the system. The present review provides an introduction to the representative sample preparation strategies to isolate target pathogenic bacteria from food sample. We further describe the nucleic acid-based detection methods, such as PCR, real-time PCR, NASBA, RCA, LCR, and LAMP. Nucleic acid-based methods are by far the most sensitive and effective for the detection of a low number of target pathogens whose performance is greatly improved by combining with the sample preparation methods.

• Food Science and Industry
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• v.45 no.3
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• pp.2-14
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• 2012

• Korean Journal of Veterinary Research
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• v.56 no.2
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• pp.57-66
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• 2016

The gut epithelial barrier, which is composed of the mucosal layer and the intestinal epithelium, has multiple defense mechanisms and interconnected regulatory mechanisms against enteric microbial pathogens. However, many bacterial pathogens have highly evolved infectious stratagems that manipulate mucin production, epithelial cell-cell junctions, cell death, and cell turnover to promote their replication and pathogenicity in the gut epithelial barrier. In this review, we focus on current knowledge about how bacterial pathogens regulate mucin levels to circumvent the epithelial mucus barrier and target cell-cell junctions to invade deeper tissues and increase their colonization. We also describe how bacterial pathogens manipulate various modes of epithelial cell death to facilitate bacterial dissemination and virulence effects. Finally, we discuss recent investigating how bacterial pathogens regulate epithelial cell turnover and intestinal stem cell populations to modulate intestinal epithelium homeostasis.

• Korean Journal of Environmental Agriculture
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• v.40 no.4
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• pp.248-259
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• 2021

BACKGROUND: Contaminated water was a major source of food-borne pathogens in various recent fresh produce-related outbreaks. This study was conducted to investigate the microbial contamination level and correlations between the level of sanitary indicator bacteria and the detection ratio of pathogens in agricultural water by logistic regression analysis. METHODS AND RESULTS: Agricultural water was collected from 457 sites including surface water (n=300 sites) and groundwater (n=157 sites) in South Korea from 2018 to 2020. Sanitary indicator bacteria (total coliform, fecal coliform, and Escherichia coli) and food-borne pathogens (pathogenic E. coli, E. coli O157:H7, Salmonella spp., and Listeria monocytogenes) were analyzed. In surface water, the coliform, fecal coliform, and E. coli were 3.27±0.89 log CFU/100 mL, 1.90±1.19 log CFU/100 mL, and 1.39±1.26 log CFU/100 mL, respectively. For groundwater, three kinds of sanitary indicators ranged in the level from 0.09 - 0.57 log CFU/100 mL. Pathogenic E. coli, Salmonella and Listeria monocytogenes were detected from 3%-site, 1.5%- site, and 0.6%-site water samples, respectively. According to the results of correlations between the level of sanitary indicator bacteria and the detection ratio of pathogens by logistic regression analysis, the probability of pathogen detection increased individually by 1.45 and 1.34 times as each total coliform and E. coli concentration increased by 1 log CFU/100mL. The accuracy of the model was 70.4%, and sensitivity and specificity were 81.5% and 51.7%, respectively. CONCLUSION(S): The results indicate the need to manage the microbial risk of agricultural water to enhance the safety of fresh produce. In addition, logistic regression analysis is useful to analyze the correlation between the level of sanitary indicator bacteria and the detection ratio of pathogens in agricultural water.

• Korean Journal of Food Science and Technology
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• v.37 no.4
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• pp.611-617
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• 2005

Dispersed repetitive DNA elements in genomes of microorganisms differ among and within species. Because distances between repetitive sequences vary depending on bacterial strains, genomic fingerprinting with interspersed repetitive sequence-based probes can be used to distinguish unrelated organisms. Among well-known bacterial repetitive sequences, Repetitive Extragenic Palindromic (REP) sequence has been used to identify environmental bacterial species and strains. We applied REP-PCR to detect and differentiate four major Gram-negative food-borne bacterial pathogens, E. coli, Salmonella, Shigella, and Vibrio. Target DNA fragments of these pathogens were amplified by REP-PCR method. PCR-generated DNA fragments were separated on 1.5% agarose gel. Dendrograms for PCR products of each strain were constructed using photo-documentation system. REP-PCR reactions with primer pairs REP1R-I and REP2-I revealed distinct REP-PCR-derived genomic fingerprinting patterns from E. coli, Salmonella, Shigella, and Vibrio. REP-PCR method provided clear distinctions among different bacterial species containing REP-repetitive elements and can be widely used for typing food-borne Gram-negative strains. Results showed established REP-PCR reaction conditions and generated dendrograms could be used with other supplementary genotyping or phenotyping methods to identify isolates from outbreak and to estimate relative degrees of genetic similarities among isolates from different outbreaks to determine whether they are clonally related.