• Korean Journal of Food Science and Technology
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• v.38 no.5
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• pp.699-706
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• 2006

The antioxidative and antimicrobial activities of Euphorbia jolkini extracts were investigated. Total polyphenohc compounds extracted were approximately as follows: 162.08 mg/g from ethanol, 12.64 mg/g from n-hexane, 48.11 mg/g from dichloromethane, 544.08 mg/g from ethyl acetate, 176.42 mg/g from butanol, and 30.00 mg/g from water. The ethylacetate fraction of this extraction showed the highest antioxidative activity $(IC_{50})$: DPPH radical scavenging capacity was measured at $8.38\;{\mu}g/mL$, xanthine oxidase inhibitory activity was $466.01\;{\mu}g/mL$, superoxide radical scavenging capacity was $11.39\;{\mu}g/mL$, and nitric oxide scavenging capacity was $332.11\;{\mu}g/mL$. Antimicrobial activities were determined by paper disc method and minimum inhibitory concentration of E. jolkini extracts against food-borne pathogens and spoilage bacteria. The growth inhibition curves of E. jolkini extracts against Bacillus cereus, Listeria monocytogenes, and Escherichia coli were also determined. These results suggest that the ethylacetate fraction of E. jolkini has strong antimicrobial activity against the all species of microorganisms as well as strong antioxidant activity.

• The Korean Journal of Mycology
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• v.20 no.4
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• pp.337-346
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• 1992

Trichoderma spp. are an effective control agent for damping-off or other plant diseases. The interaction between. T. hamatum and Rhizoctonia solani on the rhizosphere or surface soil were examined to assess the possible roles of antibiosis or competition in the mechanisms of biological control agents as a basic research. In a proportional comparison, total bacteria, fungi, actinomycetes and Trichoderma spp were 65%, 8.8%, 25.9% and 0.28% respectively in their distribution in the soil. Among Trichoderma spp isolated, the 5 species of Trichoderma spp were indentified as T. koninggii, T. pseudokoninggii, T. aureoviridi, T. hamatum and T. viride respectively. In a mycoparasitic test, one isolate of T. hamatum strain Tr-5 showed an enzymatic ability to break fungal hyphae into piecies and infected on the R. solani hyphae showing a parasitism. Spore germination of the all isolates of Trichoderma spp showed a 1.7-7.3% of germination in natural soil conditions, but the percentage was high in sterile soil indicating all the natural soil were fungistatic on conidia of Trichoderma spp. In rhizosphere competent assay in pea plant, the antagonistic T. hamatum, T. viride, T. koninggii, T. pseudokoninggii showed a colonizing upper soil depth in rhizosphere around 1-3 cm in root zone, but the colonizing ability was much reduced along the deeper the soil depth. Propagule density was decreased in deeper the soil layer. Disease development rate treated alone with plant pathogens, Fusarium solani, Rhizoctonia solani, Cylindrocarpon destructans increased, but disease incidence rate reduced in treatment with combinations with antagonistic T. hamatum strain Tr-5.

• Food Science of Animal Resources
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• v.32 no.1
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• pp.103-111
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• 2012

This study was carried out to examine foodborne pathogenic contamination from 1,080 samples of cooked hams and sausages at 10 Korean processing facilities in 2010. The samples were collected from the six primary and additional sterilization products in same lot. To detect Salmonella spp., Staphylococcus aureus, Listeria monocytogenes and Clostridium perfringens in those products (n=1,080), the domestic standard method for Processing and Ingredients Specification of Livestock Products was used. As a result, Salmonella spp. was not detected in all 636 ham and 444 sausage samples. However, L. monocytogenes was detected in four (0.6%) ham and eight (1.8%) sausage samples from five manufactures. S. aureus was also only detected in 4 (0.6%) ham samples from two manufacturers, and C. perfringens was detected in 3 (0.5%) ham samples from three manufacturers, the contamination levels of these pathogens were less than 100 CFU/g. In conclusion, the results of this study indicate that the additional sterilization step of processing manufacturers could not assist to control the foodborne pathogenic bacteria.

• Microbiology and Biotechnology Letters
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• v.38 no.3
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• pp.295-301
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• 2010

Sheath rot and dry rot disease caused by Pseudomonas marginalis and Fusarium oxysporum were serious problems in garlic farmland. In this study, total of 160 indigenous antagonistic bacteria were isolated from 16 farmlands in Yeongcheon, Korea. Among these, 15 strains were able to inhibited P. marginalis and F. oxysporum. The 16s rDNA genes of the selected 15 strains were amplified and sequenced. The strains has strong antagonistic ability against garlic pathogens was achieved Bacillus subtilis YC82, B. vallismortis YC84, B. amyloliquefaciens YC240. The selected 3 strains tested for investigation of antifungal mechanisms further analyses; 3 strains of these validated for production of siderophore, ${\beta}$-glucanase and chitinase using CAS (chrome azurol S) blue agar, CMC-congo red agar and DNS method. The 3 strains were able to utilized insoluble phosphate as dertermined by vanado-molybdate method. The 3 strains verified for production of auxin and gibberellic acid using Salkowski test and holdbrook test. Also, 3 strains showed stimulation germination, stem growth promoting activity on the in vivo test. The 3 strains were able to effectively suppress P. marginalis and F. oxysporum causing sheath rot and dry rot diseases on the in vivo pot test.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.957-963
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• 1998

Several medicinal herbs, which are nontoxic and have been used widely in traditional folk medicine, were extracted and antimicrobial activity of the extracts was investigated against various foodborne pathogens or food poisioning microorganisms. The ethanol extract of Sansa, Hwangryun, Cheukbaek, and Seokchangpo showed strong antimicrobial activities against Gram postive and Gram negative bacteria, whereas those of Sakunja, Sukjihwang and Baekji had little antimicrobial activities on microorganisms tested. Among medicinal herb extracts, ethanol extract of Coptis chinensis Franch (hwangryun) showed the strongest antimicrobial activity. Antimicrobial activity of ethanol extract of Coptis chinensis Franch was not destroyed by heating at $100^{\circ}C$ for 60 min and at $121^{\circ}C$ for 30 min, which is very stable over heat. The pH effect on minimal inhibitory concentrations (MIC) of the extract of Coptis chinensis Franch indicated that MIC was reduced with increasing the pH value of the medium. The inhibitory effect of partially purified substance from the ethanol extract of Coptis chinensis Franch on the growth of Listeria monocytogenes and Staphylococcus aureus was investigated. Growth of those strains occurred at the concentration of $100{\;}{\mu}g/mL$ and were inhibited at $500{\;}{\mu}g/mL$, whereas those strains was completely inactivated in the presence of $1000{\;}{\mu}g/mL$.

• Journal of Food Hygiene and Safety
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• v.38 no.3
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• pp.123-130
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• 2023

Salmonella spp. are prevalent foodborne pathogens that are infective at relatively low concentrations, thus posing a serious health threat, especially to young children and the elderly. In several countries, the management and regulation of Salmonella spp. in food, including seafood, adhere to a negative detection standard. The risk of infection is particularly high when seafood is consumed raw, which underscores the importance of timely detection of pathogenic microorganisms, such as Salmonella. Accordingly, this study aimed to develop a combined pre-treatment and detection method that includes pre-culture and DNA extraction in order to detect five species of Salmonella at concentrations below 10 CFU/mL in seafood. The effectiveness of the proposed method was assessed in terms of the composition of the enrichment (pre-culture) medium, minimum incubation time, and minimum cell concentration for pathogen detection. Furthermore, a practical DNA extraction method capable of effectively handling high salt conditions was tested and found to be successful. Through polymerase chain reaction, Salmonella spp. Were detected and positively identified in shellfish samples at cell concentrations below 10 CFU/g. Thus, the proposed method, combining sample pre-treatment and cell culture with DNA extraction, was shown to be an effective strategy for detecting low cellular concentrations of harmful bacteria. The proposed methodology is suitable as an economical and practical in situ pre-treatment for effective detection of Salmonella spp. in seafood.