• Title/Summary/Keyword: food borne pathogens

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Screening on Antimicrobial Activity of Leaf Mustard (Brassica juncea) Extract (갓 (Brassica Juncea) 추출물의 항균활성 검색)

  • Kang, Seong-Koo;Sung, Nack-Kie;Kim, Yong-Doo;Shin, Soo-Cheol;Seo, Jae-Sin;Choi, Kap-Seong;Park, Seok-Kyu
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.23 no.6
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    • pp.1008-1013
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    • 1994
  • To develope naatural food preservatives, ethanol and water extracts were prepared from the leaf mustard (Brassica juncea Coss.) and antimicrobial activities were examined against 15 microorganisms which were food borne pathogens and/or food poisioning microorganisms and food-related bacteria and yeasts. Ethanol extract exhibited anitmicrobial activities for the microorganism tested, especially, minimum inhibitory concnetrations exhibited antimicrobial activities for the microorganism tested, especially, minimum inhibitory concentrations (MIC) for Bacillus subtilis and Bacillus natto were as low as 10mg/ml. MIC of water extract was 40-60mg/ml for bacteria and yeast. The ethanol extract showed the antimicrobial activity by 3~6 times higher than the water extract. Antimicrobial activity of the ethanol extract was not destroyed by the heating at $121^{\circ}C$ for 15 min and not affected by pH.

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Effects of Ethanol Extract of Leaf Mustard (Brassica juncea) on the Growth of Microoranisms (갓(Brassica juncea)의 에탄올추출물이 미생물 생육에 미치는 영향)

  • Kang, Seong-Koo;Sung, Nack-kie;Kim, Youg-Doo;Lee, Jae-Keun;Song, Bo-Hyeon;Kim, Young-whan;Park, Seok-kyu
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.23 no.6
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    • pp.1014-1019
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    • 1994
  • To develope natural food preservatives, ethanol extract was preapred from the leaf mustard (Brassica juncea Coss) and antimicrobial activities were examined against 12 microorganisms which were food borne pathogens and/or food poisioning microorgaism and food-related bacteria and yeasts. The most active animicrobial concentration of the ethanol extract for most Gram positive microorganisms, Gram negative microorganisms, and lactic bacteria and yeasts was found to be 10, 20 and 40 mg/ml, respectively. when tested by a dose-response manner. Growth of Escherichia coli and STaphylococcus aureus were completely inhibited 4 hours after the addition of more than 20mg/ml of ethanole ethanol extract to the logarithic phase. Scanning electron icrographs of E. coli and Staph, aureus treated with ethanol extrract exhibited morphological changes, including the irregularly contracted cell surface of E. coli and expanded ellipsoidal shape of the Staph. aureus.

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Antimicrobial Activity of the Solvent Extracts from of Chestnut (밤 부위별 추출물의 항균활성)

  • Kim Yong Doo;Cho Duk Boung;Kim Kyung Je;Kim Ki Man;Hur Chang Ki;Cho In Kyung
    • Food Science and Preservation
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    • v.12 no.3
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    • pp.257-262
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    • 2005
  • To develop natural food preservatives, ethanol and water extracts were prepared from chestnut. Antimicrobial activities were examined about 10 microoganisms which were food-borne pathogens and food-poisoning microoganisms, food-related bacteria and yeasts. Ethanol extract exhibited the antimicrobial activity for the microoganisms tested, except lactic acid bacteria and yeast Especially, minimum inhibitory concentrations(MIC) of the ethanol extracts were determined as 0.5 mg/mL in chestnut leaf and 1.0 mg/mL in chestnut balk against bacteria. Antimicrobial activity of the ethanol extracts was not destroyed by the heating at $121^{\circ}C$ for 15 min, and not affected by pH $3{\sim}9$. The ethanol, extract of chestnut exhibiting the high antimicrobial activities was fractionated in the other of diethylether and butanol fractions. The highest antimicrobial activity against bacteria was shown in the ethanol fraction.

Establishment of Microbial Criteria by Investigation of Microbial Contamination in Ready-to-Eat Foods (즉석섭취·편의식품류의 미생물 오염도 조사를 통한 기준·규격 재평가)

  • Song, Bo Ra;Kim, Soon Han;Kim, Jin-Kwang;Han, Jeong-A;Kwak, Hyo Sun;Chung, Kyung-Tae;Heo, Eun Jeong
    • Journal of Food Hygiene and Safety
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    • v.32 no.5
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    • pp.348-354
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    • 2017
  • Internationally different food safety regulation and standards could cause troubles in trade unless those are built on scientific knowledge. In this research, we monitored the microbial population and analyzed the results to determine the level of microbial contamination in foodstuffs using relatively new statistical analysis (microbiological sampling plan, International Commission on Microbiological Specification for Foods). The goal of this research falls on establishing entirely new standards for various food categories addressed in the Korean "Food Code". Targets for monitoring were indicator organisms (i.e. total aerobic count, coliform and Escherichia coli) and foodborne pathogens (i.e. Bacillus cereus, Staphylococcus aureus and Clostridium perfringens) in ready-to-eat (RTE) products. As the result of the monitoring, total aerobic count, coliform, E. coli, and B. cereus in RTE products were found at the mean values of 2.10 log CFU/g, -0.60 log CFU/g, -1.33 log CFU/g and -1.23 log CFU/g, respectively. S. aureus was detected with the level of -1.35 log CFU/g only in fresh-cut food, while C. perfringens was -1.37 log CFU/g only in ready-to-cook food. Other samples did not have any food borne pathogens. Total aerobic count, B. cereus, S. aureus and C. perfringens satisfied the Food Code (the MFDS). On the basis of the analysis, we proposed a draft of microbial criteria for RTE products.

Current situation and future trends for beef production in the United States of America - A review

  • Drouillard, James S.
    • Asian-Australasian Journal of Animal Sciences
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    • v.31 no.7
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    • pp.1007-1016
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    • 2018
  • USA beef production is characterized by a diversity of climates, environmental conditions, animal phenotypes, management systems, and a multiplicity of nutritional inputs. The USA beef herd consists of more than 80 breeds of cattle and crosses thereof, and the industry is divided into distinct, but ofttimes overlapping sectors, including seedstock production, cow-calf production, stocker/backgrounding, and feedlot. Exception for male dairy calves, production is predominantly pastoral-based, with young stock spending relatively brief portions of their life in feedlots. The beef industry is very technology driven, utilizing reproductive management strategies, genetic improvement technologies, exogenous growth promoting compounds, vaccines, antibiotics, and feed processing strategies, focusing on improvements in efficiency and cost of production. Young steers and heifers are grain-based diets fed for an average of 5 months, mostly in feedlots of 1,000 head capacity or more, and typically are slaughtered at 15 to 28 months of age to produce tender, well-marbled beef. Per capita beef consumption is nearly 26 kg annually, over half of which is consumed in the form of ground products. Beef exports, which are increasingly important, consist primarily of high value cuts and variety meats, depending on destination. In recent years, adverse climatic conditions (i.e., draught), a shrinking agricultural workforce, emergence of food-borne pathogens, concerns over development of antimicrobial resistance, animal welfare/well-being, environmental impact, consumer perceptions of healthfulness of beef, consumer perceptions of food animal production practices, and alternative uses of traditional feed grains have become increasingly important with respect to their impact on both beef production and demand for beef products. Similarly, changing consumer demographics and globalization of beef markets have dictated changes in the types of products demanded by consumers of USA beef, both domestically and abroad. The industry is highly adaptive, however, and responds quickly to evolving economic signals.

Discovery of Chitin Deacetylase Inhibitors through Structure-Based Virtual Screening and Biological Assays

  • Liu, Yaodong;Ahmed, Sibtain;Fang, Yaowei;Chen, Meng;An, Jia;Yang, Guang;Hou, Xiaoyue;Lu, Jing;Ye, Qinwen;Zhu, Rongjun;Liu, Qitong;Liu, Shu
    • Journal of Microbiology and Biotechnology
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    • v.32 no.4
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    • pp.504-513
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    • 2022
  • Chitin deacetylase (CDA) inhibitors were developed as novel antifungal agents because CDA participates in critical fungal physiological and metabolic processes and increases virulence in soil-borne fungal pathogens. However, few CDA inhibitors have been reported. In this study, 150 candidate CDA inhibitors were selected from the commercial Chemdiv compound library through structure-based virtual screening. The top-ranked 25 compounds were further evaluated for biological activity. The compound J075-4187 had an IC50 of 4.24 ± 0.16 µM for AnCDA. Molecular docking calculations predicted that compound J075-4187 binds to the amino acid residues, including active sites (H101, D48). Furthermore, compound J075-4187 inhibited food spoilage fungi and plant pathogenic fungi, with minimum inhibitory concentration (MIC) at 260 ㎍/ml and minimum fungicidal concentration (MFC) at 520 ㎍/ml. Therefore, compound J075-4187 is a good candidate for use in developing antifungal agents for fungi control.

Real-time PCR assay for the Detection of Toxoplasma gondii in Retail Meats: Proof-of-concept Study (유통식육에서의 톡소포자충 검출을 위한 유전자검사법 개발)

  • Yun, Han Seong;Suh, Soo Hwan;Kwak, Hyo-Sun;Joo, In-Sun
    • Journal of Food Hygiene and Safety
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    • v.32 no.3
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    • pp.199-205
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    • 2017
  • Although many PCR-based assays have been developed, the majority of rapid detection of Toxoplasma gondii in animal and their meat product has been dependent on immunogenic assays. Thus, there is still a need for more reliable PCR based detection method for T. gondii in retail meats. Recently, a 529-bp repeat element that exists in 200-300 copies per genome of T. gondii genome had been spotlighted for its usefulness as potential detection targers. In this study, the 529-bp repeat element was selected for real-time PCR to detect three types of T. gondii (type I, II and III). A primer pair targeting 82-bp of the 529-bp element detected all three types of T. gondii and showed high level of specificity against 14 different food-borne pathogens as well as 3 protozoan parasites such as Giardia lamblia, Cryptosporidium parvum and Entamoeba histolytica. Application of the new real-time PCR assay in meat samples showed improved detection sensitivity compared to the B1-gene targeted method suggesting potential new target for Toxoplasma gondii screening in retail meats.

Toxin Gene and Antibiotic Resistance of Staphylococcus aureus and Bacillus cereus Isolated from Indoor Air in Cafeteria (급식실 실내공기에서 분리된 황색포도상구균과 바실러스 세레우스의 독소 유전자 및 항생제 내성)

  • Oh, Do-Gyung;Jo, Ah-Hyeon;Kim, Chan-Yeong;Jeong, Eun-Sun;Kim, Jung-Beom
    • Journal of Food Hygiene and Safety
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    • v.36 no.6
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    • pp.520-527
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    • 2021
  • In this study, toxin gene and antibiotic resistance of food poisoning strains isolated from indoor air in the cafeteria were analyzed to prevent food poisoning. Staphylococcus aureus (16 strains) and Bacillus cereus (37 strains) isolated from indoor air in child care center were tested. The toxin genes of S. aureus and B. cereus were detected by PCR assay. The antimicrobial susceptibility test followed the disc diffusion method described by the Clinical and Laboratory Standard Institute. The seg and sei toxin genes were detected in 11 of 16 S. aureus strains (68.6%). The nheA and nheB toxin genes were detected in 37 B. cereus strains. In this study, a total of 12 toxin gene patterns of B. cereus were found, among which the nheA-nheB-nheC toxin gene was found to be the most frequent pattern. The result of the antimicrobial susceptibility test of S. aureus revealed 93.8% and 87.5% resistance to ampicillin and penicillin antibiotics, but methicillin resistance S. aureus and vancomycin resistance S. aureus were not detected. All 37 B. cereus tested in this study were resistant to ampicillin and penicillin antibiotics. Based on the result of this study, it was judged that regular ventilation and air quality management were necessary to prevent food poisoning caused by S. aureus and B. cereus contaminated in the indoor air of child care centers.

Antimicrobial Activity of Garlic Extracts according to Different Cooking Methods (조리방법을 달리한 마늘 추출물의 항균활성)

  • Kim Yong Doo;Kim Ki Man;Hur Chang Ki;Kim Eun Sun;Cho In Kyung;Kim Kyung Je
    • Food Science and Preservation
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    • v.11 no.3
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    • pp.400-404
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    • 2004
  • This study was conducted to find the antimicrobial activity of garlic extracts by various processing methods(boiled, pan fried, microwave heated, pickled). Ethanol and water extracts from garlic sample were prepared and antimicrobial activities were determined against 10 microoganisms ; food borne pathogens, food poisoning microoganisms, food-related bacteria and yeasts. The ethanol extracts from the fresh and pickled garlic showed antimicrobial activities for test microoganisms, except lactic acid bacteria and yeast. However, the antimicrobial activities were decreased by heat treatment. The minimum inhibitory concentration(MIC) of the fresh garlic extracts was determined to 0.1 mg/mL against an gram positive bacterium and 0.5 mg/mL against an gram negative bacterium. The antimicrobial activities of the ethanol extracts were affected by heating methods and not by pHs.

Crystal Structure of the Regulatory Domain of AphB from Vibrio vulnificus, a Virulence Gene Regulator

  • Park, Nohra;Song, Saemee;Choi, Garam;Jang, Kyung Ku;Jo, Inseong;Choi, Sang Ho;Ha, Nam-Chul
    • Molecules and Cells
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    • v.40 no.4
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    • pp.299-306
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    • 2017
  • The transcriptional activator AphB has been implicated in acid resistance and pathogenesis in the food borne pathogens Vibrio vulnificus and Vibrio cholerae. To date, the full-length AphB crystal structure of V. cholerae has been determined and characterized by a tetrameric assembly of AphB consisting of a DNA binding domain and a regulatory domain (RD). Although acidic pH and low oxygen tension might be involved in the activation of AphB, it remains unknown which ligand or stimulus activates AphB at the molecular level. In this study, we determine the crystal structure of the AphB RD from V. vulnificus under aerobic conditions without modification at the conserved cysteine residue of the RD, even in the presence of the oxidizing agent cumene hydroperoxide. A cysteine to serine amino acid residue mutant RD protein further confirmed that the cysteine residue is not involved in sensing oxidative stress in vitro. Interestingly, an unidentified small molecule was observed in the inter-subdomain cavity in the RD when the crystal was incubated with cumene hydroperoxide molecules, suggesting a new ligand-binding site. In addition, we confirmed the role of AphB in acid tolerance by observing an aphB-dependent increase in cadC transcript level when V. vulnificus was exposed to acidic pH. Our study contributes to the understanding of the AphB molecular mechanism in the process of recognizing the host environment.