12 research outputs found

    In vitro interaction between Agrimonia eupatoria L. extracts and antibiotic

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    Synergistic activity between water, acetone, ethanol and diethyl ether extract of Agrimonia eupatoria L. and commonly used antibiotic (ampicillin) were evaluated. Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae and Pseudomonas aeruginosa were used. Interaction between plant extracts and antibiotic were tested by checkerboard method and expressed as fractional inhibitory concentration (FIC) index showed indifferent, additive and synergistic effects. Synergism was observed against E. coli for every combination of agents. FICI values were ranged from 0.03 to 0.29. Inhibitory concentration (IC50) was evaluated for every combination of tested extracts and antibiotic and the best combinations for every tested bacteria were combination of diethyl ether extract + ampicillin and combination of acetone extract + ampicillin

    The influence of environmental factors on the planktonic growth and biofilm formation of Escherichia coli

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    In this study, the effects of environmental factors (different media, temperature, pH, salt and sugar concentrations) on the planktonic growth, biofilm formation and formed biofilm of Escherichia coli KGPMF 16 and Escherichia coli KGPMF 17 were investigated. Tested bacteria were isolated from traditionally made cheese produced in Southeastern Serbia (Sokobanja region). The influence on planktonic growth, biofilm formation and formed biofilm was determined using spectrophotometric method. The limiting factors for the planktonic growth and biofilm formation were temperature of 4 °C and all tested concentrations of salt. The growth of tested bacteria was higher in media enriched with lactose than in media containing glucose. TSB was more congenial media to the planktonic growth of bacteria than MHB broth. None of the tested bacteria demonstrated the ability to form biofilm at 4 °C and 44 °C. Only E. coli KGPMF 17 showed ability to form biofilm in TSB at 37 °C. Different concentrations of salt, glucose and lactose exhibited inhibitory effect on biofilm formation, but all tested concentrations of lactose showed stimulating effect on formed biofilm of E. coli KGPMF 17. These results contribute to better understanding of the effects of environmental factors on the development of E. coli in cheese.Publishe

    Quality assessment, antimicrobial activity organic sunflower honey and use of Maldi-tof mass spectrometry for the identification bacteria isolated from honey

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    The aim of this study was to investigate the physicochemical parameters of quality, microbiological safety and antimicrobial potential of four samples of organic sunflower honey from the Banat area (northeastern Serbia). Humidity, ash, pH, free acidity, electrical conductivity, hydroxymethylfurfural content, sugar content and diastase activity were measured. Microbiological analysis revealed the presence of total aerobic mesophilic bacteria, coliforms, aerobic endospores, lactic acid bacteria (LAB) and a good number of molds and yeasts. The isolate identification was carried out using Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The antimicrobial effect of organic sunflower honey was investigated on five ATCC strains of bacteria: Staphilococcus aureus ATCC 29213; Escherichia coli ATCC 25922; Salmonella enterica ATCC 10708; Yersinia enterocolitica ATCC 23715; and Bacillus subtilis ATCC 23857. The results of the study showed that all honey samples meet international quality standards for all physicochemical parameters. Microbiological analysis of Sunflower honey confirmed the total bacterial counts for all samples ranged from1.80 to 1.85 x10-2cfu/g-1, whereby no presence Clostridium spp., coliform bacteria, as well as molds was detected. Investigation of the antimicrobial activity of honey samples revealed that all bacteria showed clear zones of inhibition in honey concentrations of 40-100%, which is a satisfactory result for flower honey

    Autohtona mikrobiota sjeničke ovčije stelje

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    Dry-cured sheep ham is traditional products of the Western Balkans. It is produced by drying specially processed carcasses of whole sheep that are smoked in cold smoke and spontaneously fermented. The aim of this research was to investigate physicochemical properties and isolate lactic acid bacteria (LAB) and coagulase negative staphylococci (CNS) from the product. To this end, 9 samples of dry-cured sheep ham from three households were taken. Isolated LABs were identified as Lactobacillus curvatus, Lactobacillus sakei and Enterococcus faecium. CNS were identified as Staphylococcus xylosus, Staphylococcus saprophyticus, Staphylococcus equorum, Staphylococcus carnosus. LAB and CNS play a key role in defining the quality of the product.Suva ovčija stelja je tradicionalni proizvodi Zapadnog Balkana. Proizvodi se sušenjem specijalno obrađenih trupova celih ovaca koji se kratko dime na hladnom dima i spontano fermentišu. Cilj ovog istraživanja je bio da se ispitataju fizičko-hemijske karakteristike i izoluju Bakterije mlečne kiseline (BMK) i koagulaza negativne stafilokoke (KNS) iz proizvoda. U tom cilju uzeto je 9 uzoraka iz tri domaćinstva. Izolovane BMK su identifikovane kao Lactobacillus curvatus, Lactobacillus sakei i Enterococcus faecium. KNS su identifikovane kao Staphylococcus xylosus Staphylococcus saprophyticus, Staphylococcus equorum, Staphylococcus carnosus. BMK i KNS igraju ključnu ulogu u definisanju kvaliteta proizvoda

    Effect of water activity on the radial growth of fungi isolated from dry-cured sheep ham, in vitro (Serbia)

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    In the Western Balkans, traditional dry-cured sheep ham called Pastrma or Stelja is produced. Dry-cured sheep ham from Sjenica is produced in a very complex manner, and a prerequisite for its production is the sanitary safety of raw materials in accordance with veterinary and sanitary regulations. Isolation and preliminary identification of fungi from sheep ham were carried out in this study, as well as in vitro testing of the effects of water activity (aw) on the growth of isolated fungi. Fungi were isolated from 9 samples of dry-cured sheep meat taken from three households in the area of Sjenica in two productive years (2015 and 2016). Species of genus Penicillium were isolated as dominant in all the investigated samples. Water activity was tested on MY50GF agar from the series of malt extract yeast extract glucose fructose agar. Water activity was set to values of 0.87, 0.89, and 0.97. The results of the research showed that the growth of fungal colonies is under the direct influence of water activity. Fungi grew fastest at water activity of 0.97, and the highest growth of all tested species was recorded after 3 (A. niger), 7 (P. patulum), and 10 days (A. nidulans).Publishe

    Karakterizacija i antibiotska osetljivost koagulaza-negativnih stafilokoka iz Zlatiborske pršute

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    Koagulaza negativne stafilokoke u procesu fermentacije svinjske pršute utiču na formiranje ukusa, mirisa, i boje, i na taj način formiraju vrhunski kvalitet. Materijal za ovo ispitivanje činila su 3 uzorka pršute, koji su uzeti iz tri domaćinstva sa područija Zlatibora. Cilj ovog istraživanja je izolacija i preliminarna kategorizacija koagulaza negativnih stafilokoka sa posebnim akcentom na pojavu rezistencije na komercijalne antibiotike. Preliminarno su izdefinisane četiri grupe stafilokoka, od kojih dominira Staphylococcus xylosus (37,5%), zatim Staphylococcus carnosus koji je izolovan u nešto manjem procentu iz pršute od 20,83%, Staphylococcus equorum 31,25%, i Staphylococcus epidermidis u nižem procentu (8,33%). Dva izolata su pokazala rezistenciju na antibiotike.Coagulase-negative staphylococci participating in the fermentation process of pork prosciutto affect the creation of taste, smell and color and in that way give the product top quality. The material for this study consisted of 3 samples of prosciutto taken from three households in Zlatibor area. The aim of this research was isolation and preliminary categorization of coagulase-negative staphylococci with special emphasis on the emergence of resistance to commercial antibiotics. Four groups of Staphylococcus were preliminary identified , of which Staphylococcus xylosus (37.5%) dominated, followed by Staphylococcus carnosus which was isolated from prosciutto in a somewhat smaller percentage of 20.83% Staphylococcus equorum 31.25%, and Staphylococcus epidermidis in a lower percentage (8.33%). Two strains showed resistance to antibiotics

    Quality and autochthonous microbiota of dry-cured sheep ham from western Balkans

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    Dry-cured sheep ham is a traditional product of Western Balkans. It is prepared by dry curing specially treated whole sheep carcasses which are smoked for a short time and spontaneously fermented in air under uncontrolled conditions. Lactic acid bacteria (LAB) play a key role in defining the quality and organoleptic characteristics of dry-cured sheep ham. The aim of this research was to investigate the chemical parameters of drycured sheep ham quality as well as the isolation and preliminary categorization of LAB. To this end, samples of dry-cured sheep ham were obtained from nine sheep of average age of about five years, from three households from the geographical area Sjenica (Western Serbia). Physicochemical analysis has determined the content of water, protein, fat, mineral matter, water activity and pH values in the product. Phenotypic characterization of LAB isolated from dry-cured sheep ham was based on the general morphology of the cell, physiological tests and sugar fermentation patterns of LAB isolates. 124 isolates of LAB were preliminary identified as Lactobacillus curvatus , Lactobacillus sakei and Enterococcus faecium . Chemical analysis confirmed a harmonious relationship between the quality parameters of dry-cured sheep ham.Publishe

    Duvan chvarci : product characterization and comparison between traditional and industrial production

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    Research Areas: Food Science & TechnologyThis research aimed to investigate and compare traditional products called “duvan chvarci” produced using pork meat and fat, originated from local households and industries. Physical and chemical analysis demonstrated differences among the examined products, mostly in total chloride content and TBARS values. Samples collected at local households showed finer color (higher lightness and yellowness) and sensory properties (rated as “extremely acceptable”), while industrial products were rated between “very acceptable” and “extremely acceptable“. Microbiological analysis exhibited that enterobacteria, coagulase-positive staphylococci, Salmonella spp., Shigella spp., and fungi were absent from all meat products. Dominant microbiota was identified as Lactobacillus spp. and Staphylococcus spp. All tested isolates showed γ-haemolysis on blood agar plates. Tested Staphylococcus spp. were sensitive to novobiocin while Lactobacillus isolates demonstrated sensitivity to ampicillin, chloramphenicol, clindamycin, erythromycin, tetracycline, gentamycin, and streptomycin. None of the tested isolates showed full resistance to antibiotics. Overall, results indicated that duvan chvarci is a microbiologically safe product and provided the initial evidence regarding the physical, chemical, technological, and sensory properties of this widely consumed product in the Balkans.info:eu-repo/semantics/publishedVersio

    КАРАКТЕРИЗАЦИЈА КОАГУЛАЗА НЕГАТИВНИХ СТАФИЛОКОКА ИЗОЛОВАНИХ ИЗ СУВОГ МЕСА ОВЧИЈЕГ ТРУПА – СЈЕНИЧКА ОВЧИЈА СТЕЉА

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    Sheep prosciutto is a fermented meat product for whose quality and organoleptic properties are increased by microorganisms making it a high quality product. Fermentation process of sheep prosciutto is not controlled, therefore in this case, the isolated strains that make up the microbiota are wild (occur in nature). Coagulase-negative staphylococci (CNS) have an important role in defining the characteristics of this product. The aim of our work was: to isolate coagulasenegative staphylococci from sheep prosciutto, as well as characterisation of the isolated staphylococci (CNS) to precisely define and determine the dominating strain of coagulase-negative staphylococci in sheep prosciutto and how it affects the quality of the product. Materials for this research consisted of 9 samples taken from three households in Sjenica during two production years (2014 and 2015 yr.). Phenotyping of the isolates was performed by Gram staining and catalase test, and then the isolates were subjected to the coagulase test. In order to identify the isolates the following tests were performed: The ability of bacterial colonies to induce hemolysis on blood agar, mannitol fermentation, growth at different temperatures (150C and 450C), tolerance to novobiocin, lipolytic activity, proteolytic activity and synthesis of EPS (Exopolysaccharides). Based on the results, a preliminary identification of 71 isolates of coagulasenegative staphylococci from Sjenica sheep prosciutto as Staphylococcus epidermidis, Staphylococcus saprophyticus, Staphylococcus xylosus and Staphylococcus carnosus was made.Publishe

    AUTOCHTHONE MICROBIOTA FROM DRY-CURED SHEEP HAM

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    Dry-cured sheep ham is traditional products of the Western Balkans. It is produced by drying specially processed carcasses of whole sheep that are smoked in cold smoke and spontaneously fermented. The aim of this research was to investigate physicochemical properties and isolate lactic acid bacteria (LAB) and coagulase negative staphylococci (CNS) from the product. To this end, 9 samples of dry-cured sheep ham from three households were taken. Isolated LABs were identified as Lactobacillus curvatus, Lactobacillus sakei and Enterococcus faecium. CNS were identified as Staphylococcus xylosus, Staphylococcus saprophyticus, Staphylococcus equorum, Staphylococcus carnosus. LAB and CNS play a key role in defining the quality of the product.Publishe
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