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Nine species (sixteen isolates) of lactic acid bacteria (LAB) isolated from traditionally made Serbian cheese were evaluated for their enzymatic activities in order to select indigenous strains of technical interest for the manufacture of cheese. These strains were selected based on their previously determined biochemical and physiological characteristics, as well as their antimicrobial activity, and were identified as Lactococcus lactis subsp. lactis (one isolate), Lc. lactis subsp. lactis biovar. diacetylactis (five isolates), Lactobacillus fermentum (two isolates), Lb. plantarum (one isolate), Lb. brevis (one isolate), Enterococcus faecalis (three isolates), E. faecium (one isolate), E. durans (one isolate) and E. hirae (one isolate). The enzymatic activities (acid and alkaline invertases, alkaline phosphatase, alkaline protease, a-amylase) were measured by using the spectrophotometric method. The results indicated that all Lactobacillus isolates showed protease, amylase, and alkaline phosphatase activities, while the activities of acid and alkaline invertases were not observed. The Lactococcus isolates showed protease, acid invertase and alkaline phosphatase activities, except the KGPMF50 isolate, which showed no alkaline phosphatase activity. The tested Enterococcus isolates showed weakly and strain-specific enzymatic activity. The results indicated that the enzymes produced by the investigated strains have a role in the formation of the specific flavor of cheese and that these isolates, especially Lactobacillus isolates, showed the potential for use in the dairy industry or applied biotechnology.

In this paper, the effect of different temperatures, pH, and NaCl concentration on the growth of autochthonous lactic acid bacteria isolated from traditionally made Serbian cheese (Sokobanja area) was investigated by using the spectrophotometric method. Growth of tested Lactobacillus (Lb. fermentum, Lb. plantarum, and Lb. brevis) and Lactococcus lactis subsp. lactis biovar. diacetylactis five isolates were better in acidic pH, while the growth of Enterococcus isolates (E. durans, E. faecium, and E. faecalis) was better in basic pH, at 37 °C. At 4 °C after 24 h, none of the tested bacteria showed growth. Since the autochthonous isolates were tolerant to a tested range of dairy processing conditions, further studies need to include the characterization of enzymatic activity of selected isolates, as well as the ability to use these isolates like starter cultures or food supplements in dairy or non-dairy products.

In this paper, we investigated, for the first time, the enzyme activity of enterobacteria from cheese from Southeastern Serbia (Sokobanja), which was produced in a traditional way. The tested bacteria were selected from the spring, summer, and autumn collections and grown in two different broths. The enzyme activity was investigated in the two broths and measured using spectrophotometry method. It was concluded that there were differences in the amount of extracellular enzymes depending on the broths. A statistically significant rise in the amount of enzymes was demonstrated in Tripton soy broth. Bacteria in cheese do not possess the ability to produce extracellular enzymes in large amounts. Therefore, they do not change the organoleptic characteristics of the cheese. There is a possibility that if they are found outside their natural environment (cheese), without interactions with antagonists, they may exhibit stronger enzyme activity.

The purpose of this study was the investigation of the growth ability of lactic acid bacteria (LAB), isolated from traditionally made cheese from Southeastern Serbia, in the presence of different percent of sugars and sugar substitutes (fructose, lactose, inulin, and mannitol). Dextrose was included for comparative purposes. The results indicated that fructose and lactose stimulated the growth of Lactobacillus strains, with exceptions of Lactobacillus plantarum KGPMF62 and Lb. plantarum LP 299v. Lactose showed similar effects like dextrose on the growth of Lactococcus strains, while higher growth rates of Enterococcus hirae KGPMF9, E. durans KGPMF10, E. faecium KGPMF14, and E. faecalis KGPMF47 were observed for lactose and mannitol. The results indicated the potential use of tested sugars and sugar substitutes as prebiotic compounds for the development of symbiotics with tested LAB, in medical or food industry.

This study observed the preliminary investigation of Oleum Hyperici, an original product made from Hypericum perforatum flowers, collected from Goč Mountain (Serbia). Some of the chemical properties (pH, the content of metals and metalloids - As, Cr, Pb, Cd, Ni, Hg) and the microbiological safety of the product including the total count of aerobic mesophilic bacteria, coagulase positive staphylococci, Escherichia coli, Pseudomonas aeruginosa, Proteus sp., as well as fungi: molds and yeasts) were evaluated. Antimicrobial activity of H. perforatum oil against 18 species of bacteria was determined using the disc diffusion and microdilution methods, by determining the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). The antibiofilm activity of Oleum Hyperici was evaluated using the biofilm formation assay. The results indicated that oil did not contain potentially pathogenic microorganisms. Oleum Hyperici product showed the antimicrobial activity on the most of tested bacteria (inhibition zone was in a range from 14 - 24 mm), except on Klebsiella pneumoniae ATCC 70063, K. pneumoniae, E. coli ATCC 25922, P. mirabilis, Bacillus subtilis ATCC 6633 and B. subtilis IP 5832. According to the obtained results, tested bacteria (planktonic and biofilm form) showed sensitivity up to 10-2 dilution of Oleum Hyperici. Based on the obtained preliminary results, it could be concluded that Oleum Hyperici can be used in traditional medicine for development control of some potential human pathogens.

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).

The antimicrobial and antioxidant activities, as well as the DNA-binding of four square-planar Pd(II) complexes, [Pd(terpy)Cl]+ (C1), [Pd(en)Cl2] (C2), [Pd(DMEAImiPr)Cl2] (C3) and [Pd(dach)Cl2] (C4) (terpy = 2,2′:6′,2′′- -terpyridine, en = ethylenediamine, dach = trans-1,2-diaminocyclohexane and DMEAImiPr = N2-((1,3-dihydro-1,3-diisopropyl-4,5-dimethyl)-2H-imidazol-2- ylidene)-N1,N1-dimethyl-1,2-ethanediamine are reported. The antimicrobial activities of the Pd(II) complexes with the appropriate ligands were tested using the microdilution method against 18 strains of microorganisms, whereby the minimal inhibitory concentration (MIC) and the minimal microbicidal concentration (MMC) were determined. The antibiofilm activity of [Pd(terpy)Cl]+ and the corresponding ligand were determined on a formed biofilm. The intensity of antimicrobial activity varied depending on the type of microorganism and the tested compound. The C1 complex with the corresponding ligand demonstrated significantly greater overall antimicrobial activity than C2, C3 and C4. The antibacterial activity of the C1 complex was better than its antifungal activity that was overall greater than that of the positive control, fluconazole. The greatest sensitivity for C1 and L1 was with Penicillium italicum (MIC < 0.49 μg mL-1) among the fungi, and with Proteus mirabilis ATCC 12453 (MIC = 0.98 μg mL-1) among the tested bacteria. The tested compounds show low and moderate antibiofilm activity. The complexes showed weak antioxidant properties when tested using the DPPH (1,1-diphenyl-2- -picrylhydrazyl) method. The interaction of the metal complexes C1–C4 with calf thymus DNA (CT-DNA) was further examined by absorption (UV–Vis) and emission spectral studies (EthBr displacement studies). Overall, the investigated complexes exhibited good DNA interaction ability. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172011 and Grant no. 173032]

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.

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.

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Copyright of Journal of Food Safety & Food Quality / Archiv für Lebensmittelhygiene is the property of Presse Dienstleistungsges. mbH & Co. KG and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Archives of Veterinary Medicine / Arhiv Veterinarske Medicine is the property of Scientific Veterinary Institute Novi Sad and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: In this paper, we investigated the presence of enterobacteria in cheese from Southeastern Serbia which was produced in a traditional way. The samples from different households were collected in spring. Chemical and physical characteristics of samples (water content, fat content, acidity, pH, and sodium chloride content) were examined. In the analyzed samples of cheese, we found one genus of family Enterobacteriaceae, Escherichia sp. The genus Escherichia sp. includes only one species, Escherichia coli. We also determined biochemical characteristics, proteolytic and lipolytic activities, the ability to form a biofilm, sensitivity to streptomycin, chloramphenicol, and tetracycline. According to the rapid latex agglutination test, two isolates belong to serotype E. coli O157. Practical applications: These results contribute to a better understanding of the presence of enterobacteria in unexplored microbiota of cheese from Sokobanja. E. coli is the only member of enterobacteria that appears in the samples collected in spring. Since E. coli is among the indicators of contamination, it does not demonstrate the ability to change the organoleptic properties of cheese. E. coli does not exhibit lipolytic or proteolytic activity, but it demonstrates sensitivity to antibiotics. The bacteria showed no ability to form biofilm. Further research should focus on finding the sources of contamination, as well as on the interaction of E. coli with other members of the cheese microbiota. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the presence of enterobacteria in autochthonous cheese from Southeast Serbia (Sokobanja), made in the traditional way, was investigated. The samples from different households, was taken during the summer and the autumn. Chemical and physical characteristics of samples (water content, fat content, acidity, pH, and sodium chloride content) were examined. In the analyzed samples of cheese, four different genera of family Enterobacteriaceae (Klebsiella [65%], Escherichia [20%], Serratia [10%], and Enterobacter [5%]) were identified. The members of genus Klebsiella were Klebsiella oxytoca, Klebsiella pneumoniae, and Klebsiella ornithinolytica, while in the genus Escherichia only one species, Escherichia coli was identified. Besides, two species of the genus Serratia, Serratia odorifera and Serratia marcescens biogp 1, and one species of the genus Enterobacter, Enterobacter gergoviae, were identified. Biochemical characteristics, proteolytic and lipolytic activity, sensitivity to streptomycin, chloramphenicol, and tetracycline were, also, determined. According to the rapid latex agglutination test, of the four E. coli isolates, two isolates belong to serotype E. coli O157. Practical applications: The results of this study contribute to better understanding of unexplored microflora of cheese from Sokobanja. The isolated genera were Klebsiella sp., Escherichia sp., Enterobacter sp., and Serratia sp. with twenty identified species. It is well known that bacteria from family Enterobacteriaceae could affect organoleptic properties of cheese. Bacteria isolated from cheese from Sokobanja mostly did not manifest proteolytic and lipolytic activity. The most number of isolates were susceptible to tested antibiotics. Further researches may contribute to better understanding of interaction between enterobacteria and lactic acid bacteria in autochthonous cheeses. [ABSTRACT FROM AUTHOR]

This research project aimed to investigate the physico-chemical, sensory, hygienic and safety characteristics of raw goat milk, whey, brine and traditional goat cheese during the ripening period of 28 days. Physico-chemical parameters included the determination of dry matter, fat, ash, protein, pH, water activity and NaCl content. The presence of Enterobacteriaceae and fungi was estimated on milk and cheese samples, and a sensory panel evaluated the products' features and acceptability during ripening. The results show that the cheese under study belongs to the acid full-fat cheese group. A consumer panel attributed high scores to the goat cheese, until the 21st day of ripening. After this period, the overall features altered significantly, including augmented bitterness, odor intensification and the development of molds on the surface. The presence of fungi, associated with Enterobacteriaceae, suggests that the hygiene of the production processes needs to be improved. Regarding microbial safety, the detection of putative pathogens and antibiotic resistances recommend an active surveillance of traditional foods to avoid foodborne infections and/or the dissemination of resistant microorganisms along the food chain. [ABSTRACT FROM AUTHOR]

The presence, biochemical and physiological characteristics of Lactobacillus and Lactococcus species isolated from traditionally made cheese from Southeastern Serbia (Sokobanja), was investigated. The screening of their antimicrobial potentials, using agar‐well diffusion method, and the ability of biofilm formation, using crystal violet method, was evaluated. The cheese samples, from different households, were obtained during the summer and the autumn. Chemical characteristics of cheese samples were examined. The members of genus Lactobacillus were: Lb. fermentum,Lb. brevis, and Lb. plantarum. The members of genus Lactococcus were: Lc. lactis subsp. lactis and Lc. lactis subsp. lactis biovar. diacetylactis. The antagonism of Lactobacillus and Lactococcus isolates on the growth of some Gram‐negative bacteria, isolated from the same cheese, was examined. The zones of growth inhibition ranged from 10 to 26 mm. The ability of biofilm formation of isolates was strains‐specific. Lactobacillus (KGPMF 28, KGPMF 29, KGPMF 35) and Lactococcus (KGPMF 23 and KGPMF 26) isolates demonstrated the potential for further investigation in natural preservation of food. Practical applications: Lactic acid bacteria, which can be found in traditional dairy products, presents unique and autochthonous microflora responsible for fermentation and quality of dairy products. These bacteria often have a great potential in natural food preservation, but their number and diversity are depending of season, vegetation, and the nutrition of animals. In this paper, the seasonal differences in bacterial community (especially community of lactobacilli and lactococci) between cheese samples, were investigated. In addition, the antagonism against some enterobacteria, which can affect the hygienic safety of cheese, was screened. Also, it was showed that some isolates had the ability of biofilm formation. Further investigation need to include the potential of isolates to be uses like probiotic or starter cultures. [ABSTRACT FROM AUTHOR]

Wine samples, wine evaporated to dryness, dealcoholized wine and the original shape wine, made from autochthonous grapevine variety from Serbia and Montenegro, were examined in order to determine total phenols, flavonoids and proanthocyanins, as well as their antioxidant activity. Antimicrobial and anti-biofilm activities were evaluated. The grapevine variety Vranac had the best values for total phenols, flavonoids and proanthocyanins compounds. The original shape wine samples showed stronger antioxidative efficiency, with the effective concentration values at which 50% of 2,2-diphenyl-1-picrylhydrazyl radicals were scavenged ranging from 12.98 µl·ml-1 to 132.27 µl·ml-1. The strongest antimicrobial activity of samples of wine evaporated to dryness was detected against Bacillus cereus, B. subtilis IP 5832 and Lactobacillus plantarum, minimum inhibitory concentration (MIC) being from < 0.08 mg·ml-1 to 2.50 mg·ml-1. Samples of dealcoholized wine and the original shape wine showed the strongest inhibitory activity against B. cereus (MIC from < 0.39 µl·ml-1 to 0.78 µl·ml-1). Dealcoholized wine samples showed biofilm-inhibitory activity at which 50% of Staphylococcus aureus ATCC 6538 biofilm was reduced, with values ranging from 188 µl·ml-1 to 530 µl·ml-1. The results of the study contribute to the knowledge on the biological activities of Balkan red wines and the potential for developing a nutritive and health-promoting food product. [ABSTRACT FROM AUTHOR]