Amarela Terzic Vidojevic

bacteria isolated from artisanal Zlatar cheeses produced at two different geographical location. – Genetika, Vol. 41, No. 1, 117-136. Eighty-one strains of lactic acid bacteria (LAB) were isolated from white semi-hard homemade cheese, designated Zlatar BGNV, which was taken from household settled on Northern side of mountain Zlatar. The Zlatar BGNV cheese was manufactured from raw cow’s milk without addition of the starter culture. All isolates of LAB were characterized by 118 GENETIKA, Vol. 41, No. 1,117-136, 2009. phenotypic and genotypic tests. Identification of strains was done by the repetitive extragenic palindromic-polymerase chain reaction (rep-PCR) with (GTG)5 primer and 16S rDNA sequence analysis. The most present species in Zlatar BGNV cheese were Lactobacillus casei/paracasei (65.43%) and Enterococcus faecalis (29.63%). Two facultative heterofermentative rods were identified as Lactobacillus plantarum (2.47%), and two obligate hetrofermentative LAB isolates as

The present study is focused on the safety, technological characteristics, and probiotic evaluation of Enterococcus species from different artisanal raw milk dairy products, mainly cheeses with ripening. Apart from proteolytic and lipolytic activities, most enterococci show the ability to metabolize citrate and convert it to various aromatic compounds. Long-ripened cheeses therefore have a specific flavor that makes them different from cheeses produced from thermally treated milk with commercial starter cultures. In addition, enterococci are producers of bacteriocins effective against spoilage and pathogenic bacteria, so they can be used as food preservatives. However, the use of enterococci in the dairy industry should be approached with caution. Although originating from food, enterococci strains may carry various virulence factors and antibiotic-resistance genes and can have many adverse effects on human health. Still, despite their controversial status, the use of enterococci in...

Using cultivation-dependant method, we isolated 184 strains from fresh and old bee bread, pollen, larvae and adults of solitary beeOsmia cornuta. The 16S rDNA sequencing of 79 selected isolates gave the final species-specific identification of strains. Phylogenetic analysis indicated that microbiota isolated from five different sources were represented with 29 species within three different phyla, Firmicutes with 25 species, Actinobacteria with only one species and Proteobacteria with three species of Enterobacteriaceae. Bacterial biodiversity presented with Shannon–Wiener index (H′) was highest in the alimentary tract of adults and old bee bread (H′ = 2.43 andH′ = 2.53, respectively) and in the same time no dominance of any species was scored. On the contrary, results obtained for Simpson index (D) showed that in pollen samples the dominant species wasPantoea agglomerans(D= 0.42) while in fresh bee bread that wasStaphylococcussp. (D= 0.27). We assume that microbial diversity detect...

In this study two raw cow's milk cheeses of a different ripening period were examined. The cheeses were taken from a country household in the region of mountain Stara Planina and manufactured without adding of starter culture. A total 106 lactic acid bacteria (LAB) strains were isolated from both cheeses. They are tested by classical physiological tests as well as by API 50 CH tests. Proteolytic and antimicrobial activities were done too. Identification of LAB isolates was done by repetitive extragenic palindromic-polimerase chain reaction (rep-PCR) with (GTG)5 primer. The LAB isolates from cheese BGPT9 (four days old) belonged to the eight species of LAB (Lactobacillus plantarum, Lactobacillus paracasei subsp. paracasei, Lactobacillus delbrueckii, Lactobacillus brevis, Enterococcus faecium, Enterococcus faecalis, Enterococcus durans and Leuconostoc garlicum), while in the BGPT10 cheese (eight months old) only two species were present (Lactobacillus plantarum and Enterococcus fa...

The ability of lactic acid bacteria to form multi-cellular aggregates via self-aggregation is regarded as an important mechanism for stress tolerance, adhesion, colonization and genetic material exchange. The novel aggLr gene encoding for the auto-aggregation promoting protein (AggLr) of Lactococcus raffinolactis BGTRK10-1 was cloned. Heterologous expression of AggLr enabled auto-aggregation, higher hydrophobicity and collagen and fibronectin binding of the carrier strains. Domain analysis and the type of aggregates formed by cells expressing AggLr confirmed that this aggregation factor belongs to the family of high molecular weight proteins that the authors propose to be called Snow-flake Forming Collagen Binding Aggregation Factors (SFCBAF). An additional feature of SFCBAF is that they are rich in threonine and lysine and are free of cysteine in all of the aggregation factors described so far. In contrast to previously discovered SFCBAF, the gene encoding for AggLr is located on t...

Bread crumbs are obtained by grinding dried bread. Since bread crumbs can get contaminated from different sources, the aim of the work was to recognize the microbiological and sensory (colour) quality of bread crumbs, as well as the possibility of sterilization applying ionizing radiation. The minimal dosis of gamma rays, efficient for achieving of certain quality and could prolong the shelf-life of this product wad defined. The investigation results showed that the dosis amounting 5 kGy was efficient for the achieving of suitable microbiological quality of product followed by insignificant change of sensory characteristics, colour in the first place as one of the most important quality characteristics. The colour of crumbs samples was determined instrumentally as well, using the photoelectrical tristimulus colorimeter, MOM color D.

Studied lactic acid bacteria (LAB) were isolated from two types of final ready-to-eat artisanal dairy products (cheeses – Agdas, Sheki and yogurts - Karabakh, Ganja and Baku) manufactured in Azerbaijan. The Agdas cheese belongs to the group of semi hard cheeses whilst the Sheki cheese belongs to hard cheeses. Both of cheeses were produced from cow’s milk without the addition of the starter cultures. The Karabakh and Baku yogurts were produced from bovine’s milk and the Ganja yogurt from buffalo’s milk. Overall 378 isolates were collected from these dairy products and 296 of them were Gram-positive and catalase-negative. It was determined using biochemical tests and molecular methods that four species of LAB were mostly present in these cheeses: Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus paraplantarum and Enterococcus faecium while in yogurts, Lactobacillus delbrueckii subsp. lactis, Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus and Enteroc...

ABSTRACT In order to preserve the traditional manufacturing of white pickled (WPC) and fresh soft cheeses (FSC), well-characterized autochthonous lactic acid bacteria (LAB) with advantageous characteristics were applied for the production of the cheeses at small industrial scale under the controlled conditions. Selected LAB for design of defined mixed starter cultures belonged to Lactococcus lactis ZGBP5-9, Enterococcus faecium ZGPR1-54 and Lactobacillus plantarum ZGPR2-25 for FSC production and to Lc. lactis BGAL1-4, Lactobacillus brevis BGGO7-28 and Lb. plantarum BGGO7-29 for WPC production. A sensory evaluation indicated that the cheeses obtained by inoculation with selected autochthonous LAB are similar to the traditional cheese and received the best scores. Viable cell counts of LAB used for the production of both type chesses was high, over 106 cfu g-1. High viability of the surveyed strains was supported with PCR-DGGE, which confirm the retention of selected LAB strains as starter cultures in cheese production. Next, PFGE analysis showed that each single strains, selected in particular cheese mixed culture, revealed unique SmaI PFGE pattern that could enable efficient discrimination and monitoring of the strains in industrial process. As some of the selected LAB strains are attributed as potential probiotics, produced cheeses could be considered as functional food.

Traditional artisan Zlatar cheese belongs to the group of white, semi hard home-made cheeses, which are produced from no pasteurized cow's milk, without addition of any known bacterial starter culture. In total, 253 Gram-positive and catalase negative lactic acid bacteria (LAB) were isolated. Results showed that 70 out of 253 analyzed isolates produced antimicrobial compounds known as bacteriocins. Most isolates from genera Lactococcus and Enterococcus, and isolates belonging to species Lactobacillus plantarum and Lb. brevis, do not synthesize extracellular proteinase. In contrast, isolates from subspecies Lb. paracasei subsp. paracasei showed very good proteolytic activity. It was observed that good proteolytic activity of isolates was not in correlation with their good antimicrobial activity in the most of isolates.

Lactobacilli represent normal commensals of the human body, particularly in the gut and vagina where they protect these environments from incoming pathogens via a variety of mechanisms. The influence of the carbohydrate source present in reconstituted MRS growth medium on the different cell properties of two Lactobacillus rhamnosus strains were examined. Two human vaginal isolates, BGHV719 and exopolysaccharide producer strain BGHV954 were analyzed. The results demonstrated that unlike in reconstituted MRS with glucose as a carbon source, the presence of fructose, mannose, or rhamnose, significantly reduced cell surface hydrophobicity of both strains. In addition, differences in cell wall protein composition of L. rhamnosus BGHV719 and alterations in colony mucoidity of L. rhamnosus BGHV954 were also demonstrated. Light and SEM microscopy revealed differences on the cellular level when BGHV719 was cultivated in the presence of different sugars. The results of this study point out th...

The strain Lactobacillus paracasei subsp. paracasei BGUB9 that was isolated from traditionally homemade hard cheese produces bacteriocin designated as BacUB9, with an approximate molecular mass of 4 kDa. Biochemical characterization and the antimicrobial activity test of BacUB9 were performed. The onset of BacUB9 biosynthesis was observed at the end of an exponential phase of growth. Bacteriocin UB9 retained the antimicrobial activity within the pH range from 1 to 10 and after treatment at 100oC for 30 min. The bacteriocin is susceptible to the activity of proteolytic enzymes. Bacteriocin BacUB9 has a very narrow antimicrobial spectrum, limited to several strains that belong to closely related species. The effect of BGUB9 on the growth of the strain Lactobacillus paracasei subsp. paracasei BGHN14 in a mixed culture was monitored. The mode of action of BacUB9 on the strain BGHN14 was identified as bacteriostatic. Plasmid curing results indicated that a plasmid, designated as pUB9, se...

The aim of the study was to establish a protocol to evaluate the presence of Listeria spp. in food processing environments. The presence of Listeria spp. was evaluated in a selected restaurant in Serbia on three occasions. Samples were collected from 47 sampling spots in the commercial kitchen equipment and environment. The presence of Listeria spp. and Listeria monocytogenes were detected by conventional culture methods and by the PCR method. The obtained results showed that 23 swab samples were positive for Listeria spp. Interestingly, the swabs from the bread-cutting board and meat defrosting sink were positive for L. monocytogenes.

A total of 157 lactic acid bacteria (LAB) were isolated from three hand-made cheeses taken from different households in the region of the Caucasus Mountains. The cheeses were manufactured from cow's milk without the addition of a starter culture. The isolates of LAB were characterized by subjecting them to phenotypic and genotypic tests. The results of identification of LAB indicate that the examined cheeses contained 10 species, viz., Lactobacillus plantarum, Lactobacillus paraplantarum, Lactobacillus arizonensis, Lactobacillus farciminis, Lactobacillus brevis, Lactococcus lactis subsp. lactis, Leuconostoc mesenteroides subsp. mesenteroides, Leuconostoc pseudomesenteroides, Enterococcus faecium, and Enterococcus faecalis. The strains within the species L. plantarum, L. arizonensis, L. paraplantarum, L. farciminis, and L. pseudomesenteroides showed good proteolytic activity.

The goal of this study was the characterisation of indigenous lactic acid bacteria (LAB) and yeasts isolated from nine white pickled (BG) and nine fresh soft (ZG) artisanal cheeses collected in Serbia and Croatia. While LAB were present in all of the cheeses collected, yeasts were found in all BG cheeses but only in three ZG cheese samples. High LAB and yeast species diversity was determined (average H'(L)=0.4 and H'(Y)=0.8, respectively). The predominant LAB species in white pickled (BG) cheeses were Lactococcus lactis, Lactobacillus plantarum, and Leuconostoc mesenteroides, while in fresh soft (ZG) cheeses the most dominant LAB species were L. lactis, Enterococcus faecalis, and Leuconostoc pseudomesenteroides. Among the 20 yeast species found, Debaryomyces hansenii, Candida zeylanoides, and Torulaspora delbrueckii were found to be predominant in BG cheeses, while Yarrowia lipolytica was predominant in ZG cheeses. The characterisation of metabolic and technological potentials revealed that 53.4% of LAB isolates produced antimicrobial compounds, 44.3% of LAB strains showed proteolytic activity, while most of the yeast species possessed either lipolytic or proteolytic activity. In conclusion, the results obtained in this study showed that the composition of LAB and yeast populations in white pickled and fresh soft cheeses is region specific. The knowledge gained in this study could eventually be used to select region specific LAB and yeast strains for the production of white pickled and fresh soft artisanal cheeses with geographically specific origins under controlled conditions.