Genomic diversity and antimicrobial susceptibility of invasive Neisseria meningitidis in South Africa, 2016-2021.

BACKGROUND: Invasive meningococcal isolates in South Africa have in previous years (<2008) been characterized by serogroup B, C, W and Y lineages over time, with penicillin intermediate resistance (peni) at 6%. We describe the population structure and genomic markers of peni among invasive meningococcal isolates in South Africa, 2016-2021. METHODS: Meningococcal isolates were collected through national, laboratory-based invasive meningococcal disease (IMD) surveillance. Phenotypic antimicrobial susceptibility testing and whole-genome sequencing were performed, and the mechanism of reduced penicillin susceptibility was assessed in silico. RESULTS: Of 585 IMD cases reported during the study period, culture and PCR-based capsular group was determined for 477/585 (82%); and 241/477 (51%) were sequenced. Predominant serogroups included NmB (210/477; 44%), NmW (116/477; 24%), NmY (96/477; 20%) and NmC (48/477; 10%). Predominant clonal complexes (CC) were CC41/44 in NmB (27/113; 24%), CC11 in NmW (46/56; 82%), CC167 in NmY (23/44; 53%), and CC865 in NmC (9/24; 38%). Peni was detected in 16% (42/262) of isolates, and was due to the presence of a penA mosaic, with the majority harboring penA7, penA9 or penA14. CONCLUSION: IMD lineages circulating in South Africa were consistent with those circulating prior to 2008, however peni was higher than previously reported, and occurred in a variety of lineages.

Epidemiology of invasive meningococcal disease in Greece, 2006-2016.

The present study describes the epidemiology of invasive meningococcal disease (IMD) in Greece for the period 2006-2016. Combined data from notified and laboratory-confirmed IMD cases were obtained from the two involved National Centres (Epidemiology and Reference Laboratory). Laboratory identification and typing was carried out by both conventional (culture) and molecular methods (PCR, MLST, PorA, and FetA typing). A total of 796 IMD cases were notified; of those, 720 (91%) were laboratory confirmed. Overall, a decline on the annual incidence of confirmed cases was observed, ranging from 0.91 (2006) to 0.47 (2016) /100,000. A similar trend was observed in most age groups especially in children 0-4 years (7.7 to 2.9/100,000), with the exception of an increase in the incidence rate in adults > 20 years (0.21 to 0.32/100,000). The overall case fatality rate was 6.5% (52/796), annual range 2-13%. Among 658 strains which were typed by sero/genogroup, 80% were identified as MenB (annual range 65-92%); however, a decline was observed in MenB incidence from 5.3 (2006) to 2.7 (2016), among infants and toddlers, while MenW (1%), MenY (2%), and MenA (1%) remained low. During the 11 years, the annual incidence of IMD declined by 50%, especially in the 0-4-year age group, due mainly to MenB. Continuous surveillance of IMD is important for the development of future vaccination and public health policies.

Greek functional Feta cheese: Enhancing quality and safety using a Lactobacillus plantarum strain with probiotic potential.

The aim of the study was to investigate the performance of Lactobacillus plantarum T571 with probiotic potential as a co-starter culture in Feta cheese production and in its long-term storage. For this reason, Feta cheese was manufactured without (control) or with the probiotic T571 strain (probiotic) and then monitored during storage at 4 and 12 °C, respectively. The products were also inoculated with Listeria monocytogenes (3-strain cocktail). The results showed that lactic acid bacteria exceeded 6 log CFU/g during storage in all trials. The probiotic samples displayed higher acidity (≈1.5% lactic acid) and lower pH (≈4.2). Coliforms and L. monocytogenes, were inactivated in shorter time in probiotic samples, in comparison with the control ones. Pulsed field gel electrophoresis verified the presence of the probiotic strain in the cheese, until the end of storage at both temperatures, whilst the survival and distribution of the pathogenic strains depended on the trial. The sensory evaluation showed that the probiotic cheeses had desirable sensory characteristics similar to the control ones, with scores of ca. 8 on a 10 cm-scale. Finally, Fourier transform infrared spectroscopy was applied for the first time during Feta cheese storage with promising results for the rapid estimation of the microbiological counts and sensory status of cheese. Results showed that Lb. plantarum T571 highlighted desirable and robust technological properties and may be used in cheese making as an adjunct culture.

Para-κ-casein during the ripening and storage of low-pH, high-moisture Feta cheese.

The hypothesis of this research paper was that the physicochemical conditions in a low-pH, high-moisture white brined cheese such as Feta would make para-κ-casein vulnerable to residual chymosin activity during ripening and storage. It was important to address this hypothesis, since cheese para-κ-casein could theoretically be used for the assessment of the origin of cheese milk by means of various analytical methods. Feta cheese was manufactured from sheep milk and from four different mixtures of sheep and goat milk in triplicate. The para-κ-casein of Feta samples taken during 120 d of ripening and storage was estimated by means of cation-exchange HPLC and proteolysis was determined in terms of free amino groups. Despite their similarity, sheep and goat para-κ-casein were efficiently separated and the changes of their chromatographic areas indicated that hydrolysis took place during the first stage of ripening. In accordance to the evolution of free amino groups, para-κ-caseins remained stable thereafter. The hydrolysis pattern was not affected by the composition of the cheese milk mixture and after 120 d at least two thirds of the initial quantity remained intact. Considering the efficient separation of sheep and goat para-κ-caseins and their stability during Feta storage, the same method was used for the evaluation of the percentage of goat milk in the cheese milk. The actual and the estimated percentage of goat milk within the range 0-40 were strongly correlated (R = 0·997, n = 60) and the standard error of estimation was 0·914.

Comparative study of the paracasein fraction of two ewe's milk cheese varieties.

The aim of the present work was to assess the characteristics of the paracasein of two ewe's milk cheese varieties using various concentrations of urea and EDTA to solubilise caseins and calcium. The solubilised paracasein elements were evaluated by means of RP-HPLC and AAS. For this purpose cheeses with different physical and biochemical characteristics, i.e. Feta (53.1% moisture and pH 4.32) and Graviera Kritis (33.2% moisture and pH 5.54) were analysed. Soluble calcium of Feta was 71% of total calcium much higher than the 25% in Graviera. Treatment with 4 m urea fully solubilised Feta paracasein, whereas 6 m urea was needed to solubilise caseins from Graviera. Caseins were released from both cheeses by 100 mm EDTA. Solubilisation of paracasein induced by urea or EDTA was not significantly affected (P < 0.05) by the type of cheese. Similarly to urea, EDTA induced significantly (P < 0.05) lower solubilisation of αs1-casein in Graviera than in Feta, based on αs1-cn/ß-cn ratio. A great part of calcium in both cheeses was solubilised by 50 mm EDTA while the release of casein was poor, confirming the important role of types of interactions other than protein-calcium bonds in the paracasein network. Hydrophobic interactions, hydrogen bonds and electrostatic attractions, contributed substantially to the paracasein stability of both cheese types. The interactions of αs1-casein with calcium played a more significant role in Graviera cheese than in Feta. Finally, the present study demonstrated that the profile of bonds and interactions within the cheese paracasein network was dynamicly configured by the conditions of cheese manufacture.

Optimization of UF-Feta cheese preparation, enriched by peppermint extract.

Strong antioxidant activity, antimicrobial, antiviral, antitumor, and some antiallergenic potential actions have been reported in peppermint. For daily acceptance of the benefits of this plant, UF-Feta cheese, enriched by whole peppermint extract, was prepared with different levels of Peppermint Extract (PE) (220-660 µg/g cheese), starter (1.3-2.7 g/100 Kg retentate), rennet (1.3-2.5 g/100 Kg retentate), and Ripening Time (RT) (10-50 days). Simultaneous effects of the considered variables were also investigated on Water-soluble Phenolic Content (WSPC), Antioxidant Activity (AOA), and Sensory Score (SS) by means of Response surface methodology. The results showed that although rennet concentration had a little positive effect on WSPC, its effect on AOA was significantly negative. It was determined that PE had a crucial role in acceptance of cheese samples and showed a negative effect on SS. More maturation of produced cheese samples effectively increased AOA. It was found that for producing cheese with maximum SS and AOA, the optimum values of variables should be applied as follows: PE, 227 µg/g cheese; starter, 2.7 g/100 Kg retentate; rennet, 1.3 g/100 Kg retentate; RT, 41.7 days.

Incorporation of Lactobacillus adjuncts culture to improve the quality of Feta-type cheese made using buffalo milk.

Feta-type cheese was made from buffalo milk using commercial adjunct culture of Lactobacillus helveticus and Lactobacillus casei along with standard mesophillic cheese cultures. The sensory, biochemical and texture characteristics of the experimental cheeses were studied during ripening. Expert panellists observed, significant differences (P < 0.01) between the control and the experimental cheeses. The pH, titratable acidity, soluble protein and free fatty acid content of the experimental cheeses were found to be significantly (P < 0.01) higher than those of the control. The texture parameter values of the experimental cheeses were found to be significantly (P < 0.01) lower than values of the control.

Short communication: determination of lactoferrin in Feta cheese whey with reversed-phase high-performance liquid chromatography.

In the current paper, a method is introduced to determine lactoferrin in sweet whey using reversed-phase HPLC without any pretreatment of the samples or use of a separation technique. As a starting point, the most common HPLC protocols for acid whey, which included pretreatment of the whey along with a sodium dodecyl sulfate-PAGE step, were tested. By skipping the pretreatment and the separation steps while altering the gradient profile, different chromatographs were obtained that proved to be equally efficient to determine lactoferrin. For this novel 1-step reversed-phase HPLC method, repeatability was very high over a wide range of concentrations (1.88% intraday to 5.89% interday). The limit of detection was 35.46µg/mL [signal:noise ratio (S/N)=3], whereas the limit of quantification was 50.86µg/mL (S/N=10). Omitting the pretreatment step caused a degradation of the column's lifetime (to approximately 2,000 samples). As a result, the lactoferrin elution time changed, but neither the accuracy nor the separation ability of the method was significantly influenced. We observed that this degradation could be easily avoided or detained by centrifuging the samples to remove fat or by extensive cleaning of the column after every 5 samples.

Free and immobilized Lactobacillus casei ATCC 393 on whey protein as starter cultures for probiotic Feta-type cheese production.

The use of free and immobilized Lactobacillus casei ATCC 393 on whey protein as starter culture in probiotic Feta-type cheese production was evaluated. The probiotic cultures resulted in significantly higher acidity; lower pH; reduced counts of coliforms, enterobacteria, and staphylococci; and improved quality characteristics compared with cheese with no culture. Microbiological and strain-specific multiplex PCR analysis showed that both free and immobilized L. casei ATCC 393 were detected in the novel products at levels required for conferring a probiotic effect at the end of the ripening. The effect of starter culture on production of volatile compounds was investigated by the solid-phase microextraction gas chromatography-mass spectrometry analysis technique. The immobilized cells resulted in an improved profile of aroma-related compounds and the overall high quality of the novel products was ascertained by the preliminary sensory test. Finally, the high added value produced by exploitation of whey, which is an extremely polluting industrial waste, was highlighted and assessed.

Effect of rate of addition of starter culture on textural characteristics of buffalo milk Feta type cheese during ripening.

The effect of rate of addition of starter culture on textural characteristics of buffalo milk Feta type cheese was investigated during ripening period up to two months. The textural characteristics of buffalo milk Feta type cheese in terms of hardness, cohesiveness, springiness, gumminess and chewiness were analyzed by using textural profile analyzer. The maximum hardness was found with cheese made using 1% culture, while the minimum was found with 2% culture. The cohesiveness and springiness decreased as the level of addition of starter culture increased. The chewiness of cheese also decreased, as the rate of addition of starter culture increased for cheese making. In addition to this, yield, moisture, fat, FDM, protein, salt and S/M of fresh buffalo milk Feta type cheese increased with the increase in rate of addition of starter culture; however, TS of experimental cheeses decreased.

Application of multi-functional lactic acid bacteria strains in a pilot scale feta cheese production.

Feta cheese is the most recognized Greek Protected Designation of Origin (PDO) product in the world. The addition of selected autochthonous lactic acid bacteria (LAB) strains to cheese milk as adjunct cultures is gaining more attention, since they can impact the nutritional, technological and sensory properties of cheeses, as well as improve the safety of the product. The aim of this study was to produce Feta cheese with enhanced quality and safety, and distinctive organoleptic characteristics by applying autochthonous lactic acid bacteria (LAB) with multi-functional properties as adjunct cultures. Feta cheeses were produced with the commercial lactococcal starter culture and the addition of 9 LAB strains (Lactococcus lactis SMX2 and SMX16, Levilactobacillus brevis SRX20, Lacticaseibacillus paracasei SRX10, Lactiplantibacillus plantarum FRX20 and FB1, Leuconostoc mesenteroides FMX3, FMX11, and FRX4, isolated from artisanal Greek cheeses) in different combinations to produce 13 cheese trials (12 Feta trials with the adjunct LAB isolates and the control trial). In addition, Feta cheese manufactured with FMX3 and SMX2 and control Feta cheese were artificially inoculated (4 log CFU/g) with Listeria monocytogenes (a cocktail of 4 acid or non-acid adapted strains). Cheese samples were monitored by microbiological and physicochemical analyses during ripening, and microbiological, physicochemical, molecular and sensory analyses during storage at 4°C. The results showed that after manufacture, the LAB population was ca. 9.0 log CFU/g at all samples, whereas during storage, their population declined to 6.5-7.0 log CFU/g. In the Listeria inoculated samples, Listeria was absent after 60 days (end of ripening) and after 90 days in the adjunct culture, and in the control trials, respectively. Moreover, the addition of selected strains, especially Lcb. paracasei SRX10, led to cheeses with desirable and distinctive organoleptic characteristics. Furthermore, randomly amplified polymorphic PCR (RAPD-PCR) molecular analysis confirmed that the multi-functional LAB strains were viable by the end of storage. Overall, the results of this study are promising for the use of autochthonous strains in various combinations with the commercial starter culture to satisfy industry requirements and consumer demands for traditional and high added value fermented products.

Evaluation of a New Bulk Packaging Container for the Ripening of Feta Cheese.

In the present study, the quality characteristics of Feta cheese were investigated as a function of the packaging container (a stainless-steel tank (SST), a wooden barrel (WB), and a tin can (TC)) and ripening time. The results showed that the Feta cheese's pH, moisture, and lactose decreased, while fat, protein, and salt increased (p < 0.05) during ripening with SST and WB, showing similar behaviors versus that of the TC container. For the proteolysis indices, % TN,% WSN, 12% TCA, and 5% PTA showed the highest values (p < 0.05) for cheeses packaged in WB, followed by those in SST and TC, with all increasing (p < 0.05) during ripening. The most abundant odor-active volatiles were free fatty acids, alcohols, and esters following the order SST > WB > TC on day 60. On day 60, the cheeses packaged in SST and WB showed higher (p < 0.05) hardness and fracturability values, as well as aroma scores, compared to those in TC, with both parameter values increasing with the ripening time.

The nnU-Net based method for automatic segmenting fetal brain tissues.

The magnetic resonance (MR) images of fetuses make it possible for doctors to detect out pathological fetal brains in early stages. Brain tissue segmentation is prerequisite for making brain morphology and volume analyses. nnU-Net is an automatic segmentation method based on deep learning. It can adaptively configure itself, so as to adapt to a specific task via preprocessing, network architecture, training, and post-processing. Therefore, we adapt nnU-Net to segment seven types of fetal brain tissues, including external cerebrospinal fluid, gray matter, white matter, ventricle, cerebellum, deep gray matter, and brainstem. With regard to the characteristics of the FeTA 2021 data, some adjustments are made to the original nnU-Net, so that it can segment seven types of fetal brain tissues precisely as far as possible. The average segmentation results on FeTA 2021 training data demonstrate that our advanced nnU-Net is superior to the peers including SegNet, CoTr, AC U-Net and ResUnet. Its average segmentation results are 0.842, 11.759 and 0.957 in terms of Dice, HD95 and VS criteria. Moreover, the experimental results on FeTA 2021 test data further demonstrate that our advanced nnU-Net has obtained good segmentation performance of 0.774, 14.699 and 0.875 in terms of Dice, HD95 and VS, ranked the third in FeTA 2021 challenge. Our advanced nnU-Net realized the task for segmenting the fetal brain tissues using MR images of different gestational ages, which can help doctors to make correct and seasonable diagnoses.

Microbial Ecology of Artisanal Feta and Kefalograviera Cheeses, Part I: Bacterial Community and Its Functional Characteristics with Focus on Lactic Acid Bacteria as Determined by Culture-Dependent Methods and Phenotype Microarrays.

Artisanal cheesemaking is still performed using practices and conditions derived from tradition. Feta and Kefalograviera cheeses are very popular in Greece and have met worldwide commercial success. However, there is a lack of knowledge regarding their lactic acid microecosystem composition and species dynamics during ripening. Thus, the aim of the present study was to assess the microecosystem as well as the autochthonous lactic acid microbiota during the ripening of artisanal Feta and Kefalograviera cheeses. For that purpose, raw sheep's milk intended for cheesemaking, as well as Feta and Kefalograviera cheeses during early and late ripening were analyzed, and the lactic acid microbiota was identified using the classical phenotypic approach, clustering with PCR-RAPD and identification with sequencing of the 16S-rRNA gene, as well as with the Biolog GEN III microplates. In addition, the functional properties of the bacterial community were evaluated using the Biolog EcoPlates, which consists of 31 different carbon sources. In general, concordance between the techniques used was achieved. The most frequently isolated species from raw sheep's milk were Enteroroccus faecium, Lactiplantibacillus plantarum and Pediococcus pentosaceus. The microecosystem of Feta cheese in the early ripening stage was dominated by Lp. plantarum and E. faecium, whereas, in late ripening, the microecosystem was dominated by Weissella paramesenteroides. The microecosystem of Kefalograviera cheese in the early ripening stage was dominated by Levilactobacillus brevis and E. faecium, and in late ripening by W. paramesenteroides and E. faecium. Finally, Carbohydrates was the main carbon source category that metabolized by all microbial communities, but the extent of their utilization was varied. Kefalograviera samples, especially at early ripening, demonstrated higher metabolic activity compared to Feta cheese. However, dominating species within microbial communities of the cheese samples were not significantly different.

MALDI-TOF-MS integrated workflow for food authenticity investigations: An untargeted protein-based approach for rapid detection of PDO feta cheese adulteration.

Advances in Matrix-assisted Laser Desorption/Ionization -Time-Of-Flight Mass Spectrometry (MALDI-TOF-MS) have led to its supremacy for complex assessment of food authenticity studies, like dairy products fraud, holding promise for the discovery of potential authenticity (bio)markers. In this study, an integrated untargeted protein-based workflow in combination with advanced chemometrics is presented, to address authenticity challenges in PDO feta cheese which is legally manufactured by the mixture of sheep/goat milk. Potential markers attributed to specific animal origin were found from protein profiles acquired for authentic feta and white cheeses (prepared from cow milk), belonging to 4 kDa-18.5 kDa mass area. Rapid detection of feta cheese adulteration from cow milk was also achieved down to 1% adulteration level. The discriminative models showed high predictive ability for feta cheese authenticity (Q2 = 0.920, RMSEE = 0.053) and its adulteration (Q2 = 0.835, RMSEE = 0.121), introducing a reliable approach in routine analysis. The methodology was successfully applied in detection of cow milk in sheep yoghurt.

Effect of Free or Immobilized Lactiplantibacillus plantarum T571 on Feta-Type Cheese Microbiome.

BACKGROUND: Cheese microbiome plays a key role in determining the organoleptic and physico-chemical properties and may be also used as an authenticity tool for distinguishing probiotic cultures. Due to significant reduction of cell viability often witnessed during food production processes and storage, immobilization is proposed to ascertain high probiotic cell loads required to confer the potential health benefits. Hence, the aim of the present study was to investigate the effect of free or immobilized Lactiplantibacillus plantarum T571 on whey protein on feta cheese microbiome. METHODS: Next-Generation Sequencing technology was used to investigate cheese microbiome. Cheese samples containing free or immobilized Lactiplantibacillus plantarum T571 (a wild type strain isolated from Feta cheese brine) on whey protein, along with products containing commercial starter culture, were analyzed. RESULTS: The results showed a great diversity of bacteria and fungi genera among the samples. An increased presence of Lactobacillus OTUs in cheese with immobilized cells on whey protein was witnessed, highlighting the survival of the strain in the final product. The immobilized culture had also a significant impact on other genera, such as Lactococcus, Leuconostoc and Debaryomyces, which are associated with improved technological characteristics and health benefits. CONCLUSIONS: Enrichment of feta cheese with immobilized potential probiotics to secure cell viability consists of an industrial challenge and leads to distinct microbiome composition that may be used as a valuable food authenticity tool.

Comparison of the Microbiome of Artisanal Homemade and Industrial Feta Cheese through Amplicon Sequencing and Shotgun Metagenomics.

Feta is the most renowned protected designation of origin (PDO) white brined cheese produced in Greece. The fine organoleptic characteristics and the quality of Feta rely on, among other factors, its overall microbial ecosystem. In this study, we employed 16S rDNA and internal transcribed spacer (ITS) amplicon sequencing, as well as shotgun metagenomics, to investigate the microbiome of artisanal homemade and industrial Feta cheese samples from different regions of Greece, which has very rarely been investigated. 16S rDNA data suggested the prevalence of the Lactococcus genus in the homemade samples, while Streptococcus and Lactobacillus genera prevailed in the industrial control samples. Species identification deriving from shotgun metagenomics corroborated these findings, as Lactococcus lactis dominated two homemade samples while Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus were found to be dominating one industrial sample. ITS data revealed a complex diversity of the yeast population among the samples analyzed. Debaryomyces, Kluyveromyces, Cutaneotrichosporon, Pichia, Candida, and Rhodotorula were the major genera identified, which were distributed in a rather arbitrary manner among the different samples. Furthermore, a number of potential metagenome-assembled genomes (MAGs) could be detected among assembled shotgun bins. The overall analysis of the shotgun metagenomics supported the presence of different foodborne pathogens in homemade samples (e.g., Staphylococcus aureus, Listeria monocytogenes, Enterobacter cloacae, and Streptococcus suis), but with low to very low abundances. Concluding, the combination of both amplicon sequencing and shotgun metagenomics allowed us to obtain an in-depth profile of the artisanal homemade Feta cheese microbiome.

Antimicrobial activity of essential oils against vancomycin-resistant enterococci (vre) and Escherichia coli o157:h7 in feta soft cheese and minced beef meat.

Eleven essential oils (EOs) were evaluated for their antibacterial properties, against Vancomycin-Resistant Enterococci (VRE) and E. coli O157:H7. EOs were introduced into Brain Heart Infusion agar (BHI) (15ml) at a concentration of 0.25 to 2% (vol/vol) to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for each pathogen evaluated. Results showed that the most active essential oils against bacteria tested were thyme oil, with MIC90 and MBC90 for the VRA strains of 0.25% and 0.5%, respectively. Eucalyptus, juniper and clove oils were the least potent agent, with MIC90 and MBC90 of 2%. Furthermore, the inhibitory effect of these EO were evaluated against VRE and E. coli O157:H7, experimentally inoculated (10(3) cfu/g) in Feta soft cheese and minced beef meat, which was mixed with different concentrations (0.1%, 0.5% and 1%) of the EO and stored at 7 °C for 14 days. Out of eucalyptus, juniper, mint, rosemary, sage, clove and thyme oils tested against target bacteria sage and thyme showed the best results. Clove and mint did not show any effect on VRE and E. coli O157:H7 in both kinds of studied foods. The addition of thyme oil at concentrations of 0.5 and 1% caused best significant reduction in the growth rate of VRE and E. coli O157:H7 in cheese and meat at 7 (o)C. It is concluded that selected plant EOs can act as potent inhibitors of both microorganisms in a food product. The results revealed the potential of thyme oil as a natural preservative in feta soft cheese and minced beef meat against VRE and E. coli O157:H7 contamination.

Characterization of Bacterial Microbiota of P.D.O. Feta Cheese by 16S Metagenomic Analysis.

BACKGROUND: The identification of bacterial species in fermented PDO (protected designation of origin) cheese is important since they contribute significantly to the final organoleptic properties, the ripening process, the shelf life, the safety and the overall quality of cheese. METHODS: Ten commercial PDO feta cheeses from two geographic regions of Greece, Epirus and Thessaly, were analyzed by 16S metagenomic analysis. RESULTS: The biodiversity of all the tested feta cheese samples consisted of five phyla, 17 families, 38 genera and 59 bacterial species. The dominant phylum identified was Firmicutes (49% of the species), followed by Proteobacteria (39% of the species), Bacteroidetes (7% of the species), Actinobacteria (4% of the species) and Tenericutes (1% of the species). Streptococcaceae and Lactobacillaceae were the most abundant families, in which starter cultures of lactic acid bacteria (LAB) belonged, but also 21 nonstarter lactic acid bacteria (NSLAB) were identified. Both geographical areas showed a distinctive microbiota fingerprint, which was ultimately overlapped by the application of starter cultures. In the rare biosphere of the feta cheese, Zobellella taiwanensis and Vibrio diazotrophicus, two Gram-negative bacteria which were not previously reported in dairy samples, were identified. CONCLUSIONS: The application of high-throughput DNA sequencing may provide a detailed microbial profile of commercial feta cheese produced with pasteurized milk.

Enhancement of low-fat Feta cheese characteristics using probiotic bacteria.

The objective of this study was to manufacture low-fat Feta cheese (LFC) using different types of starter cultures, such as yogurt (Y) cultures (Streptococcus thermophilus and Lactobacillus bulgaricus), bifidobacterium (B) cultures (Bifidobacterium bifidum and Bifidobacterium longum), and mixed of them (Y + B) at different rates (0.4, 0.5, and 0.6%). The Y + B cultures improved the flavor and body and texture of LFC, especially at a ratio of 0.4 + 0.6% and 0.5 + 0.5%, which is similar to the typical full-fat Feta cheese. Also, the LFC maintained a higher number of probiotics and lactic acid bacteria after 30 d of storage at a range of 5 to 7 log cfu/g.