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Staka is a traditional Greek sour cream made mostly from spontaneously fermented sheep milk or a mixture of sheep and goat milk. At the industrial scale, cream separators and starter cultures may also be used. Staka is sometimes cooked with flour to absorb most of the fat. In this study, we employed culture-based techniques, amplicon sequencing, and shotgun metagenomics to analyze the Staka microbiome for the first time. The samples were dominated by Lactococcus or Leuconostoc spp. Most other bacteria were lactic acid bacteria (LAB) from the Streptococcus and Enterococcus genera or Gram-negative bacteria from the Buttiauxella, Pseudomonas, Enterobacter, Escherichia-Shigella, and Hafnia genera. Debaryomyces, Kluyveromyces, or Alternaria were the most prevalent genera in the samples, followed by other yeasts and molds like Saccharomyces, Penicillium, Aspergillus, Stemphylium, Coniospotium, or Cladosporium spp. Shotgun metagenomics allowed the species-level identification of Lactococcus lactis, Lactococcus raffinolactis, Streptococcus thermophilus, Streptococcus gallolyticus, Escherichia coli, Hafnia alvei, Streptococcus parauberis, and Enterococcus durans. Binning of assembled shotgun reads followed by recruitment plot analysis of single reads could determine near-complete metagenome assembled genomes (MAGs). Culture-dependent and culture-independent analyses were in overall agreement with some distinct differences. For example, lactococci could not be isolated, presumably because they had entered a viable but not culturable (VBNC) state or because they were dead. Finally, several LAB, Hafnia paralvei, and Pseudomonas spp. isolates exhibited antimicrobial activities against oral or other pathogenic streptococci, and certain spoilage and pathogenic bacteria establishing their potential role in food bio-protection or new biomedical applications. Our study may pave the way for additional studies concerning artisanal sour creams to better understand the factors affecting their production and the quality. [ABSTRACT FROM AUTHOR]

EN Goat milk yogurt (GMY) and raisins are popular foods with a favourable nutrient profile. Our aim was to determine the glycaemic index (GI) and postprandial responses to GMY-containing angiotensin-converting enzyme inhibitory (ACE-I) peptides carrying the RPKHPINHQ isracidin fragment and two Greek raisin varieties in an acute feeding setting. A total of twelve healthy participants (four male and eight female) consumed breakfast study foods containing 25 g available carbohydrate on seven occasions over a 3- to 9-week period: food 1: D-glucose (25 g) served as the control and was consumed on three separate occasions; food 2: GMY (617·28 g); food 3: Corinthian raisins (37·76 g); food 4: Sultana raisins (37·48 g) and food 5: GMY & C (308·64 g GMY and 18·88 g C). Postprandial glucose was measured over a 2 h period for the determination of GI and glycaemic load (GL). Subjective appetite ratings (hunger, fullness and desire to eat) were assessed by visual analogue scales (100 mm) at 0–120 min. Blood pressure (systolic and diastolic; BP) was measured at baseline and 120 min. GMY provided low GI (26), C and S provided high GI/low GL (75/10 and 70/9, respectively) and GMYC provided low GI (47) values on glucose scale compared with D-glucose. Peak blood glucose rise was significantly lower only for GMY and GMYC compared with reference food (D-Glucose), as well as C and S (P for all < 0·05). No differences were observed between test foods for fasting glucose, BP and subjective appetite. In conclusion, GMY and GMYC attenuated postprandial glycaemic responses, which may offer advantages to glycaemic control. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Increasing knowledge of the microbiome has led to significant advancements in the agrifood system. Case studies based on microbiome applications have been reported worldwide and, in this review, we have selected 14 success stories that showcase the importance of microbiome research in advancing the agrifood system. The selected case studies describe products, methodologies, applications, tools, and processes that created an economic and societal impact. Additionally, they cover a broad range of fields within the agrifood chain: the management of diseases and putative pathogens; the use of microorganism as soil fertilizers and plant strengtheners; the investigation of the microbial dynamics occurring during food fermentation; the presence of microorganisms and/or genes associated with hazards for animal and human health (e.g., mycotoxins, spoilage agents, or pathogens) in feeds, foods, and their processing environments; applications to improve HACCP systems; and the identification of novel probiotics and prebiotics to improve the animal gut microbiome or to prevent chronic non-communicable diseases in humans (e.g., obesity complications). The microbiomes of soil, plants, and animals are pivotal for ensuring human and environmental health and this review highlights the impact that microbiome applications have with this regard. [ABSTRACT FROM AUTHOR]

Kefir is a high nutritional fermented dairy beverage associated with a wide range of health benefits. It constitutes a unique symbiotic association, comprising mainly lactic acid bacteria, yeasts, and occasionally acetic acid bacteria, which is strongly influenced by the geographical origin of the grains, the type of milk used, and the manufacture technology applied. Until recently, kefir microbiota has been almost exclusively studied by culture-dependent techniques. However, high-throughput sequencing, alongside omics approaches, has revolutionized the study of food microbial communities. In the present study, the bacterial, and yeast/fungal microbiota of four home-made samples (both grains and drinks), deriving from well spread geographical regions of Greece, and four industrial beverages, was elucidated by culture-dependent and -independent analyses. In all samples, classical microbiological analysis revealed varying populations of LAB and yeasts, ranging from 5.32 to 9.60 log CFU mL–1 or g–1, and 2.49 to 7.80 log CFU mL–1 or g–1, respectively, while in two industrial samples no yeasts were detected. Listeria monocytogenes , Salmonella spp. and Staphylococcus spp. were absent from all the samples analyzed, whereas Enterobacteriaceae were detected in one of them. From a total of 123 isolates, including 91 bacteria and 32 yeasts, Lentilactobacillus kefiri , Leuconostoc mesenteroides , and Lactococcus lactis as well as Kluvyeromyces marxianus and Saccharomyces cerevisiae were the mostly identified bacterial and yeast species, respectively, in the home-made samples. On the contrary, Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus , and Lacticaseibacillus rhamnosus along with Debaryomyces hansenii and K. marxianus were the main bacterial and yeast species, respectively, isolated from the industrial beverages. In agreement with the identification results obtained from the culture-dependent approaches, amplicon-based metagenomics analysis revealed that the most abundant bacterial genera in almost all home-made samples (both grains and drinks) were Lactobacillus and Lactococcus , while Saccharomyces, Kazachstania , and Kluvyeromyces were the predominant yeasts/fungi. On the other hand, Streptococcus, Lactobacillus , and Lactococcus as well as Kluvyeromyces and Debaryomyces dominated the bacterial and yeast/fungal microbiota, respectively, in the industrial beverages. This is the first report on the microbiota of kefir produced in Greece by a holistic approach combining classical microbiological, molecular, and amplicon-based metagenomics analyses. [ABSTRACT FROM AUTHOR]

The mode of the induction of the biosynthesis of macedocin, the lantibiotic produced by Streptococcus macedonicus ACA-DC 198, is studied. The chemically prepared [[alpha].sub.S1]-casein fragment 37-55 is able to induce macedocin biosynthesis and milk protein degradation fragments have displayed a bacteriocin induction activity.

A kinetic study was conducted to investigate the influence of temperature, pH, and salt concentration conditions prevailing during Kasseri cheese production on the growth of Streptococcus macedonicus ACA-DC 198, as well as on the production of macedocin. The results showed that artificial neural networks (ANNs), though less suitable for biological interpretation, outperform a more traditional model based on the gamma concept in describing the growth behavior and bacteriocin production capacity of S. mecadonicus ACA-DC 198.

Research describes the structure and antimicrobial spectrum and mechanism of action of the bacteriocin, macedocin, produced by Streptococcus macedonicus ACA-DC 198. Results indicate that macedocin inhibits a broad spectrum of lactic acid bacteria and food spoilage and pathogenic bacteria. The bacteriocin protects against clostridia in cheese production.

The technological and probiotic potential of lactic acid bacteria isolated from artisanal Greek yoghurt and fermented milks were evaluated. Fifty-three strains were identified by rep-PCR and 16S rDNA sequencing to belong to different Lactobacillus or Enterococcus spp., as well as to Streptococcus thermophilus and Lactococcus lactis . Several strains exhibited promising technological and probiotic properties. Among them, we focused on the production of bioactive peptides with angiotensin-converting enzyme inhibitory (ACE-I) activity during milk fermentation. The majority of strains produced ACE-I peptides when grown in skimmed milk. ACE-I peptides were sometimes sequestered in the original fermented milk sample, but were released and detected following high performance liquid chromatography (HPLC) purification. Mass spectrometry analysis of major peptide peaks in HPLC fractions with ACE-I activity revealed that they derived from the N- or C-terminal of the isracidin peptide region of α S1 -casein and two internal peptide fragments, one from β-casein and one from κ-casein. [ABSTRACT FROM AUTHOR]

Abstract: Maslinic and oleanolic acids are among the most abundant triterpenic acids found in olive fruits. Both acids are considered to be important bioactive compounds which can confer multiple beneficial health effects to the consumer. In the present work, we have monitored and quantified maslinic and oleanolic acids throughout processing in alkaline-treated green olives (Spanish-style) and in natural green olives of the Conservolea variety that is particularly popular in Greece. Our findings clearly demonstrate that the fast de-bittering process with NaOH treatment in Spanish-style olives has a profound negative effect on the concentration of both acids. This decrease of concentration was more prominent regarding maslinic acid when compared to oleanolic acid. In contrast, the slow de-bittering during natural fermentation of green olives had no effect on the content of maslinic or oleanolic acid. To verify the broad applicability of our observation we have also looked into the natural processing of the Kalamon variety (Greek-style). Our findings were consistent, since once again, natural fermentation did not influence the concentration of both acids. [Copyright &y& Elsevier]

In the present study we investigated the incidence of bacteriocins produced by 236 lactic acid bacteria (LAB) food isolates against pathogenic or opportunistic pathogenic oral bacteria. This set of LAB contained several strains (≥17%) producing bacteriocins active against food-related bacteria. Interestingly only Streptococcus macedonicus ACA-DC 198 was able to inhibit the growth of Streptococcus oralis, Streptococcus sanguinis and Streptococcus gordonii, while Lactobacillus fermentum ACA-DC 179 and Lactobacillus plantarun ACA-DC 269 produced bacteriocins solely against Streptococcus oralis. Thus, the percentage of strains that were found to produce bacteriocins against oral bacteria was ~1.3%. The rarity of bacteriocins active against oral LAB pathogens produced by food-related LAB was unexpected given their close phylogenetic relationship. Nevertheless, when tested in inhibition assays, the potency of the bacteriocin(s) of S. macedonicus ACA-DC 198 against the three oral streptococci was high. Fourier-transform infrared spectroscopy combined with principal component analysis revealed that exposure of the target cells to the antimicrobial compounds caused major alterations of key cellular constituents. Our findings indicate that bacteriocins produced by food-related LAB against oral LAB may be rare, but deserve further investigation since, when discovered, they can be effective antimicrobials. [ABSTRACT FROM AUTHOR]

Abstract: Streptococcus macedonicus ACA-DC 198 was found to produce a second lantibiotic named macedovicin in addition to macedocin. Macedovicin was purified to homogeneity and mass spectrometric analysis identified a peptide of approximately 3.4 kDa. Partial N-terminal sequence analysis and tandem mass spectrometry revealed that macedovicin was identical to bovicin HJ50 and thermophilin 1277 produced by Streptococcus bovis and Streptococcus thermophilus, respectively. Macedovicin inhibits a broad spectrum of lactic acid bacteria, several food spoilage species (e.g. Clostridium spp.) and oral streptococci. We determined the complete biosynthetic gene cluster of macedovicin. Even though the gene clusters of macedovicin, thermophilin 1277 and bovicin HJ50 were almost identical at the nucleotide level, there were important differences in their predicted genes and proteins. Bovicin HJ50-like lantibiotics were also found to be encoded by Streptococcus suis strains SC84 and D12, Enterococcus columbae PLCH2, Clostridium perfringens JGS1721 and several Bacillus strains. All these lantibiotics contained a number of conserved amino acids that may be important for their biosynthesis and activity, while phylogenetic analysis supported their dispersion by horizontal gene transfer. In conclusion, the production of multiple bacteriocins may enhance the bio-protective potential of S. macedonicus during food fermentation. [Copyright &y& Elsevier]

The microflora of four batches of traditional Greek Graviera cheese was studied at 5 weeks of ripening, and 200 lactic acid bacteria (LAB) isolates were phenotypically characterized and screened for antilisterial bacteriocins. The cheeses were also analyzed for organic acids by high-performance liquid chromatography and for the potential presence of 25 known LAB bacteriocin genes directly in cheese and their microbial consortia by PCR. All batches were safe according to the European Union regulatory criteria for Listeria mohocytogenes, Salmonella, enterobacteria, and coagulase-positive staphylococci. The cheese flora was dominated by nonstarter Lactobacillus caseilparacasei (67.5%) and Lactobacillus plantarum (16.3%) strains, whereas few Streptococcus thermophilus (3.8%), Lactococcus lactis subsp. lactis (0.6%), and Leuconostoc (1.9%) organisms were present. Enterococcus faecium (9.4%) and Enterococcus durans (0.6%) were isolated among the dominant LAB from two batches; however, enterococci were present in all batches at 10- to 100-fold lower populations than mesophilic lactobacilli. Sixteen E. faecium isolates produced antilisterial enterocins. In accordance, enterocin B gene was detectable in all cheeses and enterocin P gene was present in one cheese, whereas the consortia of all cheeses contained at least two of the enterocin A, B, P, 31, L50A, and L50B genes. Plantaricin A gene was also amplified from all cheeses. Mean concentrations of lactic, acetic, citric, and propionic acids in the ripened cheeses exceeded 1.5% in total, of which approximately 0.9% was lactate. Thus, organic acid contents constitute an important hurdle factor for inhibiting growth of pathogens in traditional Graviera cheese products, with LAB bacteriocins, mainly enterocins, potentially contributing to increased cheese safety. [ABSTRACT FROM AUTHOR]

Cheese is characterized by a rich and complex microbiota that plays a vital role during both production and ripening, contributing significantly to the safety, quality, and sensory characteristics of the final product. In this context, it is vital to explore the microbiota composition and understand its dynamics and evolution during cheese manufacturing and ripening. Application of high-throughput DNA sequencing technologies have facilitated the more accurate identification of the cheese microbiome, detailed study of its potential functionality, and its contribution to the development of specific organoleptic properties. These technologies include amplicon sequencing, whole-metagenome shotgun sequencing, metatranscriptomics, and, most recently, metabolomics. In recent years, however, the application of multiple meta-omics approaches along with data integration analysis, which was enabled by advanced computational and bioinformatics tools, paved the way to better comprehension of the cheese ripening process, revealing significant associations between the cheese microbiota and metabolites, as well as their impact on cheese flavor and quality. [ABSTRACT FROM AUTHOR]

Abstract: The aim of the present work was the detection and enumeration of Streptococcus macedonicus in Greek traditional cheeses. A total of 68 traditional cheese samples have been examined. Enumeration was performed by plating on the S. macedonicus differential medium Bromothymol Blue Streptococcus macedonicus (BBSM). Detection of S. macedonicus was confirmed by species-specific polymerase chain reaction (PCR), using as template either cheese DNA or DNA from colonies isolated from the BBSM medium. Counts of S. macedonicus on BBSM medium ranged from less than 1 to 6.84logcfug−1. S. macedonicus has been detected in 15 samples out of the 68 tested, corresponding to 13 out of the 20 different cheese varieties examined, originating from various geographical areas in Greece. This indicates that S. macedonicus is widespread in Greek cheeses. However, its presence could not be correlated either with the cheese variety or the cheese manufacturing procedures. [Copyright &y& Elsevier]

Streptococcus macedonicus ACA-DC 198, a food-grade isolate from naturally fermented Greek Kasseri cheese, produces a lantibiotic named macedocin that has been previously purified and characterized. In the present study, a 15 171 bp region in the S. macedonicus ACA-DC 198 chromosome, containing the biosynthetic gene cluster of macedocin, has been sequenced. This region consists of 10 ORFs, which correspond to the genes ( mcd genes) involved in macedocin biosynthesis, regulation and immunity. The mcd genes are organized in two operons and their role is predicted on the basis of similarities to genes of known lantibiotics. Compared with its closest match, the streptococcin A-FF22 gene cluster, the macedocin one contains an additional structural gene and an insertion sequence between the regulatory and the biosynthetic operons. [ABSTRACT FROM AUTHOR]

Abstract: Streptococous macedonicus ACA-DC 198 was used both as an adjunct (Cheese B) and as sole starter (Cheese C) in Kasseri cheese production. Control cheese (Cheese A) was prepared using a commercial starter culture. In all cheeses, numbers of all microbial groups examined initially increased, but declined after Baski scalding and remained practically stable up to day 90. The presence of S. macedonicus was confirmed until the end of ripening (Cheeses B and C); this was also the case for the bacteriocin produced by S. macedonicus ACA-DC 198. X-propyl-dipeptidyl-aminopeptidase activity was detected in all cheeses after day 15. The physicochemical characteristics of the mature Cheese C were in agreement with those defined by the Greek legislation. The sensory properties of all mature cheeses corresponded with the ones characterizing the traditional Kasseri cheese. It was concluded that S. macedonicus ACA-DC 198 can be used as an adjunct in Kasseri cheese production. [Copyright &y& Elsevier]

One of the main lactic acid bacterial species found in the kefir grain ecosystem worldwide is Lactobacillus kefiranofaciens, exhibiting strong auto-aggregation capacity and, therefore, being involved in the mechanism of grain formation. Its occurrence and dominance in kefir grains of various types of milk and geographical origins have been verified by culture-dependent and independent approaches using multiple growth media and regions of the 16S rRNA gene, respectively, highlighting the importance of their combination for its taxonomic identification. L. kefiranofaciens comprises two subspecies, namely kefiranofaciens and kefirgranum, but only the first one is responsible for the production of kefiran, the water-soluble polysaccharide, which is a basic component of the kefir grain and famous for its technological as well as health-promoting properties. L. kefiranofaciens, although very demanding concerning its growth conditions, can be involved in mechanisms affecting intestinal health, immunomodulation, control of blood lipid levels, hypertension, antimicrobial action, and protection against diabetes and tumors. These valuable bio-functional properties place it among the most exquisite candidates for probiotic use as a starter culture in the production of health-beneficial dairy foods, such as the kefir beverage. [ABSTRACT FROM AUTHOR]

Probiotic Feta cheese was produced using Propionibacterium freudenreichii subsp. shermanii as an adjunct since it has been shown to induce apoptosis of colon cancer cells in vitro and in vivo through the production of propionate and acetate. Microbiological and physicochemical analysis of the cheese was performed through the 60 d period of ripening. Counts of propionibacteria increased until day 7 and then remained constant until the end of ripening (approximately 9 log cfu g −1 ). Moreover, throughout ripening the presence of P. freudenreichii subsp. shermanii LMG 16424 T was confirmed by 16S rRNA gene sequence analysis, while propionic acid was first detected on day 7 and reached a concentration of 52.1 m m on day 60. The ripened cheese containing P. freudenreichii subsp. shermanii was very well accepted by the sensory evaluation panellists. This is the first time that P. freudenreichii subsp. shermanii was studied as a probiotic adjunct in a white-brined cheese. [ABSTRACT FROM AUTHOR]

Abstract: Streptococcus macedonicus ACA-DC 198, a bacteriocin producer isolated from Greek Kasseri cheese, was used in a series of in vitro and in vivo experiments in order to evaluate its pathogenic potential. The strain was examined in vitro for haemolytic activity, antibiotic resistance and presence of pathogenicity genes encountered in Streptococcus pyogenes. Subsequently, the strain was orally administered to mice (8.9 log cfu daily), continuously over a period of 12 weeks, in order to ascertain the effects of its long term consumption on animal health and gastric inflammation. S. macedonicus ACA-DC 198 was found to be non-haemolytic and sensitive to ampicillin, chloramphenicol, ciprofloxacin, erythromycin, streptomycin, tetracycline, and vancomycin, with the only resistance observed against kanamycin. PCR amplification and DNA–DNA hybridization did not reveal the presence of any of the S. pyogenes pathogenicity genes examined, namely emm, scpA, hasA, speB, smez2, speJ, sagAB, hylA, ska, speF, speG, slo, hylP2 and mga. In the mouse study, no detrimental effects were observed in the behaviour, general well being, weight gain and water consumption of the animals receiving S. macedonicus ACA-DC 198. Histologic analysis showed no evidence of inflammation in the stomach of the animals receiving S. macedonicus ACA-DC 198, while faecal microbiological analysis revealed that the strain retained its viability passing through the mouse gastrointestinal tract. Finally, no evidence of translocation to the liver, spleen and mesenteric lymph nodes was observed. In conclusion, none of the examined virulence determinants were detected in S. macedonicus ACA-DC 198 and its long term, high dosage oral administration did not appear to induce any pathogenic effect in mice. [Copyright &y& Elsevier]

Abstract: Three fermentations in skim milk were used to study the effectiveness of the bacteriocin-producing Streptococcus macedonicus ACA-DC 198 strain to inhibit Clostridium tyrobutyricum LMG 1285T spore outgrowth under conditions prevailing during Kasseri cheese production and ripening. In fermentation A, Clostridium spores were used solely; in fermentation B, S. macedonicus ACA-DC 198 and Clostridium spores were used; in fermentation C, a commercial starter culture and Clostridium spores were used. The temperature program applied was similar to that of Kasseri cheese production and ripening. The presence of macedocin, the bacteriocin produced by S. macedonicus ACA-DC 198, was confirmed in fermentation B. The results showed that macedocin was able to inhibit the outgrowth of Clostridium spores, since significantly higher inhibition in spore outgrowth was detected in fermentation B than in fermentation C. [Copyright &y& Elsevier]

Bacteriocin production by Enterococcus faecium FAIR-E 198, isolated from Greek Feta cheese, was studied in batch fermentations, under conditions simulating Feta cheese preparation. Maximum enterocin activity and growth rate was obtained in de Man–Rogosa–Sharpe (MRS) broth at 37 °C with controlled pH 6.5. The enterocin was produced throughout the growth phase of the microorganism, showing primary metabolite kinetics with a peak activity during the mid-exponential phase. The use of skimmed milk as substrate revealed low enterocin activity. When fermentations were performed in skimmed milk in the presence of rennet, CaCl2, and a mixed starter culture, no enterocin activity was observed, although the examined strain grew well under the above conditions. Finally, when E. faecium FAIR-E 198 was applied as adjunct starter in Feta cheese making, no enterocin activity was detected throughout ripening. Results obtained underline the frequently underestimated finding that in vitro production by novel bacteriocinogenic starter or co-cultures is no guarantee for in situ efficiency. It was concluded that the complex food environment thoroughly interferes with bacteriocin production levels. [Copyright &y& Elsevier]

Artisanal cheeses, in particular those prepared from raw milk, are the most commonly used ecosystems to mine microorganisms with both technological and human-health related potential. In the present study, the microbiota of two Greek artisanal cheeses, the PDO Kalathaki and the non-PDO Melichloro, was explored via classical microbiological analysis. Lactic acid bacteria isolated mainly belonged to the genus Enterococcus (66%) and to a lesser degree to Pediococcus (15%) , Leuconostoc (8%), Lactobacillus (6%) and Lactococcus (5%). From the 112 initial isolates, 32 were selected and studied for their probiotic potential, i.e. safety traits, survival under gastrointestinal tract conditions, antimicrobial activity, adhesion, angiotensin I-converting enzyme inhibitory activity and immunomodulation of human monocytes. Two isolates, namely Lactobacillus brevis ACA-DC 1705 and Leuconostoc mesenteroides ACA-DC 1738, exhibited the most promising probiotic potential due to strong angiotensin I-converting enzyme inhibitory activity and anti-inflammatory modulation of immune cells, respectively, and, thus they could be used as adjuncts in novel functional products. • First report on the microbiota diversity of the cheeses Kalathaki and Melichloro. • Evaluation of the probiotic potential of the isolated lactic acid bacteria. • A Lactobacillus brevis showed angiotensin I-converting enzyme inhibitory activity. • A Leuconostoc mesenteroides displayed anti-inflammatory modulation of immune cells. [ABSTRACT FROM AUTHOR]

Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS), a culture based alternative for microbial diversity studies, is an attractive tool to dereplicate large numbers of isolates to a smaller set of representatives for downstream characterization. In the present study, MALDI-TOF MS, combined with a database of reference spectra compiled in previous studies, was applied to identify 88 non-starter lactic acid bacteria (NSLAB) isolated from 18 samples of four different artisanal cheeses produced in the Island of Naxos, Greece, from raw sheep and goat milk without the addition of starters. Eighty-four isolates (95.5%) could be identified directly via MALDI-TOF MS. Lactobacillus brevis and Lactobacillus plantarum were the dominant species, followed by Lactococcus lactis , Leuconostoc mesenteroides Lactobacillus paracasei , Lactobacillus rhamnosus , Pediococcus pentosaceus and Enterococcus faecium. The remaining four isolates represented species present in the database; however, within-species diversity was insufficiently covered. Additionally, pheS sequencing was applied to confirm identification. • Application of MALDI-TOF MS for the identification of lactic acid bacteria • First fingerprinting of the non-starter lactic acid bacteria of artisanal cheeses produced in the Island of Naxos, Greece • PheS sequencing was performed to validate MALDI-TOF MS identication [ABSTRACT FROM AUTHOR]

The production of Greek-style natural black table olives remains an empirical process relying on spontaneous fermentation despite its economic significance. For this reason producers often resort to increased NaCl concentration of the brine to secure quality of the product. In this study we employ two lactic acid bacteria Leuconostoc mesenteroides subsp. mesenteroides Lm139 and Lactobacillus pentosus DSM 16366 as starters in separate laboratory low salinity fermentations of "Kalamon" cultivar olives, processed according to the Greek-style method. L. mesenteroides subsp. mesenteroides Lm139 was previously isolated from Kalamon olives laboratory spontaneous fermentations, while L. pentosus DSM 16366 was isolated from fermenting green olives prepared according to the Spanish-style method. Spontaneous olives fermentation was also performed as a control. Microbiological and physicochemical analyses of the brines revealed that the use of the starters had a significant effect on the olives fermentation, leading to a faster acidification due to the more efficient consumption of soluble sugars in the brines. The final pH value reached by each starter culture used indicates a successful lactic fermentation. The production of lactic acid by the starters and the concomitant drop of the pH value proved to inhibit enterobacteria in a shorter period of time compared to the spontaneous fermentation. Concluding, the use of either of the two lactic acid bacteria as starters in Greek-style Kalamon olives fermentation could lead to a more controllable fermentation at lower salinities. The resulting product could be of higher quality with extended shelf-life while being at the same time safer for the consumer.