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In food, bacteria carrying antibiotic resistance genes could play a prominent role in the spread of resistance. Staphylococcus equorum populations can become large in a number of fermented foods, yet the antibiotic resistance properties of this species have been little studied. In this work, the resistance/susceptibility (R/S) profile of S. equorum strains (n = 30) from cheese to 16 antibiotics was determined by broth microdilution. The minimum inhibitory concentration (MIC) for all antibiotics was low in most strains, although higher MICs compatible with acquired genes were also noted. Genome analysis of 13 strains showed the S. equorum resistome to be composed of intrinsic mechanisms, acquired mutations, and acquired genes. As such, a plasmidic cat gene providing resistance to chloramphenicol was found in one strain; this was able to provide resistance to Staphylococcus aureus after electroporation. An msr(A) polymorphic gene was identified in five strains. The Mrs(A) variants were associated with variable resistance to erythromycin. However, the genetic data did not always correlate with the phenotype. As such, all strains harbored a polymorphic fosB/fosD gene, although only one acquired copy was associated with strong resistance to fosfomycin. Similarly, a plasmid-associated blaR1-blaZI operon encoding a penicillinase system was identified in five ampicillin- and penicillin G-susceptible strains. Identified genes not associated with phenotypic resistance further included mph(C) in two strains and norA in all strains. The antibiotic R/S status and gene content of S. equorum strains intended to be employed in food systems should be carefully determined. [ABSTRACT FROM AUTHOR]

Cocoa fermentation is a central step in chocolate manufacturing. In this research, we performed controlled fermentations of a fine cocoa variety to evaluate the impact of adjunct cultures of selected lactic acid bacteria (LAB) on fermentation parameters, chemical composition, and sensory profile of fine cocoa and chocolate. Improved fermentation processes were carried out at the Centre for the Integral Transformation of Cacao (CETICO) in Dominican Republic. Two strains of LAB, previously isolated from cocoa, and belonging to Lactiplantibacillus fabifermentans and Furfurilactibacillus rossiae species, were employed. Fermentation parameters, protein, peptide and free amino acid profiles of the fermented cocoa and volatile molecules were determined. Sensory analysis of the derived chocolate was also carried out. The obtained results indicated that the addition of the adjunct cultures influences the proteolytic processes and the free amino acid profile. Finally, the adjunct cultures increased the complexity of the flavour profile of the chocolate as they received a higher score for descriptors commonly used for fine chocolate, such as honey and red fruits. The results obtained showed that the selected strains can be an added value to the development of specific flavours that are desirable at industrial level. [ABSTRACT FROM AUTHOR]

This work describes the phenotypic typing and complete genome analysis of LL441, a dairy Lactiplantibacillus plantarum strain. LL441 utilized a large range of carbohydrates and showed strong activity of some carbohydrate-degrading enzymes. The strain grew slowly in milk and produced acids and ketones along with other volatile compounds. The genome of LL441 included eight circular molecules, the bacterial chromosome, and seven plasmids (pLL441-1 through pLL441-7), ranging in size from 8.7 to 53.3 kbp. Genome analysis revealed vast arrays of genes involved in carbohydrate utilization and flavor formation in milk, as well as genes providing acid and bile resistance. No genes coding for virulence traits or pathogenicity factors were detected. Chromosome and plasmids were packed with insertion sequence (IS) elements. Plasmids were also abundant in genes encoding heavy metal resistance traits and plasmid maintenance functions. Technologically relevant phenotypes linked to plasmids, such as the production of plantaricin C (pLL441-1), lactose utilization (pLL441-2), and bacteriophage resistance (pLL441-4), were also identified. The absence of acquired antibiotic resistance and of phenotypes and genes of concern suggests L. plantarum LL441 be safe. The strain might therefore have a use as a starter or starter component in dairy and other food fermentations or as a probiotic. [ABSTRACT FROM AUTHOR]

[Display omitted] • High antioxidant activity was observed in lacto-fermented garlic. • Volatilome analysis showed the dominance of sulfur compounds and alcohols. • Lacticaseibacillus, Levilactobacillus, Lactiplantibacillus were the major taxa. • Good acidification performance was observed for the lactic acid bacteria isolates. • In-vitro exopolysaccharides production was observed for a few isolates. The aim of the present study was to provide a first characterization of lacto-fermented garlic manufactured by local small-scale artisanal producers in the Lower Silesia Region (Poland). The lacto-fermented garlic samples showed high nutritional features in terms of antioxidant activity. A total of 86 compounds, belonging to various chemical classes, were identified by headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC/MS). Most of these compounds belonged to six main classes, being sulfur compounds, esters and acetates, oxygenated monoterpenes, monoterpene hydrocarbons, and alcohols. Aldehydes, acids, ketones, furans, and phenols were also identified. In the analyzed samples, counts up to 8 log cfu g−1 were observed for lactic acid bacteria. Metataxonomic analysis revealed the presence of Levilactobacillus , Lactiplantibacillus , Latilactobacillus , Secundilactobacillus , Weissella , Leuconostoc , Lactococcus , Pediococcus , and Lacticaseibacillus among the major taxa. These results were confirmed by the isolation and characterization of viable lactic acid bacteria. Indeed, the presence of the closest relatives to Lacticaseibacillus casei group, Pediococcus parvulus , Levilactobacillus brevis , Levilactobacillus parabrevis , and Lactiplantibacillus plantarum group was observed. A good acidification performance in salty garlic-based medium was observed for all the isolates that, between 8 and 15 days of fermentation, reached pH values comprised between 4 and 3.5, depending on the tested species. Of note, 15 out of the 37 lactic acid bacteria isolates (Levilactobacillus parabrevis , Pediococcus parvulus , Lactiplantibacillus plantarum group, and Lacticaseibacillus casei group) showed the presence of the hdcA gene of Gram-positive bacteria encoding for histidine decarboxylase. Furthermore, for 8 out of the 37 isolates the in-vitro exopolysaccharides production was observed. No isolate showed inhibitory activity against the three Listeria innocua strains used as surrogate for Listeria monocytogenes. [ABSTRACT FROM AUTHOR]

The objective of the present study was to improve the quality of the Egyptian hard cheese (Ras type) by adding some Lactobacillus spp. as probiotic adjunct cultures. Strains of Lb. acidophilus, Lb. helveticus and Lb. casei were used and the chemical, microbiological and sensory characteristics of the cheese during 90 days of ripening were evaluated. The obtained data indicated that pH values and moisture content were decreased, while the total nitrogen (TN), fat, fat/dry matter, titratable acidity and salt contents were increased significantly during the ripening period in all treatments. For the ripening indices, significantly higher content of soluble nitrogen (SN), SN/TN, soluble tyrosine, soluble tryptophan and total volatile fatty acids were found in the experimental cheese compared to the Control cheese. Higher Lactobacilli count were observed in the adjunct treated cheeses, which reflects the positive retention of Lactobacilli in the experimental cheeses. Also, the use of probiotic adjunct cultures reduced the growth of fungi and prevented the coliform bacteria on Ras cheese. There was higher acceptability for the experimental cheeses than for the Control. Ras cheese was considered a good carrier for Lactobacillus probiotic strains since they were found to survive during cheese manufacture, ripening and storage. [ABSTRACT FROM AUTHOR]

Cocoa fermentation is a central step in chocolate manufacturing. In this research, we performed controlled fermentations of a fine cocoa variety to evaluate the impact of adjunct cultures of selected lactic acid bacteria (LAB) on fermentation parameters, chemical composition, and sensory profile of fine cocoa and chocolate. Improved fermentation processes were carried out at the Centre for the Integral Transformation of Cacao (CETICO) in Dominican Republic. Two strains of LAB, previously isolated from cocoa, and belonging to Lactiplantibacillus fabifermentans and Furfurilactibacillus rossiae species, were employed. Fermentation parameters, protein, peptide and free amino acid profiles of the fermented cocoa and volatile molecules were determined. Sensory analysis of the derived chocolate was also carried out. The obtained results indicated that the addition of the adjunct cultures influences the proteolytic processes and the free amino acid profile. Finally, the adjunct cultures increased the complexity of the flavour profile of the chocolate as they received a higher score for descriptors commonly used for fine chocolate, such as honey and red fruits. The results obtained showed that the selected strains can be an added value to the development of specific flavours that are desirable at industrial level.

The objective of this study was to investigate probiotic, antimicrobial, technological and safety properties of lactobacillus strains isolated from local Iranian cheese made from raw milk. Six different samples were prepared, after serial dilution, culture was performed on MRS culture medium. The gram‐positive and catalase‐negative lactobacillus strains were subjected to grouping and identifying using biochemical tests, carbohydrates fermentation profiles, and 16S rDNA analysis. The results of sequence analysis showed the Lactobacillus spp. belonged to Lactobacillus brevis, Lactobacillus acidophilus, Lactobacillus plantarum, and Lactobacillus casei. After 3 hr incubation at pH=2, 3–6 log units of strains decreased which Lactobacillus acidophilus (B14) and Lactobacillus brevis (B2) showed highest resistance to low pH as well as simulated GIT juices. The highest and lowest hydrophobicity degree was belonged to L. acidophilus (B14) (65.9%) and L. casei (B22) (25.6%), respectively. Also, the highest auto‐aggregation and coaggregation were observed in L. acidophilus (B14) (51.3%) and L. plantarum (B20) (43.6%). The adhered percentage of strains varied from 2.5% to 14.6%. L. plantarum (B20) showed highest proteolytic activity followed by L. acidophilus (B14). Also, the highest autolytic activity belonged to L. acidophilus (B14). All of the strains showed low acidifying potential, except for L. acidophilus (B17) which decreased 2.05 unit of pH after 24 hr. The isolates did not show lipolytic activity as well as biogenic amines production (except L. brevis B3). All of the strains were sensitive to chloramphenicol and erythromycin except L. acidophilus (B15) and L. casei (B22). All strains showed no hemolysis activity which make them safe for consumption. Based on the obtained results, L. acidophilus (B14) presented the best probiotic and technological characteristics and is proposed for using as coculture in the dairy industrial. [ABSTRACT FROM AUTHOR]

In this study the physicochemical, microbiological, and fatty acid compositions together with the specific esterase activities of semi-hard goat cheeses made from native strains as starter and adjunct cultures were evaluated and compared against those of manufactured using commercial culture cheeses. The physicochemical composition was similar among cheeses, while the lactic acid bacteria were the predominant microbiota in all samples. The highest specific esterase activities were detected in cheeses with native strains. The fatty acid profile was significantly affected by native strains during the ripening time (60 days) since the conjugated linoleic acid (CLA) level increased from 0.60 to 1.03 g 100 g-1 of fatty acids, whereas cheeses with commercial starter showed a CLA content of about 0.60 g of fatty acids. In cheeses with native strains, it was detected the highest desirable fatty acids, Δ9-desaturase and CLA desaturase indexes and the lowest atherogenicity index. The native strains inoculated as starter and adjunct cultures, grew conveniently in the cheese, developed their full potential as reflected by the profile of the metabolites released during ripening and in the global sensory perception of cheeses, and contributed thus to the development of a healthier food.

There are different methods that have been recently applied to develop a process to manufacture low‐fat Feta cheese (LFC) with acceptable flavor and texture. The objective of this study was to produce LFC from skim buffalo's milk (SBM) using Streptococcus thermophilus (ST) and Lactobacillus bulgaricus (LB) as control LFC (T1) incorporated with other probiotic adjunct cultures (PAC), such as Lactobacillus casei (LBC) in T2, Bifidobacterium bifidum (BB) in T3, and Lactococcus lactis subsp. lactis (LL) in T4. The SBM was pasteurized and inoculated with 3% of starter cultures; then, 0.4% of rennet and 3% of salt were added. After coagulation, the cheese was cut, packed, and stored at 4°C. The chemical, microbiological, and sensory characteristics of LFC were monitored during 14 days of storage. The moisture, acidity, total protein (TP), salt, and fat of LFC were approximately 75.0%, 1.0%, 17.0%, 3.0%, and 1.2%, respectively, after 14 days of storage at 4°C. The viability of PAC was high (5–7 log cfu/g) at the end of storage, which makes LFC a functional product with a valuable source of probiotic. Moreover, the adjunct cultures improved (p <.05) the sensory characteristics of LFC, including the texture and flavor. [ABSTRACT FROM AUTHOR]

In this study a total of 220 isolates of lactic acid bacteria (LAB) recovered from 10 types of Brazilian artisanal cheeses marketed in 4 main regions of Brazil were evaluated regarding their safety and ability to produce diacetyl (a precursor of aromatic compounds), exopolysaccharides (EPS; from different sugar sources), and antagonistic activity against Listeria monocytogenes and Staphylococcus aureus. The results indicated that 131 isolates (59.6%) were classified as strong (40.5%) and moderate (19.1%) diacetyl producers; 28 isolates (12.7%) stood out due to their remarkable production of EPS from different sugars, including sucrose (3.2%), fructose (2.3%), lactose (2.3%), and glucose (6%). Furthermore, 94.1% and 95.9% of isolates presented antagonistic activity against S. aureus and L. monocytogenes , respectively, even though only 27 isolates (12.3%) exhibited positive results in the bacteriocin production test. None of the isolates tested presented hemolytic activity, and 117 were classified as safe, due to their intrinsic resistance to a maximum of 4 different antibiotics. The data obtained for assessment of antibiogram profile and technological potential (moderate and high production of diacetyl, EPS, and bacteriocins) were submitted to a multiple correspondence analysis to correlate them with the cheese of isolation. Regarding the antimicrobial profile of LAB strains, it was possible to verify an association between isolates from Minas artisanal cheeses from Araxá and resistance to tetracycline; Minas artisanal cheeses from Serro and resistance to erythromycin; Coalho and Minas artisanal cheese from Cerrado and resistance to penicillin; and isolates from Serrano and Colonial cheeses with clindamycin and ceftazidime resistance. Although the susceptibility of strains to these antibiotics was considered high (71.8–80.5%), these data may be related to the horizontal transfer of genes in the production chain of these cheeses. Results of multiple correspondence analysis also showed that isolates with antagonistic activity were mostly isolated from Manteiga, Colonial, and Coalho cheeses. The isolates with high or moderate EPS-producer ability from sucrose, glucose, and fructose were mainly associated with Minas artisanal cheeses from Cerrado. In contrast, isolates with high or moderate EPS-producer ability from lactose were isolated from Serrano, Minas artisanal cheeses from Canastra, and Campo das Vertentes microregions. Finally, isolates from Minas artisanal cheeses (from Araxá microregion), Coalho, and Caipira cheeses were associated with moderate/high diacetyl production. To the best of the authors' knowledge, this study provides, for the first time, data indicating that the dominant technological, biopreservative, and safety properties of LAB isolates can be correlated with the type of Brazilian artisanal cheeses, which denotes its singularity. This knowledge is of utmost relevance for the development of starter or adjunct cultures with tailored properties. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food & Dairy Sciences is the property of Egyptian National Agricultural Library (ENAL) 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.)

In this study the physicochemical, microbiological, and fatty acid compositions together with the specific esterase activities of semi-hard goat cheeses made from native strains as starter and adjunct cultures were evaluated and compared against those of manufactured using commercial culture cheeses. The physicochemical composition was similar among cheeses, while the lactic acid bacteria were the predominant microbiota in all samples. The highest specific esterase activities were detected in cheeses with native strains. The fatty acid profile was significantly affected by native strains during the ripening time (60 days) since the conjugated linoleic acid (CLA) level increased from 0.60 to 1.03 g 100 g-1 of fatty acids, whereas cheeses with commercial starter showed a CLA content of about 0.60 g of fatty acids. In cheeses with native strains, it was detected the highest desirable fatty acids, μ9-desaturase and CLA desaturase indexes and the lowest atherogenicity index. The native strains inoculated as starter and adjunct cultures, grew conveniently in the cheese, developed their full potential as reflected by the profile of the metabolites released during ripening and in the global sensory perception of cheeses, and contributed thus to the development of a healthier food. [ABSTRACT FROM AUTHOR]

In this research, Enterococcus species with probiotic properties were isolated from raw milk and some traditional dairy products and these species were identified by using biochemical, phenotypical and genotypic methods and their potential use in Izmir Tulum cheese production as adjunct culture were investigated. Among the isolated and identified Enterococcus species, three Enterococcus faecium and one Enterococcus durans strains with no vancomycin resistance, no decarboxylation activity, high antimicrobial activity and resistance to acidity were selected, and a mix culture was produced. This culture was mixed with commercial cheese culture containing Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris in different proportions and used in Izmir Tulum cheese production. Cheese samples were left to ripening for 180 days, and their physical, chemical, microbiological and sensory properties were evaluated with comparison to prior studies. Evaluations showed that using adjunct culture in Izmir Tulum cheese production has no negative effect on physical, chemical and microbiological properties and higher proportions of probiotic Enterococci in the culture have a positive effect on the sensory properties, especially on flavor. [ABSTRACT FROM AUTHOR]

The cheese microbiota comprises a consortium of prokaryotic, eukaryotic and viral populations, among which lactic acid bacteria (LAB) are majority components with a prominent role during manufacturing and ripening. The assortment, numbers and proportions of LAB and other microbial biotypes making up the microbiota of cheese are affected by a range of biotic and abiotic factors. Cooperative and competitive interactions between distinct members of the microbiota may occur, with rheological, organoleptic and safety implications for ripened cheese. However, the mechanistic details of these interactions, and their functional consequences, are largely unknown. Acquiring such knowledge is important if we are to predict when fermentations will be successful and understand the causes of technological failures. The experimental use of “synthetic” microbial communities might help throw light on the dynamics of different cheese microbiota components and the interplay between them. Although synthetic communities cannot reproduce entirely the natural microbial diversity in cheese, they could help reveal basic principles governing the interactions between microbial types and perhaps allow multi-species microbial communities to be developed as functional starters. By occupying the whole ecosystem taxonomically and functionally, microbiota-based cultures might be expected to be more resilient and efficient than conventional starters in the development of unique sensorial properties.

Lactic acid bacteria (LAB) have a strong mitigation potential as adjunct cultures to inhibit undesirable bacteria in fermented foods. In fresh cheese with low salt concentration, spoilage and pathogenic bacteria can affect the shelf life with smear on the surface and packaging blowing. In this work, we studied the spoilage microbiota of an Italian fresh cheese to find tailor-made protective cultures for its shelf life improvement. On 14-tested LAB, three of them, namely Lacticaseibacillus rhamnosus LRH05, Latilactobacillus sakei LSK04, and Carnobacterium maltaromaticum CNB06 were the most effective in inhibiting Gram-negative bacteria. These cultures were assessed by the cultivation-dependent and DNA metabarcoding approach using in vitro experiments and industrial trials. Soft cheese with and without adjunct cultures were prepared and stored at 8 and 14 °C until the end of the shelf life in modified atmosphere packaging. Data demonstrated that the use of adjunct cultures reduce and/or modulate the growth of spoilage microbiota at both temperatures. Particularly, during industrial experiments, C. maltaromaticum CNB06 and Lcb. rhamnosus RH05 lowered psychrotrophic bacteria of almost 3 Log CFU/g in a 5-week stored cheese. On the contrary, Llb. sakei LSK04 was able to colonize the cheese but it was not a good candidate for its inhibition capacity. The combined approach applied in this work allowed to evaluate the protective potential of LAB strains against Gram-negative communities.

Bacteriocins are ribosomally synthesized peptides produced by bacteria with antimicrobial activity. The bacteriocins produced by lactic acid bacteria (LAB) may inhibit food-borne pathogens and spoilage organisms, and therefore have potential as natural preservatives. Lactobacillus plantarum LL441 produces a lantibiotic bacteriocin known as plantaricin C, a pore-forming antimicrobial peptide containing modified amino acids that inhibits cell wall synthesis by forming a complex with the peptidoglycan precursor lipid II. The present work describes the genome sequencing of L. plantarum LL441 and the characterisation of the plantaricin C locus. The draft genome sequence of L. plantarum LL441 consisted of 170 contigs and had a total 3,124,603 bp; the GC content was 44.52%. The plantaricin C locus was found in an 18 kbp-long contig, and consisted of six genes organized in an operon-like arrangement. This locus included the bacteriocin structural gene (plnC), followed by a gene encoding a LanM-like protein thought to be involved in the maturation of plantaricin C, and four downstream genes encoding ABC-type transporter components, probably belonging to its putative immunity and export machinery. plnC encodes a precursor of the bacteriocin, i.e., a 58-amino acid peptide containing a 31-amino acid double-glycine leader peptide and a 27-amino acid core peptide. In silico analysis and hybridisation experiments placed the plantaricin C locus to be located on pLL441-1, a large plasmid of L. plantarum LL441. Joining up the gaps between the contigs by conventional PCR, sequencing of the amplicons, and sequence assemblage, allowed the complete 55.3 kbp pLL441-1 molecule to be established. A portion of pLL441-1 larger than 34 kbp, which included the plantaricin C region, was identified in a plasmid-derived contig from the L. plantarum Nizo 3893 genome. Further, the plantaricin C coding locus (about 8.7 kbp) was shown to share 91% nucleotide identity with a portion of the plasmids pPECL-6 from Pediococcus claussenii ATCC BAA-344 and pL11995-4 from Lactobacillus paracollinoides TMW 1.1995. Knowledge of the sequence of the plantaricin C coding region will help in studying its molecular components and allow their involvement in bacteriocin synthesis to be investigated, facilitating the use of the bacteriocin or its genetic elements in new biotechnological applications.

Bacteriocins are ribosomally synthesized peptides produced by bacteria with antimicrobial activity. The bacteriocins produced by lactic acid bacteria (LAB) may inhibit food-borne pathogens and spoilage organisms, and therefore have potential as natural preservatives. Lactobacillus plantarum LL441 produces a lantibiotic bacteriocin known as plantaricin C, a pore-forming antimicrobial peptide containing modified amino acids that inhibits cell wall synthesis by forming a complex with the peptidoglycan precursor lipid II. The present work describes the genome sequencing of L. plantarum LL441 and the characterisation of the plantaricin C locus. The draft genome sequence of L. plantarum LL441 consisted of 170 contigs and had a total 3,124,603 bp; the GC content was 44.52%. The plantaricin C locus was found in an 18 kbp-long contig, and consisted of six genes organized in an operon-like arrangement. This locus included the bacteriocin structural gene (plnC), followed by a gene encoding a LanM-like protein thought to be involved in the maturation of plantaricin C, and four downstream genes encoding ABC-type transporter components, probably belonging to its putative immunity and export machinery. plnC encodes a precursor of the bacteriocin, i.e., a 58-amino acid peptide containing a 31-amino acid double-glycine leader peptide and a 27-amino acid core peptide. In silico analysis and hybridisation experiments placed the plantaricin C locus to be located on pLL441-1, a large plasmid of L. plantarum LL441. Joining up the gaps between the contigs by conventional PCR, sequencing of the amplicons, and sequence assemblage, allowed the complete 55.3 kbp pLL441-1 molecule to be established. A portion of pLL441-1 larger than 34 kbp, which included the plantaricin C region, was identified in a plasmid-derived contig from the L. plantarum Nizo 3893 genome. Further, the plantaricin C coding locus (about 8.7 kbp) was shown to share 91% nucleotide identity with a portion of the plasmids pPECL-6 from Pediococcus claussenii ATCC BAA-344 and pL11995-4 from Lactobacillus paracollinoides TMW 1.1995. Knowledge of the sequence of the plantaricin C coding region will help in studying its molecular components and allow their involvement in bacteriocin synthesis to be investigated, facilitating the use of the bacteriocin or its genetic elements in new biotechnological applications. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food & Dairy Sciences is the property of Egyptian National Agricultural Library (ENAL) 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.)

Spray-drying of lactic cultures provides direct-to-vat starters, which facilitate their commercialization and use. However, this process may alter the metabolic activity and deteriorate technological features. In this work, we assessed the influence of spray-drying on the survival and aroma production of two strains of mesophilic lactobacilli: Lactobacillus paracasei 90 and Lactobacillus plantarum 91, which have already been characterized as good adjunct cultures. The spray-drying was carried out using a laboratory scale spray and the dried cultures were monitored during the storage for the survival rate. The dried cultures were applied to two cheese models: sterile cheese extract and miniature soft cheese. The influence on the carbohydrate metabolism and the production of organic acids and volatile compounds was determined. Both strains retained high levels of viable counts in the powder after drying and during the storage at 5 °C for twelve months. In addition, they also remained at high level in both cheese models during incubation or ripening. Similar profiles of carbohydrate fermentation and bioformation of volatile compounds were observed in the cheese extracts for each of the strains when tested as both fresh and dried cultures. In addition, the ability of Lb. paracasei 90 to increase the production of acetoin and diacetyl remarkably in cheese models was also confirmed for the spray-dried culture. [ABSTRACT FROM AUTHOR]

Functional foods could differently affect human health in relation to the gender. Recent studies have highlighted the anti-Candida and anti-Chlamydia activities of some Lactobacillus strains isolated from the vagina of healthy women. Considering these important beneficial activities on women's health, the preparation of functional food containing active vaginal lactobacilli can represent a great scientific challenge for the female gender. In this context, the aim of this work was to study some functional and technological properties of 17 vaginal strains belonging to the species Lactobacillus crispatus, Lactobacillus gasseri, and Lactobacillus vaginalis in the perspective to include them in dairy products. The antagonistic activities against the pathogenic and spoilage species associated to food products and against the principal etiological agents of the genitourinary tract infections were evaluated. Moreover, the vaginal lactobacilli were characterized for their antibiotic resistance, and for their fermentation kinetics and viability during the refrigerated storage inmilk. Finally, the volatile molecule profiles of the obtained fermented milks were determined. The results showed that several strains, mainly belonging to the species Lactobacillus crispatus, exhibited a significant antagonistic activity against spoilage and pathogenic microorganisms of food interest, as well as against urogenital pathogens. All the vaginal lactobacilli showed antimicrobial activity against strains belonging to the foodborne pathogenic species Listeria monocytogenes, Listeria innocua, Eenterococcus faecalis and Escherichia coli. In addition, most of the Lactobacillus strains were active toward the main pathogens responsible of vaginal and urinary tract infections including Staphylococcus aureus, Enterococcus faecium, Gardnerella vaginalis, and Proteus mirabilis. The antimicrobial activity can be attributed to the high production of organic acids. The fermentation kinetics in milk indicated the unsuitability of these lactobacilli as fermentation starters for the industrial production of dairy products. However, some strains, belonging to the species Lactobacillus crispatus and Lactobacillus gasseri, maintained a high viability in pasteurized milk at 4°C for over a month, showing their potential application as adjunct cultures for the production of female gender foods. These data represent a first step for the set-up of a new functional dairy product, directed to the women well-being, contributing also to innovate the dairy sector. [ABSTRACT FROM AUTHOR]

The aim of this work was to examine the biodiversity of bacteriocin- producing lactic acid bacteria from homemade cheeses produced in Veracruz (México) and assess their contribution as adjunct cultures in dairy products. Ninety-three presumptive bacteriocinogenic strains were detected by direct antagonism assays and 29 of them were active against Enterococcus faecalis NRRL-B537, Listeria innocua 062 AST, or Listeria monocytogenes ATCC19115 by the well diffusion test using cell-free supernatants, adjusted to pH 6.0 to exclude inhibition by organic acids. Positive isolateswere identified by partial sequencing of the 16s rDNA as Pediococcus acidilactici (four isolates), Enterococcus faecium (17 isolates), Lactobacillus plantarum (six isolates) and Lactobacillus fermentum (two isolates). RAPD-PCR discriminated seven groups with a 50% similarity and revealed the presence of the same isolates. The coding genes for the synthesis of plantaricin EF, plantaricin JK, plantaricin N, plantaricin NC8 and the inducing peptide plantaricin A were detected by PCR in L. plantarum. Similarly, enterocin P and pediocin PA-1 genes were amplified from Enterococcus and Pediococcus genomic DNA, respectively. Overall, co-culturing of bacteriocin producing Lactobacillus and Pediococcus strains with the dairy starter Lactococcus lactis IPLA947 did not interfere with milk acidification. Lactose consumption, acidification rate and production of lactic acid were unchanged. Nonetheless, higher levels of acetic acid, ethanol and succinic acid were detected depending on the strain. Our results demonstrate the diversity of bacteriocinogenic species in homemade Mexican cheeses which may be used as adjunct cultures to enhancing safety of this well-appreciated cheese while providing a richer range of metabolites. [ABSTRACT FROM AUTHOR]

Four batches of Cebreiro-type cheese were made in duplicate from pasteurized milk. A control batch was manufactured with only a commercial O-starter. The other three batches were made with the same starter plus: (i) a commercial culture of Enterococcus faecium ; (ii) a selected Kluyveromyces lactis adjunct culture used in a cheese-milk pre-ripening step; and (iii) the combination of both adjunct cultures. The cheeses made with the yeast adjunct were characterized by higher values of overall proteolysis, pH and a w , and showed total and lactic acid bacteria (LAB) counts at least 2 log units than the batches made with only LAB. The volatile profiles of the cheeses made with added K. lactis were distinguished by high contents of esters, branched-chain alcohols, fatty acids, acetoin and 2-pnenylethanol. These batches had a more friable and sticky texture, and exhibited differential piquant, yeasty, alcoholic, acetic and fruity flavors. Furthermore, the addition of enterococci seemed to help achieve more desirable sensory characteristics. The batches manufactured with both adjunct cultures were awarded the highest scores for texture preference, flavor intensity, flavor preference, and overall sensory preference. The sensory profiles of the cheeses made with added yeast closely resembled those of traditional 'good quality' raw-milk Cebreiro cheese. • K. lactis and E. faecium adjuncts modify the volatile profile of Cebreiro cheese. • K. lactis and E. faecium adjuncts modify the sensory profile of Cebreiro cheese. • K. lactis and E. faecium adjuncts add quality and consistency to Cebreiro cheese. [ABSTRACT FROM AUTHOR]

Mesophilic lactobacilli are the most important components of the non-starter lactic acid bacteria (NSLAB) microbiota of cheese. This reviews up-dates the most relevant findings concerning the sources of contamination, energy compounds, diversity, genome features and environmental adaptation responses, which enable their growth in cheese during ripening as the main determinant of secondary proteolysis. The use of NSLAB as adjunct cultures is positively documented but it is not free from drawbacks. Attenuation of adjunct cultures could be achieved through promising treatments. Notwithstanding the agreeable and in some cases standard features of traditional raw milk cheeses, mesophilic lactobacilli should not be considered simply as NSLAB because a number of pros may strengthen their use as secondary/adjunct starters with the potential to better control and improve cheese ripening. [ABSTRACT FROM AUTHOR]

This work describes the phenotypic typing and complete genome analysis of LL441, a dairy Lactiplantibacillus plantarum strain. LL441 utilized a large range of carbohydrates and showed strong activity of some carbohydrate-degrading enzymes. The strain grew slowly in milk and produced acids and ketones along with other volatile compounds. The genome of LL441 included eight circular molecules, the bacterial chromosome, and seven plasmids (pLL441-1 through pLL441-7), ranging in size from 8.7 to 53.3 kbp. Genome analysis revealed vast arrays of genes involved in carbohydrate utilization and flavor formation in milk, as well as genes providing acid and bile resistance. No genes coding for virulence traits or pathogenicity factors were detected. Chromosome and plasmids were packed with insertion sequence (IS) elements. Plasmids were also abundant in genes encoding heavy metal resistance traits and plasmid maintenance functions. Technologically relevant phenotypes linked to plasmids, such as the production of plantaricin C (pLL441-1), lactose utilization (pLL441-2), and bacteriophage resistance (pLL441-4), were also identified. The absence of acquired antibiotic resistance and of phenotypes and genes of concern suggests L. plantarum LL441 be safe. The strain might therefore have a use as a starter or starter component in dairy and other food fermentations or as a probiotic.

High throughput sequencing has recently revealed the presence of Tetragenococcus -related DNA sequences in dairy environments such as brine and cheeses. In the present work, a selective medium was developed to isolate Tetragenococcus spp. from two ripened, traditional, Spanish, blue-veined cheese varieties made from raw milk. The strains recovered belonged to either Tetragenococcus koreensis or Tetragenococcus halophilus species. Twenty of these isolates (15 of T. koreensis and 5 of T. halophilus) were then subjected to a battery of phenotypic and genetic tests, and six strains (4 T. koreensis and 2 T. halophilus) to genome sequencing. Wide genetic and phenotypic diversity was noted. All strains grew poorly in milk, producing small quantities of lactic and acetic acids. Most strains used lactose as a carbon source and ferment milk citrate. In agreement, genome analysis detected in the genome of the six strains analyzed gene clusters harboring several lactose/galactose-related genes and genes encoding citrate metabolic enzymes (permease, citrate lyase, and oxaloacetate decarboxylase). Most of the tested strains were resistant to erythromycin and clindamycin, and a few to other antimicrobial agents, but neither known mutations nor acquired genes conferring resistance to antibiotics were identified in their genomes. Neither were genes coding for pathogenicity or virulence factors detected. Decarboxylase-encoding genes involved in biogenic amine production were not identified, in keeping with the strains' negative biogenic amine-producer phenotype. Genome comparison revealed vast arrays of genes (similar in number to those described in other lactic acid bacteria) coding for components of proteolytic and lipolytic systems. Tetragenococcus strains showing desirable traits plus the absence of detrimental features might be exploitable in the form of secondary, adjunct or ripening cultures to ensure the typical bouquet of traditional blue-veined cheeses is obtained, or to diversify the final flavor in other varieties. • Tetragenococcus spp. were retrieved from two Spanish traditional blue-veined cheeses. • High phenotypic and genetic diversity among the isolates was discovered. • Genome analysis of six strains revealed a complex, cheese-related gene content. • Strains did not produce biogenic amines or contain acquired antibiotic resistance genes. • Adjunct cultures with selected strains could help ensure the cheeses' typical bouquet. [ABSTRACT FROM AUTHOR]