Biodiversity Of Lactic Acid Bacteria Research Articles

Microbiological survey and physicochemical analysis of Moroccan durum, soft and red wheat landraces

Morocco possesses a significant genetic diversity of wheat cultivars in the form of landraces conserved by local farmers in several regions. This study aimed to evaluate the microbiological quality of refined flour and bran derived from 75 samples of Moroccan durum, soft, and red wheat landraces and to estimate their microbiological stability for controlling and preventing undesirable microbial proliferation. Various microbial and physicochemical parameters were evaluated according to ISO and AOAC standards, and results were interpreted based on Codex Alimentarius Commission regulation. Compliance of the analyzed refined flour and bran samples with current regulatory limits and satisfactory microbiological quality were observed. The phenotypic characterization revealed the identification of 16 yeast species belonging to the genera Trichosporon, Candida, Cryptococcus, Rhodotorula, and Saccharomyces, which had not been previously explored. Furthermore, the biodiversity of lactic acid bacteria is notably characterized by the predominance of Pediococcus acidilactici and Lactobacillus plantarum species. The analysis of moisture content and water activity exhibited values falling below the maximum limits defined by international standards, demonstrating the effectiveness of the implemented processing and storage practices. The neutral pH recorded confirms the absence of excessive proliferation of the assessed microbial contaminants. The abundant availability of carbohydrates, lipids, proteins, and minerals creates a favorable non-competitive environment essential for maintaining their functional stability in the analyzed samples. These findings hold significant implications for the agricultural and food industries, providing insights into preserving indigenous wheat varieties and producing safe wheat-based products with high nutritional quality.

Insights into population adaptation and biodiversity of lactic acid bacteria in challenged date palm leaves silaging, using MALDI–TOF MS

Insights into population adaptation and biodiversity of lactic acid bacteria in challenged date palm leaves silaging, using MALDI–TOF MS

ANALYTICAL REVIEW OF BIOTECHNOLOGICAL PROBLEM OF UKRAINIAN HARD CHEESES

An analytical review of the biotechnological process of production of various hard and semi-hard cheeses in the EU and Ukraine, as well as domestic recipes of fermented cheeses for production at craft cheese factories and at home, was conducted. An analysis of the conditions of the key stages of production, including fermentation, coagulation and ripening, was carried out. The composition and type of lactic acid bacteria in sourdough for fermented cheeses, as well as enzymes for fermentolysis and coagulation of milk casein, were studied. As a result of a complex study, a total of 73 types of hard and semi-hard cheeses were analyzed: 35 recipes of the New England Cheesemaking Supply Company by Jim Wallace; 30 production processes of hard and semi-hard cheeses from the EU; 8 technical conditions of hard cheeses of Ukrainian producers. It is shown that the prospects for optimizing the development of new types of hard and semi-hard cheeses in Ukraine are mainly related to the regulation of the time and temperature of fermentation, cooking and ripening of cheeses, as well as the expansion of the biodiversity of the primary and secondary microbiome of starter cultures to improve the taste and aroma of the ready-to-use product. Purpose: to analyze the fermentation process and recipes for the production of hard cheeses in Ukraine with the main world samples, to compare the composition and type of lactic acid bacteria in industrial and craft starters, as well as the types of enzymes for fermentolysis and casein coagulation of milk, in order to optimize production to improve the taste and aroma of ready-to-use product. Materials and methods. Methodical analysis and abstract-logical method for summarizing the evaluation criteria of the biotechnological process of various hard and semi-hard domestic cheeses with world samples according to recommendations, requirements and standards with the development of patents, technical conditions of their production in the EU and Ukraine; DSTU 6003 (Solid cheeses); New England Cheesemaking Supply Company cheese recipes by Jim Wallace. The obtained data were processed by methods of statistical analysis, systematization, comparison and generalization of information. Results. In this study, the documentation was examined and the data of standards, regulations, requirements and recommendations regarding the biotechnology of hard and semi-hard cheeses were analyzed, an analysis of the market of hard cheeses and the peculiarities of the fermentation process of their production was carried out with the determination of critical points and key stages of production using industrial deposited fermentation producers and protein enzymes coagulation and biodiversity of lactic acid bacteria in sourdoughs for fermented cheeses at world productions, with an assessment of the prospects for developing new and improving the biotechnology of Ukrainian benign and safe hard cheeses for healthy nutrition.

Biodiversity of Lactic Acid Bacteria in Traditional Fermented Foods in Yunnan Province, China, and Comparative Genomics of Lactobacillus plantarum

The diversity of lactic acid bacteria (LAB) in fermented foods in Yunnan currently lacks large-scale and systematic research. A total of 638 fermented foods were collected from 84 regions in Yunnan for diversity analyses. The results show that the dominant strains in various types of fermented foods were different. Additionally, the majority of the LAB were better adapted to regions with a temperature of 15–20 °C and a humidity of 64–74%. Lactobacillus plantarum (L. plantarum) was the most abundant of all the strains and was widely distributed in the 84 regions. Genetically, the guanine plus cytosine (GC) content of L. plantarum ranged from 35.60% to 47.90%, with genome sizes from 2.54 Mb to 5.76 Mb. A phylogenetic analysis revealed that the habitat source and geographic origin had little influence on the homologous genes of L. plantarum. The genetic diversity of L. plantarum was mostly represented by functional genes and carbohydrate utilization. This research provides valuable insights into the microbiota of different types of fermented foods in Yunnan. Meanwhile, a genetic diversity analysis of L. plantarum may help us to understand the evolutionary history of this species.

Characterization, molecular identification, and antimicrobial activity of lactic acid bacteria isolated from selected fermented foods and beverages in Malaysia.

The present work investigated the profile and biodiversity of lactic acid bacteria (LAB) isolated from selected manufactured and homemade fermented foods in Malaysia. A total of 55 LAB were isolated from 20 samples, and identified based on the sequencing of 16S rRNA gene. The LAB isolates were identified as Lacticaseibacillus rhamnosus (34.5%), Lactiplantibacillus plantarum (20%), Limosilactobacillus fermentum (20%), Lacticaseibacillus paracasei (12.7%), Lacticaseibacillus casei (3.6%), Lactobacillus sp. (1.8%), Enterococcus faecalis (3.6%), Enterococcus faecium (1.8%), and Enterococcus durans (1.8%). Majority (94%) of the LAB isolates exhibited broad-spectrum antimicrobial activity against selected foodborne pathogens, and four isolates (L. fermentum SC1001, L. paracasei K2003, and L. rhamnosus KF1002 and MK2003) could produce bacteriocin-like inhibitory substance (BLIS). Lacticaseibacillus paracasei M1001 (homemade mozzarella) exhibited high-temperature tolerance and acid resistance, was homofermentative, and generated good antimicrobial activity, which strongly implied its potential for industrial applications. The present work results would potentially widen our knowledge of LAB diversity in Malaysian fermented foods and provide a potential for their applications in the food industry or other purposes.

Liquid sourdough from stone-ground soft wheat (Triticum aestivum) flour: Development and exploitation in the breadmaking process

The aim of the study was to set up a liquid sourdough obtained using stone-ground soft wheat (Triticum aestivum) flour to be exploited in breadmaking. Therefore, a Type II sourdough (dough yield = 350) was developed from a stable stone-ground wheat Type I sourdough (dough yield = 156) used as inoculum. Both sourdoughs were analyzed for lactic acid bacteria (LAB) viable counts, pH and total titratable acidity (TTA), LAB biodiversity by a combined culture-dependent and -independent approach (PCR-DGGE) and they were tested for their breadmaking ability. In addition, the chemical and rheological features and volatile organic compounds of the stone-ground soft wheat flour used in the experiment were investigated.The flour had a high protein content, good bakery properties and it also presented a rich aroma pattern characterized not only by the prevalence of green grass, flowery, and sweet aromas but also nutty, roasted and popcorn aromas.The sourdoughs I and II used in the trial were characterized by viable LAB counts, pH and TTA values typical of mature sourdoughs, i.e., approximately 9 log cfu gr-1 and mL, pH 3.9 and 10 mL 0.1 N NaOH. In addition, Levilactobacillus brevis and Companilactobacillus paralimentarius species represented the LAB stable microbiota of both sourdoughs.Both sourdoughs efficiently produce acceptable experimental breads characterized by different volatile profiles thus indicating that the type of sourdough fermentation significantly influenced the features of the final products. Overall, for the first time in the present study stone-ground wheat flour and bread have been characterized for their volatile aroma profile and sensory properties.

Biodiversity and succession of lactic microbiota involved in Brazilian buffalo mozzarella cheese production.

The biodiversity and succession of lactic acid bacteria (LAB) involved in the production and storage of Brazilian buffalo mozzarella cheese were evaluated. The isolates were characterized by Gram staining and catalase test, by the ability to grow at different conditions: temperatures, pH, concentrations of NaCl, and production of CO2 from glucose. The biodiversity and succession of 152 LAB isolated during cheese production were evaluated by 16S rRNA gene sequencing, Random Amplified Polymorphic DNA (RAPD-PCR), and Restriction Fragment Length Polymorphism (RFLP-PCR) techniques. Most of the strains grow well at 30°C and are tolerant to 6.5% of NaCl, and in general, the best pH for growing was 9.6. Leuconostoc mesenteroides, Lacticaseibacillus casei, Limosilactobacillus fermentum, and Enterococcus sp. were prevalent and present in almost all steps of production. The LAB strains are typically found in the traditional Italian cheese, except the Leuconostoc citreum species. Sixty clusters were obtained by RAPD-PCR with 85% of similarity (114 isolates) while most of the LAB was clustered with 100% of similarity by the RFLP-PCR technique. The applied techniques enabled a valuable elucidation of the LAB biodiversity and succession, contributing to a better understanding of the specific microbial cultures with a technological aptitude of this cheese.

Cocoa bean turning as a method for redirecting the aroma compound profile in artisanal cocoa fermentation

Two artisanal fermentation processes for Criollo cocoa beans with different turning start times (24 h and 48 h) were studied. The aromatic profile of cocoa turned every 24 h (B1) displayed volatile compounds associated with fermented, bready, and fruity aromas. When cocoa beans were fermented with a different turning technique with a start time of 48 h (B2), they provided volatile compounds mainly associated with descriptors of floral, woody, sweet, fruity and chocolate aromas. The turning start time of 48 h stimulated a microbial profile dominated by yeast such as Hanseniaspora opuntiae, Pichia manshurica, and Meyerozyma carpophila, favoring the production of several key aroma markers associated with cocoa bean fermentation quality, such as phenylethyl acetate, 2-phenylacetaldehyde, 3-methylbutanal, 2-phenylethyl alcohol, 2,3-butanedione, 3-methylbutanoic acid, and 2-methylpropanoic acid, while an immediate turning start time (24 h) favored an aerobic environment that stimulated the rapid growth of Acetobacter pasteurianus, Bacillus subtilis and a higher biodiversity of lactic acid bacteria (LAB) (e.g., Lactobacillus plantarum and Pediococcus acidilactici), which increased the production of ethyl acetate and 3-hydroxy-2-butanone. Volatile compound generation and microbial populations were evaluated and analyzed by multivariate analysis (principal component analysis and partial least squares discriminant analysis) to find correlations and significant differences. This study shows that the method of turning Criollo cacao beans can lead to the formation of desirable aromatic compounds.

Biodiversity of lactic acid bacteria of wild honey bee and Sumbawa horse milk by using RAPD-PCR

Wild honey bee and Sumbawa horse milk is the local product from West Nusa Tenggara, Indonesia, which has the characteristic of little sour in taste. The sour taste indicates lactic acid bacteria (LAB) existence that has a potential function as probiotics. The objection of this study is analysis of lactic acid bacteria biodiversity from wild honey bee and Sumbawa horse milk by using Random Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR). The genome of cultured samples from M17 and MRS medium were extracted, then identified by RAPD-PCR with primer (GTG)5 (5-GTGGTGGTGGTGGTG-3). The scoring of DNA fragments was analyzed using the Numerical Taxonomy and Multivariate Analysis System (NTSYS) application. The result show five clusters from a common ancestor indicated the broad diversity of LAB in wild honey bee and Sumbawa horse milk.

Biochemical and Microbiological Characteristics of Raw Milk and Curdled Milk Originated from the Central Region of Burkina Faso

Milk and dairy products play an important role in human nutrition in Burkina Faso as in several developing countries. This study aimed to describe the curdled milk process in the Central region of Burkina Faso through a monitoring of the production and to study the biochemical and microbiological characteristics of raw milk and curdled milk. Microbiological and biochemical characteristics of the products were determined using standard methods. Biodiversity of lactic acid bacteria in curdled milk was determined using (GTG) 5-PCR and 16S rRNA gene sequencing. Processing of curdled milk takes place in calabashes or plastic containers, without heat treatment of raw milk. The fermentation is spontaneous and lasts for 24 - 48 h at ambient temperature. Biochemical analysis showed a low mean pH of curdled milk (4.34 ± 0.10) compared to that of raw milk (6.47 ± 0.02). Dry matter (DM), protein and lipid contents were respectively 7.85%; 16.96 g/L DM and 37.11 g/L DM for raw milk while those of curdled milk were 15.85%; 20.85 g/L DM and 27.03 g/L DM. An increase from 0.22 to 0.37 g/L DM of phosphorus and from 1.10 to 2.46 of calcium was observed with the fermentation. However, iron and zinc contents obtained were 0.55 mg/L DM and 1.97 mg/L DM for raw milk and 0.27 mg/L and 1.6 mg/L for curdled milk, respectively. Microbiological analyzes indicated a high number of aerobic mesophilic bacteria for raw milk (1.9. 107 UFC/mL) as for curdled milk (3.9. 108 UFC/mL). In addition, Enterobacteriaceae counts from raw milk and curdled milk were higher than the acceptable limit of 102 CFU/mL for dairy products. Lactobacillus fermentum, Enterococcus durans/feacium, Lactococcus lactis, Lactobacillus helveticus and Enterococcus feacalis were the predominant species identified in the curdled milk.

Biodiversity and techno-functional properties of lactic acid bacteria in fermented hull-less barley sourdough

The aim of this study was to characterize the biodiversity of lactic acid bacteria (LAB) isolated from spontaneously-fermented hull-less barley sourdough and to determine its technological properties. Biodiversity was investigated by analysis of colonies isolated from sourdough on four different agar media. Of the 80 isolates, 67 were rapidly pre-identified as LAB using Fourier transforms infrared spectroscopy (FTIR). As a result of cluster analysis, 32 lactic acid bacteria chosen from different branches were identified. According to the polymerase chain reaction (PCR) results, 9 different species were identified: Pediococcus (dominant species), Lactobacillus curvatus, Lactobacillus brevis, Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus musae, Lactobacillus paralimentarius, Leuconostoc mesenteroides and Lactobacillus equigenerosi. The most species and strain diversity among the media was determined in ModMRS environment. Unlike other studies about hull-less barley, Lactobacillus equigenerosi was identified in this study. LABs were identified with salt and acid tolerance. Generally, different levels of antibacterial activity in these species were shown against (rope spoilage) food borne pathogens. The greatest antimicrobial effect was observed for Pediococcus acidilactici SAB26, Lactobacillus plantarum SAB15 and Pediococcus acidilactici SAB13 compared to the other strains. Pediococcus species were found to have the highest antifungal effect against Penicillium carneum, Aspergillus flavus and A. niger. The phytase activity of LAB, which increases mineral bioavailability, was observed to be highest in Lactobacillus plantarum, Pediococcus pentosaceus, and Leuconostoc mesenteroides.

Metagenomic analysis and biodiversity of Lactic Acid Bacteria (LAB) on masin (fermented sauce) from Sumbawa, West Nusa Tenggara, Indonesia

Abstract. Manguntungi B, Saputri DS, Mustopa AZ, Ekawati N, Afgani CA, Sari AP, Triratna L, Sukmarini L, Fatimah, Kusmiran A, Yanti S, Irawan S, Prasetyo MD, Fidien KA. 2020. Metagenomic analysis and biodiversity of Lactic Acid Bacteria (LAB) on masin (fermented sauce) from Sumbawa, West Nusa Tenggara, Indonesia. Biodiversitas 21: 3287-3293. Masin is a spontaneously fermented sauce from Sumbawa, West Nusa Tenggara Indonesia that is made of shrimp paste, chili, turmeric flower, and herbs mixed with some spices. This study aims to isolate Lactic Acid Bacteria (LAB) and analyze the metagenomic and biodiversity of its bacteria. Genome isolation for metagenomic analysis was using ZymoBIOMICSTM DNA Miniprep Kit. Sequencing analysis to identify LAB strain form masin was using 16S rRNA universal primer. Metagenomic analysis showed that relative abundance bacteria in masin for order taxon was Lactobacillales, the family taxon was Enteroccocaceae, and the genus was Tetragenoccocus. Six different groups were obtained from the phylogenetic tree analysis of 40 isolates found in masin. The representatives of each group taken were isolates number 2, 17, 11, 34, 28,  and 5. Based on the results of sequencing analysis, the 6 isolates found in masin are Staphylococcus piscifermentans strain CIP103958 (Isolate Code 2), S. piscifermentans strain BULST54 (Isolate Code 17), S. piscifermentans strain SK03 (Isolate Code 11), S. piscifermentans strain ATCC 51136 (Isolate Code 34), S. piscifermentans strain PCM 2409 (Isolate Code 28) and S. piscifermentans strain PU-87 (Isolate Code 5). Through this research, it has been described a whole diversity of bacteria contained in masin, one of them is Lactic acid bacteria. The six LAB isolates that have been identified can be developed as starter candidates for masin production.

Identifikasi molekuler Bakteri Asam Laktat dari Tempe dan Tape Berdasarkan Sekuen Gen 16S rRNA

Indonesia has varied of fermented food. However, the discovery of the microbial diversity in the Indonesian traditional fermented food is inadequately conducted. In this study, we determined the lactic acid bacteria (LAB) diversity from tempeh and tape based on the nucleotide sequence of 16S rRNA gene to obtain information on the biodiversity of lactic acid bacteria in tempeh and tape origin Bali Province, and collection of lactic acid bacteria isolates have beneficial for the development of starters, food science, and genetic resources. A total of six samples of tempeh and six samples of tape were collected from Bali province. A viable count method showed that the LAB population in tempeh was 3.8 x 10 8 – 2.2 x 10 9 cfu/g and in tape was 4 x 10 5 - 1.1 x 10 8 cfu/g. A molecular identification based on the nucleotide sequence of16S rRNA gene determined six LAB species existed in tempeh ( Lactobacillus fermentum, L. plantarum, Enterococcus faecalis, E. faecium , Pediococcus pentosaceus, Weissella paramesenteroide ) and six species in tape ( L. fermentum , L. kunkeei , L. plantarum , L. vini , Leuconostoc mesenteroides , P. pentosaceus , W. paramesenteroides . Physiological characterization showed that all LAB isolates grew on medium containing 3% NaCl at pH 4 and pH 6.5, and at temperatures of 30°C and 45°C. Three isolates of P. pentosaceus (Su-ls21, Su-ls22, Su-ls24) exhibited catalase activity and 17 isolates belong to halotolerant bacteria, which can grow on medium containing 6.5% NaCl.

Role of lactic acid bacteria in fermented vegetables

The consumption of fermented vegetables is widespread throughout the world and represents an important component of the human diet with considerable contribution to the food supply for a world popula­tion in continuous growth. Many of the fermented vegetables share a general process which requires salting and acidification steps. Among the microorganisms responsible for fermentation, lactic acid bacteria are the most relevant with important organoleptic, quality and safety benefits. This review deals with the microbial ecology of fermented vegetables focusing on the biodiversity of lactic acid bacteria, the most important molecular tech­niques used for their identification and genotyping, their importance for the formation of biofilms as well as their use as starter cultures for obtaining high-quality and safe vegetable products.

Lactobacillus plantarum, a New Biological Tool to Control Malolactic Fermentation: A Review and an Outlook

Malolactic fermentation (MLF) in wine is an important step in the vinification of most red and some white wines, as stands for the biological conversion of l-malic acid into l-lactic acid and carbon dioxide, resulting in a decrease in wine acidity. MLF not only results in a biological deacidification, it can exert a significant impact on the organoleptic qualities of wine. This paper reviews the biodiversity of lactic acid bacteria (LAB) in wine, their origin, and the limiting conditions encountered in wine, which allow only the most adapted species and strains to survive and induce malolactic fermentation. Of all the species of wine LAB, Oenococcus oeni is probably the best adapted to overcome the harsh environmental wine conditions and therefore represents the majority of commercial MLF starter cultures. Wine pH is most challenging, but, as a result of global warming, Lactobacillus sp. is more often reported to predominate and be responsible for spontaneous malolactic fermentation. Some Lactobacillus plantarum strains can tolerate the high alcohol and SO2 levels normally encountered in wine. This paper shows the potential within this species for the application as a starter culture for induction of MLF in juice or wine. Due to its complex metabolism, a range of compositional changes can be induced, which may positively affect the quality of the final product. An example of a recent isolate has shown most interesting results, not only for its capacity to induce MLF after direct inoculation, but also for its positive contribution to the wine quality. Degrading hexose sugars by the homo-fermentative pathway, which poses no risk of acetic acid production from the sugars, is an interesting alternative to control MLF in high pH wines. Within this species, we can expect more strains with interesting enological properties.

Evaluation of Malolactic Bacteria Associated with Wines from Albariño Variety as Potential Starters: Screening for Quality and Safety

The biodiversity of lactic acid bacteria in musts and wines of Albariño variety has been studied. The identification of species was addressed through a combination of biochemical and genetic methods (API® 50 CHL test, 16S rDNA and recA gene sequences, Amplified Ribosomal DNA Restriction Analysis -ARDRA- and 16S-26S intergenic region analysis). The results grouped the isolates into six species predominating those of the genus Lactobacillus and showing a typical biogeographical distribution. Among sixteen strains evaluated, eight of them showed malolactic activity. The study of the presence of genes hdc, odc, and tdc, along with the LC/MS-MS analysis of biogenic amines in wine, showed five strains lacking aminogenic ability. The absence of the pad gene in the above-mentioned strains discards its ability to produce volatile phenols that may adversely affect the aroma. Finally, all malolactic strains showed β-glucosidase activity so that they could contribute to enhance and differentiate the aromatic profile of Albariño wines.

Genomic Insights Into Five Strains of Lactobacillus plantarum With Biotechnological Potential Isolated From chicha, a Traditional Maize-Based Fermented Beverage From Northwestern Argentina.

Lactic acid bacteria (LAB) are indigenous microorganisms that have been involved in food fermentations throughout history to preserve food and also to give special characteristics to them. The traditional fermented foods that are still being elaborated in indigenous populations around the world are a potential source of LAB with important biotechnological properties and/or beneficial to health. In a previous work, LAB biodiversity associated with chicha, a traditional maize-based fermented beverage from Northwestern Argentina, was studied, both by culture dependent and independent methods. From that study, 392 isolates were recovered, mostly members of Lactobacillus and Leuconostoc. Biotechnological characterization of representative isolates led to the selection of five strains belonging to the species Lactobacillus plantarum for their ability to produce vitamin B2 (riboflavin) and vitamin B9 (folates), their antimicrobial properties and antibiotics susceptibility. In this work, we present the Whole Genome Sequences (WGS) of these five strains that have been deposited in the Spanish Type Culture Collection: M5MA1 (= CECT 8962), M9MM1 (= CECT 8963), M9MM4 (= CECT 8964), M9MG6 (= CECT 8965), and M9Y2 (= CECT 8966), and a detailed description of their characterization, through a genomic approach, analyzing the genes responsible for these biotechnological properties, making a comparative study of the five genomes and reporting the aspects related to food safety, in accordance with the recommendations of the European Food Safety Authority (EFSA FEEDAP Panel, 2018) aiming at their use in the design of functional foods. The analysis unveiled, for the five strains, the complete set of genes for folate and riboflavin biosynthesis, the absence of pathogenic factors, the presence of CRISPR and cas genes, phage sequences, insertion elements and an aminoglycosides resistance gene, aadA, whose resistance could not be proved phenotypically in any strain. Genomic comparisons showed that strain CECT 8962 was significantly different in terms of genetic content and allowed the identification of carbohydrates metabolism and membrane transport related genes as the main components of the unique and accessory genome.

Lactic Acid Bacteria Biota and Aroma Profile of Italian Traditional Sourdoughs From the Irpinian Area in Italy.

This study identified the lactic acid bacteria (LAB) biota and the volatilome profile of 28 typical sourdoughs of Irpinia—a large area of the Campania region of Southern Italy where numerous breads are produced, even today, following the ancient procedures of sourdough fermentation and for which information on the microbiological and sensory profile is lacking in literature. For this purpose, microbial quality, LAB biodiversity, chemical, and technological characteristics, as well as aroma profile by solid-phase microextraction technique (SPME)–gas chromatography/mass spectrometry (GC/MS) of Irpinian sourdoughs were investigated. The dominant LAB microbiota was examined by both culture-dependent and culture-independent methods Polymerase Chain Reaction/Denaturing Gradient Gel Electrophoresis (PCR-DGGE). Results showed a high biodiversity in LAB community whereas the most frequent lactobacilli species recognized were Lactobacillus plantarum (ca. 22% of total LAB isolates), Lactobacillus sanfranciscensis (11%), Lactobacillus paralimentarius (8%), and Lactobacillus rossiae (6.5%), whereas LAB cocci could be mainly referred to Pediococcus pentosaceus (9.5% of total LAB isolates), Leuconostoc spp. (7.8%), and Weissella cibaria (7.7%). Sourdoughs were characterized by the dominance of one or two LAB species, thus proving that the environment influences the selection and the establishment of few key LAB species and that no specific correlation can be traced between microbial composition and geographical origin of the samples. Furthermore, although sourdoughs were characterized by different qualitative and quantitative volatile organic compound (VOC) compositions, no noticeable correlation between volatilome profile and geographical origin was found. However, it emerged that for more isolated locations, it was possible to find the existence of microbial biotypes and sensory profiles with a strong identity, thus revealing the existence of highly traditional and evocative bread recipes in those geographical contexts.

Can Coalho cheese lactic microbiota be used in dairy fermentation to reduce foodborne pathogens?

In order to study the biodiversity of lactic acid bacteria (LAB) and evaluate their potential for use in dairy fermentation to inhibit foodborne pathogens, we collected two types of Coalho cheese made with raw milk from an artisanal production located in Venturosa, Agreste Region in the state of Pernambuco. From 480 isolates, 210 (Gram-positive; catalase-negative; able to clot skim milk) were identified as LAB and 78 were identified at genus level. The genera found were Enterococcus (37.1%), Streptococcus (25.6%), Lactococcus (19.2%) and Leuconostoc (15.3%). The technology potential showed that most of the LAB exhibited proteolytic activity (82.9%), diacetyl production (65.7%), grown in 3, 4 and 6.5% NaCl (more than 50%), and rapidly acidified milk (52.6%) due to the production of lactic acid. The antagonistic potential showed that most LAB inhibited the growth of Staphylococcus aureus ATCC 6538 (82.89%) and Escherichia coli ATCC 25922 (88.15%), and 72.36% of the LAB presented antimicrobial activity against the two indicators. Among the Enterococcus strains, most (more than 70%) were gama-hemolitic and none produced gelatinase. This study allowed for the selection of strains with promising potential for use in dairy fermentation that could reduce the contamination of milk and cheese by foodborne pathogens.

Biodiversity of lactic acid bacteria isolated from fermented milk products in Xinjiang, China

ABSTRACTFermented dairy products have been produced and consumed for thousands of years in Xinjiang, China. In this study, traditional culture-dependent methods and 16S rRNA gene analyses were performed to analyze the composition of lactic acid bacteria (LAB) from 86 samples of traditional fermented dairy products collected from four regions of Xinjiang. Quantitative polymerase chain reaction (qPCR) was used to quantify Bifidobacterium and Lactobacillus species. The LAB isolates (N = 705) were identified as belonging to seven genera and 26 species or subspecies. The predominant species of all isolates were Lactobacillus (Lb.) delbrueckii subsp. bulgaricus, Lb. fermentum, and Lb. helveticus. The LAB counts of these samples ranged from 5.35 to 10.06 Log CFU/mL. The bacterial counts of seven lactobacilli species and Bifidobacterium ranged from 0.98 ± 0.14 Log CFU/mL (for Lb. sakei from fermented mare milk) to 9.91 ± 0.17 Log CFU/mL (for Lb. helveticus from fermented mare milk). While the microbiota was significantly different between yak and cow milk, there was no significant difference between the Tex and Zhaosu counties. In conclusion, LAB communities in traditional fermented dairy products are complex and differ among local regions within Xinjiang.