Technological properties of autochthonous Lactobacillus plantarum strains isolated from sucuk (Turkish dry-fermented sausage)

Screening of Wild Lactic Acid Bacteria from Algerian Traditional Cheeses and Goat Butter to Develop a New Probiotic Starter Culture

Twenty-five lactic acid bacterial (LAB) strains have been isolated from traditional goat butter and three types of cheese (dry Klila, frech Klila, and Bouhezza) and evaluated for technological abilities, probiotic properties, and potentials as starter cultures. The twenty-five LAB strains comprised eight strains belonging to Lactobacillus, four strains belonging to Lactococcus, eleven strains belonging to Enterococcus, and two strains belonging to Leuconostoc. A non-hierarchical cluster analysis was performed in order to select the performing strains. After carrying out the preliminary phenotypic characterizations and the probiotic potential, three strains designated as BM10, B15, and C30 belonging to the genus Lactobacillus and Enterococcus with good tolerance to acidity were selected. The strains showed a significant resistance to 0.5% bile salts and 0.4% phenol. Hemolytic activity was not detected; in addition, good hydrophobicity and autoaggregation was obtained. A significant antimicrobial activity was exhibited by all selected strains against Listeria innocua. Genotypic identification by 16S rRNA allowed the identification of B15, BM10, and C30 as Lactobacillus plantarum, Lactobacillus casei, and Enterococcus durans, respectively. The results of the current study suggest that the strains isolated from Algerian fermented dairy products have high potential as probiotic starter cultures in the goat butter and cheese industry.

Antimicrobial activity against Staphylococcus aureus and genome features of Lactiplantibacillus plantarum LR-14 from Sichuan pickles

The persistence of Staphylococcus aureus within biofilm can lead to contamination of medical devices and life-threatening infections. Luckily, lactic acid bacteria (LAB) have an inhibitory effect on the growth of these bacteria. This study aims to select LAB strains from fermented vegetables, and analyze their potential inhibition activities against S. aureus. In total, 45 isolates of LAB were successfully isolated from Sichuan pickles, and the CFS of Lactiplantibacillus plantarum LR-14 exerted the strongest inhibitory effect against S. aureus. Moreover, S. aureus cells in planktonic and biofilm states both wrinkled and damaged when treated with the CFS of L. plantarum LR-14. In addition, whole genome sequencing analysis indicates that L. plantarum LR-14 contains various functional genes, including predicted extracellular polysaccharides (EPS) biosynthesis genes, and genes participating in the synthesis and metabolism of fatty acid, implying that L. plantarum LR-14 has the potential to be used as a probiotic with multiple functions.

Optimized Ensiling Conditions and Microbial Community in Mulberry Leaves Silage With Inoculants

Mulberry leaves (ML) are a promising alternative fodder source due to their high protein content and the abundance of active components. A test of three inoculants in various combinations revealed that high-quality ML silage was produced at an inoculum ratio of 1:1:0 (50% Saccharomyces cerevisiae, 50% Lactobacillus plantarum, and 0% Bacillus subtilis). Using dry matter (DM) loss, pH, ammonia-N and amino acid contents, total antioxidant activity, and total flavonoids content to evaluate silage quality, this inoculant mixture was shown to produce high-quality silage within a range of inoculum size (5–15%), moisture contents (50–67%), ensiling temperatures (27–30°C), and ensiling duration (14–30 days). A third trial comparing silages produced after 30 days at 28°C and 50% moisture content revealed that silage E, prepared using an L. plantarum inoculant alone, displayed the lowest DM loss and pH, and low bacterial diversity, and it was dominated by Lactobacillus (88.6%), with low abundance of Enterobacter (6.17%). In contrast, silage B5, prepared with equal ratios of L. plantarum and S. cerevisiae, was dominated by Enterococcus (67.16%) and Lactobacillus (26.94%), with less marked yeast persistence, and reducing the DM content from 50 to 40% altered these relative abundances to 5.47 and 60.61, respectively. Control silages produced without an inoculant had the highest pH and ammonia-N content (indicative of poor quality), had the lowest antioxidant activity, had higher bacterial diversity, and were dominated by Carnobacterium (74.28%) and Enterococcus (17.3%). In summary, ensiling of ML conditions with proper inoculants yielded high-quality silage with a favorable microbial community composition.

Technological and Safety Attributes of Lactic Acid Bacteria and Yeasts Isolated from Spontaneously Fermented Greek Wheat Sourdoughs

The aim of the present study was to assess the technological and safety potential of 207 lactic acid bacteria (LAB) and 195 yeast strains isolated from spontaneously fermented Greek wheat sourdoughs. More accurately, the amylolytic, proteolytic, lipolytic, phytase and amino acid decarboxylase activities, along with the production of exopolysaccharides and antimicrobial compounds by the LAB and yeast isolates, were assessed. A well diffusion assay revealed seven proteolytic LAB and eight yeast strains; hydrolysis of tributyrin was evident only in 11 LAB strains. A further Sodium Dodecyl Sulphate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) indicated partial hydrolysis of gluten. Lipolysis kinetics over 21 days was applied, exhibiting that lipolytic activity ranged from 6.25 to 65.50 AU/mL. Thirteen LAB inhibited Penicillium olsonii and Aspergillus niger growth and 12 yeast strains inhibited Pe. chrysogenum growth. Twenty-one Lactiplantibacillus plantarum strains exhibited inhibitory activity against Listeria monocytogenes, as well as several sourdough-associated isolates. The structural gene encoding plantaricin 423 was detected in 19 Lcb. plantarum strains, while the structural genes encoding plantaricins NC8, PlnE/F, PlnJ/K, and S were detected in two Lcb. plantarum strains. None of the microbial strains tested exhibited exopolysaccharide (EPS) production, amino acid decarboxylase, amylolytic or phytase activity. The technological and safety potential of the Lcb. plantarum and Wickerhamomyces anomalus strains was highlighted, since some of them exhibited proteolytic, lipolytic, antibacterial and antimould activities.

Indigenous Microbiota to Leverage Traditional Dry Sausage Production

The main issue addressed in this review is the need for innovation in the artisanal production of dry fermented sausages—leveraging rather than discarding tradition, together with some practical strategies available to achieve it. Throughout the text, emphasis is placed on the autochthonous microbiota responsible for the identity and unique sensory characteristics of these products. The available strategies to introduce innovation in this manufacturing process rely on metabolic flexibility of microbial strains. In this sense, this review evaluates the application of several tools aimed at improving the quality and safety of artisanal dry fermented sausages focusing on the microbial community role. The most studied alternatives to enhance dry sausage production comprise the use of autochthonous starter cultures—including functional and/or probiotic strains, the production of bacteriocins, and the generation of bioactive peptides, which have been thoroughly covered herein. The purpose of this work is to review recent research about novel different strategies available for food technologists to improve safety and quality in the manufacture of dry fermented sausages. Additional support strategies—quality product registers and innovation through tradition—have been suggested as complementary actions towards a successful introduction of indigenous microbial communities into traditional dry sausage production.