scholarly journals Exploration of the Microbial Biodiversity Associated with North Apulian Sourdoughs and the Effect of the Increasing Number of Inoculated Lactic Acid Bacteria Strains on the Biocontrol against Fungal Spoilage

Fermentation ◽  
2019 ◽  
Vol 5 (4) ◽  
pp. 97 ◽  
Author(s):  
Mattia Pia Arena ◽  
Pasquale Russo ◽  
Giuseppe Spano ◽  
Vittorio Capozzi
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Shelf Life ◽  
Restriction Analysis ◽  
Rflp Analysis ◽  
Food Preservation ◽  
Rrna Gene ◽  
Microbiological Analysis ◽  
Bread Making ◽  
Dna Restriction

In this study, we explored the diversity of yeasts and lactic acid bacteria (LAB) associated with six spontaneous sourdough fermentations from the northern part of the Apulian region (Italy). Bacterial and yeast isolates from sourdough were investigated by amplified ribosomal DNA restriction analysis (ARDRA) and restriction fragment length polymorphism (RFLP) analysis, respectively. The identification of the isolates was confirmed by sequencing bacterial 16S gene and yeast ITS1–5.8S–ITS2 rRNA gene amplicons. Microbiological analysis of all sourdough samples revealed that LAB and yeast counts ranged between 1.7 × 105 and 6.5 × 108 cfu/g, and 7.7 × 105 and 2.5 × 107 cfu/g, respectively. The molecular identification at species level revealed the occurrence of Lactobacillus plantarum as the dominant LAB and Saccharomyces cerevisiae as the dominant yeast species in all different sourdough samples. Then, the ability of all isolated strains to inhibit and/or reduce the growth of several selected fungi was valued through the overlay method. In light of their antifungal performances, ten LAB strains were inoculated, singularly and in combination, in subsequent bread-making trials. Overall, we confirmed the potential of LAB to extend the shelf life of bread through spoilage inhibition and, for the first time, we observed a synergistic effect due to the combination of several isolated LAB on the inhibition behavior against selected fungal spoilage strains. Our findings suggest the exploration of a LAB-based approach in order to extend the shelf life of bread, reducing, at the same time, the use of chemical agents for food preservation.

scholarly journals Diversity of Lactic Acid Bacteria Associated with Fish and the Fish Farm Environment, Established by Amplified rRNA Gene Restriction Analysis

2007 ◽  
Vol 73 (9) ◽  
pp. 2947-2955 ◽  
Author(s):  
Christian Michel ◽  
Claire Pelletier ◽  
Mekki Boussaha ◽  
Diane-Gaëlle Douet ◽  
Armand Lautraite ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Opportunistic Infections ◽  
Restriction Analysis ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Fish Food ◽  
Group A ◽  
Gene Restriction

ABSTRACT Lactic acid bacteria have become a major source of concern for aquaculture in recent decades. In addition to true pathogenic species of worldwide significance, such as Streptococcus iniae and Lactococcus garvieae, several species have been reported to produce occasional fish mortalities in limited geographic areas, and many unidentifiable or ill-defined isolates are regularly isolated from fish or fish products. To clarify the nature and prevalence of different fish-associated bacteria belonging to the lactic acid bacterium group, a collection of 57 isolates of different origins was studied and compared with a set of 22 type strains, using amplified rRNA gene restriction analysis (ARDRA). Twelve distinct clusters were delineated on the basis of ARDRA profiles and were confirmed by sequencing of sodA and 16S rRNA genes. These clusters included the following: Lactococcus raffinolactis, L. garvieae, Lactococcus l., S. iniae, S. dysgalactiae, S. parauberis, S. agalactiae, Carnobacterium spp., the Enterococcus “faecium” group, a heterogeneous Enterococcus-like cluster comprising indiscernible representatives of Vagococcus fluvialis or the recently recognized V. carniphilus, V. salmoninarum, and Aerococcus spp. Interestingly, the L. lactis and L. raffinolactis clusters appeared to include many commensals of fish, so opportunistic infections caused by these species cannot be disregarded. The significance for fish populations and fish food processing of three or four genetic clusters of uncertain or complex definition, namely, Aerococcus and Enterococcus clusters, should be established more accurately.

scholarly journals Effect of peroxyacetic acid spray and storage temperature on the microbiota and sensory properties of vacuum packed subprimal cuts

2021 ◽  
Author(s):  
Xianqin Yang ◽  
Hui Wang ◽  
Scott Hrycauk ◽  
Mark D. Klassen
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Shelf Life ◽  
Storage Temperature ◽  
Life Extension ◽  
Rrna Gene ◽  
Peroxyacetic Acid ◽  
Microbial Profiling ◽  
Antimicrobial Interventions ◽  
The Impact

We investigated the impact of peroxyacetic acid (PAA; 200 ppm) spray on the microbiota and shelf life of commercial vacuum packed beef stored at chiller temperatures. Ribeye cuts (n=147) were collected from a local beef plant on the day of production for two consecutive days, with one set collected at the start of work with the PAA spray nozzles turned off (control) and during the routine production with the PAA spray nozzles turned on (PAA) on each day. Packs were stored at 4, 2 and -1°C for up to 34, 104 and 180 days, and sampled at appropriate intervals for sensory assessment, microbial enumeration and microbial profiling by 16S rRNA gene amplicon analysis. Treatment with PAA did not affect the initial meat pH, the initial numbers of total aerobes, lactic acid bacteria or Enterobacteriaceae (p>0.05) before storage; however, it delayed the onset of spoilage by 7, 21 and 54 days at 4, 2 and -1°C, respectively. Square root models of the variation of growth rate with temperature indicated lactic acid bacteria grew faster and Enterobacteriaceae grew slower on PAA treated than not treated meat. Negative associations between pH and deterioration of meat during storage were observed for PAA treated meat. During storage, the microbiota were primarily dominated by Carnobacterium and Lactobacillus/Lactococcus on control meat, but by Leuconostoc on PAA treated meat. Serratia, Yersinia and Clostridium were identified by LEfSe analysis as biomarkers for control meat, the latter of which was found in high abundance in samples that had the highest spoilage scores. IMPORTANCE The findings of this study show that PAA solutions applied at low concentrations under commercial settings positively modulated the meat microbiota. It did not have bactericidal effects for beef subprimals with very low microbial load. However, it differentially impacted the members of the microbiota, which resulted in delayed onset of spoilage of vacuum packed beef subprimal stored at all three temperatures (4, 2 and -1°C). This differential impact could be through one or a combination of the following factors: favoring the growth of lactic acid bacteria which may in turn exert a competitive exclusion that might be due to production of antimicrobial compounds such as organic acids and bacteriocins; exerting synergistic antimicrobial effects with low temperatures against members of Enterobacteriaceae; direct or indirect inhibitory effects against members of clostridia. These findings not only advance our understanding of the microbial ecology of vacuum packed meat stored at chiller temperatures, but also suggest bacteriostatic concentrations of antimicrobial interventions can be explored for shelf life extension.

Morphological and Molecular Characterization of Lactic acid Bacteria from intestine of Freshwater Fishes and Their Possible Role in Probiotic Feeding in Aquaculture

2015 ◽  
Vol 5 (3) ◽  
pp. 101-106
Author(s):  
Dinesh Kumar Kumawat ◽  
Nadim Chishty
Keyword(s):  
Antibacterial Activity ◽  
Lactic Acid ◽  
Salt Tolerance ◽  
Lactic Acid Bacteria ◽  
Bile Salt ◽  
Micrococcus Luteus ◽  
Food Preservation ◽  
Rrna Gene ◽  
Gram Staining

  Lactic acid bacteria (LAB) are a group of gram positive, non spore forming, cocci or rod shaped, catalase negative organisms. Generally they are known as "GRAS" (Generally Recognized As Safe) organisms. In the present study, an attempt was made to isolate lactic acid bacteria from gut of two freshwa-ter fishes in Udaipur region to obtain various efficient LAB strains for indus-trial applications. A total of 12 bacterial isolates were isolated from different fishes caught from Pichola lake, Udaipur on MRS agar at 37oC. All the isolates were tested for catalase activity, colony morphology and gram staining. Further these isolates were checked for technological properties (antibacterial activity, antibiotic susceptibility and bile salt tolerance). Based on technologi-cal properties results, two isolate (F-4 & F-11) have been tentatively selected for use as probiotic cultures in the aquaculture industries. They have strong antibacterial activity against various pathogens viz. Staphylococcus aureus (ATCC 9144), Micrococcus luteus (ATCC 10240), Listeria monocytogens (MTCC 1143) and have bile salt tolerance limit up to 0.7%. These are the main features for selection of probiotic candidates. To differentiate the same species molecular typing was attempted, 16S rRNA gene amplification was done using specific 16S rDNA primers and amplified gene products were di-gested with different restriction endonuclease enzymes viz EcoRI and HindIII. A total of 2 different groups out of 12 isolates were obtained. This finding reveals that isolated LAB are useful for aquaculture and also used in food preservation.

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

Foods ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 99 ◽  
Author(s):  
Jacobo López-Seijas ◽  
Belén García-Fraga ◽  
Abigail F. da Silva ◽  
Xavier Zas-García ◽  
Lucía C. Lois ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Restriction Analysis ◽  
Reca Gene ◽  
Quality And Safety ◽  
Volatile Phenols ◽  
Biogeographical Distribution ◽  
Genus Lactobacillus ◽  
Identification Of Species ◽  
Dna Restriction

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.

scholarly journals Diversity and Antimicrobial Activity towards Listeria spp. and Escherichia coli among Lactic Acid Bacteria Isolated from Ready-to-Eat Seafood

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 271
Author(s):  
Jelena Stupar ◽  
Ingunn Grimsbo Holøymoen ◽  
Sunniva Hoel ◽  
Jørgen Lerfall ◽  
Turid Rustad ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Antimicrobial Effect ◽  
Food Preservation ◽  
Rrna Gene ◽  
E Coli ◽  
Preservation Technology ◽  
Smoked Salmon

Biopreservation is a food preservation technology using microorganisms and/or their inherent antimicrobial metabolites to inhibit undesirable microorganisms. The aim of the present study was to explore the diversity and antimicrobial activity of lactic acid bacteria (LAB) strains (n = 99) isolated from ready-to-eat (RTE) seafood (cold-smoked salmon (CSS), gravlax, and sushi) towards two strains of Listeria monocytogenes (CCUG 15527, F11), Listeria innocua (CCUG 15531) and Escherichia coli (CCUG 38079). The LAB strains were assigned to five different genera (Carnobacterium spp., Lactobacillus spp., Leuconostoc spp., Weissella spp., and Enterococcus sp.) by sequencing a 1150 bp stretch of the 16S rRNA gene. A significant association between the seafood source and the distribution of LAB genera was found (p < 0.001), of which Leuconostoc spp. were most prevalent in sushi and Carnobacterium sp. and Lactobacillus sp. were most frequently isolated from CSS and gravlax. Antimicrobial activity among the LAB was significantly affected by LAB genera (F= 117.91, p < 0.001, one-way ANOVA), product of origin (F = 3.47, p < 0.05), and target (F = 4.64, p = 0.003). LAB isolated from sushi demonstrated a significantly higher antimicrobial effect than LAB from CSS and gravlax (p < 0.05). In general, a significantly higher antimicrobial activity was found towards Listeria spp. than E. coli (p < 0.05). However, Leuconostoc spp. demonstrated similar antimicrobial effects towards E. coli and Listeria spp., except for L. monocytogenes F11 being more sensitive (p < 0.05). This study suggested that seafood-derived LAB strains could be selected for technological application in RTE seafood systems.

scholarly journals Isolation and Characterization of Lactic Acid Bacteria and Yeasts from Typical Bulgarian Sourdoughs

2021 ◽  
Vol 9 (7) ◽  
pp. 1346
Author(s):  
Mariana Petkova ◽  
Petya Stefanova ◽  
Velitchka Gotcheva ◽  
Angel Angelov
Keyword(s):  
Lactic Acid ◽  
Sequence Analysis ◽  
Lactic Acid Bacteria ◽  
Antimicrobial Properties ◽  
Matter Content ◽  
Starter Cultures ◽  
Rrna Gene ◽  
Dry Matter Content ◽  
Isolation And Characterization ◽  
Selection Of

Traditional sourdoughs in Bulgaria were almost extinct during the centralized food production system. However, a rapidly developing trend of sourdough revival in the country is setting the demand for increased production and use of commercial starter cultures. The selection of strains for such cultures is based on geographical specificity and beneficial technological properties. In this connection, the aim of this study was to isolate, identify and characterize lactic acid bacteria (LAB) and yeasts from typical Bulgarian sourdoughs for the selection of strains for commercial sourdough starter cultures. Twelve samples of typical Bulgarian sourdoughs were collected from different geographical locations. All samples were analyzed for pH, total titratable acidity and dry matter content. Enumeration of LAB and yeast was also carried out. Molecular identification by 16S rDNA sequence analysis was performed for 167 LAB isolates, and 106 yeast strains were identified by ITS1-5.8S-ITS2 rRNA gene partial sequence analysis. The LAB strains were characterized according to their amylolytic and proteolytic activity and acidification capacity, and 11 strains were selected for further testing of their antimicrobial properties. The strains with the most pronounced antibacterial and antifungal activity are listed as recommended candidates for the development of starter cultures for sourdoughs or other food products.

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