Starter Lactic Acid Bacteria Research Articles

Detection of Enteric Viruses and Core Microbiome Analysis in Artisanal Colonial Salami-Type Dry-Fermented Sausages from Santa Catarina, Brazil.

Microbial fermentation plays an important role in the manufacturing of artisanal sausages and can have major effects on product quality and safety. We used metagenomics and culture-dependent methods to study the presence of Hepatitis E virus (HEV) and Rotavirus-A (RV-A), and fungal and bacterial communities, in artisanal Colonial salami-type dry-fermented sausages in Santa Catarina state, Brazil. Lactic acid bacteria (LAB) and yeast dominated the microbiome. Latilactobacillus sakei and Debaryomyces hansenii were ubiquitous and the most abundant species. The DNA of some foodborne pathogens was found in very low concentrations although viable cells of most of these species were undetectable by cultivation methods. The characteristics of the raw material and hygiene of the artisanal sausage manufacturing process resulted in high loads of beneficial microorganisms and the absence of HEV and RV-A viruses as determined by RT-qPCR assays. In conclusion, high LAB load in sausages was more relevant to preventing pathogen growth than the ripening time and/or physicochemical characteristics. However, the presence of Clostridium spp. and other pathogens in some samples must be taken into account for the development of future preservation methods; appropriate LAB starter cultures and health surveillance are required in the production process to prevent foodborne outbreaks.

FERMENTE SALAMURA OTLARDAN İZOLE EDİLEN MAYALARIN ENZİMATİK KARAKTERİZASYONU

This study aims to identify yeasts from spontaneously fermented herbs used for Van herby cheese and to evaluate their enzymatic activities. Sequencing of partial 26S rRNA gene revealed the species of Pichia membranifaciens (n = 8), Kazachstania servazzii (n = 6), Debaryomyces hansenii (n = 2), Kluyveromyces marxianus (n = 2), and Pichia fermentans (n = 2). Enzyme profiles were determined using API-ZYM strips. The isolates had diverse enzyme activities, including alkaline and acid phosphatase, esterase, esterase lipase, aminopeptidases, and proteases mostly at different levels, which may have crucial roles during ripening of the cheese. K. marxianus M8.1, D. hansenii M6.1, and M6.3, P. membraniciens M13.1, M13.2, and M14.1 had superior and diverse enzymatic characteristics. Such enzymatic activities could be of great technological importance for the determination of adjunct culture along with starter lactic acid bacteria for the production of Van herby cheese.

Phenol content and antioxidant activity in seaweed fermented with lactic acid bacteria

Antioxidants and antimicrobials are rich in seaweed. Seaweed has been used as food for a long time and the potency to be used as a functional food. One of the most versatile foods is fermented beverages. Fermentation can increase the amount of antioxidants. This study aims to determine seaweed (Gelidium sp. and Eucheuma cottonii) extract fermentation with lactic acid bacteria (LAB), namely Lactobacillus plantarum and Lactobacillus acidophilus, as a starter on phenol content and antioxidant activity. The method used was an experimental laboratory. The seaweed was obtained from Yogyakarta. Seaweed extract was given a LAB starter and then fermented for 24 hrs. The samples were analyzed before and after fermentation in parameter reducing sugar, TPC, LAB viability, pH, phenol content, and antioxidant activity IC50 tests. The result showed that both in Gelidium sp. and Eucheuma cottonii, reducing sugar does not change before and after fermentation with the LAB starter. Fermentation could increase the TPC, LAB viability, phenol content, antioxidant activity IC50, and lower the pH sample. Eucheuma cottonii fermented with L. acidophilus gives the best characteristic of antioxidant.

Lactic acid bacteria starter in combination with sodium chloride controls pathogenic Escherichia coli (EPEC, ETEC, and EHEC) in kimchi

Kimchi is one of the primary sources of high sodium content in the Korean diet. Low-sodium kimchi is commercially manufactured to minimize the health effects of high salt. We investigated the influence of lactic acid bacteria (LAB) as starter culture in combination with 1% or 2.5% salt on the survival of pathogenic Escherichia coli and physicochemical properties of kimchi during fermentation at 10 °C and 25 °C. Among ten strains of LAB isolated from kimchi, Leuconostoc mesenteroides (KCTC 13374) and Lactobacillus plantarum (KCTC 33133) exhibited antimicrobial activities against pathogenic E. coli (EPEC, ETEC, and E. coli O157:H7) and strong tolerance to low pH (2 and 3) and 0.3% bile salts. Thus, L. mesenteroides and L. plantarum were used as starter cultures for kimchi that contained 1% and 2.5% salt. All pathogenic E. coli strains survived in kimchi regardless of starter cultures or salt concentration for over 15 days at 10 °C, but they died off within 4 days at 25 °C. Survival of pathogenic E. coli was better in naturally fermented kimchi (titratable acidity:0.65%) than kimchi fermented with starter cultures (titratable acidity:1.0%). At 10 °C, the average delta value of E. coli O157:H7 (16.15 d) was smaller than those of EPEC (20.76 d) and ETEC (20.20 d) in naturally fermented kimchi. Overall, survival ability of E. coli O157:H7 was lower than EPEC and ETEC, although differences were not significant. Reduced salt concentration from 2.5% to 1% in kimchi did not affect the growth of LAB and the fermentation period. Pathogenic E. coli died at a faster rate in kimchi fermented with starter cultures and 1% salt than in naturally fermented kimchi with 2.5% salt.

Effect of Different Pediococcus pentosaceus and Lactobacillus plantarum Strains on Quality Characteristics of Dry Fermented Sausage after Completion of Ripening Period

The aim of this study was to evaluate the effect of three different strains of lactic acid bacteria (LAB) starter cultures: Pediococcus pentosaceus (KC-13100) (PP), Lactobacillus plantarum (KCTC-21004) (LP1), and L. plantarum (KCTC-13093) (LP2) on the physicochemical and microbiological characteristics, and sensory quality of dry fermented sausages after 21 days of drying and ripening period. Treatments added with PP and LP2 strains showed a significant higher (p<0.05) LAB and total plat counts, and water activity (aw) of all three treatments was below 0.85 after the completion of the ripening process. A significant variation (p<0.05) in pH values of treatments was exhibited due to the difference in acidification capacity of the LAB strains: LP2<PP<LP1. Treatments had significant difference (p<0.05) in the thiobarbituric acid reactive substances (TBARS) content, in the following order: LP1>PP>LP2. Substantial variations (p<0.05) in shear force values were detected amongst three batches (LP2>LP1>PP). In sensory attributes, PP treated samples had significantly higher (p<0.05) color and overall acceptability scores. The current findings proved how important the optimal assortment of starter culture. Inoculation with PP produced importantly beneficial effects on sensory quality improvement of dry fermented sausage.

Reclaiming lost nutrition

Reclaiming lost nutrition

SCREENING OF ANTI-CLOSTRIDIAL LACTIC ACID BACTERIA STRAINS ISOLATED FROM URUGUAYAN DAIRY FARMS

A total of 130 strains of lactic acid bacteria (starter lactic acid bacteria -SLAB- and non-starter lactic acid bacteria -NSLAB-) were isolated from milk, whey and cheese. Anti-clostridial activity was detected in 56 isolates against Clostridium tyrobutyricum ATCC 25755. Seven strains with the highest inhibitory activity were selected to determine their inhibitory mechanisms. Anti-clostridial activity of strains Streptococcus macedonicus 23, S. macedonicus 24, Lactobacillus casei/paracasei 29 and Lactobacillus rhamnosus 104 was due to organic acids production. Inhibitory mechanisms of strains L. casei 26 and 95 were acid production, bacteriocin and hydrogen peroxide. While anti-clostridial activity of Lactobacillus delbrueckii subsp. bulgaricus 76 was due to acid and hydrogen peroxide production. Cell-free supernatants obtained from strains 26, 95 and 76 conserved their anti-clostridial activity after thermal treatments at 70 and 100 °C. Supernatants obtained from bacteriogenic strains 26 and 95 were analyzed by RP-HPLC. RP-HPLC fractions with anti-clostridial activity were analyzed by mass spectrometry (MALDI-TOF). A peptide with molecular weight of 1162.54 Da was detected in HPLC fraction of L. casei 95. No results were obtained for MALDI-TOF analysis of another HPLC fractions. Based on the thermostability and low molecular weight, L. casei 95 anti-clostridial peptide would belong to a class I or II bacteriocin according to Gram-positive bacteria antimicrobial peptides classification.

Lacticaseibacillus casei SJRP38 and buriti pulp increased bioactive compounds and probiotic potential of fermented milk

The effect of passion fruit and buriti pulps on probiotic and starter lactic acid bacteria growth and on fermented milk (FM) was evaluated. Buriti pulp showed higher amounts of lipids, total phenolic compounds (PC), β-carotene, lycopene and antioxidant activity (AA) than passion fruit. However, passion fruit was used more efficiently as a carbon source by all strains. Lacticaseibacillus casei SJRP38 showed the best results in the presence of passion fruit (1.8 log CFU/mL increase compared to the initial population) and the lowest reduction in the presence of buriti, thus it was selected to produce FM. Acidified milk (AM) with the same fruit pulps was used as a control. The buriti pulp did not affect the kinetic parameters of FM compared to the control. However, the addition of fruit pulps increased the PC in both FM and AM, and FM showed a greater increase (33.4–141.6%) than AM (21.4%–87.9%). Also, buriti pulp was able to increase (6–8%) the AA of the FM when compared to the AM. FM with buriti pulp stood out for its high amount of total PC, which indicates its high potential to be used as a functional food.

Metataxonomic analysis of microbiota from Pakistani dromedary camelids milk and characterization of a newly isolated Lactobacillus fermentum strain with probiotic and bio-yogurt starter traits.

This study was undertaken to investigate the starter and probiotic potential of lactic acid bacteria isolated from dromedarian camel's milk using both culture-dependent and -independent approaches and metataxonomic analysis. Strains of lactic acid bacteria recovered were examined in vitro for tolerance to gastric acidity, bile, and lysozyme. Bile salt hydrolysis, serum cholesterol-lowering, oxalate degradation, proteolytic activity, exopolysaccharide production, and cell surface characteristics necessary for colonizing intestinal mucosa were also evaluated. A single strain of the species, Lactobacillus fermentum named NPL280, was selected through multivariate analysis as it harbored potential probiotic advantages and fulfilled safety criteria. The strain assimilated cholesterol, degraded oxalate, produced exopolysaccharides, and proved to be a proficient alternate yogurt starter with good viability in stored bio-yogurt. A sensorial analysis of the prepared bio-yogurt was also found to be exemplary. We conclude that the indigenous L. fermentum strain NPL280 has the desired traits of a starter and adjunct probiotic culture for dairy products.

Effects of Glycine and Lactic Acid Bacteria Starter on the Quality, Function and Bacterial Community of Pickles

Effects of Glycine and Lactic Acid Bacteria Starter on the Quality, Function and Bacterial Community of Pickles

Functional Genomics, Metabolic Engineering and Mutagenesis Study of Lactic Acid Bacterial Strains in Traditional Food Fermentation, Human Health and Their Potential Applications

In the past decades, functional genomics, metabolic engineering and mutagenesis screening have been reported on lactic acid bacteria found in food fermentation. The identification and adaptation of novel processes are being researched and applied into the artisanal and industrial fermentation of foods. Genomics and metabolic engineering have been identified and these innovative processes have been shown to optimize the production of metabolites and enhance the functionality of fermented foods production and processing. In the long history, lactic acid bacteria have been used as a probiotic as well as starter functioning for various traditional food fermentation and human health. Novel probiotic microbial starter cultures are being formulated having diverse health benefits and being used for the production of fermented foods and beverages, functional foods and nutraceuticals and single cell protein. In the last decade, functional genomics approaches have been reported for lactic acid bacteria found in diary fermentation products. However, functional and comparative genomic studies have targeted a variety of foods where much attention has been focused on starter lactic acid bacteria and non-starter lactic acid bacterial microbial strains. This review is focusing on the potential of functional genomic, metabolic engineering and mutagenesis approaches to unravel the molecular processes in lactic acid bacteria used in industrial fermentation process that determine their functional efficacy in food industry. Keywords: Fermentation, Genomics, Lactic acid bacteria, Metabolic engineering, Mutagenesis DOI: 10.7176/ALST/83-03 Publication date: November 30 th 2020

Genomics of tailless bacteriophages in a complex lactic acid bacteria starter culture

Our previous study on a model microbial community originating from an artisanal cheese fermentation starter revealed that bacteriophages not only co-exist with bacteria but also are highly abundant. Here we describe the genomic content of phage particles released by 6 different strains in the starter culture. The identified prophages belong to three different subgroups of the Siphoviridae P335 phage group. Remarkably, most analysed prophages show disruptions in different tail encoding genes, explaining the common tailless phenotype. Furthermore, a number of potentially beneficial features for the host carried by prophages were identified. The prophages carry up to 3 different phage defence systems per genome that are potentially functional in protecting the host from foreign phage infection. We suggest that the presumably defective prophages are a result of bacteria-phage coevolution and could convey advantages to host bacteria.

Thermophilic lactic acid bacteria affect the characteristics of sourdough and whole-grain wheat bread

Application of selected starter cultures for sourdough propagation may ensure stable lactic acid bacteria (LAB) diversity and defined properties of sourdough that affect quality. The impact of Lactobacillus delbrueckii ssp. bulgaricus MI, L. rossiae GL14 and L. acidophilus DSM 20079 as starter cultures were investigated for spoilage prevention and whole-grain wheat and sourdough bread properties. Whole-grain wheat sourdough propagated with these strains showed high phytase, amylase and xylanases activities. The highest phytase activity was obtained in sourdough prepared with L. bulgaricus MI. The results of gas chromatography–mass spectrometry using solid-phase microextraction showed that the compositions of volatile compounds in sourdough and whole-grain wheat bread depended on the LAB starter. In bread with L. acidophilus, 3-octen-2-ol and n-hexadecane were found, whereas those compounds were not found in other bread samples or in sourdough. Tetrahydrofurfuryl acetate was found only in bread prepared with L. bulgaricus MI sourdough. N-Pentadecane was found only in bread prepared with L. rossiae sourdough and bread prepared with spontaneous sourdough. The application of thermophilic sourdough increased bread porosity, elasticity, crumbliness and moisture content, but did not influence crumb hardness. Moreover, the fungal spoilage on the bread crust surface was suppressed using sourdough prepared with thermophilic LAB. The strain of LAB used for sourdough preparation influenced the shelf-life of bread.

Sensory and Physicochemical Characterization of Sourdough Bread Prepared with a Coconut Water Kefir Starter.

There is a recognized need for formulating functional food products using selected lactic acid bacteria (LAB) starter cultures from various sources such as kefir, yoghurt or kombucha that have health benefits. The principle objective of this study was to investigate the use of a coconut water kefir-based fermentation starter culture using Lactobacillus fermentum and Lactobacillus plantarum to develop a sourdough bread. Check-all-that-apply (CATA) sensory profiling was used in this study to evaluate the sensory profile of sourdough breads that varied with culture type, culture concentrations, with and without added yeast, and with fermentation for 18 and 24 h. Based on correspondence analysis (CA) of the CATA results, bread samples with positive sensory attributes were chosen for further physicochemical analysis. Physicochemical analyses (texture, proximate composition, shelf life, carboxylic acid analysis and amino acid analysis) were carried out on breads formulated with starter culture concentrations of 8.30 log CFU/mL of L. fermentum, 4.90 log CFU/mL of L. fermentum and 9.60 log CFU/mL of L. plantarum, each fermented for 24 h without baker’s yeast. The bread sample that was formulated with a coconut water kefir (CWK) starter culture containing 9.60 log CFU/mL of L. plantarum, without dry yeast and fermented for 24 h, had significantly higher values for almost all amino acids and a lower protein content compared to samples formulated using CWK cultures containing 8.30 log CFU/mL of L. fermentum and 4.90 log CFU/mL of L. fermentum, both without dry yeast and fermented for 24 h. The bread sample formulated with CWK starter culture containing 9.60 log CFU/mL of L. plantarum, without dry yeast and fermented for 24 h, also produced significant quantities of organic acids (pyruvic acid, acetic acid, lactic acid and succinic acid). These changes in the physicochemical properties can improve overall bread quality in terms of flavor, shelf life, texture and nutritional value.

Malt and wort bio-acidification by Pediococcus acidilactici HW01 as starter culture

In a previous study, indigenous bacteriocin-producing Pediococcus acidilactici HW01 was isolated from malt. The bacterium was chosen as it is properly adapted to the malting conditions, and it showed a strong antagonistic effect against beer-spoilage lactic acid bacteria (LAB) in the previous study. Strain HW01 was added to the malting process for bio-acidification and bio-preservation of LAB. Changes in the microorganisms, enzymes, pH, total soluble nitrogen, free amino nitrogen, colour, filtration time and viscosity of wort were compared with the control. The LAB starter culture improved several characteristics of malt modification, such as microbiological stability, viscosity and filtration time. Especially, the starter culture protected the malt from the beer-spoilage bacteria of the genus Pseudomonas, by producing several acids and antimicrobial substances. The potential of using HW01 strains for bio-acidification and the bio-preservation of LAB are discussed.

Probiotic Potential of Lactic Acid Starter Cultures Isolated from a Traditional Fermented Sorghum-Millet Beverage.

The purpose of this study was to establish the probiotic potential of lactic acid bacteria (LAB) starter cultures, Lb. plantarum MNC 21, L. lactis MNC 24, and W. confusa MNC 20, isolated from a traditionally fermented sorghum-millet beverage from Uganda. The cultures were examined for tolerance to acid and bile salts, bile salt hydrolase (BSH) activity, antibiotic susceptibility, biogenic amine production, mucin degradation, hydrophobicity, auto-aggregation, adherence to the ileum, coaggregation, and antimicrobial properties against selected pathogenic species. Lb. rhamnosus yoba 2012, a known probiotic, was the reference. The isolates were tolerant to acid (pH = 3) and bile (1%). W. confusa MNC 20 and Lb. plantarum MNC 21 exhibited medium BSH activity (11–15 mm diameter of hydrolysis zone) while L. lactis and Lb. rhamnosus yoba 2012 exhibited low BSH activity (<10 mm diameter of hydrolysis zone). All isolates lacked mucolytic activity. Lb. plantarum MNC 21 and W. confusa MNC 20 produced agmatine. The candidate and reference microorganisms were resistant to 10 of 21 and 5 of 21 antibiotics, respectively. The isolates exhibited hydrophobic, auto-aggregation and coaggregation properties. These three properties were exhibited more (p < 0.05) by the reference than the potential probiotics. The ability of the potential probiotics to attach onto the goat ileum (7.3–8.0 log cfu/cm2) was comparable to that of Lb. rhamnosus yoba 2012 (7.6 log cfu/cm2). The four LAB inhibited E. coli, S. aureus, and S. enterica to the same extent (p < 0.05). The findings indicated potential probiotic activity of the starter cultures. However, further in vivo examination of these isolates is required to confirm their probiotic capabilities.

Microbiological and Physicochemical Qualities of Moo Som (Traditional Thai Fermented Meat) Inoculated with Lactic Acid Bacteria Starter

The effects of different strains of lactic acid bacteria (LAB) inoculation on the fermentation rates and qualities of moo som, a traditional Thai fermented pork, were evaluated. Lactobacillus plantarum KL102 (spontaneous starter) and L. plantarum TISIR543 (commercial starter) were used as starter cultures in the production of moo som. The decreased amounts of Staphylococcus aureus and coliforms in moo som inoculated with L. plantarum KL102 were at faster rates than those in Moo som inoculated with L. plantarum TISIR543. However, the final products of moo som inoculated with both LAB starters did not find S. aureus or and coliform loadings. Inoculation of both LAB starters could control growth of yeast in samples during fermentation. Furthermore, both starter cultures exhibited a higher rate of fermentation than the control (without inoculum), as demonstrated by the faster rate pH drop and acid production (p &lt; 0.05) during fermentation, while the fermentation of all samples were completed within 3 d. Due to higher acid production rate, texture, and especially hardness, gumminess and chewiness of inoculated moo som were higher than control moo som in the final products (p &lt; 0.05). From the results, the inoculation of LAB starter was more beneficial in color and in overall sensory evaluation (p &lt; 0.05). The overall quality was positively correlated with the color, odor, and texture of moo som (p &lt; 0.01). Based on microbiological and physicochemical qualities and sensory evaluation, KL102 is a potential LAB starter for moo som production.

Effects of combining two lactic acid bacteria as a starter culture on model kimchi fermentation

This study aimed to establish a mixed starter culture to standardize the flavor of kimchi, a traditional Korean food. Leuconostoc mesenteroides and Lactobacillus sakei were selected for the culture based on their key roles in kimchi fermentation. The effects of various starter culture mixing ratios on the overall fermentation process were investigated. Fermentation was carried out at 15 °C for 72 h. In the microbial community analysis, a similar ratio to the initial mixed inoculated ratio was observed in the microbial environments. Treatment with high-rate L. mesenteroides inoculation, exhibiting hetero-fermentative characteristics, led to the production of mannitol (1393.11 mg/100 g), acetic acid (57.70 mg/kg), and lactic acid (1141.90 mg/kg), in addition to the induction of a rapid increase in the number of viable cells, thereby reducing the pH (pH 3.9). Conversely, treatment with high-rate L. sakei inoculation, exhibiting homo-fermentative characteristics, led to the production of less mannitol and acetic acid, with more lactic acid. Principal component analysis score plots showed a distinct difference in kimchi metabolites depending on the lactic acid bacteria (LAB) starter culture. Therefore, by using mixed LAB starter strains, this study demonstrated the value of various characteristics and standardized manufacturing of kimchi. LAB types and inoculation ratios greatly affected the types and concentration of metabolites in kimchi fermentation.

Nutritional, Functional, and Technological Characterization of a Novel Gluten- and Lactose-Free Yogurt-Style Snack Produced With Selected Lactic Acid Bacteria and Leguminosae Flours.

Aiming at meeting consumers’ requirements for healthy foods, dietary needs (vegetarianism, lactose- and gluten-free), as well as the nutrition recommendations of the Health Authorities in terms of protein, fibers and bioactive compounds, the present study proposes a novel yogurt-style snack made with plant-derived ingredients. The biotechnological protocol includes the fermentation of a thermal-treated blend of cereal and legume flours by the selected lactic acid bacteria (LAB) Lactoplantibacillus plantarum DSM33326 and Levilactobacillus brevis DSM33325. The yogurt-style snack was characterized by protein and fiber concentration of 3 and 4%, respectively, and a low-fat content. Compared to the unfermented control, the yogurt-style snack was characterized by a significant higher concentration of free amino acids and lower contents of the antinutritional factors, i.e., phytic acid, condensed tannins, saponins and raffinose (up to 90%) mainly due to the LAB metabolic activity. Hence, an in-vitro protein digestibility of 79% and improvements of all the nutritional indexes related to the quality of the protein fraction (e.g., GABA) were achieved at the end of fermentation. According to the Harvard Medical School recommendations, the novel snack can be potentially classified as low-glycemic index food (53%). Antioxidant properties of the fermented snack were also improved by means of increased the total phenol content and radical scavenging activity. High survival rate of the starter LAB and a commercial probiotic (added to the snack) was found through 30 days storage under refrigerated conditions. The biotechnological protocol to make the novel snack here proposed is suitable for the large-scale application in food industry, giving a platform product with a peculiar and appreciated sensory profile.

Quality characteristics of fermented mushroom and vegetable product using a mixed starter of lactic acid bacteria

Lactic acid fermentations can be performed through inoculation in order to ensure consistent product quality and safety. This research investigates the effect of the use of Lactobacillus plantarum and Lactobacillus johnsonii as a mixed starter in mushroom and vegetables fermentation on its product quality. The fermented product showed pH, titratable acidity and total phenolic content of 4.01±0.02, 1.00±0.03% and 519±11 mg GAE/kg respectively. Lactic acid bacteria counts in the fermented product were between 8.5-9.5 log cfu/g throughout the storage time. The results from this research suggests quality satisfaction of the fermented product in microbial, chemical and sensory after 30-day storage at 4C. This study showed that the fermented mushroom and vegetable product has the potential to be used as a probiotic carrier food.