Traditional Fermented Milk Research Articles

Comparing the Quality Properties of Cow Milk and Hazelnut Milk Fermented by Viili Yogurt Culture

ABSTRACT Viili is ropey and sticky traditional fermented milk that originated in Scandinavia. In this study, raw hazelnut milk (HM) with a nutritionally rich composition was used in developing new plant-based fermented products by using Viili starter cultures in order to produce health-promoting and functional plant-based dairy-like products. For this purpose, physicochemical, microbiological, and sensory properties were determined by producing Viili yogurt from both raw cow milk (VY) and fermented HM. Microbial analysis results showed that the defined formulation yielded high probiotic survivals (6.68–7.14 log CFU/g of TMAB, 6.90–7.85 log CFU/g of yeast-mold, 5.80–7.91 log CFU/g of LAB, and 5.14–7.60 log CFU/g of Lactococcus spp.) during the storage period. Sensory analysis showed that the properties of FHM such as color and appearance, structure, consistency, flavor, and odor were less appreciated than VY, whereas some other properties were found to be sufficient for consumption.

Application of Lactic Acid Bacteria (LAB) in Sustainable Agriculture: Advantages and Limitations.

Lactic acid bacteria (LAB) are significant groups of probiotic organisms in fermented food and are generally considered safe. LAB regulate soil organic matter and the biochemical cycle, detoxify hazardous chemicals, and enhance plant health. They are found in decomposing plants, traditional fermented milk products, and normal human gastrointestinal and vaginal flora. Exploring LAB identified in unknown niches may lead to isolating unique species. However, their classification is quite complex, and they are adapted to high sugar concentrations and acidic environments. LAB strains are considered promising candidates for sustainable agriculture, and they promote soil health and fertility. Therefore, they have received much attention regarding sustainable agriculture. LAB metabolites promote plant growth and stimulate shoot and root growth. As fertilizers, LAB can promote biodegradation, accelerate the soil organic content, and produce organic acid and bacteriocin metabolites. However, LAB show an antagonistic effect against phytopathogens, inhibiting fungal and bacterial populations in the rhizosphere and phyllosphere. Several studies have proposed the LAB bioremediation efficiency and detoxification of heavy metals and mycotoxins. However, LAB genetic manipulation and metabolic engineered tools provide efficient cell factories tailor-made to produce beneficial industrial and agro-products. This review discusses lactic acid bacteria advantages and limitations in sustainable agricultural development.

Development technology of starter cultures using lactic acid bacteria isolated from fermented Camel milk with cholesterol lowering ability

The aim of the study is to develop a technology of starter cultures for fermented milk using new strains of lactic acid bacteria isolated from Mongolian traditional fermented camel milk. “Khoormog” samples are collected from Inner Mongolia, China. Totally 230 Lactobacillus strains are isolated and screened by acid-, bile- tolerance, lactose decomposition and acid production ability. The cholesterol lowering abilities and adhesiveness on Caco-2 are evaluated. The top 2 strains are identified as Lactobacillus plantarum. These 2 strains are prepared as the starter cultures in milk fermentation. The development technology of starter cultures is studied.

Lactic acid bacteria isolated from Kazakh traditional fermented milk products affect the fermentation characteristics and sensory qualities of yogurt.

Lactic acid bacteria (LAB) play a crucial role in the development of the taste, texture, and aroma of traditional fermented milk products. Five LABs from Kazakh traditionally prepared dairy products showed continuous subculture stability, as well as proper acidification and coagulation ability. They were identified as Pediococcus pentosaceus (1–5, 1–7), Enterococcus faecium (1–19), and Lactobacillus plantarum (1–12, 1–15). Their coagulation time and acidity values ranged from 5.97 to 12.78 h and 76.47 to 89.39°T. Yogurts prepared with L. plantarum were more condensed and textural integrity than those with P. pentosaceus and E. faecium. Determination of the volatile compound profiles suggested a higher diversity of volatile compounds than the control. The sensory evaluation presented positive overall sensory quality scores for the yogurts prepared with 1–12 and 1–15. The results provide additional information regarding the contributions of native LABs to the unique flavor and sensory qualities of traditionally prepared milk products. They may help to select starters or adjunct starters for developing distinctive, traditional nomadic fermented milk to satisfy consumer demand and increase market acceptability.

Evaluation of the Probiotic Potential of Lactobacillus delbrueckii ssp. indicus WDS-7 Isolated from Chinese Traditional Fermented Buffalo Milk In Vitro.

The present study aimed to evaluate the probiotic potential of lactic acid bacteria (LAB) isolated from Chinese traditional fermented buffalo milk. Out of 22 isolates, 11 were putatively identified as LAB preliminarily. A total of six LAB strains displayed strong adhesion to HT-29 cells and all these strains showed preferable tolerance to artificially simulated gastrointestinal juices. WDS-4, WDS-7, and WDS-18 exhibited excellent antioxidant capacities, including DPPH radical, ABTS+ radical, and superoxide anion scavenging activities. Compared with the other two LAB strains, WDS-7 had a stronger inhibition effect on four pathogens. Based on the 16S rRNA gene sequencing and phylogenetic analysis, WDS-7 was identified as Lactobacillus delbrueckii ssp. indicus and selected to assess the potential and safety of probiotics further. The results revealed that WDS-7 strain had a strong capacity for acid production and good thermal stability. WDS-7 strain also possessed bile salt hydrolase (BSH) activity. Compared to LGG, WDS-7 was a greater biofilm producer on the plastic surface and exhibited a better EPS production ability (1.94 mg/ml as a glucose equivalent). WDS-7 was proved to be sensitive in the majority of tested antibiotics and absence of hemolytic activity. Moreover, no production of biogenic amines and β-glucuronidase was observed in WDS-7. The findings of this work indicated that L. delbrueckii ssp. indicus WDS-7 fulfilled the probiotic criteria in vitro and could be exploited for further evaluation in vivo.

Limosilactobacillus fermentum ING8, a Potential Multifunctional Non-Starter Strain with Relevant Technological Properties and Antimicrobial Activity.

Lactic acid bacteria (LAB) have gained particular attention among different exopolysaccharide-producing microorganisms due to their safety status and effects on human health and food production. Exopolysaccharide-producing LAB play a crucial role in different ways, such as improving texture, mouthfeel, controlling viscosity, and for low-calorie food production. In this study, we isolated a multifunctional strain with good exopolysaccharide production properties. Limosilactobacillus fermentum ING8 was isolated from an Indian traditional fermented milk (Dahi) and evaluated for its safety, enzymatic activity, NaCl resistance and temperature tolerance, milk coagulation, and storage stability. Finally, the complete genome of this strain was sequenced and subjected to safety in silico evaluation and genomic analysis. The results revealed that L. fermentum ING8 possesses relevant technological properties, such as exopolysaccharide production, antimicrobial activity, and galactose utilization. Besides, this strain showed very high stability to storage conditions at refrigeration temperature. In addition, the genomic analysis did not evidence any possible deleterious elements, such as acquired antibiotic resistance genes, virulence genes, or hemolysis-related genes. However, all structural genes related to the galactose operon and EPS production were detected. Therefore, L. fermentum ING8 can be considered a promising multifunctional bacterium to be proposed as non-starter in different types of dairy productions.

Lactic acid bacteria as pro-technological, bioprotective and health-promoting cultures in the dairy food industry

Lactic acid bacteria (LAB) constitute pivotal microorganisms for the food industry due to their considerable technological and functional potential. Fermented dairy products, that is ancient traditions worldwide, still have been accepted and consumed today for their nutritional and organoleptic attributes. In accordance with the current trends in the market and greater awareness of consumer well-being, a detailed assessment of the health effects of dairy product consumption has been undertaken with particular reference to the production of bioactive metabolites including i.e., γ-aminobutyric acid, conjugated linoleic acid, bioactive peptides, exopolysaccharides as well as vitamins during LAB fermentation. The long histories of yogurt, kefir, and traditional fermented milk drink as sources of some certain probiotic bacteria as well as the opportunity to bio-fortify the matrix with bioactive microbial compounds in situ make fermented dairy products an attractive model in the efforts to develop sustainable functional food systems. Therefore, this review provides the main biochemical characteristics and biotechnological application of LAB as pro-technological, bioprotective, and health-promoting in the food chain.

Isolation and Identification of Lactic Acid Bacteria from Traditional Fermented Milk "Dahi" Towards Developing Probiotic Dahi in Bangladesh

Objective: An attempt was made herein to isolate lactic acid bacteria (Lactobacillus sp. and Streptococcus thermophilus) from local Dahi to develop Dahi with isolated culture. Methods: These bacteria were identified by morphological characteristics, microscopic observation, catalase reaction, and finally examined by Polymerase Chain Reaction (PCR). Five Dahi samples (T1, T2, T3, T4, and T5) were prepared using the PCR culture. Dahi samples (T1, T2, and T3) were prepared using three Lactobacillus sp., T4 by Streptococcus thermophilus, and T5 by a combination of Lactobacillus sp. (T3) and Streptococcus thermophilus (T4) bacteria. Physicochemical, microbiological, and sensory properties were measured to assess the quality of the developed Dahi. The shelf life of the products was assessed through the determination of pH and titrable acidity of the samples measured on day 1 and 7, respectively. Results: Ash and protein percentage of T3 sample were significantly (P<0.05) better than others. The viable count was well above the minimum recommended value (106cfu/ml) in all the Dahi samples. Results of sensory properties namely taste, aroma, and overall acceptability of T3 and T4 Dahi were significantly (P<0.05) found superior compared to other samples. Conclusion: The lactic acid bacteria isolated and utilized in this study demonstrate great potential in the production of probiotic Dahi in future.

A Combined In Vitro and In Vivo Assessment of the Safety of the Yeast Strains Kluyveromyces marxianus A4 and A5 Isolated from Korean Kefir.

Kefir is a traditional fermented milk containing beneficial bacteria and yeasts. Despite Kluyveromyces marxianus, isolated from kefir, gaining increasing attention as a potential probiotic yeast owing to its biological function, Saccharomyces boulardii is the only species considered as a probiotic yeast. We evaluated the safety of K. marxianus strains A4 and A5, isolated from Korean kefir, in comparisonwith that of S. boulardii. Virulence attributes were preliminarily assessed in vitro including their ability of gelatin hydrolysis, pseudohyphae formation, and hemolysis. To evaluate in vivo safety, the strains were challenged in a healthy animal model, four-week-old female BALB/c mice. Mice were orally administered 0.2mL of 0.9% sterilized saline (NC_S; n = 6), S. boulardii ATCC MYA-796 (high concentration, S.b_H; low concentration, S.b_L; n = 6 for each), K. marxianus A4 (high concentration, A4_H; low concentration, A4_L; n = 6 for each), or K. marxianus A5 (high concentration, A5_H; low concentration, A5_L; n = 6 for each) for 2weeks. At study end, body weight, spleen and liver weights, and blood parameters were assessed. K. marxianus A4 and A5 were tested negative for gelatinase and hemolysis. Overall, hematological, plasma biochemical, and cytokine (interleukin-1β and tumor necrosis factor-α) parameters were comparable between the experimental and negative control (NC) groups. Notably, the interleukin-6 level of the A5_H group was significantly lower than that of the NC group (p < 0.05), suggesting anti-inflammatory potential of K. marxianus A5.

Antioxidant properties of lactic acid bacteria isolated from traditional fermented yak milk and their probiotic effects on the oxidative senescence of Caenorhabditis elegans.

The objectives of the current study were to screen antioxidant lactic acid bacteria (LAB) strains isolated from traditionally fermented Tibetan yak milk, and to evaluate their probiotic effects on the oxidative senescence of Caenorhabditis elegans (C. elegans). A total of 10 LAB isolates were assessed for their antioxidant activity by in vitro assays, and three strains with high activity were selected for an investigation of their probiotic functions in C. elegans. The results indicated that Lactobacillus plantarum As21 showed high anti-oxidant capacity and had a high survival rate (64%) in a simulated gastrointestinal tract. The lifespan of C. elegans treated with As21 was increased by 34.5% compared to the control group. Strain As21 also showed improved motility and enhanced resistance to heat stress and H2O2 stimulation in C. elegans. Moreover, treatment with As21 reduced the production of age-related reactive oxygen species (ROS) and malondialdehyde (MDA) damage and promoted the production of the antioxidants superoxide dismutase (SOD), catalase (CAT) and glutathione GSH. These results suggest that Lactobacillus plantarum strain As21 could be a potential probiotic strain for retarding ageing and could be used in functional foods.

Bacterial diversity of Gambian traditional fermented milk, "Kosam".

We have clarified the microbiological characterization of Gambian traditional fermented milk (FM), "Kosam." Two samples of FM were collected at two regions in The Gambia in 2019. The microbiota of these samples was analyzed by culture-dependent methods and Illumina sequencing. The number of lactic acid bacteria (LAB) in FM from Central River Region (CRR) and Lower River Region (LRR) was 8.27 ± 0.08 log CFU/ml and 7.21 ± 0.09 log CFU/ml, respectively. While no coliforms and Escherichia coli were detected in CRR-FM, LRR-FM contained 5.73 ± 0.17 log CFU/ml of coliforms and 4.82 ± 0.13 log CFU/ml of E. coli. The dominant viable LAB in FM from CRR was Lactobacillus delbrueckii, followed by Streptococcus lutetiensis, while that from LRR was Lactococcus lactis. The metagenomic analysis also revealed that these species were dominant in these Gambian traditional FM. Furthermore, it also revealed the possibility of the presence of pathogens such as Klebsiella spp. This study enhanced the knowledge of Gambian FM and contributed to the elucidation of microbial communities.

Production of Ryazhenka, a traditional Ukrainian fermented baked milk, by using electro-activated whey as supplementing ingredient and source of lactulose

In this work, electro-activated whey (EAW) was used as ingredient in the preparation of Ryazhenka, a fermented baked milk, at a supplementation level of 3 and 9%. Fermentation kinetics, viscosity, color, antioxidant capacity, and protein profiles of the final product were studied. Moreover, effect of electro-activation on β-lactoglobulin allergenicity was evaluated by a specific ELISA test. The results showed that addition of electro-activated whey as supplementing ingredient is technologically feasible in the process of Ryazhenka production. The fermentation kinetics showed that this process was in the technologically accepted interval even if the addition of EAW delayed the fermentation phase. The viscosity study showed that addition of EAW permitted to obtain a final product with good followability corresponding to good consistency of drinkable dairy beverages. Moreover, addition of EAW prevented syneresis during the refrigerated storage at 4 °C and enriched the product with lactulose which is a recognized prebiotic. The chromatic evaluation of the final product showed a compatibility of EAW with Ryazhenka which is known for its specific yellowish-brownish color. Addition or EAW significantly improved the antioxidant capacity of the Ryazhenka with values of IC50DPPH = 2.54 ± 0.02 and IC50PFRAP = 244.03 ± 28.83 for the Ryazhenka produced by adding 9% EAW to the milk after the baking process and prior to fermentation. Moreover, by using a β-lactoglobulin specific ELISA test, this study showed a significant decrease of whey and pure β-lactoglobulin allergenicity by 95%. This decrease was also observed in Ryazhenka supplemented with 9% EAW but at lower level. Thus, it can be concluded that electro-activated whey can be considered as a promising functional ingredient containing a prebiotic lactulose as functional ingredient in the dairy industry.

Characterization of the microbial community compositions and diversities in the traditional fermented yak milk from different ecotopes on the Qinghai-Tibetan plateau

This study investigated the bacterial and fungal diversities and compositions in the traditional fermented yak milk from 5 major ecotopes of the Qinghai-Tibetan plateau. Totally 47 lactic acid bacteria species or subspecies were found in the traditional fermented yak milk, and the dominant bacterial species were Lactobacillus delbrueckii, Streptococcus salivarius, and S. thermophiles. Although differences in the relative abundances of bacteria were found among the samples from 5 ecotopes, there were no correlations between the dominant lactic acid bacteria species and the pH of traditional fermented yak milk or altitude, longitude, and latitude of sampling sites. There were 9 yeast species and Saccharomyces cerevisiae, Pichia kudriavzevii and Debaryomyces hansenii were the dominant fungal species. Among the 5 ecotopes, samples from the ecotope located in the western region of the plateau with the harshest environment (altitude 4591–4977 m) had the lowest relative abundance of L. delbrueckii but the highest S. salivarius and S. thermophiles. In brief, the present study provides important information on an overview of the microbial resources in the traditional fermented yak milk from the Qinghai-Tibetan plateau, and the ecological regions had a remarkable influence on the microbial compositions in the traditional fermented yak milk.

Genetic diversity of Lactobacillus delbrueckii isolated from raw milk in Hokkaido, Japan

Lactic acid bacteria (LAB) play important roles in acid production and flavor formation in fermented dairy products. Lactic acid bacteria strains with distinct characteristics confer unique features to products. Diverse LAB have been identified in raw milk and traditional fermented milk prepared from raw milk. However, little is known about LAB in raw milk in Japan. To preserve diverse LAB as potential starters or probiotics for future use, we have isolated and identified various kinds of LAB from raw milk produced in Japan. In this study, we focused on Lactobacillus delbrueckii, one of the most important species in the dairy industry. We identified L. delbrueckii subspecies isolated from raw milk in Hokkaido, Japan, by analyzing intraspecific diversity using 4 distinct methods, hsp60 cluster analysis, multilocus sequence analysis, core-genome analysis, and whole-genome analysis based on average nucleotide identity. The subspecies distribution and a new dominant subset of L. delbrueckii from raw milk in Japan were revealed. The discovery of new strains with different genotypes is important for understanding the geographic distribution and characteristics of the bacteria and further their use as a microbial resource with the potential to express unconventional flavors and functionalities. The strains identified in this study may have practical applications in the development of fermented dairy products.

Development of starters for dairy products based on goat's milk

For milk and dairy products, 70 % of the Kazakh market accounts for the products of foreign companies. Geographically, the problem of the production of domestic products, the ecology of which is characteristic of the population of the country, has not yet been solved. The existing starter cultures are currently mainly intended for cow's milk, and are not adapted to the milk of other animal species. However, the production and processing of camel, mare and goat milk is a dairy farm with a history and traditions in the Republic of Kazakhstan. The fermentation process with the help of lactic acid bacteria is the basis for the preparation of products such as kefir, koumiss and shubat. There are data on the use of lactic acid bacteria in starters, but there is little data in studies on their use as starter cultures for camel, mare and goat milk, there are no scientific experimental results. Despite the economic rates of production of fermented products based on camel, mare and goat milk in the Republic of Kazakhstan, their production is slowed down at the industrial level due to the lack of yeast cultures and dairy technology for these types of milk. In this scientific work, fermenting consortia based on goat's milk was developed from active strains of microorganisms isolated from traditional fermented milk products, taking into account their compatibility, biochemical characteristics and scientific foundations. The technological, nutritional and microbiotic properties of the finished starters were adapted to the probiotic effect of camel, mare and goat milk by changing their composition. As a result of the study, a consortium of starters with a very high probiotic effect, safe for life, prone to survival in the digestive system was proposed.

Metagenomic features of traditional fermented milk products

This study analyzed the microbiomes of 23 Chinese koumiss samples using deep metagenomic sequencing, as well as metagenome datasets of 20 nunu, 18 kefir, and 12 yogurt samples retrieved from public genome databases. There were large variations in the microbiota composition between sample types, reflected by the great differences in their profiles of dominant species. One-hundred fifty-three metagenome-assembled genomes were assembled, including four novel species belonging to the Lactobacillus, Streptococcus, Acetobacter, Rothia genera. The novel genomes contained various gene elements, encoding carbohydrate-active enzymes, secondary metabolite clusters, and bacteriocins, which might influence food flavor, quality and/or safety. Bacteriocin-encoding genes were common, which might help control undesirable microorganisms. Our metagenomic analysis also revealed the content of bacteriophage sequences of these products, meanwhile uncovering complex interactions between fermented milk-associated bacteriophages and bacteria, including the history of bacteriophage infection and relationship between Lactobacillaceae and bacteriophages. This study highlighted the microbial diversity and heterogeneity across fermented milk products. Our data demonstrated the power of deep metagenomic sequencing in expanding our understanding of low-complexity microbial communities.

Genome Sequence of Lacticaseibacillus rhamnosus Strain NCDC610, Isolated from a Traditional Cereal-Based Fermented Milk Product (Raabadi).

ABSTRACTWe announce the draft genome sequence of Lacticaseibacillus rhamnosus NCDC610, an isolate from an Indian traditional cereal-based fermented milk product (Raabadi). The genome size of Lacticaseibacillus rhamnosus NCDC610 is 2.91 Mb with the assembled sequence, and the genome consists of 67 contigs.

Antimicrobial activity of bacteriocin like inhibitory substance (BLIS) and lactic acid bacteria (LAB) isolated from traditional fermented buffalo milk from West Sumatra, Indonesia

Food preservation by chemical preservatives addition is not recommended in large quantities. However, lactic acid bacteria (LAB) metabolites can be used as a safe alternative. LAB can produce a type of antimicrobial peptide known as bacteriocin. One source of LAB that can be used as a bacteriocin-producing candidate is dadih, a traditional fermented buffalo milk product from West Sumatra, Indonesia. In this study, eight bacterial isolates isolated from dadih were identified using the catalase test and Gram straining and obtained 6 isolates that were taken as LAB. An antimicrobial activity test was carried out using the diffusion method on LAB liquid isolates suspension and crude bacteriocins from the six isolates. The isolates with the highest antimicrobial activity were DK8, the diameter of inhibiting zone of liquid isolates was 15.75 mm (Salmonella sp.), 14.25 mm (Escherichia coli), and 12.25 mm (Staphylococcus aureus). Meanwhile, the diameter of crude bacteriocin inhibition of DK 8 isolates was 8 mm (Salmonella sp.). 8 mm (E. coli), and 8.5 mm (S. aureus). Furthermore, 16S rRNA sequencing confirmed DK8 as Lactobacillus pentosus.

M226 MILK-ALLERGY TAPERED TO CULTURE

Cow’s milk protein allergy (CMPA) is among the most-common diagnoses in infants, with a prevalence of 2 to 3% in the first-years of life. We present the first case report of successful oral-food challenge (OFC) to traditional South-Asian fermented milk dahi, previously only tested for antiallergenic effects in mouse-models. Studies of CMP modification by fermentation have been limited to inconclusive data on β-casein detectability in commercial yogurts, an animal-model of antiallergenic immune modulation by heat treated lactic acid bacteria, and a small case-control study on baked-milk and yogurt tolerance.

Kefir and ayran – traditional fermented products of Russia

The objective of this study was to determine antibacterial activity two traditional fermented milk products from Russia: kefir and ayran. Freshly prepared kefir and ayran was diluted 1/10 with nutrient broth and inoculated with pathogens (log10 5.5-6.5 initial) Escherichia coli EPEC 8621, VTEC 12900VT, Staphylococcus aureus 8632, Clostridia difficile 13832 and Salmonella Typhimurium LT2 and incubated for 24 h at 370C. Growth of all pathogens was suppressed by kefir and ayran with decrease in viable count below the initial value being seen in the cases of kefir and ayran vs Staphylococcus aureus and kefir vs Salmonella typhimurium. In addition, the influence of novel, potential prebiotics, lactitol and chitozan succinate, added to fermented products on antibacterial effect was studied. We concluded that both additives had no additional effect on the antibacterial activity of the fermented products.