Lactic Starter Cultures Research Articles

Study of the process of infrared drying of lactic starter cultures

An assessment of the current state of the Russian lactic starter market is given, which reflects the dependence on imported raw materials mainly from European manufacturers. To reduce dependence and ensure food security during the sanction period, the scientific and technical community of the Russian Federation has been set with a task to create technologies that allow obtaining high-quality lactic starter cultures and fermented products based on them. The article discusses the drying of lactic starter culture to increase storage terms and conditions. An important point in the dehydration process is the preservation of biologically active substances (lactic acid organisms, bifidobacteria) in the starter dry residue. The basic technologies of starter culture drying are considered, an alternative technology of IR radiation with the use of membranous electric heaters is proposed. The experimental kinetic dependences and the equation of the drying process of lactic starter cultures were obtained on the manufactured laboratory stand. Laboratory tests of the dried starter culture showed full compliance of the content of biologically active substances with the starting material, GOST RF and a high degree of recoverability, which indicates the feasibility of developing IR radiation technologies and introducing them into the processing of lactic and lactic acid raw materials.

Inhibition of Virulence Gene Expression in Salmonella Dublin, Escherichia coli F5 and Clostridium perfringens Associated With Neonatal Calf Diarrhea by Factors Produced by Lactic Acid Bacteria During Fermentation of Cow Milk.

Diarrhea is a major health problem in neonatal and young calves worldwide. It can be caused by a variety of infectious agents, including the bacteria Salmonella enterica serovar Dublin (S. Dublin), enterotoxigenic Escherichia coli (ETEC), and Clostridium perfringens. Preventive alternatives to antibiotic treatment should be identified. As a first step toward this, the aim of the current study was to examine whether cell-free supernatants from cow milk fermented by lactic acid bacteria affects virulence-gene expression in strains of S. Dublin, ETEC E. coli F5 and C. perfringens. pH-neutralized, cell-free, spent medium of milk (nCFSM) fermented by 61 different lactic acid bacteria (LAB) and non-LAB starter cultures belonging to 17 genera was assayed for their effect on expression of important virulence factors (S. Dublin hilA, ssrB, ssaG, flhD, prgI, fliC; ETEC E. coli F5 fanC, estA, fim41a; C. perfringens cpa), when the bacteria were grown in the nCFSM. Screening was done using either a promoter-reporter expression system or RT-qPCR. nCFSM from Bifidobacterium longum BL-15955 and Limosilactobacillus reuteri LR-33016 downregulated the expression of fanC, fim41a and estA genes in the four tested ETEC E. coli F5 strains without affecting their growth, while mainly B. longum BL-15955 downregulated expression of cpa in the four tested strains of C. perfringens. nCFSM from the mixed cultures; NU-TRISH® BY-Mild (Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus and Bifidobacterium BL-15954) and COMBO4 (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus), as well as Lactobacillus helveticus CNRZ32 downregulated the tested virulence genes in the three tested strains of S. Dublin. To enable possible downregulation of the expression of virulence genes in all three target bacteria simultaneously, nCFSM was prepared from NU-TRISH® By-Mild in combination with B. longum BL-15955 (i.e. a four-strain combination). The nCFSM from this combination downregulated the virulence genes expression in all the three species. In the future, NU-TRISH® By-Mild and B. longum BL-15955 in combination could potentially be used for prevention of neonatal calf diarrhea caused by S. Dublin, E. coli F5, and C. perfringens, reducing the need for antimicrobial treatment, however, field studies are needed to prove that.

The fermented soy whey produced by a combined lactic acid bacteria starter shows improved flavor and the function in alleviating dextran sulphate sodium induced colitis in mice

ABSTRACT In this study, Lactiplantibacillus plantarum BC299, Lactobacillus delbrueckii subsp. bulgaricus 717 and Streptococcus thermophilus 176 were used as combined starter cultures to produce a fermented soy whey beverage. The results showed that the fermentation of the combined starter cultures increased the content of lactic acid, acetic acid, succinic acid, and malic acid, while decreased the content of citric acid, fumaric acid and propionic acid. Meanwhile, the fermentation also effectively changed the proportion of volatile flavor substances. The higher sensory score of the fermented soy whey also confirmed the flavor improvement effect of the combined starter cultures. In addition, the in vivo results of animal experiments showed that the fermented soy whey could significantly improve the disease activity index (DAI) and colon morphology in dextran sulfate sodium (DSS) induced colitis mice. This study showed that the combined lactic acid bacteria starter cultures had important value-added relevance on the effective reuse of the soy whey by-product.

Effect of process variables on the physicochemical and rheological properties of yogurt

In this research, the effect of the lactic starter culture, the fermentation time, the incubation temperature and the percentage of fat on the firmness and consistency of a fermented milk drink was evaluated through physicochemical characteristics of total acidity, pH, syneresis and flow behavior. The purpose was to find the best formulation that extends the shelf life of yogurt, leading to an improvement in the manufacturing process of a local dairy company in Barrancabermeja (Santander, Colombia). Quality criteria were evaluated by means of the percentage of acidity and pH of the yogurt, as well as its syneresis and rheological parameters during a storage time of 24 hours and 7 days in refrigeration. Acceptable quality parameters were obtained for the yogurt prepared with an inoculum concentration of 2%, an incubation temperature of 40°C and an incubation time of 150 minutes. In addition, better properties of firmness and consistency were found, with absence of syneresis and viscosity in the accepted range, for this dairy product.

Bee pollen as a novel substrate in pilot-scale probiotic-mediated lactic fermentation processes

Different process conditions were evaluated to induce lactic acid fermentation of bee pollen at the pilot scale using three different commercial starter cultures. Clean and dry Colombian high Andean bee pollen was used as the sole source of nutrients (substrate). The effect of substrate preparation conditions (water:pollen ratio and initial substrate acidity) on lactic fermentation was evaluated by monitoring pH, titratable acidity, and pollen morphology in 6-kg-fermentation units. A 2:1 water:pollen mixture with an initial pH adjusted to 5.8, pretreated with heat/pressure (10 min; 80 kPa; 115 °C), was determined to be an adequate substrate for pilot-scale lactic fermentation for all lactic starter cultures. At the selected conditions, the kinetics of lactic acid production and the growth of specific lactic bacteria were determined. The fermentation process time was 30 h, after which a significant decline in bacterial populations was observed. Among the starter cultures tested, one constituted exclusively by probiotic Lactobacillus acidophilus NCFM presented the best performance in terms of lactic acid production, with a concentration of 1.65% wt, after 30 h. The results highlight the feasibility of producing fermented bee pollen at a commercial scale as a functional food product with probiotic features.

Изучение влияния различных ингредиентов на органолептические и функционально-технологические свойства сердца говяжьего

Offals are of interest to both factures of meat products and consumers. At the same time, the ambiguity of the organoleptic properties of offals and the lasted of their processing create barriers to the growth of their consumption. The studies carried out allowed us to demonstrate the most effective approaches to obtain the necessary organoleptic properties of a product with high functional -technological characteristics. The most effective approach to improve the properties of products from beef heart is using of lactic acid starter culture and citric acid.

Development of Technology for Producing Organic Pork With the Introduce of Probiotics, Prebiotics and Synbiotics into the Diet

As a result of the work, adequately new data were obtained on the change in the intestinal microbiocenosis of pigs during their entire life. The degree of influence of the probiotic, prebiotic and synbiotic on the change in the microbiocenosis of the intestines of pigs is determined. A scheme for the introduction of lactic starter cultures, "Baliz-V" and lactic starter cultures and "Baliz-V" together. The effect of the new diet on growth indicators, microbiocenosis, immunity and the quality of raw meat was studied. The positive effect of the synbiotic effect on the quantitative composition of lactic acid bacteria in the intestines of young pigs was 3-4 orders of magnitude higher than in the control. The use of a probiotic, prebiotic and synbiotic led to an improvement in intestinal microbiocenosis, strengthening the body's resistance, and an increase in live weight gain, respectively, by 8.4; 9.6 and 10.7%.

Growth prediction of two bacterial populations in co-culture with lactic acid bacteria.

The co-culture growth of Staphylococcus aureus, Escherichia coli and lactic acid bacteria starter culture in milk was quantitatively evaluated and modelled with a set of coupled differential equations originally proposed by Baranyi and Roberts and by Gimenez and Dalgaard (BR-GD model). The lactic acid bacteria starter culture showed the ability to induce an early stationary phase of both E. coli and S. aureus populations at different combination of temperature (ranging from 12 to 37 ℃) and lactic acid bacteria inocula (from approx. 103 to 106 CFU/ml). First, the prediction ability was performed only with parameters estimated from individual growth curves of E. coli, S. aureus and the lactic acid bacteria in milk (Dataset 1, 21 experiments). Subsequently, the model was extended with the average competition coefficients (E-BR-GD model) that represented quantitative relations among the populations. The prediction ability of this model was validated with the second dataset consisting of seven experiments. Results and also their statistical indices (accuracy and bias factors) showed that the E-BR-GD model improved growth prediction of all involved populations. Thus, the total root mean square error decreased from 0.457, 0.840 and 0.322 log CFU/ml (BR-GD model) to 0.290, 0.245 and 0.333 log CFU/ml (E-BR-GD) for S. aureus, E. coli and lactic acid bacteria, respectively. This approach in growth prediction of multiple competing microbial populations can be used in assessment of S. aureus and E. coli exposure from raw milk cheeses consumption and contribute to decision making in prevention of staphylococcal enterotoxin production.

Inkjet Printed Interdigitated Biosensor for Easy and Rapid Detection of Bacteriophage Contamination: A Preliminary Study for Milk Processing Control Applications

Bacteriophages are responsible for significant material and time losses in the dairy industry. This because these viruses infect the selected lactic starter cultures used for milk fermentation, i.e., the first stage toward cheese production. Standard detection techniques are time- and labor-consuming, causing huge costs related to production plant sanitation and product wasting. A new type of biosensor for early detection of bacteriophage contamination is highly demanded by the milk processing market, and inkjet-printed electrochemical sensors could be the answer. Inkjet printing is a well-known technology that has been revisited in recent years, using silver nanoparticle (AgNP) based inks for low-cost and easy fabrication of sensing and biosensing systems on flexible and eco-compatible substrates. In this research, we studied inkjet printing for the manufacturing of both interdigitated electrodes arrays (IDEAs), and a versatile system to monitor bacterial cultures by electrochemical impedance spectroscopy (EIS). In particular, we studied this biosensing system for the detection of bacteriophages by comparing its performance with standard microbiological methods. We performed electrical and morphological characterizations of the devices produced with a consumer-use inkjet printer with commercial AgNPs ink on flexible substrates, such as office paper, polyethylene (PET), and photo paper. We used light microscopy optical analysis, profilometry, atomic force microscopy (AFM), and scanning electron microscopy (SEM) imaging to define the objects resolution, their real dimensions, and thickness. We also investigated the devices’ conductivity and layout, by EIS measurements with a standard buffer solution, i.e., phosphate buffered saline (PBS). Finally, we tested our system by monitoring Lactococcus lactis cultures and bacteriophage infection. We compared the results to those obtained by two standard microbiological methods in terms of response time, proving that our technique requires less than half the time of other methods and no specialized personnel.

Effect of autochthonous Pediococcus acidilactici on volatile profile and some properties of heat-treated sucuk

The possibility of using Pediococcus acidilactici S147 as a starter culture in heat-treated sucuk production has been investigated in the research. P. acidilactici S147 showed a good growth during fermentation and caused a rapid pH drop. In the starter culture group, a decrease in lactic acid bacteria count was determined by about 1 log unit during the heat treatment. In Microccoccus/Staphylococcus count, less reduction was observed during the heat treatment than the lactic acid bacteria count. In the final product, moisture content was 50.54 ± 0.62% in the control group and 48.53 ± 0.67% in the group with starter culture. However, it was determined that P. acidilactici S147 has a significant effect only on 4 of the total 66 volatile compounds identified in the heat-treated sucuk. P. acidilactici S147 strain used in the production showed the desired decrease in pH and a limited effect on the volatile compounds. Practical applications Heat-treated sucuk, categorized as a semi-dry fermented sausage, has a short-term fermentation. The use of lactic starter cultures is quite important for food safety as well as products' properties. In the present study, the possibilities of using autochthonous Pediococcus acidilactici S147 strain (isolated/identified from sucuk) as starter culture in heat-treated sucuk production were investigated. This strain achieved the desired decrease of pH value during fermentation and can survive during the heat treatment. However, P. acidilactici S147 showed a limited effect on the volatile compounds.

(III)凍結または乾燥による乳酸菌スターターの活性維持(V.活性保持の実用例,セミナー「生物的生活の保持技術」)

(III)凍結または乾燥による乳酸菌スターターの活性維持(V.活性保持の実用例,セミナー「生物的生活の保持技術」)

Development of Lactic Starter Cultures for Low Salted Pickles

Development of Lactic Starter Cultures for Low Salted Pickles

Influence of oregano essential oil on traditional Argentinean cheese elaboration: Effect on lactic starter cultures

The aim of this work is to study the oregano essential oil (OEO) composition from Northwestern Argentinean regions and to evaluate its effect on the lactic starter cultures. The oregano used, Origanum vulgare var hirtum, was obtained from Andalgalá, Catamarca. The essential oil presented high amounts of α-terpinene (10%), γ-terpinene (15.1%), terpinen-4-ol (15.5%) and thymol (13.0%) as the main components. No negative effect on growth or metabolic activity of lactic acid bacteria Streptococcus thermophilus CRL 728 and CRL 813, Lactobacillus delbrueckii subsp. bulgaricus CRL 656 and CRL 468, and Lactococcus lactis subsp. lactis CRL 597 up to the maximum concentration (200μg/g) assayed was observed. No differences in the organoleptic characteristics of semi-hard cheeses flavored with oregano essential oil (200μg/g) and homemade cheeses flavored with oregano leaves were found. With respect to the microbiological quality of the products, neither enterobacteria nor mold and yeast were detected during ripening in essential-oil flavored cheese compared to control cheese (enterobacteria 2×103UFC/g) and cheese flavored with oregano leaves (mold/yeast 4×104CFU/g). Our results showed that the use of oregano essential oil and lactic starter culture considerably improved cheese quality.

Lactobacillus helveticus: importance in food and health.

Lactobacillus helveticus: importance in food and health.

Changes in the phase variant spectra in the populations of lactic acid bacteria under antibiotic treatment

Effect of the antibiotics kanamycin and ampicillin on growth and phase variation of the populations of four strains of lactic acid bacteria (Lactobacillus sp. M67AT, L. casei MB, Enterococcus faecium M, and E. faecium M3185) was studied. The presence of antibiotics in the medium resulted in a dose-dependent decrease in viable cell numbers and in partial or complete substitution of the dominant S variant with the minor Sm and Sb variants. The variants differed in colony morphology, as well as in some physiological, biochemical, biotechnological, and probiotic characteristics. The Sm type variants of all strains exhibited the highest resistance to antibiotics. High production of exopolysaccharides was found in Sb variants of lactobacilli and in S variants of enterococci. The highest antibacterial activity was found in Sm variants of lactobacilli, especially in Lactobacillus sp. M76AT The latter is biotechnologically the most promising strain, since all variants fermented milk yielding the products with uniformly pronounced functional and organoleptic properties. These patterns are of importance for the understanding of the mechanisms of antibiotic resistance and for selection of the variants with desired properties, as well as for quality control of the lactic acid bacteria starter cultures.

Assessment of the Potential of Lactic Acid Bacteria as Dried Starter Culture for Cereal Fermentation

The kinetic growth parameters [maximal specific growth rate μm (h-1), and generation time g (h)] and viability after stress treatments (dehydration with glycerol solution of increasing concentration, freezing or heating stress) of four lactic acid bacteria [Lactobacillus plantarum (LP), L. fermentum (LF), Leuconostoc spp. (M1) and Lactococcus spp. (M2)] were determined. The maximal specific growth rate (μm) and generation time g ranged between 0.51 h-1 to 0.14 h-1 and 0.61 h to 1.33 h, respectively. We observed that the strains were sensitive to a change in water activity (aw 0.32 final), storage and incubation temperatures. The Strain LF obtained a higher cell concentration and viability, as well as a lower g compared to those obtained by the other strains. The kinetic growth parameters (μm, g) together with viability after stress treatments could be used for the screening of dried lactic acid starter cultures.

Behaviour of Escherichia Coli O157:H7 During the Manufacture and Ripening of an Italian Traditional Raw Goat Milk Cheese.

Formagelle di capra is a raw goat cheese produced from whole chilled goat milk; traditional technology involving unpasteurised milk and indigenous lactic starter cultures is employed for its production in Italy. The purpose of this study was to assess the behaviour of Escherichia coli O157:H7 during the manufacturing and ripening of this raw goat milk cheese. Raw milk was experimentally inoculated with E. coli O157:H7 in a laboratory scale plant and the count was monitored during production and 30 days of ripening required for this cheese. Results showed that E. coli O157:H7 count increased to more than 1.5 Log cfu g–1 during cheese production and remained constant until the end of ripening. The evidence that E. coli O157:H7 is able to survive during the manufacturing and ripening process suggests that the 30-day ripening period alone is insufficient to eliminate levels of viable E. coli O157:H7 in Formaggelle di capra cheese and that the presence of low numbers of E. coli O157:H7 in milk destined for the production of raw goat milk cheeses could represent a potential source of infection for humans and a threat for consumers.

Rheology of spreadable goat cheese made with autochthonous lactic cultures differing in their ability to produce exopolysaccharides

The aim of this study was to compare the rheology of spreadable cheeses elaborated with autochthonous lactic starter cultures without the addition of exopolysaccharide-producing strain in the same starter with exopolysaccharide-producing strain. From a rheological standpoint, both samples were characterized as weak viscoelastic gels and pseudoplastic products. It was concluded that cheese made with exopolysaccharide-producing strain showed smaller G', G, and η* values over the range of frequencies studied and smaller critic stress values than the cheese without exopolysaccharide-producing strain. The results obtained indicate that cheeses without exopolysaccharide-producing strain need to be added with any texture enhancer product.

Dried Tomato‐Flavored Probiotic Cream Cheese with Lactobacillus paracasei

A dried tomato-flavored probiotic cream cheese (P) containing Lactobacillus paracasei Lpc-37 was developed for the purpose of this study. The same product, but without probiotic addition (C) was used as control. Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris were used as lactic starter cultures. Chemical composition analyses and sensory tests were performed on days 1 and 7, respectively. Titratable acidity, pH value and L. paracasei population were determined every 7 d during the refrigerated storage (21 d) of the cream cheeses. The experiment and analyses were performed in triplicate, using standard methods. Probiotic population remained greater than 10(7) CFU/g throughout the storage period, thereby characterizing the product as potentially probiotic. Cream cheeses C and P did not differ on the sensory tests, both obtaining good overall acceptance by the consumers, of which 82.6% stated that they certainly or probably would buy the product. Lactobacillus paracasei Lpc-37 is a probiotic bacterium and clinical studies have shown that this microorganism beneficially affects its host. In general, dried tomato-flavored products and cream cheese are products with good acceptance by the consumers. Thus, regular consumption of the probiotic cream cheese developed in this study may have positive effects on health and well being of people if incorporated into their diet.

Use of Different Lactic Starter Cultures in the Production of Tarhana

In this study, Lactobacillus plantarum and L. brevis were used as starter cultures in tarhana production. The samples that had L. plantarum (P) and L. brevis (B) added to them had lower acidity values than the control samples (C). In the first 4 days of production, total antioxidant capacity and total phenol contents were not significantly different. B had lower protein in vitro digestibility values than C and, all the samples had generally higher values on the third day of fermentation. The analysis of total aerobic mesophilic bacteria, total lactic acid bacteria, total coliform group bacteria, Escherichia coli, Staphylococcus aureus and yeast–mold counts were conducted. These showed that, during fermentation, there were some significant differences in microbial counts, but sample type had no significant effect on the microbiological load of the final dried products. The evaluated data displayed the effect of starter cultures on some properties of tarhana during fermentation. PRACTICAL APPLICATIONS The quality of tarhana, as with other fermented food products depends highly on microbial yield and type. The use of lactic starter culture is essential to provide a more controlled and standardized fermentation process; it is important to know how the main properties of tarhana changes or are affected when different lactic starter cultures are used in the production. This information can be helpful in optimizing tarhana production.