Effective survival of immobilized Lactobacillus casei during ripening and heat treatment of probiotic dry-fermented sausages and investigation of the microbial dynamics

Inactivation of Cronobacter sakazakii in powdered infant formula with probiotics and metagenomic analysis

In the present study, proper manual for powdered infant formula with probiotics (PIF-P) to prevent the contamination of Cronobacter sakazakii was investigated. First, the population of C. sakazakii and LAB in three different PIF-P samples were quantitatively analyzed after reconstituted with hydrothermal treatments. When C. sakazakii was inoculated into reconstituted infant formula with probiotics (RIF-P), it was immediately reduced below the detection limit by 60-65 °C hydrothermal treatment whereas reduction levels of LAB was 1-2 log CFU/g. When heat resistance of C. sakazakii inoculated to PIF-P with 4 h drying was compared with that inoculated to RIF-P samples, the heat resistance of C. sakazakii increased significantly after the inoculation in PIF-P with drying. Metagenomic analysis revealed that Lactobacillus and Bifidobacterium were dominant genus in all three groups and there was no significant difference in the microbial community of untreated PIF sample and hydrothermal treated samples.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01503-x.

Removal of Hydrogen Sulfide from Swine-Waste Biogas on a Pilot Scale Using Immobilized Paracoccus versutus CM1

Hydrogen sulfide (H2S) is a toxic and corrosive component that commonly occurs in biogas. In this study, H2S removal from swine-waste biogas using sulfur-oxidizing Paracoccus versutus CM1 immobilized in porous glass (PG) and polyurethane foam (PUF) biofilters was investigated. Bacterial compositions in the biofilters were also determined using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The biofilters were first tested on a laboratory scale under three space velocities (SV): 20, 30, and 40 h−1. Within 24 h, at an SV of 20 h−1, PG and PUF biofilters immobilized with P. versutus CM1 removed 99.5% and 99.7% of H2S, respectively, corresponding to the elimination capacities (EC) of 83.5 and 86.2 gm−3 h−1. On a pilot scale, with the horizontal PG-P. versutus CM1 biofilter operated at an SV of 30 h−1, a removal efficiency of 99.7% and a maximum EC of 113.7 gm−3 h−1 were achieved. No reduction in methane content in the outlet biogas was observed under these conditions. The PCR-DGGE analysis revealed that Paracoccus, Acidithiobacillus, and Thiomonas were the predominant bacterial genera in the biofilters, which might play important roles in H2S removal. This PG−P. versutus CM1 biofiltration system is highly efficient for H2S removal from swine-waste biogas.

Novel Probiotic/Bacterial Cellulose Biocatalyst for the Development of Functional Dairy Beverage

The development of innovative functional products with potential health benefits, under the concept of bio-economy, is flourishing. This study undertook an evaluation of non-dairy lactobacilli Lactiplantibacillus pentosus B329 and Lactiplantibacillus plantarum 820 as “ready to use” starter cultures. Lactic acid bacteria (LAB) cultures were evaluated for their fermentation efficiency, before and after freeze-drying, using cheese whey (CW) as a fermentation substrate and subsequent immobilization on bacteria cellulose (BC) to produce a novel biocatalyst. The biocatalyst was applied in functional sour milk production and compared with free cells via the assessment of physicochemical and microbiological properties and sensory evaluation. Evidently, LAB strains exhibited high fermentative activity before and after freeze-drying. Results of a 5-month storage stability test showed that viability was 19% enhanced by immobilization on BC, supporting the concept of “ready to use” cultures for the production of fermented beverages. Likewise, sour milk produced by the BC biocatalyst presented higher organoleptic scores, compared to the free cells case, whereas immobilization on BC enhanced probiotic viability during post-fermentation storage (4 °C, 28 days). The obtained high viability (>107 log cfu/g) demonstrated the efficacy of the proposed bioprocess for the production of functional/probiotic-rich beverages. Ultimately, this work presents a consolidated scheme that includes the advantages and the cooperative effect of probiotic LAB strains combined with a functional biopolymer (BC) towards the formulation of novel functional products that coincide with the pillars of food systems sustainability.

Functional Characteristics of Lactic Acid Bacteria In Vitro Isolated from Spontaneously Fermented Sour Porridge with Broomcorn Millet in Northwestern Shanxi Province of China

Eighteen strains of lactic acid bacteria were isolated from spontaneously fermented sour porridge with broomcorn millet in Northwestern Shanxi Province of China, and their probiotic characteristics were investigated in vitro. Survival rates under gastrointestinal conditions, cholesterol reduction, antibacterial capabilities, antioxidant activities, and safety assessments were examined. Results showed that five strains were selected as probiotics and identified as Levilactobacillusbrevis. Strain L10 exhibited excellent probiotic characteristics, with an 86% survival rate under pH 2.0 for 2 h, 80% survival rate in 0.3% bile salt for 6 h, the highest survival rate (78%) in simulated gastrointestinal juice for 3 h, the highest hydrophobicity (42% to xylene and 39% to hexadecane), the highest aggregation (39% auto-aggregation and 10.4–18.13% co-aggregation), relative higher cholesterol reduction rate (80%), the highest antibacterial activities, the highest antioxidant activity, sensitive to most antibiotics tested, without hemolytic and hydrolyze gelatinase activity and could not produce biogenic amine. Therefore, strain L10 could be applied to functional foods.

Lactic Acid Bacteria as Antimicrobial Agents: Food Safety and Microbial Food Spoilage Prevention

In the wake of continual foodborne disease outbreaks in recent years, it is critical to focus on strategies that protect public health and reduce the incidence of foodborne pathogens and spoilage microorganisms. Currently, there are limitations associated with conventional microbial control methods, such as the use of chemical preservatives and heat treatments. For example, such conventional treatments adversely impact the sensorial properties of food, resulting in undesirable organoleptic characteristics. Moreover, the growing consumer advocacy for safe and healthy food products, and the resultant paradigm shift toward clean labels, have caused an increased interest in natural and effective antimicrobial alternatives. For instance, natural antimicrobial elements synthesized by lactic acid bacteria (LAB) are generally inhibitory to pathogens and significantly impede the action of food spoilage organisms. Bacteriocins and other LAB metabolites have been commercially exploited for their antimicrobial properties and used in many applications in the dairy industry to prevent the growth of undesirable microorganisms. In this review, we summarized the natural antimicrobial compounds produced by LAB, with a specific focus on the mechanisms of action and applications for microbial food spoilage prevention and disease control. In addition, we provide support in the review for our recommendation for the application of LAB as a potential alternative antimicrobial strategy for addressing the challenges posed by antibiotic resistance among pathogens.

Functional fermented meat products with probiotics-A review

Fermentation has been an important strategy in the preservation of foods. The use of starter cultures with probiotic activity has gained the attention of researchers to produce functional fermented meat products. This review aims to overview the main strengths, weakness, opportunities and threats of fermented meat products with probiotics. Fermented meat products can be considered as a relevant matrix for the delivery of probiotics with potential health benefits. Moreover, fermented meat products produced by traditional methods are sources of probiotics that can be explored in the production of functional meat products. However, some barriers are limit the progression with these products: the complex selection process to obtain new and tailored probiotic strains, the current perception of healthiness associated with meat and meat products, and the limited application of probiotic to fermented sausages. Promising opportunities to improve the value of functional fermented meat products have been developed by exploring new meat products as functional fermented foods, improving the protection of probiotics with microencapsulation and improving the quality of meat product (reducing nitrate and nitrate salts, adding dietary fibre, and exploring the inherent antioxidant and cardioprotective activity of meat products). Attention to potential threats is also indicated such as the unclear future changes in meat and meat products consumption due to changes in consumer preferences and the presence of competitors (dairy, fruit and vegetable-based products, for instance) in more advanced stages of development and commercialization. SIGNIFICANCE AND IMPACT OF STUDY: This review provides an overview of the Strengths, Weakness, Opportunities and Threats related to the development of functional fermented meat products with probiotics. Internal and external factors that explain the current scenario and strategies to advance the production are highlighted.

Co-Encapsulated Synbiotics and Immobilized Probiotics in Human Health and Gut Microbiota Modulation

Growing interest in the development of innovative functional products as ideal carriers for synbiotics, e.g., nutrient bars, yogurt, chocolate, juice, ice cream, and cheese, to ensure the daily intake of probiotics and prebiotics, which are needed to maintain a healthy gut microbiota and overall well-being, is undeniable and inevitable. This review focuses on the modern approaches that are currently being developed to modulate the gut microbiota, with an emphasis on the health benefits mediated by co-encapsulated synbiotics and immobilized probiotics. The impact of processing, storage, and simulated gastrointestinal conditions on the viability and bioactivity of probiotics together with prebiotics such as omega-3 polyunsaturated fatty acids, phytochemicals, and dietary fibers using various delivery systems are considered. Despite the proven biological properties of synbiotics, research in this area needs to be focused on the proper selection of probiotic strains, their prebiotic counterparts, and delivery systems to avoid suppression of their synergistic or complementary effect on human health. Future directions should lead to the development of functional food products containing stable synbiotics tailored for different age groups or specifically designed to fulfill the needs of adjuvant therapy.

Marinated Sea Bream Fillets Enriched with Lactiplantibacillus plantarum and Bifidobacterium animalis subsp. lactis: Brine Optimization and Product Design

This study aimed to design marinated sea bream fillets, inoculated with either Lactiplantibacillus plantarum (strains 11, 68, 69) or Bifidobacterium animalis subsp. lactis DSM 10140. In the first step, the optimization of brine composition was performed through a centroid; the factors of the design were citric acid, vinegar, and salt. As a result of optimization, the optimal composition of brine was set to 0.75% citric acid, 55% vinegar, and 3% NaCl. In the second step, sea bream fillets were inoculated with L. plantarum strain 69 and B. animalis subsp. lactis, marinated and then packed in a conditioning solution (oil or diluted brine); the samples were stored at 4 °C for 21 days. The viability of the strains and sensory scores were assessed. The bacteria retained a high viability throughout storage (21 days); however, the sensory scores were at their highest level for 4 days. In particular, sensory assessment suggested a preference for a conditioning solution with oil, rather than with a diluted brine. In addition, a slightly higher preference was found for B. animalis subsp. lactis.

Strategies to Improve Meat Products' Quality

Meat products represent an important component of the human diet, their consumption registering a global increase over the last few years. These foodstuffs constitute a good source of energy and some nutrients, such as essential amino acids, high biological value proteins, minerals like iron, zinc, selenium, manganese and B-complex vitamins, especially vitamin B12. On the other hand, nutritionists have associated high consumption of processed meat with an increased risk of several diseases. Researchers and processed meat producers are involved in finding methods to eliminate nutritional deficiencies and potentially toxic compounds, to obtain healthier products and at the same time with no affecting the sensorial quality and safety of the meat products. The present review aims to summarize the newest trends regarding the most important methods that can be applied to obtain high-quality products. Nutritional enrichment with natural bioactive plant compounds (antioxidants, dietary fibers) or probiotics, reduction of harmful components (salt, nitrate/nitrite, N-nitrosamines) and the use of alternative technologies (high-pressure processing, cold plasma, ultrasounds) are the most used current strategies to accomplish this aim.

Immune Responses Raised in an Experimental Colon Carcinoma Model Following Oral Administration of Lactobacillus casei

The role of dietary probiotic strains on host anticancer immune responses against experimental colon carcinoma was investigated. We have previously shown that Lactobacillus casei administration led to tumor growth suppression in an experimental colon cancer model. Here, we investigated the underlying immune mechanisms involved in this tumorgrowth inhibitory effect. BALB/c mice received daily live lactobacilli per os prior to the establishment of a syngeneic subcutaneous CT26 tumor. Tumor volume, cytokine production, T cell differentiation and migration, as well as tumor cell apoptosis were examined to outline potential immunomodulatory effects following L. casei oral intake. Probiotic administration in mice resulted in a significant increase in interferon gamma (IFNγ), Granzyme B and chemokine production in the tumor tissue as well as enhanced CD8⁺ T cell infiltration, accompanied by a suppression of tumor growth. Cytotoxic activity against cancer cells was enhanced in probioticfed compared to control mice, as evidenced by the elevation of apoptotic markers, such as cleaved caspase 3 and poly (ADPribose) polymerase 1 (PARP1), in tumor tissue. Oral administration of Lactobacillus casei induced potent Th1 immune responses and cytotoxic T cell infiltration in the tumor tissue of tumorbearing mice, resulting in tumor growth inhibition. Thus, the microorganism may hold promise as a novel dietary immunoadjuvant in raising protective anticancer immune responses.

Assessment of Freeze-Dried Immobilized Lactobacillus casei as Probiotic Adjunct Culture in Yogurts

Freeze-dried immobilized Lactobacillus casei ATCC 393 on casein and apple pieces were assessed as a probiotic adjunct culture for novel probiotic yogurt production. The effect of probiotic culture on physicochemical characteristics, probiotic cell survival, volatile aroma compounds, and sensory quality were evaluated during 28 days of storage at 4 °C. The use of L. casei resulted in lower pH values (3.92–4.12), higher acidity (0.88–1.10 g lactic acid/100 g of yogurt), and lower syneresis (40.8%–42.6%) compared to traditionally produced yogurt (pH 4.29; acidity 0.83 g lactic acid/100 g of yogurt; syneresis 44.1%). Microbiological and strain-specific multiplex PCR (Polymerase Chain Reaction) analysis confirmed that immobilized L. casei ATCC 393 cells were detected in yogurts at levels >7 log cfu g⁻¹ after 28 days. In addition, probiotic supplementation significantly affected the concentrations of key volatile compounds, like acetic and other organic acids, 2-ethyl-1-hexanol, acetoin, and 2-butanone, as revealed by GC-MS (Gas Chromatography–Mass Spectrometry) analysis. Finally, the sensory evaluation demonstrated that the new products exhibited improved characteristics compared to traditionally produced yogurts.

Effect of Sugar Content on Quality Characteristics and Shelf-Life of Probiotic Dry-Fermented Sausages Produced by Free or Immobilized Lactobacillus casei ATCC 393

The aim of the present study was to investigate the effect of sugar content (0, 0.30, and 0.60%) on quality attributes and shelf-life of dry-fermented sausages stored for 66 days containing free or immobilized Lactobacillus casei ATCC 393 on wheat. For comparison, dry-fermented sausages with no starter culture were also produced. Physicochemical characteristics ranged within the levels usually observed in fermented sausages, while a drastic decrease was recorded in numbers of enterobacteria, staphylococci, and pseudomonads during ripening in all cases. Noticeably, sugar addition and the probiotic culture resulted in significant increase of shelf-life, whereas levels of L. casei ATCC 393 after 66 days of ripening persisted above 6 log cfu/g. Sugar addition had a positive effect on sensory attributes; although all products were of high quality, the immobilized cells provided a distinctive characteristic aroma and a fine taste.

Encapsulation of Lactobacillus fermentum K73 by Refractance Window drying

The purpose of this work was to model the survival of the microorganism and the kinetics of drying during the encapsulation of Lactobacillus fermentum K73 by Refractance Window drying. A whey culture medium with and without addition of maltodextrin were used as encapsulation matrices. The microorganism with the encapsulation matrices was dried at three water temperatures (333, 343 and 353 K) until reaching balanced moisture. Microorganism survival and thin layer drying kinetics were studied by using mathematical models. Results showed that modified Gompertz model and Midilli model described the survival of the microorganism and the drying kinetics, respectively. The most favorable process conditions found with the mathematical modelling were a drying time of 2460 s, at a temperature of 353 K. At these conditions, a product with 9.1 Log CFU/g and a final humidity of 10% [wet basis] using the culture medium as encapsulation matrix was obtained. The result shows that Refractance Window can be applied to encapsulate the microorganism probiotic with a proper survival of the microorganism.

Lactobacillus paracasei K5 displays adhesion, anti-proliferative activity and apoptotic effects in human colon cancer cells

Lactobacillus paracasei K5 is a lactic acid bacteria (LAB) strain, isolated recently from feta-type cheese. Its probiotic potential has been demonstrated in a series of established in vitro tests. Moreover, incorporation of L. paracasei K5 as starter culture offered organoleptic and technological advantages to novel fermented food products. In the present study, further investigation of the potential probiotic activity of L. paracasei K5 was performed and its mechanisms of action were investigated. Employing quantitative analysis and confocal, fluorescent microscopy the adhesion properties of the above strain were studied. L. paracasei K5 displayed efficient adherence capacity to Caco-2 colon cancer cells, similarly to the reference strains Lactobacillus casei ATCC 393 and Lactobacillus rhamnosus GG. Moreover, treatment of Caco-2 cells with L. paracasei K5 inhibited cell proliferation in a time-and dose-dependent manner. The anti-proliferative effects appear to be mediated through induction of apoptosis via modulation of expression of specific Bcl-2 family proteins. These results elucidate the mechanisms of action of L. paracasei K5 and enhance its potential probiotic activity.

Biogenic Synthesis of Novel Functionalized Selenium Nanoparticles by Lactobacillus casei ATCC 393 and Its Protective Effects on Intestinal Barrier Dysfunction Caused by Enterotoxigenic Escherichia coli K88

Selenium (Se) is an essential element for human and animal health. Biogenic selenium nanoparticles (SeNPs) by microorganism possess unique physical and chemical properties and biological activities compared with inorganic Se and organic Se. The study was conducted to investigate the mainly biological activities of SeNPs by Lactobacillus casei ATCC 393 (L. casei 393). The results showed that L. casei 393 transformed sodium selenite to red SeNPs with the size of 50–80 nm, and accumulated them intracellularly. L. casei 393-SeNPs promoted the growth and proliferation of porcine intestinal epithelial cells (IPEC-J2), human colonic epithelial cells (NCM460), and human acute monocytic leukemia cell (THP-1)-derived macrophagocyte. L. casei 393-SeNPs significantly inhibited the growth of human liver tumor cell line-HepG2, and alleviated diquat-induced IPEC-J2 oxidative damage. Moreover, in vivo and in vitro experimental results showed that administration with L. casei 393-SeNPs protected against Enterotoxigenic Escherichia coli K88 (ETEC K88)-caused intestinal barrier dysfunction. ETEC K88 infection-associated oxidative stress (glutathione peroxidase activity, total superoxide dismutase activity, total antioxidant capacity, and malondialdehyde) was ameliorated in L. casei 393-SeNPs-treated mice. These findings suggest that L. casei 393-SeNPs with no cytotoxicity play a key role in maintaining intestinal epithelial integrity and intestinal microflora balance in response to oxidative stress and infection.

Production of probiotic bovine salami using Lactobacillus plantarum 299v as adjunct

BACKGROUND

Five probiotic lactobacilli were tested, alone or in combination with two commercial starters, to select the most suitable strain for a probiotic bovine salami production. Lactobacillus plantarum 299v was used with both starters, to make salami according to a traditional recipe. Salami obtained by using just the starters and by spontaneous fermentation, served as control. Microbial dynamics, as well as the main physico-chemical parameters, were monitored throughout ripening. The survival of probiotic 299v was confirmed by strains' tracking by means of RAPD-PCR coupled to a culture-independent approach PCR-DGGE-based.

RESULTS

The results showed a remarkable viability of the probiotic strain even after 60 days of storage. Experimental salami exhibited the same level of sensory acceptance of control salami, were hygienically safe, and characterised by pH, weight loss and microbiological loads within the ranges conventionally advocated for optimal fermented sausages.

CONCLUSION

Outcomes indicate the workable possibility of using second-quality beef cuts for probiotic salami production. © 2017 Society of Chemical Industry.

Characterization of a Sea Buckthorn Extract and Its Effect on Free and Encapsulated Lactobacillus casei

Probiotics are bacteria that can provide health benefits to consumers and are suitable to be added to a variety of foods. In this research, viability of immobilized Lactobacillus casei in alginate with or without sea buckthorn lipid extract were studied during heat treatment and with an in vitro gastrointestinal model. The characterization of the lipid extract was also done using the UV-Vis spectrometry (UV-Vis), high-performance liquid chromatography photodiode array detection method (HPLC-PDA), gas chromatography coupled with mass spectrometry (GS-MS) and Cryo scanning electron microscopy (Cryo-SEM). During heat treatment, the entrapped probiotic cells proved high viability (>6 CFU log/g), even at temperatures above 50 °C. The rich in monounsaturated fatty acids sea buckthorn fraction improved the in vitro digestion passage regarding the probiotic viability. The survival of the probiotic cells was 15% higher after 2 h in the acidic medium of the simulated gastric fluid in the sample where L. casei was encapsulated with the sea buckthorn extract compared with the samples where no extract was added. Thus, this approach may be effective for the future development of probiotic-supplemented foods as foods with health welfare for the consumers.

Potentially probiotic Lactobacillus strains with anti-proliferative activity induce cytokine/chemokine production and neutrophil recruitment in mice

Lactobacillus pentosus B281 and Lactobacillus plantarum B282 are two Lactobacillus strains previously isolated from fermented table olives. Both strains were found to possess probiotic properties and displayed desirable technological characteristics for application as starters in novel functional food production. In the present study the anti-proliferative and immunostimulatory activities of the two strains were investigated. Firstly, we demonstrated that live L. pentosus B281 and L. plantarum B282 significantly inhibited the growth of human colon cancer cells (Caco-2) in a time- and dose-dependent manner. By employing the air pouch system in mice, we showed that administration of both strains led to a rapid and statistically significant infiltration of leukocytes in the air pouch exudates. The phenotypical characterisation of the recruited immune cells was performed by flow cytometry analysis. We demonstrated that the majority of the infiltrated leukocytes were neutrophils. Finally by using the Mouse Cytokine Array Panel A Detection Antibody cocktail, we showed that both strains induced the expression of granulocyte-colony stimulating factor, interleukin (IL)-1α, IL-1β, IL-6, chemokine (C-X-C motif) ligand (CXCL)-1, chemokine (C-C motif) ligand (CCL)-3, CCL-4, and CXCL-2 and diminished the expression levels of soluble intercellular adhesion molecule, macrophage colony-stimulating factor and metallopeptidase inhibitor 1. Our results showed that both strains display anti-proliferative and immunostimulatory properties equal or even better in some cases than those of established and commonly used probiotic strains. These findings further support the probiotic character of the two strains.

Analysis of microbial diversity in Shenqu with different fermentation times by PCR-DGGE

Shenqu is a fermented product that is widely used in traditional Chinese medicine (TCM) to treat indigestion; however, the microbial strains in the fermentation process are still unknown. The aim of this study was to investigate microbial diversity in Shenqu using different fermentation time periods. DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) profiles indicated that a strain of Pediococcus acidilactici (band 9) is the predominant bacteria during fermentation and that the predominant fungi were uncultured Rhizopus, Aspergillus oryzae, and Rhizopus oryzae. In addition, pathogenic bacteria, such as Enterobacter cloacae, Klebsiella oxytoca, Erwinia billingiae, and Pantoea vagan were detected in Shenqu. DGGE analysis showed that bacterial and fungal diversity declined over the course of fermentation. This determination of the predominant bacterial and fungal strains responsible for fermentation may contribute to further Shenqu research, such as optimization of the fermentation process.

Enhancement of Pork Jerky Using Co-cultures of Lactobacillus bulgaricus and Angel Yeast

Strains of Lactobacillus bulgaricus and Angel Yeast were combined to ferment raw pork and make pork jerky. After fermentation, the jerky was dried and then tested for sensory evaluation, pH and free amino acid content. The results showed that the optimal conditions for fermentation using L. bulgaricus and Angel Yeast were: a pH of 6.5, a 1:1 (v/v) ratio of L. bulgaricus to Angel Yeast, a fermentation time of 42 h and temperature of 25 °C. The results showed that the pork jerky fermented with the combined strains was not very sour which was close to the pH of 7.0 and had a higher free amino acid content which was more than 68.3 mg/100 g compared with the pork jerky fermented by either L. bulgaricus or Angel Yeast alone. Overall, the results demonstrate that fermentation of raw pork with combined strains of L. bulgaricus and Angel Yeast improves the quality and flavor of pork jerky.

Molecular Detection of Two Potential Probiotic Lactobacilli Strains and Evaluation of Their Performance as Starter Adjuncts in Yogurt Production

A molecular method for efficient and accurate detection and identification of two potential probiotic lactobacilli strains isolated from fermented olives, namely Lactobacillus pentosus B281 and Lb. plantarum B282, was developed in the present study. Random Amplified Polymorphic DNA (RAPD) analysis was performed, and strain specific primers were designed and applied in a multiplex polymerase chain reaction (PCR) assay. The specificity of the assay was tested and successfully confirmed in 27 and 22 lactobacilli strains for Lb. pentosus B281 and Lb. plantarum B282, respectively. Moreover, the two strains were used as starter cultures in yogurt production. Cell enumeration followed by multiplex PCR analysis demonstrated that the two strains were present in yogurt samples at levels ≥6 log CFU/g even after 35 days of storage at 4 °C. Microbiological analysis showed that lactobacilli and streptococci were present within usual levels, whereas enterobacteriaceae and yeast/mold counts were not detected as expected. Although the pH values of the novel products were slightly lower than the control ones, the yogurt containing the probiotic cultures scored similar values compared to the control in a series of sensory tests. Overall, these results demonstrated the possible use of the two strains as starter adjuncts in the production of yogurt with potential probiotic properties.

Lactobacillus casei Exerts Anti-Proliferative Effects Accompanied by Apoptotic Cell Death and Up-Regulation of TRAIL in Colon Carcinoma Cells

Probiotic microorganisms such as lactic acid bacteria (LAB) exert a number of strain-specific health-promoting activities attributed to their immunomodulatory, anti-inflammatory and anti-carcinogenic properties. Despite recent attention, our understanding of the biological processes involved in the beneficial effects of LAB strains is still limited. To this end, the present study investigated the growth-inhibitory effects of Lactobacillus casei ATCC 393 against experimental colon cancer. Administration of live Lactobacillus casei (as well as bacterial components thereof) on murine (CT26) and human (HT29) colon carcinoma cell lines raised a significant concentration- and time-dependent anti-proliferative effect, determined by cell viability assays. Specifically, a dramatic decrease in viability of colon cancer cells co-incubated with 10(9) CFU/mL L. casei for 24 hours was detected (78% for HT29 and 52% for CT26 cells). In addition, live L. casei induced apoptotic cell death in both cell lines as revealed by annexin V and propidium iodide staining. The significance of the in vitro anti-proliferative effects was further confirmed in an experimental tumor model. Oral daily administration of 10(9) CFU live L. casei for 13 days significantly inhibited in vivo growth of colon carcinoma cells, resulting in approximately 80% reduction in tumor volume of treated mice. Tumor growth inhibition was accompanied by L. casei-driven up-regulation of the TNF-related apoptosis-inducing ligand TRAIL and down-regulation of Survivin. Taken together, these findings provide evidence for beneficial tumor-inhibitory, anti-proliferative and pro-apoptotic effects driven by this probiotic LAB strain.

Optimization of compositional and structural properties in probiotic sausage production

In this study, the effects of different fat levels and different particle sizes on compositional and structural characteristics of probiotic fermented sausage were investigated. In order to obtain probiotic character, Lactobacillus casei CRL431 was added. The physicochemical, microbiological and sensory analysis were done. The effect of fat level x mincer hole diameter interaction on hardness values were statistically significant (p < 0.005). At the end of the fermentation-ripening period, L.casei CRL-431 count has reached to sufficient microbial count (10(6) cfu/g of probiotic bacteria) to demonstrate the character of probiotic food. A significant positive correlation was found between L.casei CRL431 count and surface appearance, texture and overall acceptability scores (r = 0.60, 0.52, 0.53). The values of TBARS number of probiotic sucuk samples increased during fermentation-ripening. A significant correlation between taste-aroma scores and fat level was detected (r = -0.61,p = 0.0008). Consiquently, the best sensorial quality was determined in L3 samples and the worst sensorial quality was determined in H8 samples.

Trends in dairy and non-dairy probiotic products - a review

Health awareness has grown to a greater extent among consumers and they are looking for healthy probiotic counterparts. Keeping in this view, the present review focuses recent developments in dairy and non-dairy probiotic products. All over the world, dairy probiotics are being commercialized in many different forms. However, the allergy and lactose intolerance are the major set-backs to dairy probiotics. Whereas, flavor and refreshing nature are the major advantages of non-dairy drinks, especially fruit juices. Phenotypic and genotypic similarities between dairy and non-dairy probiotics along with the matrix dependency of cell viability and cell functionality are reviewed. The heterogeneous food matrices of non-dairy food carriers are the major constraints for the survival of the probiotics, while the probiotic strains from non-dairy sources are satisfactory. Technological and functional properties, besides the viability of the probiotics used in fermented products of non-dairy origin are extremely important to get a competitive advantage in the world market. The functional attributes of dairy and non-dairy probiotic products are further enhanced by adding prebiotics such as galacto-oligosaccharide, fructo-oligosaccharide and inulin.