The first dairy product exclusively fermented by Propionibacterium freudenreichii: A new vector to study probiotic potentialities in vivo

Dairy propionibacteria display probiotic properties which require high populations of live and metabolically active propionibacteria in the colon. In this context, the probiotic vector determines probiotic efficiency. Fermented dairy products protect propionibacteria against digestive stresses and generally contain a complex mixture of lactic and propionic acid bacteria. This does not allow the identification of dairy propionibacteria specific beneficial effects. The aim of this study was to develop a dairy product exclusively fermented by dairy propionibacteria. As they grow poorly in milk, we determined their nutritional requirements concerning carbon and nitrogen by supplementing milk ultrafiltrate (UF) with different concentrations of lactate and casein hydrolysate. Milk or UF supplemented with 50 mM lactate and 5 g L⁻¹ casein hydrolysate allowed growth of all dairy propionibacteria studied. In these new fermented dairy products, dairy propionibacteria remained viable and stress-tolerant in vitro during minimum 15 days at 4 °C. The efficiency of milk fermented by the most tolerant Propionibacterium freudenreichii strain was evaluated in piglets. Viability and SCFA content in the colon evidenced survival and metabolic activity of P. freudenreichii. This work results in the design of a new food grade vector, which will allow preclinical and clinical trials.     

Probiotic potential and biochemical and technological properties of Lactococcus lactis ssp. lactis strains isolated from raw milk and kefir grains

Lactococcus lactis ssp. lactis is one of the most important starter bacteria used in dairy technology and it is of great economic importance because of its use in the production of dairy products, including cheese, butter, cream, and fermented milks. Numerous studies have evaluated the biochemical and probiotic properties of lactococci; however, limited studies on the probiotic characteristics of lactococci were conducted using strains originating from raw milk and dairy products. Characterizing the probiotic properties of strains isolated from raw milk and fermented milk products is important in terms of selecting starter culture strains for the production of functional dairy products. In this study, biochemical properties (including antibiotic sensitivity, lipolytic activity, amino acid decarboxylation, antioxidant activity) and probiotic properties (including antimicrobial activity, growth in the presence of bile salts, bile salts deconjugation, and hydrophobicity) of 14 Lactococcus lactis strains isolated from raw milk and kefir grains were investigated. Strains originating from kefir grains had better characteristics in terms of antimicrobial activity and bile salt deconjugation, whereas strains from raw milk had better hydrophobicity and antioxidant activity characteristics. None of the strains were able to grow in the presence of bile salt and did not show amino acid decarboxylation or lipolytic activities. Biochemical and probiotic properties of L. lactis strains varied depending on the strain and some of these strains could be used as functional cultures depending on their properties. However, these strains did not possess all of the properties required to meet the definition of a probiotic.     

Potential for prevention of non‐O157 Shiga toxin‐producing Escherichia coli contamination in traditionally fermented African maize gruel by fermentative probiotic Lactobacillus plantarum

Non‐O157 Shiga toxin‐producing Escherichia coli (STEC) are a frequent cause of STEC‐related infections such as diarrhoea. Fermentation by presumptive probiotic Lactobacillus plantarum strain B411 isolated from cereal fermentation was investigated to prevent the growth of acid‐adapted (AA) and non‐acid‐adapted (NAA) non‐O157 STEC in traditionally fermented maize gruel, a widely used complementary food in Africa. L. plantarum strain B411 possessed probiotic characteristics and antimicrobial activity against selected pathogenic bacteria. Growth of AA and NAA non‐O157 STEC strains was substantially inhibited by 3.6 and 4.8 log reductions, respectively, in the maize gruel fermented with the L. plantarum B411, while their growth was only inhibited by 1.0 and 1.2 log reductions, respectively, by traditional fermentation alone. Inclusion of fermentative strains of L. plantarum exhibiting probiotic activity is a feasible method to ensure safety of traditionally fermented African cereal porridges through inhibition of non‐O157 STEC.     

Safety and functional aspects of pre‐selected pediococci for probiotic use in Iberian dry‐fermented sausages

The purpose of this study was to investigate pre‐selected pediococci for potential probiotic use in Iberian dry‐fermented sausages. A total of twelve strains isolated from Iberian dry‐fermented sausages and pig faeces were evaluated according to safety and functional characteristics including biogenic amines and d ‐lactic acid production, antibiotic susceptibility, cell adhesion and antimicrobial activity against food‐borne pathogens. The strain P. acidilactici SP979 was able to establish itself and compete with enteropathogens such as Salmonella choleraesuis on the intestinal epithelium and an inhibition of such pathogenic bacteria as Listeria monocytogenes and Staphylococcus aureus in vitro. This strain was also considered safe to be used with regard to its void aminogenic potential, low d ‐lactic acid production and antibiotic resistance pattern; being identified as a potential probiotic meat starter culture suitable for manufacture of dry‐fermented Iberian sausages.     

发酵乳的最新进展

综述了发酵乳在科学、枝术和市场方面最新进展。介绍了在分子水平和菌株水平的乳酸菌和益生菌的菌种鉴定、乳酸菌和新益生菌株的安全性、乳酸菌胞外多糖、减少发酵乳生产过程中黏度降低的因素，以及乳酸菌和益生菌的功能保健作用。根据近年来消费者对酸奶的温和味道、香气和质地更高的要求，叙述了酸奶和其他发酵乳新产品开发的进展。     

Potentially probiotic acetic acid bacteria isolation and identification from traditional dairies microbiota

Among probiotics, acetic acid bacteria (AAB) can be used as preservative agents because of their high fermentation and acidification activities. This study aimed to isolate, identify and biologically characterise Acetobacter strains from traditional Iranian dairy products. Acetobacter strains were identified by catalase assay, Gram staining, and combined repetitive sequence‐based PCR [(GTG)₅‐PCR fingerprints] and 16S rDNA gene sequencing. We identified eight strains belonging to four species, including Acetobacter aceti, Acetobacter indonesiensis, Acetobacter cibinongensis and Acetobacter syzygii. The molecular techniques could be used as an effective and rapid alternative tool to identify and characterise dairy‐associated AAB. Primary probiotic assessments, including low pH and high bile salt tolerance tests, antagonistic activity test against pathogens, and antibiotic susceptibility confirmed the probiotic properties of these AAB, particularly A. cibinongensis 34L strain, which was isolated from curd. Therefore, this strain can be introduced as novel candidate probiotics that could be used in the food industry.     

Lactiplantibacillus plantarum L67 probiotics vs paraprobiotics for reducing pro-inflammatory responses in colitis mice

Probiotics improve intestinal symptoms and reduce damage in patients with inflammatory bowel disease (IBD). However, live bacteria are not consistently effective for IBD patients because of their weaker immune system and damaged intestinal epithelial cells. This study compared the suppression effect of probiotic (L67) and paraprobiotic Lactiplantibacillus plantarum L67 (PPL67) cells on dextran sulphate sodium (DSS)-treated Institute of Cancer Research mice. The results showed that the administration of PPL67 to DSS-treated mice mitigated the symptoms of colitis as evidenced by reductions in DAI define levels and the pro-inflammatory factors. So, these results indicate that L. plantarum L67 may prevent the pathogenesis of chronic colitis in a safer and more stable way.     

Bile salt deconjugation activity of Propionibacterium strains and their cholesterol co‐precipitation abilities

The present study investigated the deconjugation of bile salts and co‐precipitation of cholesterol with deconjugated bile salts by seven Propionibacterium spp. strains in vitro. Propionibacterium spp. could deconjugate sodium glycocholate (1.53–5.31 mM) and sodium taurocholate (0.08–0.25 mM) bile salts. The highest cholesterol precipitation (47.8 µg/mL) was determined with Propionibacterium freudenreichii subsp. freudenreichii SP3 strain in a 0.15% oxgall‐containing medium. Significant (P < 0.05) correlations were observed between cholesterol co‐precipitation and deconjugation of sodium glycocholate among the strains. In vitro bile salt deconjugation activity studies of P. freudenreichii subsp. freudenreichii SP3 strain revealed that this strain may have potential as a probiotic strain for deconjugation of bile salts in vivo studies.     

Anti-Helicobacter pylori activity of fermented milk with lactic acid bacteria

BACKGROUND: Ten strains of lactic acid bacteria (LAB) were investigated for their anti‐Helicobacter pylori effects. The bactericidal activity and organic acid content in spent culture supernatants (SCS) from fermented milk were measured. In addition, the exclusion effect of SCS against H. pylori infection of human gastric epithelial AGS cells was assayed. RESULTS: Three LAB strains, LY1, LY5 and IF22, showed better anti‐Helicobacter effects than the other strains. There were no significant differences in the bactericidal activity of LAB strains between original SCS, artificial SCS and SCS treated by heating or protease digestion. However, neutralised SCS lost this activity. These results suggest that the anti‐H. pylori activity of SCS may be related to the concentration of organic acids and the pH value but not to protein components. In the AGS cell culture test, both fermented LY5‐SCS and artificial LY5‐SCS significantly reduced H. pylori infection and urease activity (P < 0.05). CONCLUSION: In this study, in vitro methods were used to screen potential probiotics with anti‐H. pylori activity. This may provide an excellent and rapid system for studying probiotics in the functional food and dairy industries. Copyright © 2011 Society of Chemical Industry     

Probiotics: The scientific evidence in the context of inflammatory bowel disease

Inflammatory bowel disease (IBD) generally comprises Crohn's disease (CD) and ulcerative colitis (UC), and their main characteristic is the intestinal mucosa inflammation. Although its origin is not yet fully known, there is growing evidence related to genetics, intestinal microbiota composition, and the immune system factors such as precursors for the initiation and progression of intestinal conditions. The use of certain probiotic microorganisms has been touted as a possible and promising therapeutic approach in reducing the risk of inflammatory bowel disease, specifically ulcerative colitis. Several mechanisms have been proposed to explain the benefits of probiotics, indicating that some bacterial strains are able to positively modulate the intestinal microbiota and the immune system, and to produce metabolites with anti-inflammatory properties. The aim of this paper is to bring together the various results and information, based on scientific evidence, that are related to probiotics and inflammatory bowel disease, emphasizing the possible mechanisms involved in this action.     

In vitro tolerance to digestive stresses of propionibacteria: influence of food matrices

This study investigated Propionibacterium freudenreichii tolerance to stresses encountered during food technology or in the digestive tract. The impact of food matrices on stress survival was evaluated. The ability of P. freudenreichii strains SI 41 and CNRZ 81 to survive both acid and bile salts stresses was studied in vitro. Stress tolerance was examined after inclusion of bacteria in different food matrices (alginate beads, xanthan–gellan beads, fermented milk) and compared to the stress tolerance of the same strains in pure cultures (either in exponential growth phase, in stationary phase, or after freeze-drying). Fermented milk was determined as the best probiotic vector to protect propionibacteria from this trial. This in vitro investigation gave promising results. Indeed, some food matrices can significantly improve protection of bacterial cells from stress injury. These data, which should be confirmed in an in vivo study, will be taken into consideration for the improvement of technological processes and for the choice of an adequate probiotic vector.     

Probiotic potentials of cereal-based beverages

Probiotics offer remarkable potential for the prevention and management of various infective and noninfective disorders. They are reported to play key roles in the suppression of gastrointestinal infections, antimicrobial activity, improvement in lactose metabolism, reduction in serum cholesterol, immune system stimulation, antimutagenic properties, anticarcinogenic properties, anti-diarrheal properties, and improvement in inflammatory bowel disease. Although probiotic foods are classically confined to beverages and cheese, containing live organisms of the lactic acid bacteria family, such health-promoting foods are traditionally dairy-based, comprising milk and its fermented products. However, recent research focuses on the probiotic potentials of fermented cereal-based beverages which are especially consumed in developing countries characterized by low nutritional security and high incidence of gut pathogen infections. Moreover, lactose intolerance and cholesterol content associated with dairy products, coupled with the vegetarian tendencies of diverse populations in the third world, tend to enforce the recent recourse to nondairy beverages. Probiotic microorganisms are mostly of human or animal origin; however, strains recognized as probiotics are also found in nondairy fermented substrates. This review examines the potentials of some traditional cereal-based beverages to serve as probiotic foods, their microbial and functional properties, as well as their process optimization and storage for enhanced utilization.     

INHIBITORY ACTIVITY OF LACTIC ACID BACTERIA ISOLATED FROM THAI FERMENTED FOOD AGAINST PANDEMIC STRAINS OF VIBRIO PARAHAEMOLYTICUS

Since 1996, Vibrio parahaemolyticus serotype O3:K6 and its clones have been reported to cause human infections worldwide. In Thailand, infections caused by these pandemic strains are still high. In order to control these infections, an attempt has been made to use probiotic bacteria. In this study, 327 strains of lactic acid bacteria were isolated from 22 types of fermented Thai foods. They were screened for probiotic properties. One isolate designated as PSU-LAB 71 strongly inhibited the pandemic strains of V. parahaemolyticus and also Vibrio cholerae. PSU-LAB71 was isolated from naturally fermented pork and was identified as Lactobacillus plantarum. The mechanism of its ability to inhibit V. parahaemolyticus was most likely caused by acid production. PSU-LAB71 showed high adhesion to an enterocyte-like Caco-2 cell line. This study highlighted the possibility of using PSU-LAB71 as a probiotic strain to control infections by pandemic V. parahaemolyticus.

PRACTICAL APPLICATIONS

Asian countries use many fermented foods containing lactic acid bacteria. This study describes a method to isolate potential probiotic bacteria from fermented foods that have inhibitory properties against pathogenic Vibrio species, especially pandemic strains of Vibrio parahaemolyticus . This report may initiate other countries that face problems caused by this pathogen to isolate their local lactic acid bacteria that have the potential to act as probiotics to control infections.     

Effects of rare sugar D-allulose on acid production and probiotic activities of dairy lactic acid bacteria

It has recently been reported that the rare sugar d-allulose has beneficial effects, including the suppression of postprandial blood glucose elevation in humans, and can be substituted for sucrose as a low-calorie food ingredient. To examine the applications of d-allulose in the dairy industry, we investigated the effects of d-allulose on the acid production of 8 strains of yogurt starter (Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus) and 4 strains of lactococci, including potential probiotic candidates derived from dairy products. Acid production by 2 L. delbrueckii ssp. bulgaricus yogurt starter strains in milk was suppressed by d-allulose, but this phenomenon was also observed in some strains with another sugar (xylose), a sugar alcohol (sorbitol), or both. In contrast, among the dairy probiotic candidates, Lactococcus lactis H61, which has beneficial effects for human skin when drunk as part of fermented milk, was the only strain that showed suppression of acid production in the presence of d-allulose. Strain H61 did not metabolize d-allulose. We did not observe suppression of acid production by strain H61 with the addition of xylose or sorbitol, and xylose and sorbitol were not metabolized by strain H61. The acid production of strain H61 after culture in a constituted medium (tryptone–yeast extract–glucose broth) was also suppressed with the addition of d-allulose, but growth efficiency and sugar fermentation style were not altered. Probiotic activities—such as the angiotensin-converting enzyme inhibitory activity of H61-fermented milk and the superoxide dismutase activity of H61 cells grown in tryptone–yeast extract–glucose broth—were not affected by d-allulose. d-Allulose may suppress acid production in certain lactic acid bacteria without altering their probiotic activity. It may be useful for developing new probiotic dairy products from probiotic strains such as Lactococcus lactis H61.     

Invited review: Potential antiobesity effect of fermented dairy products

The growing prevalence of obesity affects millions of people around the world and has gained increased attention over the years because it is associated with the development of other chronic degenerative diseases. Different organizations recommend lifestyle changes to treat obesity; nevertheless, other strategies in addition to lifestyle changes have recently been suggested. One of these strategies is the use of probiotics in fermented dairy products; however, a need exists to review the different studies available related to the potential antiobesity effect of these products. Because probiotic fermented dairy products that support weight management are not available in the market, there is a great opportunity for the development of functional dairy products with new lactic acid bacteria that may present this added health benefit. Thus, the purpose of this overview is to highlight the importance of probiotic fermented dairy products as potential antiobesogenic functional foods and present in vitro and in vivo studies required before this kind of product may be introduced to the market. Overall, most studies attributed the antiobesity effect of fermented dairy foods to the probiotic strains present; however, bioactive peptides released during milk fermentation may also be responsible for this effect.     

Is there any place for alimentary probiotics, prebiotics or synbiotics, for patients with inflammatory bowel disease?

The pathogenesis of inflammatory bowel disease (IBD) involves an interaction between genetically determined host susceptibility, dysregulated immune response, and the enteric microbiota. Ecological treatments including probiotics, prebiotics, and synbiotics are actively studied in Crohn's disease (CD), ulcerative colitis (UC) and pouchitis. We review herein the literature on the rational use of probiotics in IBD considering efficacy (as evaluated in randomized controlled trials), mechanisms of action and safety issues. A probiotic effect is strictly restricted to one defined strain and cannot be generalized from one to another. There is evidence of efficacy of some probiotic drugs in pouchitis (VSL#3), and in the prevention of recurrence of UC (Escherichia coli Nissle 1917). However, the evidence for efficacy of probiotic drugs in CD is still low as well as that of dietary ecological treatments. Despite an ecological (hopefully nutritional) treatment of IBD is promising, many questions remain unanswered and further clinical and fundamental studies are needed.     

西藏曲拉和发酵乳中抗氧化和益生特性乳酸菌的筛选及鉴定

以抗过氧化氢、清除自由基为抗氧化指标,耐酸、耐胆盐为益生特性指标,对采集自西藏的自然发酵曲拉和发酵乳中乳酸菌进行了分离、筛选和鉴定。结果表明:从9份样品中分得的62株菌有23株对0.3%过氧化氢具备耐受性,其中4-C、5-D、5-E、9-E对DPPH·和·OH清除率最高分别为86.97%±0.11%、27.62%±0.28%;经鉴定5-D、5-E、9-E、4-C分别为Lactobacillus delbrueckii subsp. Jakobsenii、Lactobacillus delbrueckii subsp. Jakobsenii、Lactobacillus gasseri、Pediococcus pentosaceus;此外,菌株5-D、5-E对酸碱和0.3%胆盐均有较好的耐受能力,具备抗氧化和益生特性,有较大潜力应用于天然抗氧化剂的研究与开发,同时也丰富了西藏地区传统牦牛乳制品中乳酸菌资源库的挖掘工作。     

Incorporation of Propionibacterium shermanii subsp. freudenreichii in probiotic dairy drink production: physicochemical,rheological, microbiological and sensorial properties

The aim of this study was to investigate the use of Propionibacterium shermanii subsp. freudenreichii as a combined culture with Lactobacillus acidophilus (AP), Bifidobacterium animalis subsp. lactis (BP), Lactobacillus casei (CP) and Lactobacillus rhamnosus (RP) in probiotic dairy drink production. Although Propionibacterium spp. is used for many purposes including biopreservative and adjunct culture, in this study, probiotic dairy drinks containing P. freudenreichii were evaluated in terms of their physicochemical, rheological, microbiological and sensory properties. The results of the study showed that P. freudenreichii can also be suitable for the production of probiotic drinks and that there are no adverse effects on the product characteristics.     

New insights into physiology and metabolism of Propionibacterium freudenreichii

Dairy propionibacteria are Actinobacteria, mainly isolated from dairy environments. Propionibacterium freudenreichii has been used for a long time as a ripening culture in Swiss-type cheese manufacture, and is more and more considered for its potent probiotic effects. This review summarises the knowledge on the main P. freudenreichii pathways and the main features explaining its hardiness, and focuses on recent advances concerning its applications as a cheese ripening agent and as a probiotic for human health. Propionibacteria have a peculiar metabolism, characterised by the formation of propionic acid as main fermentation end-product. They have few nutritional requirements and are able to use a variety of carbon substrates. From the sequence of P. freudenreichii CIRM-BIA1^T genome, many pathways were reconstituted, including the Wood-Werkman cycle, enzymes of the respiratory chain, synthesis pathways for all amino acids and many vitamins including vitamin B₁₂. P. freudenreichii displays features allowing its long-term survival. It accumulates inorganic polyphosphate (polyP) as energy reserve, carbon storage compounds (glycogen), and compatible solutes such as trehalose. In cheese, P. freudenreichii plays an essential role in the production of a variety of flavour compounds, including not only propionic acid, but also free fatty acids released via lipolysis of milk glycerides and methyl-butanoic acids resulting from amino acid degradation. P. freudenreichii can exert health-promoting activities, such as a bifidogenic effect in the human gut and promising immunomodulatory effects. Many P. freudenreichii properties involved in adaptation, cheese ripening, bio-preservation and probiotic effects are highly strain-dependent. The elucidation of the molecular mechanisms involved is now facilitated by the availability of genome sequence and molecular tools. It will help in the selection of the most appropriate strain for each application.     

CHANGES IN THE PROFILE OF ORGANIC ACIDS IN PLAIN SET AND STIRRED YOGURTS DURING MANUFACTURE AND REFRIGERATED STORAGE1

The organic acids profile in fermented dairy foods is an indicator of the metabolic activity of added bacterial cultures. These acids act as natural preservatives and contribute to the characteristic sensory properties. This study was done to determine the effect of encapsulation on the metabolic activity of probiotic supplements, i.e. bifidobacteria, in plain yogurts. Metabolically active bifidobacteria may increase the concentration of certain organic acids, mainly acetic and propionic acids, which might lead to decreased acceptability of the product. Changes in the profiles of organic acids were determined in plain set and stirred‐type yogurts containing the starter culture and microencapsulated and nonencapsulated probiotic strains of either Bifidobacterium longumB6 or B. longum ATCC15708. Ion‐exchange high‐performance liquid chromatography was used for the separation and quantification of the organic acids. Concentrations of acetic and lactic acid increased during storage, while those of citric and uric acid remained stable. No particular pattern was observed for propionic or butyric acid, while pyruvic acid initially decreased and then increased during storage.