Lactobacillus Rhamnosus LC705 Research Articles

Probiotic supplementation restores normal microbiota composition and function in antibiotic-treated and in caesarean-born infants

BackgroundInfants born by caesarean section or receiving antibiotics are at increased risk of developing metabolic, inflammatory and immunological diseases, potentially due to disruption of normal gut microbiota at a critical developmental time window. We investigated whether probiotic supplementation could ameliorate the effects of antibiotic use or caesarean birth on infant microbiota in a double blind, placebo-controlled randomized clinical trial. Mothers were given a multispecies probiotic, consisting of Bifidobacterium breve Bb99 (Bp99 2 × 108 cfu) Propionibacterium freundenreichii subsp. shermanii JS (2 × 109cfu), Lactobacillus rhamnosus Lc705 (5 × 109 cfu) and Lactobacillus rhamnosus GG (5 × 109 cfu) (N = 168 breastfed and 31 formula-fed), or placebo supplement (N = 201 breastfed and 22 formula-fed) during pregnancy, and the infants were given the same supplement. Faecal samples of the infants were collected at 3 months and analyzed using taxonomic, metagenomic and metaproteomic approaches.ResultsThe probiotic supplement had a strong overall impact on the microbiota composition, but the effect depended on the infant’s diet. Only breastfed infants showed the expected increase in bifidobacteria and reduction in Proteobacteria and Clostridia. In the placebo group, both birth mode and antibiotic use were significantly associated with altered microbiota composition and function, particularly reduced Bifidobacterium abundance. In the probiotic group, the effects of antibiotics and birth mode were either completely eliminated or reduced.ConclusionsThe results indicate that it is possible to correct undesired changes in microbiota composition and function caused by antibiotic treatments or caesarean birth by supplementing infants with a probiotic mixture together with at least partial breastfeeding.Trial registrationclinicaltrials.gov NCT00298337. Registered March 2, 2006.

A clinical reading on “World Allergy Organization-McMaster University Guidelines for Allergic Disease Prevention (GLAD-P): Probiotics”

To the Editor Since the immunomodulatory properties of probiotics have been described, the effect of probiotic supplementation has been investigated in several trials and it has been also proposed as a preventive intervention for the development of allergic diseases. Recently two important evidence-based recommendations about the use of probiotics in the prevention of allergy were published [1, 2] with conflicting conclusions, in particular the most recent guideline [1] seems to be partially in contradiction with the previous statements about prevention of eczema. For these reasons, we tried to analyze the evidences leading to these recommendations [1] to highlight the aspects that can be more directly related or correlated with clinical practice. This clinical reading was addressed to offer some reflections about the methods used to formulate such recommendations, and the possibility to adopt in the clinical practice the proposed conclusions. We tried to retraces the path proposed by the Authors to analyse three important questions about the efficacy of probiotics in preventing allergic diseases if administrated to pregnant women (first question), to breastfeeding mothers (second question) and in healthy infants (third question). These questions have been investigated by using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach [3], to perform a systematic review of randomized controlled trials and formulate recommendations. In summary, the GRADE method aims to define a rigorous and explicit method for the production of clinical recommendations. According to this method, the knowledge of advantages and disadvantages, benefits and risks of an intervention is necessary to make decisions in the health field. The GRADE approach also provides a three-phases decisional framework: a) formulation of a clinical question, with the choice and the formal evaluation of its related outcomes, and systematic evaluation of the scientific literature and the quality of the evidence; b) evaluation of the benefits and risks associated to the intervention, taking also in consideration its feasibility, the necessary resources and the patients’ preferences; c) formal definition of the strength of the recommendation. From a methodological point of view, it should be noted that the recommendations are directed to patients, clinicians and other health care professionals with different objectives, as clearly explained in the guidelines introduction. Each recommendation can have different levels of strength: strong recommendation indicates that patients would like to receive the intervention and that clinicians should actuate it. Conditional or weak recommendation indicates that the majority of patients would like to receive the intervention, but many other not, as well as they hope that clinicians would recognize that different choices may be appropriate for different patients, by taking advantage of decision-making tools to help patients to make consistent choices. In the results section of the guidelines we can read that “Currently available evidence does not indicate that probiotic supplementation reduces the risk of developing * Correspondence: giampaolo.ricci@unibo.it Pediatric Unit, Department of Medical and Surgical Sciences, University of Bologna, S. Orsola-Malpighi Hospital, Pad 16, via Massarenti 11, 40138 Bologna, Italy Full list of author information is available at the end of the article

Molecular Cloning, Expression of minD Gene from Lactobacillus acidophilus VTCC-B-871 and Analyses to Identify Lactobacillus rhamnosus PN04 from Vietnam Hottuynia cordata Thunb.

The minD gene encoding an inhibitor cell division MinD homolog from Lactobacillus acidophilus VTCC-B-871 was cloned. We showed that there were 97% homology between minD genes of L. acidophilus VTCC-B-871 and Lactobacillus rhamnosus GG and Lactobacillus rhamnosus Lc705. Based on the analysis of the DNA sequence data from the L. rhamnosus genome project and sequenced minD gene of L. acidophilus VTCC-B-871, a pair of primers was designed to identified the different minD genes from L. acidophilus ATCC 4356, L. rhamnosus ATCC 11443. Besides, the polymerase chain reaction product of minD gene was also obtained in L. rhamnosus PN04, a strain was isolated from Vietnamese Hottuynia cordata Thunb. In addition, we performed a phylogenetic analysis of the deduced amino acid sequence of MinD homologs from L. acidophilus VTCC-B-871 with the other strains and compared the predicted three-dimension structure of L. acidophilus VTCC-B-871 MinD with Escherichia coli MinD, there are similarity that showed evolution of these strains. The overexpression of L. acidophilus VTCC-B-871 MinD in E. coli led to cell filamentation in IPTG and morphology changes in different sugar stresses, interestingly. The present study is the first report characterizing the Lactobacilus MinD homolog that will be useful in probiotic field.

Real-time PCR assays for strain-specific quantification of probiotic strains in human faecal samples

Strain-specific real-time PCR assays were developed for the probiotic strains Bifidobacterium breve 99, Lactobacillus rhamnosus LC705 and Propionibacterium freudenreichii ssp. shermanii JS, used in combination, for quantification of the strains in human faecal samples. Unique randomly amplified polymorphic DNA (RAPD) sequences or a phage-related sequence of the strains were used as a basis for designing strain-specific primers and probes. The real-time PCR conditions were optimised and the specificities of the assays were confirmed by analysing DNA from related bacterial strains and from faecal samples originating from an intervention study. The assays allowed quantification with a linear range of six orders of magnitude, from 101 to 107 target genomes per assay. The detection limit was 4 × 105 genome copies per g of faeces. The strain-specific quantitative real-time PCR assays developed were suitable for identification and quantification of probiotic strains in human faecal samples in a controlled intervention trial.

Effect of protective culture and biopreservatives on strained yoghurt quality

In this research, the protective culture (Lactobacillus rhamnosus LC705 andPropionibacterium freudenreichii JS) and biopreservatives as Nisin (Nisaplin), Delvocid®(natamycin) or Nipasol M (propyl paraben) on the physical, chemical and sensory properties of strained yoghurt were studied in relation to its viability of undesirable yeasts-moulds during storage at 4±1°C for 28 days. Based on chemical and physical characteristics studied, there were no effective or negative effect originated from these preservatives. Moreover control samples had lower scores especially at the end of storage. The preservative supplemented strained yoghurts were protected from yeast and mould growth. The inhibitory action of protective culture against yeast and moulds depended on type of preservatives. Also, use of protective culture or bio preservatives did not affect sensory properties of strained yoghurt. Key words: Biopreservatives, fermented milks, protective cultures, strained yoghurt, yoghurt.

Consumption of Galactooligosaccharides together with Probiotics Stimulates the In Vitro Peripheral Blood Mononuclear Cell Proliferation and IFNγ Production in Healthy Men

Probiotics and prebiotics modify the intestinal environment and could have immunomodulatory effects. The proliferation of spontaneous and phytohemagglutinin-stimulated peripheral blood mononuclear cells (PBMCs) and their production of interleukin-4, interleukin-5, transforming growth factor-β1, and interferon-γ (IFNγ) were determined in eighteen men at the baseline and during a 2-week period of probiotics (mixture of Lactobacillus rhamnosus GG, Lactobacillus rhamnosus LC705, Propionibacterium freudenreichii ssp. shermanii JS, and Bifidobacterium breve Bb99) and galactooligosaccharides (GOSs) (3.8 g/day). The spontaneous and stimulated proliferation of PBMC increased from the baseline during probiotics+GOS (P<0.001). The secretion of IFNγ, but not other cytokines, by stimulated PBMC increased during the same period (P<0.05). In conclusion, the consumption of this probiotic mixture including GOS appears to increase the capacity of PBMC to proliferate and release IFNγ selectively in healthy men.

The role of copper in the manufacture of Finnish Emmental cheese

The effects of added copper in the manufacture of Finnish Emmental cheese were studied. Consequently, cheeses were produced with or without the copper supplement and a facultative heterofermentative strain, Lactobacillus rhamnosus Lc705, which is currently utilized as a protective culture in large-scale manufacture in Finland. Cheeses were examined at 1, 7, 30, 60, and 90 d from the microbiological, chemical, and sensory points of view. Organic acid production was affected by the presence of copper in the cheeses. The addition of copper to cheesemilk increased the level of primary proteolysis and slowed secondary proteolysis as measured by nitrogen content in different extracts after citrate fractionation of cheeses, in pH 4.4-soluble nitrogen and 5% phosphotungstic acid-soluble nitrogen, respectively. The presence of copper appears to positively regulate the sensory characteristics of the cheese produced in our conditions; in particular, consistency was affected significantly. The role of the Lb. rhamnosus Lc705 protective strain has not been shown to have important effects on most of the parameters that influence the final quality of the cheeses. Although the traditional plating systems for revealing bacterial populations during cheese manufacture did not reveal any drastic differences caused by the presence of copper, the results from chemical and sensory analyses suggest that its use plays a significant role in the regulation of bacterial physiological and biochemical activities, which in turn affect the sensory quality of Emmental cheese.

Investigation of lactobacilli from mother’s breast milk who were placed on probiotic diet

Human milk contains a group of bacteria with potential to be used as probiotics but the origin of these bacteria is debated. This study was aimed to identify and isolate lactobacilli in breast milk and investigate the role of consuming probiotic supplements on the lactobacilli microflora of breast milk. Ten out of twenty mothers were placed on the probiotic diet and the others were considered as controls. The breast milks of these mothers were cultured on MRS. The whole genome of 16s ribosomal DNA of different colonies was amplified using polymerase chain reaction for identification down to the strain level. Finally Lactobacillus rhamnosus LC705 was isolated just from four mothers who were placed on probiotic diet. Since this strain was dominant bacteria in capsules which used as a source of probiotic diets, it may imply that modulation of the mother’s intestinal microflora can have an effect on the health of infants and therefore, would open new perspectives for using breast milk as a source of probiotic bacteria with bacteriotherapy approach.

91 Can Postnatal Supplementation with Probiotics Reduce the Risk for Allergic Disease in Infancy?

Background and aims: The increasing allergy prevalence may depend on a reduced microbial exposure early in life. Probiotics may prevent eczema in infants. Prenatal maternal supplementation might be crucial for this effect. The mixture of probiotic strains used in the present study reduced eczema when previously supplemented both pre- and postnatally. The aim of this study was to evaluate the effect of only postnatal probiotic supplementation on allergic manifestations during the first two years of life and to explore the impact of environmental factors on allergy development.Methods: In the double-blind placebo-controlled PRODIA study, infants with HLA risk genotype for type 1 diabetes were supplemented from two until six months of age with placebo or the probiotic strains Lactobacillus rhamnosus GG, Lactobacillus rhamnosus LC705, Bifidobacterium breve Bbi99 and Propionibacterium freudenreichii ssp. Shermani JS. 177 of the families completed questionnaires addressing allergy development until two years of age.Results: The cumulative incidence of eczema was not significantly different in the probiotic (21.7%) and the placebo group (14.1%). Children receiving probiotics, as compared with placebo, had a lower cumulative incidence of wheeze, 34.1% versus 49.4% (p=0.04). Children attending day-care had a lower cumulative incidence of eczema (p=0.03). Recurrent wheeze was associated with treatment with antibiotics (p=0.005) and care in the neonatal ward (p=0.02).Conclusion: Postnatal probiotic supplementation did not affect the development of infant eczema in children with genetic risk for diabetes, but showed association with a lower incidence of wheeze. Allergy development was associated with environmental factors potentially modulating microbial load.

Saccharomyces Cerevisiae And Probiotic Bacteria Potentially Inhibit Aflatoxins Production In Vitro And In Vivo Studies

Saccharomyces cerevisiae and Lactic acid bacteria (Lactobacillus rhamnosus GG and Lactobacillus rhamnosus LC705) potentially inhibited Aspegillus flavus growth and aflatoxins production in YES liquid media. Six groups of rats orally administrated SC (10 CFU / ml) and LGG & LC705 (10 CFU/ ml) daily for 15 days alone or with 2 mg / ml aflatoxin B1 (AFB1) in corn oil, significantly reduced serum ALT, AST, GGT, creatinine, and BUN compared with AFB1-tereated group. No deaths occurred in any combined treatment with AFB1, while a 30% mortality rate was recorded in the AFB1-treated group. Blood glutathione (GSH) levels significantly increased in groups treated with single-treatment of S. cerevisiae, LGG & LC705 or concomitant with AFB1; however, AFB1treatment alone severely depleted GSH level more than other treatments. Histopathological examination of liver and kidney in rats treated with AFB1 showed necrosis, vacuolar degeneration and fatty changes in hepatocytes; cellular swelling and pyknotic nuclei of proximal convoluted tubules in renal tissue. DNA content decreased significantly in liver and kidney tissues with AFB1administration, these findings were ameliorated by probiotec bacteria and S.cervisiae treatment. Conclusion: These probiotics may have good medical benefits to diminish the aflatoxins production in vitro and in vivo studies.

Lactobacillus rhamnosus LC705 Together with Propionibacterium freudenreichii ssp shermanii JS Administered in Capsules Is Ineffective in Lowering Serum Lipids

Objective: The aim of this study was to examine the effect of the administration of Lactobacillus rhamnosus strain LC705 and Propionibacterium freudenreichii ssp shermanii strain JS in capsules on serum cholesterol and triglyceride levels in mildly or moderately hypercholesterolemic men.Methods: Thirty-eight basically healthy men, mean age 42 years (range 24–55), mean cholesterol 6.2 mmol/L (5.3–8.2 mmol/L), participated in this double-blind, randomised, placebo-controlled, two-period crossover study with 4-week treatment periods. The subjects consumed daily two probiotic capsules containing viable Lactobacillus rhamnosus LC705 and Propionibacterium freudenreichii ssp shermanii JS (2 × 1010 colony forming units of each strain daily) or two placebo capsules. Serum lipids were assessed before the intervention, at the end of both 4-week treatment periods, and 2 weeks after the second treatment period. Dietary and lifestyle habits were carefully monitored.Results: All the subjects completed the study, and the probiotic capsules were well tolerated. Dietary habits and the intake of energy and nutrients, such as saturated fatty acids and cholesterol, did not differ between the treatment groups. No changes in total cholesterol, HDL cholesterol, LDL cholesterol or triglyceride levels were observed during the consumption of the probiotics compared to placebo.Conclusions: The administration of Lactobacillus rhamnosus LC705 and Propionibacterium freudenreichii ssp shermanii JS did not affect serum lipids.

Effects of Multispecies Probiotic Combination on Helicobacter pylori Infection In Vitro

Probiotic bacteria alleviate many gastrointestinal symptoms, but the current trend of combining bacteria for additional benefit may make their effects more complex. We characterize four probiotics and their combination in terms of pathogen adhesion, barrier function, cell death, and inflammatory response in Helicobacter pylori-infected epithelial cells. H. pylori-infected Caco-2 cells were pretreated with Lactobacillus rhamnosus GG, Lactobacillus rhamnosus Lc705, Propionibacterium freudenreichii subsp. shermanii Js, Bifidobacterium breve Bb99, or all four organisms in combination. We evaluated the adhesion of H. pylori by in situ immunofluorescence; epithelial barrier function by measurement of transepithelial resistance; apoptosis by measurement of caspase 3 activation; cell membrane leakage by measurement of lactate dehydrogenase release; and inflammation by measurement of interleukin-8 (IL-8), IL-10, prostaglandin E(2) (PGE(2)), and leukotriene B(4) (LTB(4)) release. All probiotics inhibited H. pylori adhesion. L. rhamnosus GG, L. rhamnosus Lc705, P. freudenreichii subsp. shermanii Js, and the combination inhibited H. pylori-induced cell membrane leakage. L. rhamnosus GG, L. rhamnosus Lc705, and the combination initially improved epithelial barrier function but increased the H. pylori-induced barrier deterioration after incubation for 24 to 42 h. L. rhamnosus GG, L. rhamnosus Lc705, and P. freudenreichii subsp. shermanii Js inhibited H. pylori-induced IL-8 release, whereas L. rhamnosus GG, L. rhamnosus Lc705, and B. breve Bb99 suppressed PGE(2) release. None of these anti-inflammatory effects persisted when the probiotics were used in combination. The combination thus increased the levels of IL-8, PGE(2), and LTB(4) released from H. pylori-infected epithelial cells. The proinflammatory actions of the individual components dominated the anti-inflammatory effects when the probiotic bacteria were used in combination. Our results stress that the therapeutic response can be optimized if probiotic strains are characterized before they are used in combination.

Microbial composition and fecal fermentation end products from colicky infants - a probiotic supplementation pilot

Objectives: The etiology of infantile colic has remained unknown. The present study aimed to identify possible differences in the fecal microbial composition and metabolic end products between colicky and non-colicky infants and to examine whether an orally administered probiotic supplementation has any effect on the microbiota and relief in colicky symptoms. Subjects and methods: The study population consisted of nine colicky and nine non-colicky infants. Five colicky infants received probiotic supplementation ( Lactobacillus rhamnosus GG, Lactobacillus rhamnosus LC705, Bifidobacterium breve Bbi99, and Propionibacterium freudenreichii ssp. shermanii JS) and four colicky infants received placebo for 2 weeks. Fecal microbiota of all infants was studied by culture, cellular fatty acid (CFA) analysis, and gas and short chain fatty acid (SCFA) production in 48 h fermentation. Microbial parameters and crying profiles were compared between the cases and controls at baseline and between the probiotic and placebo supplementation after 2 weeks. Results: Although SCFA and gas production and bacterial total counts were similar, the prevalence of indole-producing coliforms was significantly higher in colicky infants compared with controls (89% vs 33%), while many aerobic genera present in controls were not detected in colicky infants. CFA composition reflected the differences, since >2% of the CFAs were present exclusively in the colicky group. After probiotic supplementation, the total counts of anaerobic bacteria, especially lactobacilli and bifidobacteria, increased significantly. Fermentation parameters were not extensively affected; however, acetic and lactic acid production tended to increase and hydrogen production tended to decrease. No significant difference was observed in crying patterns between the probiotic and placebo group. Conclusion : The composition of the intestinal microbiota differs between colicky and noncolicky infants. Although no apparent relief in colicky symptoms was achieved, the probiotic supplementation seems to increase the bacterial diversity and strengthen the succession towards a balanced commensal gut microbiota. Key words: infantile colic, fecal bacteria, probiotics, colonization, SCFA

Effects of multispecies probiotic supplementation on intestinal microbiota in irritable bowel syndrome

A multispecies probiotic has shown beneficial effects in irritable bowel syndrome. In addition, certain other probiotics have demonstrated advantageous effects, but the mechanisms behind this are poorly understood. To investigate the mode of action of a multispecies probiotic consisting of Lactobacillus rhamnosus GG, Lactobacillus rhamnosus Lc705, Propionibacterium freudenreichii ssp. shermanii JS and Bifidobacterium breve Bb99 by monitoring its effects on intestinal microbiota and markers of microbial activity. A total of 55 irritable bowel syndrome patients participated in this placebo-controlled double-blind trial. Subjects received either multispecies probiotic or placebo supplementation daily during a 6-month period. The composition of intestinal microbiota was analysed with real-time polymerase chain reaction, short-chain fatty acids with gas chromatography and enzymes with spectrophotometer. Each supplemented probiotic strain was detected in faecal samples. Intestinal microbiota remained stable during the trial, except for Bifidobacterium spp., which increased in the placebo group and decreased in the probiotic group (P = 0.028). No changes in short-chain fatty acids occurred. A decrease in ss-glucuronidase activity was detected in 67% of the subjects in the probiotic group vs. 38% in the placebo group (P = 0.06). Factors other than the microbial groups and metabolites studied herein seem responsible for the alleviation of irritable bowel syndrome symptoms by the multispecies probiotic.

Probiotic bacteria as potential detoxification tools: assessing their heavy metal binding isotherms

Dietary exposure to heavy metals may have detrimental effects on human and animal health, even at low concentrations. Specific probiotic bacteria may have properties that enable them to bind toxins from food and water. We assessed the interaction of probiotic bacteria with cadmium and lead in vitro as an initial screening step to identify strains for heavy metal decontamination in food and intestinal models. Binding isotherms for cadmium and lead were characterized for Lactobacillus rhamnosus LC-705, Propionibacterium freudenreichii subsp. shermanii JS and a mix of them used by the food industry. Differences among the strains and their combinations in binding performance at a range of concentrations between 0.1 and 100 mg.L-1 were evaluated with the Langmuir model for biosorption. The effects of pH, contact time, and viability on the binding capacities were also investigated. All strains and their combinations were found to bind cadmium and lead efficiently at low concentration ranges commonly observed in foods. However, the two strains and their combinations differed significantly in their maximum binding capacities and affinities represented by the Langmuir constants Qmax and b, respectively. The binding seemed to occur instantaneously and in a pH-dependent manner, which can be perfectly described by a segmented linear-plateau model.

Aflatoxin B1 Binding by a Mixture of Lactobacillus and Propionibacterium: In Vitro Versus Ex Vivo

Aflatoxin B1 (AFB1) is a well-known carcinogen and reducing its bioavailability is of great interest for human and animal health. Several probiotic bacteria are able to bind AFB1 in vitro, including Lactobacillus rhamnosus LC-705 and Propionibacterium freudenreichii subsp. shermanii JS. A mixture of these two probiotics is used by the food and feed industry as biopreservative (Bioprofit), making it a promising candidate for future applications. Consequently, this study aims to investigate the in vitro and ex vivo ability of this probiotic mixture to bind AFB1. For in vitro experiments, probiotic mixture was suspended in an AFB1 solution (5 μM), incubated for 1 to 30 min, centrifuged, and AFB1 residues were quantitated in supernatant and pellet. For ex vivo experiments, duodenal loops of chicks were ligated and injected with either AFB1 solution alone or probiotic mixture suspension and AFB1 solution. Lumen content was centrifuged and AFB1 was quantitated in supernatant and pellet. Additionally, AFB1 was extracted from duodenal tissue to calculate tissue uptake. In vitro, 57 to 66% of AFB1 was removed from the solution by the probiotic mixture, but only 38 to 47% could be extracted from the bacterial surface. In ex vivo experiments, only up to 25% of AFB1 was bound by bacteria, and tissue uptake of AFB1 was significantly reduced when probiotic bacteria were present in the duodenal loop. Furthermore, the effect of intestinal mucus on the bacterial binding ability was investigated in vitro and was found to significantly reduce AFB1 binding by the probiotic mixture. However, probiotic mixture could only retard but not prevent AFB1 absorption in duodenal loops. Further work needs to assess the potential of probiotics in different experimental setups.

The effect of a protective culture and exclusion of nitrate on the survival of enterohemorrhagic E. coli and Listeria in Edam cheese made from Finnish organic milk

Abstract This study compared the chemical composition and hygienic quality of Finnish organic and conventional milk. The composition and quality of milk from 126 Finnish organic and conventional farms from January 2000 to November 2001 were investigated. Finnish organic milk contained significantly less fat, and protein, and had a lower total bacterial count than conventional milk. Organic milk contained significantly more lactose and had a similar, or higher, somatic cell count and a similar, or lower, urea content than conventional milk. Although the differences between organic and conventional milk are rather small, they are of economical significance in large-scale cheese manufacture. This study also determined the effects of the exclusion of nitrate and the introduction of a protective culture on the microbiological safety and the counts of Listeria and non-pathogenic enterohemorrhagic Escherichia coli (EHEC) in organic Edam cheese. Nitrate failed to inhibit the growth of EHEC and Listeria . Thus, compared to Edam cheese from conventional milk, Edam cheese from organic milk without added KNO 3 poses no additional health risk with respect to Listeria and EHEC. The use of a protective culture containing Lactobacillus rhamnosus LC705, however, inhibited the growth of Listeria in Edam cheeses from organic milk.

Physicochemical Alterations Enhance the Ability of Dairy Strains of Lactic Acid Bacteria To Remove Aflatoxin from Contaminated Media

Lactobacillus rhamnosus GG and Lactobacillus rhamnosus LC-705, previously shown to effectively bind to aflatoxin B1, were subjected to various Chemical and physical treatments to examine the effects of these treatments on the binding affinity of these strains towards aflatoxin B1. Treatment of bacterial pellets of both strains with hydrochloric acid significantly (P < 0.05) enhanced the binding ability when compared to nontreated pellets or pellets treated by other methods. An enhancement of bacterial ability to bind aflatoxin B1 was also observed when the bacterial pellets were subjected to heat treatment by either autoclaving or boiling at 100°C in a water bath, but the impact of these two treatments was not as effective as the acid treatment. Ethanol, UV radiation, sonication, alkaline, or pH treatments either had no effect or reduced the binding ability of the bacteria.

Adhesion of Two Lactobacillus Strains, One Lactococcus and One Propionibacterium Strain to Cultured Human Intestinal Caco-2 Cell Line

Adhesion to intestinal surfaces is considered a prerequisite for effective probiotic bacterial strains. In this study, the in vitro adhesion properties of dairy strains Lactobacillus rhamnosus LC-705, Lactococcus lactis ssp. cremoris ARH 74 and Propionibacterium freudenreichii ssp. shermanii JS were investigated using human intestinal Caco-2 cell cultures. Lactobacillus strain GG (ATCC 53103) was used as a positive probiotic control, because the strain is known to adhere to Caco-2 cell cultures. Enterotoxigenic human E. coli (H 10407) and bovine E. coli (B 44) strains were used as positive and negative control, respectively. Bacteria were radioactively labeled, and the adhesion to Caco-2 cell cultures was assessed using liquid scintillation. The tested strains adhered to Caco-2 cell cultures and the adherence was similar to that of Lactobacillus strain GG. The adhesion was significantly higher when compared to the negative E. coli control. Adhesion was concentration dependent and no saturation level was achieved with bacterial concentrations used in this study. The Caco-2 cell cultures were also pretreated with nonlabeled bacteria of one strain prior to adhesion of radiolabeled bacteria. The nonlabeled adhered bacteria influenced the adhesion of radiolabeled bacteria in only one case: the adhesion of P. freudenreichii was significantly reduced by previously adhered L. rhamnosus LC-705. This result may indicate competition for adhesion sites between these strains. The adhesion properties of Lc. lactis and P. freudenreichii to intestinal cells make the strains interesting as potential new probiotic strains.