Inhibitory effects of laminaran and low molecular alginate against the putrefactive compounds produced by intestinal microflora in vitro and in rats

The inhibitory effects of laminaran and low molecular weight sodium alginate (MW = 49,000) against formation of ammonia, indole compounds and phenol compounds, putrefactive and harmful compounds, induced by human fecal microflora, were examined in vitro. Laminaran was fermented to acetate, propionate, n-butyrate and lactate. The alginate was fermented to acetate and propionate. Both of these polysaccharides inhibited formation of the putrefactive compounds. In the case of rats fed diet containing 2% (w/w) laminaran or low molecular alginate, the fermentation pattern agreed with that of the in vitro experiment. Laminaran suppressed indole, p-cresole and sulfide, significantly. These putrefactive compounds, in rats fed low molecular alginate, also tended to be lower. These results suggest that the fermentation of laminaran by intestinal bacteria suppresses the putative risk markers for colon cancer.     

Evaluation of gastrointestinal transit in rats fed dietary fibres differing in their susceptibility to large intestine fermentation

The rate and extent of in situ digesta transit after ingestion of diets containing dietary fibres differing in their susceptibility to large intestine fermentation were investigated. One hundred and twenty rats were fed diets containing 7.5% cellulose, inulin, potato fibre or maize starch for 3 days, then the same diets with titanium dioxide (TiO₂) for 3 days, followed by diets without TiO₂ for 2 days. In all diets, TiO₂ ratios rapidly increased within 24 h and reached a maximum level in duodenum, caecum and colon within 2–3 days. Inulin, potato fibre and maize starch-fed rats showed higher levels of caecal short-chain fatty acids, lower faecal polysaccharide concentrations, and reduced faecal output than the rats fed cellulose. Inulin was highly susceptible to caecal microbial fermentation compared to the other dietary fibres. Transit of these dietary fibres through the GI tract was rapid, and the rate of digesta transit was not affected by dietary fibre fermentability in the large intestine.     

Effects of early dietary intervention with a fermentable fibre on colonic microbiota activity and mucin gene expression in newly weaned rats

Colonic microbiota composition and metabolic processes were investigated after modifying the diet immediately post-weaning in rats. Three-week old Sprague–Dawley rats were fed cellulose or inulin diet for 0 day (d), 7 d or 14 d. Real-time PCR quantification showed significantly higher colonic Bifidobacterium spp. in rats fed inulin on d7 and d14. Inulin was effective in increasing the total bacteria, Bacteroides-Prevotella-Porphyromonas group and Faecalibacterium prausnitzii, while decreasing Lactobacillus spp. Higher concentrations of short-chain fatty acids (SCFAs: acetic, butyric and propionic acids), lactic acid and succinic acid were observed in inulin-fed rats. Inulin ingestion altered colonic mucin (MUC)-3 gene expression, and increased the colon crypt depth with more goblet cells per crypt. Significant positive correlations between SCFAs concentrations and MUC3 expression were observed. Dietary supplementation with inulin altered microbiota composition, and their fermentation end-products may have aided in modifying mucin gene expression and morphology in the colon of young rats.     

Porcine artery elastin preparation reduces serum cholesterol level in rats

The effect of porcine artery elastin on serum cholesterol level was investigated in rats fed a cholesterol-free diet. Rats were fed for 4 weeks, with a diet (ED) containing 15% casein and 5% of porcine artery elastin in comparison with a diet (CD) containing 20% casein. The total serum and non-HDL-cholesterol concentrations were lower (P < 0.001) in ED-fed group than the CD-fed group at the end of the experiment. Caecal propionate concentration and Bifidobacterium and Lactobacillus population were higher (P < 0.05) in ED-fed group than the CD-fed group. The results of this study suggest that porcine artery elastin could be considered as a functional dietary protein with hypocholesterolaemic ability. Favourable amino acid composition and lysine derived cross links may at least be partially responsible for the hypocholesterolaemic ability of ED. Moreover, the higher caecal propionic acid concentration in the ED-fed group may have suppressed the cholesterol synthesis in the liver, and reduced the serum cholesterol level.     

Polyphenol-rich longan (Dimocarpus longan Lour.)-flower-water-extract attenuates nonalcoholic fatty liver via decreasing lipid peroxidation and downregulating matrix metalloproteinases-2 and -9

Longan-flower-water-extract (LFWE) contains large amounts of phytochemicals where gentisic acid and epicatechin are the major compounds in phenolic acid and flavonoid compound, respectively. The objective of this study was to investigate if drinking LFWE could protect the liver from a hypercaloric dietary habit. Only rats fed the hypercaloric diet (HCD) with 25 g/L (w/v) LFWE solution (HCD_2X) group demonstrated lower (p < 0.05) serum triglyceride levels compared to those fed the HCD with normal distilled water (HCD_NDW) and HCD with 12.5 g/L (w/v) LFWE solution (HCD_1X) groups. However, drinking LFWEs decreased (p < 0.05) hepatic lipids in the HCD rats. Lower (p < 0.05) hepatic MDA levels, GOT and GPT values, and higher (p < 0.05) hepatic GSH levels were observed in HCD rats drinking LFWE. Besides, drinking LFWE downregulated (p < 0.05) gene expressions and activities of hepatic matrix metalloproteinases-2 and -9 (MMP-2/9) in HCD rats. In conclusion, polyphenol-rich LFWE displayed hepatoprotective characteristics against an energy-dense dietary habit.     

Effect of cryoprotectants,prebiotics and microencapsulation on survival of probiotic organisms in yoghurt and freeze-dried yoghurt

The survival of probiotic microorganisms including Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus rhamnosus and Bifidobacterium spp. was evaluated in yoghurt and freeze-dried yoghurt after processing and storage. The effectiveness of microencapsulating probiotic organisms as well as adding cryoprotectants and prebiotics in improving their viability was also investigated. The viability of Bifidobacterium infantis 17930 and L. rhamnosus GG was reduced by 0.07 log, while that of L. casei 1520 and Bifidobacterium longum 1941 was reduced by 0.28 and 0.39 log, respectively. There was a 7% improvement in the viability of L. casei 1520 when cryoprotectant ‘Unipectine™ RS 150’ was added at 2.5% (w/v). The prebiotic ‘Raftilose^®P95’ when added at 1.5% w/v to yoghurt improved the viability of the combined selected probiotic organisms by 1.42 log during four weeks of storage at 4 °C. Microencapsulation with alginate improved viability of combined selected probiotic organisms by 0.31 log in freeze-dried yoghurt stored at 21 °C.     

Effect of different activated coatings containing enterocin AS-48 against Listeria monocytogenes on apple cubes

Enterocin AS-48 is a circular bacteriocin with strong anti-Listeria activity. The purpose of the present study was to evaluate the effect of the bacteriocin incorporated into different coating solutions on a cocktail of five L. monocytogenes strains previously inoculated on apple cubes. Coating solutions were made with chitosan, caseinate, alginate, k-carrageenate, xanthan gum, pectin, starch, carboxymethyl cellulose or methyl cellulose. Coatings were applied singly or combined with enterocin AS-48 at 20 or 40 μg/ml. Samples were stored at 4 °C for 7 days. The single application of coatings had almost no effect (as in alginate and methyl cellulose) or had a low effect on Listeria viability (< 2.0 log cycles), with the exception of chitosan coating which showed a strong anti-Listeria activity (up to 3.7 log cycles at day 7). Coatings dosed with 20-μg/ml enterocin AS-48 reduced viable Listeria counts gradually during storage in most cases, achieving significant reductions (p < 0.05) of 1.0 to 1.9 log cycles after 7 days for k-carrageenate, xanthan gum, pectin, starch, carboxymethyl cellulose and methyl cellulose compared to the single coating. At 40 μg/ml, enterocin AS-48 significantly reduced viable counts (p < 0.05) for most coatings (by 1.4 to 3.3 log cycles, depending on the coating) compared with coatings without bacteriocin (except for chitosan). Chitosan, pectin, xanthan gum and carboxymethyl cellulose coatings, supplemented or not with 40 μg/ml AS-48 were further investigated in combination with 20 mM EDTA or with 2.0% sodium lactate. The single addition of sodium lactate showed the greatest effects at day 7, where it reduced viable counts significantly (p < 0.05) by 1.1 to 2.2 log cycles compared to the single coatings (except for chitosan), whereas the combination of sodium lactate and AS-48 reduced viable counts below detection levels also at day 7 for all coatings. The combination of EDTA and AS-48 was much more effective, reducing Listeria counts below detection levels from day 1 for most of the coatings tested. The combination of EDTA and AS-48 was also the most effective at time 0, achieving reductions of viable counts between 2.0 and 2.7 log cycles depending on the coating immediately after treatment compared with single coatings.Industrial relevanceResults from the present study suggest the potential of edible coatings containing enterocin AS-48 and EDTA for inactivation of L. monocytogenes on apple surfaces. Since edible coatings are widely used on fruit surfaces, coatings activated with enterocin AS-48 and EDTA could find application as a hurdle against L. monocytogenes in fresh-cut apple pieces.     

Soluble polysaccharides from flaxseed kernel as a new source of dietary fibres: Extraction and physicochemical characterization

Flaxseed (Linum usitatissimum L.) is rich in soluble and insoluble dietary fibres. Recent study in our research group discovered that the kernel of flaxseed contained about 20% (w/w) of dietary fibres, which has not been reported before. Scanning electron microscope (SEM) images revealed that flaxseed kernel dietary fibres (FKDF) are mostly in the supporting structure of the cell walls. To study the structure and physicochemical properties of FKDF, a modified sequential extraction and fractionation procedure was utilised, and five separate FKDF fractions were obtained as flaxseed kernel (FK) water-extracted polysaccharides (FK-WP), FK EDTA-extracted polysaccharides (FK-EP), FK Na₂CO₃-extracted polysaccharides (FK-NP), FK 1 M KOH-extracted polysaccharides (FK-KPI), and FK 4 M KOH-extracted polysaccharides (FK-KPII). FKDF fractions were all water-soluble. The average molecular weight of FK-WP was 486 kDa, FK-EP 593 kDa, FK-NP 704 kDa, FK-KPI 770 kDa, and FK-KPII 1660 kDa. Monosaccharide compositions were different among FKDF fractions; alkaline solution extracted FKDF fractions had relatively higher percentage of arabinose, but relatively lower content of glucose compared with FK-WP and FK-EP. All FKDF fractions had the ability to lower the surface tension of water, among which FK-KPI exhibited the best surface activity. Rheological properties showed that FKDF fractions had low viscosity and 2% (w/v) FKDF water solution exhibited viscoelastic behaviour at 25 °C. Those findings could benefit the related food industries for providing healthier and more value-added flaxseed products.     

Stability of probiotic Lactobacillus plantarum in dry microcapsules under accelerated storage conditions

This study investigated the stability of freeze dried and fluid bed dried alginate microcapsules coated with chitosan containing model probiotic bacteria, Lactobacillus plantarum, during storage for up to 45 days at different water activities (0.11, 0.23, 0.40 and 0.70) and temperatures (4, 30 and 37 °C). The loss in cell viability was around 0.8 log in the case of fluid bed drying and around 1.3 in the case of freeze drying, with the former method resulting in dried capsules of smaller size (~ 1 mm vs 1.3 mm), more irregular shape, and with a rougher surface. In both cases, the water activity and water content were less than 0.25 and 10% w/w, respectively, which favours high storage stability. The storage stability studies demonstrated that as the water activity and temperature decreased the survival of the dried encapsulated cells increased. Considerably better survival was observed for fluid bed dried encapsulated cells compared to freeze dried encapsulated cells and freeze dried free cells with 10% sucrose (control), and in some cases, e.g. at 4 and 30 °C at water activities of 0.11, 0.23 and 0.40, there was more than 1 log difference after 45 days, with concentrations higher than 10⁸ CFU/g after 45 days of storage. The results indicate that fluid bed drying is an effective and efficient manufacturing method to produce probiotic containing capsules with enhanced storage stability.     

Physical and antibacte rial properties of alginate-based edible film incorporated with garlic oil

Antibacterial alginate-based edible film has been studied by incorporation of garlic oil as a natural antibacterial agent. Initially, 0.1% v/v garlic oil was tested in in vitro experiments against some food pathogenic bacteria. The presence of 0.1% v/v garlic oil in the nutrient broth decreased viable cell counts for Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and Bacillus cereus by 2.28, 1.24, 4.31 and 5.61 log cycles, respectively after 24 h incubation. Meanwhile, an increased cell population occurred on all accompanying controls. Antimicrobial alginate films were prepared by incorporating garlic oil up to 0.4% v/v. They were characterized for antibacterial activity, mechanical and physical properties. The edible film exhibited antibacterial activity against Staphylococcus aureus and B. cereus among bacteria tested by using agar diffusion assay. Tensile strength and elongation at break were significantly (p < 0.05) changed by incorporation of garlic oil at 0.3% and 0.4% v/v, respectively. Water vapor permeability decreased significantly (p < 0.05) with 0.4% v/v garlic oil incorporation, whereas total color difference remained same until 0.4% v/v. These results revealed that garlic oil has a good potential to be incorporated into alginate to make antimicrobial edible film or coating for various food applications.     

Electrostatic spraying of organic acids on biofilms formed by E. coli O157:H7 and Salmonella Typhimurium on fresh produce

Electrostatic spraying which has an even and retained surface coverage could be an effective novel technique to completely cover the surface of fresh produce to disrupt biofilm formation by pathogenic bacteria. Spinach leaves and cantaloupe rind were spot-inoculated with a bacterial culture and stored at 8 °C for 72 h to allow biofilm formation. Among various green fluorescent protein-labeled strains, ED 14 strain of E. coli O157:H7 and SD 10 strain of Salmonella Typhimurium had the best attachment based on colony counts. The produce samples were electrostatically sprayed with malic (MA) and lactic (LA) acid solutions alone (1.0/2.0/3.0/4.0% w/v) or in combination (0.5 + 0.5/1.0 + 1.0/1.5 + 1.5/2.0 + 2.0% w/v) to test for a reduction in the attached bacteria. A combined treatment of LA 2.0% w/v + MA 2.0% w/v had the highest log reduction (CFU/disk) of 4.14 and 3.6 on the attached E. coli strain ED 14 (spinach) and Salmonella strain SD 10 (cantaloupe), respectively. Crystal violet assay demonstrated the disruptive effect of organic acids on biofilms formed by the pathogenic bacteria. Application of electrostatic spray with a combination of malic and lactic acids resulting in a log reduction (CFU/disk) of 3.6 or higher can improve the microbial safety of spinach and cantaloupe by preventing the pathogenic biofilm formation and bacterial growth.     

Simultaneous detection and enumeration of viable lactic acid bacteria and bifidobacteria in fermented milk by using propidium monoazide and real-time PCR

This study describes a procedure that allows specific detection and enumeration of viable bacteria in four species of lactic acid bacteria (Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus casei subsp. casei and Lactobacillus acidophilus) and of Bifidobacterium lactis, mixed in fermented milk products. The procedure is based on the combined use of propidium monoazide (PMA), able to distinguish between viable and irreversibly damaged cells, with species-specific quantitative real-time PCR (RTi-PCR). Loss of viability of the species in a fermented milk through storage at 4 °C was similarly (P < 0.05) detected by PMA–RTi-PCR and selective plate counts. Furthermore, comparison of results obtained by both methods showed a Pearson linear correlation of 0.995. The enumeration of viable bacteria by PMA–RTi-PCR could be performed in 3 h, whereas enumeration by selective plate counts required three days. The procedure developed is a fast method for the identification, enumeration and discrimination of viability of lactic acid bacteria and bifidobacteria mixed in fermented milk products.     

Effects of a black rice extract (Oryza sativa L. indica) on cholesterol levels and plasma lipid parameters in Wistar Kyoto rats

This study was designed to evaluate the efficacy of an anthocyanin pigmented rice (e.g. black rice) to mitigate the onset of hypercholesterolemia in rats-fed atherogenic diets. Male Wistar (n = 10/group) rats were fed with atherogenic diets containing 0.5% cholesterol in the presence and in the absence of bile salt (e.g. 0.05% cholic acid) along with a standardized black rice extract (BRE) (e.g. 3%, w/w). All animals were individually housed in stainless steel cages and fed with the experimental diets during a 12-h period for 10 weeks. Body weights of rats were measured every week of the experiment. After 10 weeks fed on experimental diets, rats were sacrificed and plasma total cholesterol, HDL and LDL cholesterol and triacylglycerols were measured immediately. The total cholesterol (TC) content in the liver, heart and aorta, and the concentration of triacylglycerol (TAG) were measured after lipid extraction using Folch method. Rats fed with 0.5% cholesterol containing diets which also included bile salt exhibited a considerably more severe hypercholesterolemia than counterparts fed diets containing only 0.5% cholesterol. The inclusion of the BRE in diets significantly (p < 0.05) decreased the level of TC, LDL–TC and TAG in plasma of rats-fed control diets that either contained or were absent in bile salt (p < 0.05). There were no differences in HDL-level. Liver crude lipids and total cholesterol levels were also significantly (p < 0.05) decreased in experimental groups relative to the control group in both experiments. Thus, supplementation of atherogenic experimental diets with BRE effectively decreased lipid levels in hypercholesterolemic rats. In lieu of the mixture of bioactive components present in BRE, it is possible that more than one mechanism underlying this reduction in lipids is involved.     

Effect of temperature on growth and metabolism of probiotic bacteria in milk

The growth and metabolism of six probiotic strains with documented health effects were studied in ultra-high temperature (UHT) treated milk supplemented with 0.5% (w/v) tryptone or 0.75% (w/v) fructose at different temperatures. The probiotic strains were Lactobacillus acidophilus La5, Lb. acidophilus 1748, Lb. johnsonii LA1, Lb. rhamnosus GG, Lb. reuteri SD 2112 and Bifidobacterium animalis BB12. Fermentation was followed for 48 h at 20, 30, 37 and 45 °C and the samples were analysed for pH, log cfu mL⁻¹, volatile compounds, organic acids and carbon dioxide. All six probiotic strains showed very different profiles of metabolites during fermentation, however, the two Lb. acidophilus strains were the most alike. All strains, except Lb. reuteri SD 2112, showed viable cell numbers above 6.5 log cfu mL⁻¹ after 48 h fermentation at 30, 37 and 45 °C. The probiotic strains produced different amounts of metabolic products according to temperature and fermentation time illustrating the importance of controlling these parameters.     

An exploratory study on the influence of orange juice on gut microbiota using a dynamic colonic model

The aim of this research was to evaluate the influence of fresh orange juice (FOJ) and pasteurized orange juice (POJ) on gut microbiota using the Simulator of the Human Intestinal Microbial Ecosystem (SHIME®) in a long-term experiment. SHIME® vessels were used to investigate orange juice fermentation throughout the colon and to assess changes in microbial composition and fermentation metabolites (short-chain fatty acids, or — SCFA, and ammonium). Antioxidant activity of the SHIME® vessels and juice was also evaluated. The FOJ increased (p ≤ 0.05) Lactobacillus spp., Enterococcus spp., Bifidobacterium spp., and Clostridium spp. and reduced (p ≤ 0.05) enterobacteria. The POJ increased (p ≤ 0.05) Lactobacillus spp. and reduced (p ≤ 0.05) enterobacteria. The PCR-DGGE analysis showed a reduction in total bacteria population richness values. The FOJ and POJ increased (p ≤ 0.05) butyric, acetic, and propionic acid concentrations, whereas ammonium production was reduced. High values of antioxidant activity were observed as a result of the FOJ and POJ treatments. Principal component analysis indicated that both POJ and FOJ juices had a positive influence on gut microbiota. The FOJ and POJ were found to exhibit selective prebiotic activity, particularly in terms of gut microbiota. This finding is in agreement with increases in both SCFAs and commensal bacteria, as well as with decreases in ammonium levels, though total bacteria richness values were reduced.     

Effects of probiotic administration in swine

In the present work we evaluated the effects of probiotic strains administration in pigs. On the 35th day of age, 30 pigs were distributed into 2 groups: the non-treated control group (initial average BW: 8.3 ± 0.6 kg) and a probiotic supplemented fed group (initial average BW: 8.7 ± 0.4 kg). Each experimental group was fed ad libitum on a commercial diet with free access to tap water for 35 days. A mixed probiotic culture (10⁸ CFU/ml) was orally delivered, every day, to the animals of the probiotic supplemented fed group. Body weight (BW), feed intake (FI), efficiency (BW: Feed), and faecal microflora, were studied before and throughout the experimental trial. At the end of the fifth week, 5 animals of each dietary treatment were slaughtered and intestinal samples were taken for histology. The results obtained showed that the group receiving probiotic bacteria exhibited lower FI values and better efficiency than control group (P ≤ 0.05), but mean final BW values were not significantly different. Only significant changes (P ≤ 0.05) were found in enterobacteria population between control and probiotic supplemented fed group during the experimental period. By histological techniques it was observed that the treatment group has intestinal morphological structures more preserved than control group. These results suggest that probiotic bacteria administrated in this study could be used widespread as a way to improve growth performance parameters of animals avoiding the use of antibiotics as growth-promoting factors.     

Inactivation of food spoilage bacteria by high pressure processing: Evaluation with conventional media and PCR–DGGE analysis

Microbial diversity and dynamic changes of sliced vacuum-packed cooked ham during refrigerated storage (0–90 days) after high pressure processing (400 MPa at 22 °C for 10 min) was investigated by using culture-dependent and culture-independent approaches. Isolation of genome DNA and total RNA directly from meat samples, followed by PCR–denaturing gradient gel electrophoresis (DGGE) and RT-PCR–DGGE on 16S rDNA V3 region, was performed to describe the structure of the bacterial community and active species in pressurized sliced cooked ham. The DGGE profile showed that most spoilage bacteria including Lactococcus garvieae, Weissella cibaria, Lactobacillus sakei, Lactobacillus curvatus, Weissella paramesenteroides, Leuconostoc carnosum and Lactococcus lactis subsp. lactis were completely inactivated after high pressure processing (HPP), whereas Weissella viridescens and Weissella minor survived HPP and induced the final spoilage. The microbial diversity of HPP samples during the whole refrigerated storage period was extremely simple. Our results clearly indicated that HPP was an efficient method for avoiding the growth of the major spoilage bacteria and could be used to prolong the shelf-life of sliced vacuum-packed cooked ham.     

The protective effect of monosodium glutamate on survival of Lactobacillus rhamnosus GG and Lactobacillus rhamnosus E-97800 (E800) strains during spray-drying and storage in trehalose-containing powders

The use of trehalose as a means of preserving Lactobacillus rhamnosus GG (LGG) and L. rhamnosus E-97800 (E800) during spray-drying and the effects of incorporated monosodium glutamate (MSG) in the carrier medium on the survival rates during drying and storage were examined. E800 was more resistant to heat than LGG in 20%, w/w, trehalose; the d-values at 65 °C were 14 s and 5.1 s, respectively. An air outlet temperature of 65–70 °C was taken as optimal for the drying process, as the resultant moisture levels in trehalose containing these bacteria were 4.1% (w/w) and 3.79% (w/w) with corresponding viable counts of 3.65 × 10⁸ cfu mL^?1 and 1.80 × 10⁹ cfu mL^?1, respectively. The presence of MSG increased the final viable counts of LGG and E800 to 3.05 × 10⁹ cfu mL^?1 and 1.30 × 10⁹ cfu mL^?1, respectively. Survival of LGG and E800 remained constant at a minimum level of ～10⁸ cfu mL^?1 during storage at 25 °C in trehalose–MSG medium.     

Evaluation of pea protein–polysaccharide matrices for encapsulation of acid-sensitive bacteria

Protein–polysaccharide capsules containing Bifidobacterium adolescentis were produced and tested in a series of in vitro survival experiments to evaluate capsule protection of the bacterium to simulated stomach conditions, as well as their ability to release the encapsulated bacteria under conditions similar to those found in the lower gut. A protein fraction isolated from peas (pea protein isolate: PPI; 2.0%; w/v) was mixed with each of three different polysaccharides (0.5% (w/v) of either sodium alginate, iota-carrageenan and gellan gum) to produce capsules ranging in size from 2 to 3 mm diameter. All capsule formulations provided significant protection for cells exposed to synthetic stomach juice at 37 °C relative to non-encapsulated bacteria. In addition, PPI-alginate and PPI-iota-carrageenan capsules were found to dissolve in simulated intestinal fluid at 37 °C, releasing 70–79% of their bacteria “payload” within 3 h, with higher cell numbers being released from the freeze-dried capsules. PPI-gellan gum capsules did not dissolve to the same extent and the number of released cells was ~ 26–30% lower. Following a temporal rat feeding study with the test bacterium encapsulated in PPI-alginate, B. adolescentis-specific PCR and qPCR analyses confirmed the presence of DNA from this species in rat feces, but only during the period of capsule intake.