Comparative survival rates of human-derived probiotic Lactobacillus paracasei and L. salivarius strains during heat treatment and spray drying

Water-soluble microencapsulation using gum Arabic and skim milk enhances viability and efficacy of Pediococcus acidilactici probiotic strains for application in broiler chickens

OBJECTIVE

This study aimed to develop and evaluate the effectiveness of a water-soluble microencapsulation method for probiotic strains using gum Arabic (GA) and skim milk (SKM) over a three-month storage period following processing.

METHODS

Four strains of Pediococcus acidilactici (BYF26, BYF20, BF9, and BF14) that were typical lactic acid bacteria (LAB) isolated from the chicken gut were mixed with different ratios of GA and SKM as coating agents before spray drying at an inlet temperature 140°C. After processing, the survivability and probiotic qualities of the strains were assessed from two weeks to three months of storage at varied temperatures, and de-encapsulation was performed to confirm the soluble properties. Finally, the antibacterial activity of the probiotics was assessed under simulated gastrointestinal conditions.

RESULTS

As shown by scanning electron microscopy, spray-drying produced a spherical, white-yellow powder. The encapsulation efficacy (percent) was greatest for a coating containing a combination of 30% gum Arabic: 30% skim milk (w/v) (GA:SKM30) compared to lower concentrations of the two ingredients (p<0.05). Coating with GA:SKM30 (w/v) significantly enhanced (p<0.05) BYF26 survival under simulated gastrointestinal conditions (pH 2.5 to 3) and maintained higher survival rates compared to non-encapsulated cells under an artificial intestinal juices condition of pH 6. De-encapsulation tests indicated that the encapsulated powder dissolved in water while keeping viable cell counts within the effective range of 106 for 6 hours. In addition, following three months storage at 4°C, microencapsulation of BYF26 in GA:SKM30 maintained both the number of viable cells (p<0.05) and the preparation's antibacterial efficacy against pathogenic bacteria, specifically strains of Salmonella.

CONCLUSION

Our prototype water-soluble probiotic microencapsulation GA:SKM30 effectively maintains LAB characteristics and survival rates, demonstrating its potential for use in preserving probiotic strains that can be used in chickens and potentially in other livestock.

Recent Advances in the Understanding of Stress Resistance Mechanisms in Probiotics: Relevance for the Design of Functional Food Systems

In recent years, more and more scientific community, food producers, and food industry show increased interest in functional foods containing probiotics, which is a big challenge. The consumption of probiotics in the context of a balanced diet through the consumption of functional foods or through the intake of pharmaceutical preparations has proven to contribute to the improvement of human health, even contributing to the prevention of diseases. In order for probiotics to be considered suitable for consumption, they must contain a minimum concentration of viable cells, namely, at least 107 colony forming units of beneficial microbes per gram. Ensuring the viability of bacterial cells until the moment of consumption is the overriding priority of functional probiotic food manufacturers. Probiotic bacteria are subject to stress conditions not only during food manufacturing but also during gastrointestinal passage, which limit or even compromise their functionality. This paper first examines all the stressful conditions faced by probiotic cells in their production stages and related to the conditions present in the bioreactor fermentation and drying processes as well as factors related to the food matrix and storage. The stress situations faced by probiotic microorganisms during the gastrointestinal transit especially during stomach and intestinal residence are also analyzed. In order to understand the adaptation mechanisms of probiotic bacteria to gastrointestinal stress, intrinsic and adaptive mechanisms identified in probiotic strains in response to acid stress and to bile and bile acid stress are analyzed. In addition, improvement strategies for multiple stress tolerance of lactic acid bacteria through directions dealing with stress, accumulation of metabolites, use of protectants, and regulation of technological parameters are examined. Finally, the definition of postbiotics, inanimate microorganisms and/or their components conferring health benefits, is also introduced. Postbiotics include cell lysates, enzymes, and cell wall fragments derived from probiotic bacteria and may represent an alternative to the use of probiotics, when they do not tolerate stressful conditions.

Process and formulation parameters influencing the survival of Saccharomyces cerevisiae during spray drying and tableting

Probiotic microorganisms provide health benefits to the patient when administered in a viable form and in sufficient doses. To ensure this, dry dosage forms are preferred, with tablets in particular being favored due to several advantages. However, the microorganisms must first be dried as gently as possible. Here, the model organism Saccharomyces cerevisiae was dried by spray drying. Various additives were tested for their ability to improve yeast cell survival during drying. In addition, the influence of various process parameters such as inlet temperature, outlet temperature, spray rate, spray pressure and nozzle diameter was investigated. It was possible to dry the yeast cells in such a way that a substantial proportion of living microorganisms was recovered after reconstitution. Systematic variation of formulation and process parameters showed that the use of protective additives is essential and that the outlet temperature determines the survival rate. The subsequent compression of the spray-dried yeast reduced viability and survival could hardly be improved by the addition of excipients, but the tabletability of spray-dried yeast protectant particles was quite good. For the first time, loss of viability during compaction of spray-dried microorganisms was correlated with the specific densification, allowing a deeper understanding of the mechanism of cell inactivation during tableting.

Soy lecithin increases the stability and lipolysis of encapsulated algal oil and probiotics complex coacervates

BACKGROUND

Co-encapsulation of probiotics and omega-3 oil using complex coacervation is an effective method for enhancing the tolerance of probiotics under adverse conditions, whereas complex coacervation of omega-3 oil was found to have low lipid digestibility. In the present study, gelatin (GE, 30 g kg^-1 ) and gum arabic (GA, 30 g kg^-1 ) were used to encapsulate Lactobacillus plantarum WCFS1 and algal oil by complex coacervation to produce microcapsules containing probiotics (GE-P-GA) and co-microcapsules containing probiotics and algal oil (GE-P-O-GA), and soy lecithin (SL) was added to probiotics-algal oil complex coacervates [GE-P-O(SL)-GA] to enhance its stability and lipolysis. Then, we evaluated the viability of different microencapsulated probiotics exposed to freeze-drying and long-term storage, as well as the survival rate and release performance of encapsulated probiotics and algal oil during in vitro digestion.

RESULTS

GE-P-O(SL)-GA had a smaller particle size (51.20 μm), as well as higher freeze-drying survival (90.06%) of probiotics and encapsulation efficiency of algal oil (75.74%). Moreover, GE-P-O(SL)-GA showed a higher algal oil release rate (79.54%), lipolysis degree (74.63%) and docosahexaenoic acid lipolysis efficiency (64.8%) in the in vitro digestion model. The viability of microencapsulated probiotics after simulated digestion and long-term storage at -18,4 and 25 °C was in the order: GE-P-O(SL)-GA > GE-P-O-GA > GE-P-GA.

CONCLUSION

As a result of its amphiphilic properties, SL strongly affected the physicochemical properties of probiotics and algal oil complex coacervates, resulting in higher stability and more effective lipolysis. Thus, the GE-P-O(SL)-GA can more effectively deliver probiotics and docosahexaenoic acid to the intestine, which provides a reference for the preparation of high-viability and high-lipolysis probiotics-algal oil microcapsules. © 2022 Society of Chemical Industry.

Administration of microencapsulated Enterococcus faecium ABRIINW.N7 with fructo-oligosaccharides and fenugreek on the mortality of tilapia challenged with Streptococcus agalactiae

We investigated the probiotic potential of a microencapsulated Enterococcus faecium ABRIINW.N7 for control of Streptococcus agalactiae infection in hybrid (Oreochromis niloticus × Oreochromis mossambicus) red tilapia. A two-phase experiment approach was completed in which E. faecium bacteria were propagated, from which a culture was isolated, identified using molecular techniques, and microencapsulated to produce a stable commercial fructooligosaccharide (FOS) and fenugreek (Fk) product of optimal concentration. The FOS and Fk products were assessed in a 90-days in vivo challenge study, in which red hybrid tilapia were allocated to one of five treatments: (1) No Streptococcus agalactiae (Sa) challenge (CON); (2) Sa challenge only (CON+); (3) Sa challenge in a free cell (Free Cell); (4) Sa challenge with 0.8% (w/v) Alginate; (5) Microencapsulated FOS and Fk. In vitro results showed high encapsulation efficiency (≥98.6 ± 0.7%) and acceptable viability of probiotic bacteria within the simulated fish digestive system and high stability of viable cells in all gel formulations (34 < SR% <63). In vivo challenges demonstrated that the FOS and Fk products could be used to control S. agalactiae infection in tilapia fish and represented a novel investigation using microencapsulation E. faecium as a probiotic diet for tilapia fish to control S. agalactiae infection and to lower fish mortality. It is recommended that local herbal gums such as 0.2% Persian gum and 0.4% Fk in combination with 0.8% alginate (Formulation 7) can be used as a suitable scaffold and an ideal matrix for the encapsulation of probiotics. These herbal gums as prebiotics are capable of promoting the growth of probiotic cells in the food environment and digestive tract.

Lacticaseibacillus rhamnosus: A Suitable Candidate for the Construction of Novel Bioengineered Probiotic Strains for Targeted Pathogen Control

Probiotics, with their associated beneficial effects, have gained popularity for the control of foodborne pathogens. Various sources are explored with the intent to isolate novel robust probiotic strains with a broad range of health benefits due to, among other mechanisms, the production of an array of antimicrobial compounds. One of the shortcomings of these wild-type probiotics is their non-specificity. A pursuit to circumvent this limitation led to the advent of the field of pathobiotechnology. In this discipline, specific pathogen gene(s) are cloned and expressed into a given probiotic to yield a novel pathogen-specific strain. The resultant recombinant probiotic strain will exhibit enhanced species-specific inhibition of the pathogen and its associated infection. Such probiotics are also used as vehicles to deliver therapeutic agents. As fascinating as this approach is, coupled with the availability of numerous probiotics, it brings a challenge with regard to deciding which of the probiotics to use. Nonetheless, it is indisputable that an ideal candidate must fulfil the probiotic selection criteria. This review aims to show how Lacticaseibacillus rhamnosus, a clinically best-studied probiotic, presents as such a candidate. The objective is to spark researchers’ interest to conduct further probiotic-engineering studies using L. rhamnosus, with prospects for the successful development of novel probiotic strains with enhanced beneficial attributes.

Preparation of Saccharomyces boulardii powder by spray drying: thermoprotectants optimization and stability evaluation

Saccharomyces boulardii as the probiotic yeast was widely used in the pharmaceutical, feed and food industries. The influence of skim milk, gelatin, and carbohydrates on the heat resistance of S. boulardii is explored in the article. Response surface methodology was effectively applied to optimize the thermoprotectant composition for S. boulardii during spray-drying. The accelerated test is applied to evaluate its the subsequent storage stability. The results show that the thermoprotectants composition was comprehensively optimized such as: 15.12% skim milk, 1.81% gelatin, and 9.73% trehalose. The highest viability was 17.77%, which was basically the same as the predicted value of 18.21%. The inactivation rate constant of spray-dried powder was k_-18 = 1.04 × 10^-5 h^-1, the quantity of viable cells stored at this temperature for 1 and 10 years was 8.25 × 10⁸ CFU/g and 1.25 × 10⁸ CFU/g, separately. This work provides a thermoprotectants formula for the S. boulardii during the spray drying process.

Cryoprotective effect of turanose on lyophilized Lactobacillus paracasei subsp. paracasei, L. casei 431

The lyophilization process is the most convenient and successful method to preserve probiotics, although microorganisms are exposed to conditions of extremely low freezing temperatures as well as dehydration. In this study, we evaluated the cryoprotective effect of turanose on Lactobacillus paracasei subsp. paracasei, L. casei 431 (L. casei 431) as a method to increase survival rate by improving cell viability. The results indicated that the viability of L. casei 431 was 9.6% without the cryoprotective agent, whereas bacterial cell viability was increased to 67.1% with the addition of 12% turanose. When turanose-treated freeze-dried cells were stored at 4 °C for 30 days, the survival rate decreased from 67.1 to 53.4%. Furthermore, cell viability significantly decreased by 50% after 30 days when stored at 25 °C with the same amount of turanose. Overall, turanose may be used as an effective cryoprotectant to preserve probiotics against the freeze-drying process and for extended storage at 4 °C.

Self-nanoemulsifying composition containing curcumin, quercetin, Ganoderma lucidum extract powder and probiotics for effective treatment of type 2 diabetes mellitus in streptozotocin induced rats

Liquid self-nanoemulsifying drug delivery system (L-SNEDDS) of curcumin and quercetin were prepared by dissolving them in isotropic mixture of Labrafil M1944CS®, Capmul MCM®, Tween-80® and Transcutol P®. The prepared L-SNEDDS were solidified using Ganoderma lucidum extract, probiotics and Aerosil-200® using spray drying. These were further converted into pellets using extrusion-spheronization. The mean droplet size and zeta potential of L-SNEDDS were found to be 63.46 ± 2.12 nm and - 14.8 ± 3.11 mV while for solid SNEDDS pellets, these were 72.46 ± 2.16 nm and -38.7 ± 1.34 mV, respectively. The dissolution rate for curcumin and quercetin each was enhanced by 4.5 folds while permeability was enhanced by 5.28 folds (curcumin) and 3.35 folds (quercetin) when loaded into SNEDDS pellets. The Cmax for curcumin and quercetin containing SNEDDS pellets was found 532.34 ± 5.64 ng/mL and 4280 ± 65.67 ng/mL, respectively. This was 17.55 and 3.48 folds higher as compared to their naïve forms. About 50.23- and 5.57-folds increase in bioavailability was observed for curcumin and quercetin respectively, upon loading into SNEDDS pellets. SNEDDS pellets were found stable at accelerated storage conditions. The developed formulation was able to normalize the levels of blood glucose, lipids, antioxidant biomarkers, and tissue architecture of pancreas and liver in streptozotocin induced diabetic rats as compared to their naïve forms.

From by-product to functional food: the survival of L. casei shirota, L. casei immunitas and L. acidophilus johnsonii, during spray drying in orange juice using a maltodextrin/pectin mixture as carrier

The study reports the production of an innovative functional orange powder supplemented with probiotics and prebiotics, by implementing new ecofriendly and sustainable technologies, such as spray drying. The survival of Lactobacillus casei shirota, Lactobacillus casei immunitas and Lactobacillus acidophilus johnsonii, during spray drying in orange juice was proven and the stability of the powder obtained at room temperature and at 4 °C was investigated. Furthermore, the study highlighted the possibility to enhance the pectin obtained from the food agroindustry as a carrier for the spray-drying process. Combining maltodextrins and pectins at a 10:1 weight ratio. The study showed the efficiency of the maltodextrin/pectin mixture as carriers for the spray-drying process and the viability of the tested microorganisms during both the storage at room temperature and at 4 °C, showing that the latter represents the best storing condition for a longer viability of the microorganisms.

Application of Pickering emulsions in probiotic encapsulation- A review

Probiotics are live microorganisms that confer health benefits to host organisms when consumed in adequate amounts and are often incorporated into foods for human consumption. However, this has negative implications on their viability as large numbers of these beneficial bacteria are deactivated when subjected to harsh conditions during processing, storage, and passage through the gastrointestinal tract. To address these issues, numerous studies on encapsulation techniques to protect probiotics have been conducted. This review focuses on emulsion technology for probiotic encapsulation, with a special focus on Pickering emulsions. Pickering emulsions are stabilized by solid particles, which adsorb strongly onto the liquid-liquid interfaces to prevent aggregation. Pickering emulsions have demonstrated enhanced stability, high encapsulation efficiency, and cost-effectiveness compared to other encapsulation techniques. Additionally, Pickering emulsions are regarded as safe and biocompatible and utilize natural materials, such as cellulose and chitosan derived from plants, shellfish, and fungi, which may also be viewed as more acceptable in food systems than common synthetic and natural molecular surfactants. This article reviews the current status of Pickering emulsion use for probiotic delivery and explores the potential of this technique for application in other fields, such as livestock farming, pet food, and aquaculture.

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Probiotics play an important role in maintaining the health of humans and animals.

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Encapsulation improves probiotic viability in harsh environments.

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Probiotics can be encapsulated by many techniques such as emulsification.

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Pickering emulsions use particles instead of molecules to stabilize emulsions.

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Natural particles are more acceptable to some consumers than synthetic emulsifiers.

Effect of Fluidized Bed Drying, Matrix Constituents and Structure on the Viability of Probiotic Lactobacillus paracasei ATCC 55544 during Storage at 4 °C, 25 °C and 37 °C

The stabilization of probiotics for application in non-refrigerated food products is a challenging task. In the present study, probiotic Lactobacillus paracasei (Lacticaseibacillus paracasei) ATCC 55544 cells were immobilized in a dairy matrix comprising of whole milk powder, skim milk powder, or milk protein isolate using fluidized bed drying technology. The samples were taken out at different drying stages, with an apparent water activity (a_w) of a_w 0.5, a_w 0.4, and a_w 0.3, respectively, and vacuum-packed to maintain the a_w and stored at three different temperatures of 4 °C, 25 °C, and 37 °C. The study evaluated the impact of matrix constituents, milk fat, protein, and carbohydrate on the viability of encapsulated probiotic L . paracasei ATCC 55544 during storage for 1 month. The whole milk powder matrix provided superior protection to the bacteria. Confocal Laser Scanning Microscopy (CLSM) was used to investigate the structure of the immobilizing matrix and the location of the probiotic L. paracasei cells embedded within the matrix. The CLSM study revealed that the probiotic bacterial cells are mostly embedded as clusters beneath the top layer. We hypothesize that the biofilm-like structure, together with the protective whole milk powder matrix, helps to retain the superior viability of probiotic cells during storage at non-refrigerated storage conditions of 25 °C and 37 °C.

Ligilactobacillus salivarius functionalities, applications, and manufacturing challenges

Ligilactobacillus salivarius is a lactic acid bacteria that has been gaining attention as a promising probiotic. Numerous strains exhibit functional properties with health benefits such as antimicrobial activity, immunological effects, and the ability to modulate the intestinal microbiota. However, just a small number of them are manufactured at an industrial scale and included in commercial products. The under exploitation of L. salivarius strains that remain in the freezer of companies is due to their incapacity to overcome the environmental stresses induced by production and stabilization processes.The present study summarizes the functionalities and applications of L. salivarius reported to date. It aims also at providing a critical evaluation of the literature available on the manufacturing steps of L. salivarius concentrates, the bacterial quality after each step of the process, and the putative degradation and preservation mechanisms. Here, we highlight the principal issues and future research challenges for improving the production and long-term preservation at the industrial scale of this microorganism, and probably of other probiotics.Key points• L. salivarius beneficial properties and commercialized products.• Production conditions and viability of L. salivarius after stabilization processes.• Prospects for identifying preservation mechanisms to improve L. salivarius stability.

The efficacy of three double-microencapsulation methods for preservation of probiotic bacteria

Lactic acid bacteria (LAB) are used as a probiotic alternative to antibiotics in livestock production. Microencapsulation technology is widely used for probiotic preservation. A variety of microencapsulation protocols have been proposed and compared based on chemicals and mechanical procedures. This study aimed to develop a double-encapsulated coating from alginate (1.5%) and chitosan (0.5%) by extrusion, emulsion, and spray drying methods using the LAB strains Lactobacillus plantarum strains 31F, 25F, 22F, Pediococcus pentosaceus 77F, and P. acidilactici 72N, and to monitor the basic probiotic properties of the encapsulated prototypes. The final products from each microencapsulation protocol were analysed for their appearance, probiotic properties and viable cell count. Using the spray drying method, particles smaller than 15 μm in diameter with a regular spherical shape were obtained, whereas the other methods produced larger (1.4–52 mm) and irregularly shaped microcapsules. After storage for 6 months at room temperature, the LAB viability of the spray-dried particles was the highest among the three methods. In all the LAB strains examined, the encapsulated LAB retained their probiotic properties in relation to acid-bile tolerance and antibacterial activity. This study highlights the efficacy of double-coating microencapsulation for preserving LAB properties and survival rate, and demonstrates its potential for probiotic application in livestock farms.

Whey permeate as a substrate for the production of freeze-dried Lactiplantibacillus plantarum to be used as a malolactic starter culture

The aim of this work was to obtain freeze-dried biomass of the native Patagonian Lactiplantibacillus plantarum strain UNQLp 11 from a whey permeate (WP)-based medium and compare it with the growth in commercial MRS broth medium. Survival and activity of the freeze-dried Lb. plantarum strain were investigated after inoculation in wine as a starter culture for malolactic fermentation (MLF). The effect of storage and rehydration condition of the dried bacteria and the nutrient supplementation of wine were also studied. The freeze-dried cultures from WP and those grown in MRS showed similar survival results. Rehydration in MRS broth for 24 h and the addition of a rehydration medium to wine as nutrient supplementation improved the survival under wine harsh conditions and guaranteed the success of MLF. Storage at 4 °C under vacuum was the best option, maintaining high cell viability for at least 56 days, with malic acid consumption higher than 90% after 7 days of inoculation in a wine-like medium. These results represent a significant advance for sustainable production of dried malolactic starter cultures in an environmentally friendly process, which is low cost and easy to apply in winemaking under harsh physicochemical conditions.

Probiotics in the dairy industry-Advances and opportunities

The past two decades have witnessed a global surge in the application of probiotics as functional ingredients in food, animal feed, and pharmaceutical products. Among food industries, the dairy industry is the largest sector where probiotics are employed in a number of dairy products including sour/fermented milk, yogurt, cheese, butter/cream, ice cream, and infant formula. These probiotics are either used as starter culture alone or in combination with traditional starters, or incorporated into dairy products following fermentation, where their presence imparts many functional characteristics to the product (for instance, improved aroma, taste, and textural characteristics), in addition to conferring many health-promoting properties. However, there are still many challenges related to the stability and functionality of probiotics in dairy products. This review highlights the advances, opportunities, and challenges of application of probiotics in dairy industries. Benefits imparted by probiotics to dairy products including their role in physicochemical characteristics and nutritional properties (clinical and functional perspective) are also discussed. We transcend the traditional concept of the application of probiotics in dairy products and discuss paraprobiotics and postbiotics as a newly emerged concept in the field of probiotics in a particular relation to the dairy industry. Some potential applications of paraprobiotics and postbiotics in dairy products as functional ingredients for the development of functional dairy products with health-promoting properties are briefly elucidated.

Red fluorescence threshold for assessing the lesion activity of early caries

PURPOSE

The aim of this study was to determine a red fluorescence threshold for differentiating active from inactive non-cavitated carious lesions.

METHODS

Using the Nyvad criteria, 30 human teeth with non-cavitated carious lesions were divided into active lesions (15 teeth) and inactive lesions (15 teeth). Using the blue light of a quantitative light-induced fluorescence-digital camera, the red fluorescence of the lesions was measured as the ΔR value. By live/dead bacterial staining, bacterial viability was calculated as the Ratio_G/G+R. The ΔR and Ratio_G/G+R of active and inactive lesions were compared. The relationship between ΔR and Ratio_G/G+R was also analyzed. The ΔR threshold was determined for the classification of lesion activity, and its validity was tested.

RESULTS

The mean ΔR of active lesions was 1.85 fold higher than that of inactive lesions (p < 0.001), and the Ratio_G/G+R of active lesions was 1.97 fold higher than that of inactive lesions (p < 0.001). There was a significant positive correlation between the ΔR and the Ratio_G/G+R in non-cavitated carious lesions (p < 0.05). The ΔR threshold for the differentiating non-cavitated carious lesions by activity status was 37.55, and the sensitivity and specificity were both 83.33 %.

CONCLUSIONS

A red fluorescence threshold for categorizing non-cavitated carious lesion activity based on microbial metabolic activity was determined. Accurate evaluation of the activity status of non-cavitated carious lesions will assist in diagnosis and treatment planning for patients with dental caries.

Immobilization of Phosphatidylserine by Ethanol and Lysozyme on the Cell Surface for Evaluation of Apoptosis-Like Decay in Activated-Sludge Bacteria

Accurate determination of microbial viability can be crucial in microbe-dominated biosystems. However, the identification of metabolic decay in bacterial cells can be elaborate and difficult. We sought to identify apoptosis-like bacterial processes by using annexin V-fluorescein isothiocyanate (FITC) (AVF), a probe typically used to stain phosphatidylserine (PS) on exposed cell membranes. The bacterial cell wall provides a barrier that is responsible for low efficiency of direct PS staining of decayed bacterial cells. This can be overcome by pretreatment of the bacteria with 70% ethanol, which fixates the bacteria and preserves the PS status, combined with lysozyme treatment to hydrolyze the cell wall. That treatment improved the efficiency of AVF staining considerably, as shown for pure strains of an Ochrobactrum sp. and a Micrococcus sp. Using this method, decayed bacterial cells (induced by starvation) were more strongly stained, indicating externalization of PS to a greater extent than seen for cells harvested at logarithmic growth. A multispecies microbial sludge was artificially decayed by heat treatment or alternating anoxic-oxic treatment, which also induced increased AVF staining, again presumably via decay-related PS externalization. The method developed proved to be efficient for identification of bacterial decay and has potential for the evaluation of multispecies bacterial samples from sources like soil matrix, bioaerosol, and activated sludge.IMPORTANCE Since the externalization of phosphatidylserine (PS) is considered a crucial characteristic of apoptosis, we sought to identify apoptosis-like decay in bacterial cells by PS staining using AVF. We show that this is possible, provided the bacteria are pretreated with ethanol plus lysozyme to remove a physical staining barrier and preserve the original, decay-related externalization of PS. Our work suggests that PS externalization occurs in starved bacteria and this can be quantified with AVF staining, providing a measure of bacterial decay. Since PS is the common component of the lipid bilayer in bacterial cell membranes, this approach also has potential for evaluation of cell decay of other bacterial species.

Whole genome sequence analysis and in vitro probiotic characteristics of a Lactobacillus strain Lactobacillus paracasei ZFM54

AIM

The aim was to identify a Lactobacillus strain with potential probiotic characteristics by whole-genome sequence analysis and in vitro experimental studies.

METHODS AND RESULTS

The whole-genome sequencing was carried out using PacBio RSII sequencing method and Illumina's paired-end sequencing technology. Gene prediction and annotation were achieved using GlimmerVersion 3.02 and NCBI prokaryotic Genome Annotation Pipeline. Identification was done by biochemical tests and 16S rRNA sequence analysis. mega 6 software was used to build phylogenetic tree. Antagonism against pathogen was determined by agar well diffusion method. Resistance and stability to bile, simulated gastric acid, different salt concentration and thermostability were investigated. Hydrophobicity assay, aggregation assay and anti-oxidation assay were performed to check further probiotic traits. Finally antibiotic susceptibility and acute oral toxicity of the strain in mice were investigated to check its safety status. The strain showed >99% similarity to Lactobacillus paracasei which was further confirmed by biochemical tests. It significantly inhibited pathogens in agar well diffusion assay. It showed tolerance to simulated gastric acid (pH 3), 0·3% bile salt and 10% NaCl. Significant hydrophobic, aggregation and anti-oxidizing activities were observed. No resistance to antibiotics tested was observed and no adverse effects during acute oral toxicity in mice were detected.

CONCLUSIONS

Lactobacillus paracasei ZFM 54, a new and safe Lactobacillus strain was identified with numerous probiotic-associated genes and characteristics confirmed by experimental studies.

SIGNIFICANCE AND IMPACT OF THE STUDY

A new probiotic strain has been identified which is highly stable, safe and suitable to be used in health and food industries.

Influence of Storage Temperature and Packaging on Bacteria and Yeast Viability in a Plant-Based Fermented Food

Optimization of food storage has become a central issue for food science and biotechnology, especially in the field of functional foods. The aim of this work was to investigate the influence of different storage strategies in a fermented food product (FFP) and further determine whether the regular storage (room temperature (RT) and standard packaging (SP)) could be refined. Eight experimental conditions (four different temperatures × two packaging) were simulated and changes in FFP's microbial ecology (total bacteria, lactic acid bacteria (LAB), and yeasts) and physicochemical characteristics (pH and moisture content (MC)) were determined following 1, 3, 6, and 12 months. All conditions tested showed a decline in microbial content due to the effect of the temperature, 37 °C being the most detrimental condition, while -20 and 4 °C seemed to be better than RT in some parameters. Vacuum packaging (VP) only had a major effect on MC and we found that VP preserved greater MC values than SP at 3, 6, and 12 months. The correlation analysis revealed that total bacteria, LAB, and yeasts were positively associated, and also both pH and MC showed a correlation. According to our results and with the purpose to maintain the load of viable microorganisms, we observed that the best storage conditions should contemplate SP and freezing or cooling temperature during a period no longer than 3 months.

Effect of Dietary Probiotic Lactobacillus helveticus on Growth Performance, Antioxidant Levels, and Absorption of Essential Trace Elements in Goldfish (Carassius auratus)

In this study, we have investigated the effect of probiotic Lactobacillus helveticus CD6 supplemented into simple laboratory fish feed (LFF) and complex, multi-ingredient market fish feed (MFF) on growth performance, antioxidant levels, and essential trace element absorption in goldfish (Carassius auratus). Twenty-four healthy goldfish (average weight 3-4 g) were acclimatized and divided into four experimental diets supplemented with 3 × 10⁷ CFU/g of probiotic (LFF + Pro, MFF + Pro) and without probiotic (LFF, MFF) for 14 weeks. Fish fed with probiotic were healthy, active, and intense orange-gold as compared to control (without probiotic). At 14 weeks, fish fed with MFF + Pro/LFF + Pro showed 91/47% weight gain as compared to 34/- 12% weight observed with MFF/LFF. The average weight gain differences recorded between probiotic and control diets were not significant. No mortality to report when fish fed with probiotic. In contrast, fish fed without probiotic showed mortalities (LFF, two fish; MFF, one fish) during the trial. DPPH activity revealed high levels of antioxidants into the intestine of probiotic-fed fish. Trace element analysis showed that probiotic colonization enhanced diet-dependent absorption of Fe and Zn. The in vitro antimicrobial activity was exhibited by probiotic L. helveticus CD6 against infected fish isolate Aeromonas spp. JA showed an ability to protect fish from infections. Moreover, complex, multi-ingredient feed had a highest impact on viability of probiotic during storage. In conclusion, L. helveticus CD6 did not significantly enhance growth performance; however, it improved health and reduced mortalities in goldfish (C. auratus) regardless of the composition of the diet.

Effect of Lactobacillus acidophilus D2/CSL (CECT 4529) supplementation in drinking water on chicken crop and caeca microbiome

In this study we gained insights into the effects of the supplementation with Lactobacillus acidophilus D2/CSL (CECT 4529) in the chicken drinking water on crop and caeca microbiomes. The probiotic was supplemented at the concentrations of 0.2 g Lactobacillus acidophilus/day/bird and 0.02 g Lactobacillus acidophilus/day/bird and its effect on the crop and caeca microbiomes was assessed at 14 and 35 days of rearing. The results showed that mean relative abundance of Lactobacillus acidophilus in the caeca did not show significative differences in the treated and control birds, although Lactobacillus acidophilus as well as Faecalibacterium prausnitzii, Lactobacillus crispatus and Lactobacillus reuteri significantly increased over time. Moreover, the treatment with the high dose of probiotic significantly increased the abundance of Clostridium asparagiforme, Clostridium hathewayi and Clostridium saccharolyticum producing butyrate and other organic acids supporting the chicken health. Finally, at 35 days, the Cell division protein FtsH (EC 3.4.24.-) and the Site-specific recombinase genes were significantly increased in the caeca of birds treated with the high dose of probiotic in comparison to the control group. The results of this study showed that Lactobacillus acidophilus D2/CSL (CECT 4529) supplementation in the drinking water at the concentrations of 0.2 and 0.02 g Lactobacillus acidophilus/day/bird improved beneficial microbes and functional genes in broiler crops and caeca. Nevertheless, the main site of action of the probiotic is the crop, at least in the early stage of the chicken life. Indeed, at 14 days Lactobacillus acidophilus was significantly higher in the crops of chickens treated with the high dose of LA in comparison to the control (14.094 vs 1.741%, p = 0.036).

In vivo assessment and characterization of lactic acid bacteria with probiotic profile isolated from human milk powder

Introduction

Introduction: breast milk (MH) contains nutrients and bioactive compounds for child development, including probiotic bacteria, which contribute to intestinal maturation. This benefit accompanies the individual until adulthood. There are new methods such as spray drying that give this compound a good conservation without loss of microbiota. Objective: the aim of this study was to analyze the viability of lactic acid bacteria isolated from human milk with probiotic potential after the spray drying process, as well as to evaluate the possible adhesion in the colon of mice of the Balb/C strain after feeding them powdered human milk and a commercial formula milk. Method: we isolated and identified the presence of lactic acid bacteria with possible probiotic potential in powdered human milk using the MALDI-TOF MS technique. Powdered human milk and a commercial formula milk were fed to mice of the Bald/C strain for 14 weeks. Glucose level and weight were measured in the mice. The feces were collected to verify the presence of lactic bacteria. The mice were sacrificed and their intestines were weighed, isolating the lactic acid bacteria both from the intestines and from the feces. The strains isolated from mice fed human milk were evaluated for their probiotic potential, analyzing their ability to inhibit pathogens, resistance to pH, temperature, adhesion, and hydrophobicity. Results: the presence of Lactobacillus fermentum LH01, Lactobacillus rhamnosus LH02, Lactobacullis reuteri LH03, and Lactobacillus plantarum LH05 in powdered human milk was identified. All strains showed a possible probiotic profile due to the ability of bacteria to resist low pH, bile salts, and exposure to gastric enzymes, as well as their hydrophobicity and self-aggregation capacity, and their failure to show hemagglutination or hemolysis activity in a culture medium rich in erythrocytes. We observed that the consumption of powdered human milk prevented weight gain and constipation in mice. Conclusions: after spray drying, strains with possible probiotic potential may be preserved in human milk. The consumption of powdered human milk with probiotic bacteria prevents constipation and weight gain in mice, when compared to those fed a commercial formula milk.

Enhanced gastrointestinal survivability of recombinant Lactococcus lactis using a double coated mucoadhesive film approach

Vaccine administration via the oral route is preferable to parenteral routes due to ease of administration. To date, most available oral vaccines comprises of live attenuated pathogens as oppose to peptide-based vaccines due to its low bioavailability within the gastrointestinal (GI) tract. Over the years, probiotic-based peptide delivery vehicles comprising of lactic acid bacteria such as Lactococcus lactis has emerged as an interesting alternative due to its generally recognized as safe (GRAS) status, a fully sequenced genome, transient gut colonization time, and is an efficient cellular factory for heterologous protein production. However, its survivability through the GI tract is low, thus better delivery approaches are being explored to improve its bioavailability. In this study, we employ the incorporation of a double coated mucoadhesive film consisting of sodium alginate and Lycoat RS 720 film as the inner coat. The formulated film exhibits good mechanical properties of tensile strength and percent elongation for manipulation and handling with an entrapment yield of 93.14±2.74%. The formulated mucoadhesive film is subsequently loaded into gelatin capsules with an outer enteric Eudragit L100-55 coating capable of a pH-dependent breakdown above pH 5.5 to protect against gastric digestion. The final product and unprotected controls were subjected to in vitro simulated gastrointestinal digestions to assess its survivability. The product demonstrated enhanced protection with an increase of 69.22±0.67% (gastric) and 40.61±8.23% (intestinal) survivability compared to unprotected controls after 6 hours of sequential digestion. This translates to a 3.5 fold increase in overall survivability. Owing to this, the proposed oral delivery system has shown promising potential as a live gastrointestinal vaccine delivery host. Further studies involving in vivo gastrointestinal survivability and mice immunization tests are currently being carried out to assess the efficacy of this novel oral delivery system in comparison to parenteral routes.

Survival of probiotic Lactobacillus plantarum and Enterococcus faecium in alginate beads during stress treatments

Purpose

This study aims to protect Lactobacillus plantarum and Enterococcus faecium encapsulated in alginate beads during stress treatments, such as high temperatures and concentrations of sodium chloride (NaCl) and sodium nitrite (NaNO2).

Design/methodology/approach

Free and encapsulated probiotics were subjected to 70 and 80°C during 5, 10, 20 and 30 min. In addition, the probiotics were subjected to concentrations of 0.5, 1.0, 2.5 and 5.0 per cent NaCl and 0.5 and 1.0per cent of NaNO2.

Findings

Free Lactobacillus plantarum was more resistant to heat than free Enterococcus faecium. Alginate-encapsulated Lactobacillus plantarum (ALP) also was more resistant to heat treatments than alginate-encapsulated Enterococcus faecium (AEF). After 30 min at 70°C, ALP showed levels about 6.9 log CFU/g while AEF presented 4.3 log CFU/g (p = 0.005). However, at 80°C, ALP maintained levels higher than 6 log CFU/g for up to 10 min, while AEF was able to maintain those levels only for approximately 5 min (p = 0.003). Encapsulation process provided adequate protection for both probiotics against NaCl. In relation to NaNO2 concentrations, 0.5 and 1.0 per cent reduced viability of both probiotics (p = 0.014), either as free cells or as alginate-encapsulated forms.

Practical implications

Alginate beads containing probiotics is an interesting alternative for application in foods such as cooked meat products.

Originality/value

Alginate beads elaborated with milk powder, inulin and trehalose were effective to protect probiotics in stress situations similar to those can be found in the processing of foods, such as cooked meat products.

Adaptation of Lactobacillus acidophilus to Thermal Stress Yields a Thermotolerant Variant Which Also Exhibits Improved Survival at pH 2

Loss in probiotic viability upon exposure to stressful storage and transport conditions has plagued the probiotic market worldwide. Lactobacillus acidophilus is an important probiotic that is added to various functional foods. It is known to be fairly labile and susceptible to temperature variations that it encounters during processing and storage which increases production cost. It has been repeatedly demonstrated that pre-exposure to sub-lethal doses of stress, particularly, temperature and pH, leads to improved survival of various probiotics when they subsequently encounter the same stress of a much greater magnitude. Attempts to adapt L. acidophilus to temperatures as high as 65 °C to arrive at a thermotolerant variant have not been reported previously. To improve viability at elevated temperatures, we gradually adapted the L. acidophilus NCFM strain to survival at 65 °C for 40 min. Following adaptation, the variant showed a 2-log greater survival compared to wild-type at 65 °C. Interestingly, this thermotolerant variant also demonstrated a 2-log greater stability compared to wild-type at pH 2.0. The improved pH and temperature stress tolerance exhibited by this variant remained unaltered even when the strain was lyophilized. Moreover, the thermotolerant variant demonstrated improved stability compared to wild-type when stored for up to a week at 37 and 42 °C. Probiotic properties of the variant such as adherence to epithelial cells and antibacterial activity remained unaltered. This strain can potentially help address the issue of significant loss in viable cell counts of L. acidophilus which is typically encountered during probiotic manufacture and storage.

In vitro characterisation of two Lactobacillus strains and evaluation of their suitability as probiotics for growing-finishing pigs

In this study, we evaluated the probiotic properties of two strains Lactobacillus reuteri ZLR003 and Lactobacillus salivarius ZLS006. The two strains displayed tolerance of acid and heat, and demonstrated antimicrobial ability in vitro. Furthermore, their potential functions in vivo were also tested. A total of 120 crossbred (Landrace × Large White) growing pigs were divided into three groups: a control diet, the same diet supplemented with L. reuteri ZLR003 (2.0 × 109 cfu/kg of diet) or L. salivarius ZLS006 (3.50 × 109 cfu/kg of diet). The results showed that the average daily gain and feed conversion ratio were significantly improved in L. reuteri ZLR003- (1–5 weeks and 1–9 weeks) (P &lt; 0.05) and L. salivarius ZLS006-treated pigs (1–5 weeks, 6–9 weeks and 1–9 weeks) (P &lt; 0.05) compared with the control group. Dietary supplementation with L. salivarius ZLS006 increased the apparent digestibility of nitrogen at Week 9 (P &lt; 0.05). The faecal Lactobacillus populations increased at the end of experiment, and the Escherichia coli and Staphylococcus aureus in faeces decreased in the two Lactobacillus treatments compared with the control at Week 5 (P &lt; 0.05) and Week 9 (P &lt; 0.05), respectively. Furthermore, the total cholesterol, alanine transferase, aspartate transferase, blood urea nitrogen and haptoglobin levels in serum were significantly decreased following L. reuteri ZLR003 and L. salivarius ZLS006 treatments (P &lt; 0.05). In conclusion, these data suggest that the two Lactobacillus strains may be promising candidates for probiotic products in growing-finishing pigs.

The effects of exhaustive swimming and probiotic administration in trained rats: Oxidative balance of selected organs, colon morphology, and contractility

The duration and intensity of exercise are significant factors in oxidative, morphological, and functional changes of the gastrointestinal tract. This study aimed to investigate the effects of both exhaustive swimming and probiotic VSL#3 on rats that had been previously trained with moderate swimming. The rats were divided into four groups labeled: control (C), probiotic (P), exercise (E), and probiotic-exercise (PE). Groups P and PE were fed with probiotic mixture VSL#3. Groups E and PE had a 5-week moderate swimming program (1 h/day for 5 days/week), followed by a 1-week exhaustive swimming program (trained like in moderate program but 3 times with 150 min resting sessions, for 5 days/week). At the end of the program, the rats were euthanized. Malondialdehyde, superoxide dismutase, catalase, and reduced glutathione levels were measured in tissue samples from the gastrocnemius muscle, heart, liver, kidney, and colon. In vitro contractile activity and histomorphology of the colon were also determined. Exercise and/or probiotic decreased the oxidative stress and also increased the level of one or more of the antioxidant enzymes in some of the organs. Probiotics had more pronounced effects on colon morphology than exercise but unexpectedly this effect was non-trophic. In the colon, the thickness of the tunica muscularis and the number of goblet cells were not affected; however, probiotic administration decreased the crypt depth and tunica mucosa thickness. Exercise increased the E_max value of acetylcholine (ACh), while decreased its sensitivity. These findings suggest that exhaustive swimming does not cause oxidative stress and that probiotic consumption improves oxidative balance in trained rats. The probiotic intake does not alter the effect of exercise on the contractile activity of the colon. Colon mucosal changes induced by probiotics are independent of exercise.