Safety of probiotics

Comparing technology and regulatory landscape of probiotics as food, dietary supplements and live biotherapeutics

Application of beneficial microorganisms as probiotics targets a broad range of intended uses, from maintaining health and supporting normal bodily functions to curing and preventing diseases. Currently, three main regulatory fields of probiotic products can be defined depending on their intended use: the more similar probiotic foods and probiotic dietary supplements, and live biotherapeutic products. However, it is not always straightforward to classify a probiotic product into one of these categories. The regulatory nuances of developing, manufacturing, investigating and applying each category of probiotic products are not universal, and not always apparent to those unfamiliar with the various global probiotic regulatory guidelines. Various global markets can be significantly different regarding legislation, possible claims, market value and quality requirements for the development and commercialization of probiotic products. Furthermore, different probiotic product categories are also linked with variable costs at different stages of product development. This review outlines the current landscape comparing probiotic foods, probiotic dietary supplements, and live biotherapeutics as probiotic products from a regulatory lens, focusing on product development, manufacturing and production, and clinical research agenda. The aim is to inform and promote a better understanding among stakeholders by outlining the expectations and performance for each probiotic product category, depending on their intended use and targeted geographical region.

Postbiotic Metabolite of Lactiplantibacillus plantarum PD18 against Periodontal Pathogens and Their Virulence Markers in Biofilm Formation

Alternative methods to reduce infectious diseases caused by bacterial pathogens and their virulence factors, biofilm formations, have arisen to reduce the pressure on existing or currently developed disinfectants and antimicrobial agents. The current strategies for reducing the severity of periodontal pathogen-caused disease by using beneficial bacteria and their metabolites are highly desirable. Probiotic strains of lactobacilli related to foods from Thai-fermented foods were selected and their postbiotic metabolites (PM) were isolated with inhibitory activity on periodontal pathogens and their biofilm formation. The PM from Lactiplantibacillus plantarum PD18 (PD18 PM) with the highest antagonistic effect against Streptococcus mutans, Porphyromonas gingivalis, Tannerella forsythia and Prevotella loescheii was selected from 139 Lactobacillus isolates. The minimal inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC) values of PD18 PM against the pathogens ranged from 1:2 to 1:4. The PD18 PM demonstrated the ability to prevent the biofilm formation of S. mutans and P. gingivalis by showing a significant reduction in viable cells, high percentages of biofilm inhibition at 92.95 and 89.68%, and the highest effective contact times at 5 and 0.5 min, respectively. L. plantarum PD18 PM showed potential as a promising natural adjunctive agent to inhibit periodontal pathogens and their biofilms.

Commercial probiotic products in public health: current status and potential limitations

Consumption of commercial probiotics for health improvement and disease treatment has increased in popularity among the public in recent years. The local shops and pharmacies are brimming with various probiotic products such as probiotic food, dietary supplement and pharmaceuticals that herald a range of health benefits, from nutraceutical benefits to pharmaceutical effects. However, although the probiotic market is expanding rapidly, there is increasing evidence challenging it. Emerging insights from microbiome research and public health demonstrate several potential limitations of the natural properties, regulatory frameworks, and market consequences of commercial probiotics. In this review, we highlight the potential safety and performance issues of the natural properties of commercial probiotics, from the genetic level to trait characteristics and probiotic properties and further to the probiotic-host interaction. Besides, the diverse regulatory frameworks and confusing probiotic guidelines worldwide have led to product consequences such as pathogenic contamination, overstated claims, inaccurate labeling and counterfeit trademarks for probiotic products. Here, we propose a plethora of available methods and strategies related to strain selection and modification, safety and efficacy assessment, and some recommendations for regulatory agencies to address these limitations to guarantee sustainability and progress in the probiotic industry and improve long-term public health and development.

The Gut Microbiota Influenced by the Intake of Probiotics and Functional Foods with Prebiotics Can Sustain Wellness and Alleviate Certain Ailments like Gut-inflammation and Colon-Cancer

The gut microbiota is composed of several microbial strains, with diverse and variable combinations in healthy and sick persons, changing at different stages of life. A healthy balance between host and gut microorganisms must be maintained in order to perform the normal physiological, metabolic, and immune functions and prevent disease development. Disturbances in the balance of the gut microbiota by diverse reasons initiate several health issues and promote the progression of certain diseases. This review is based on published research and reports that describe the role of probiotic microorganisms in the sustainability of health and the alleviation of certain diseases. Information is presented on the GRAS strains that are used as probiotics in the food industry for the production of fermented milk, yogurt, fermented food, functional foods, and probiotic drinks. To maintain a healthy microbiota, probiotic supplements in the form of freeze-dried live cells of probiotic strains are also available in different forms to consumers. The health benefits of lactic acid bacteria and other microorganisms and their role in the control of certain diseases such as gut inflammation, diabetes, and bowel cancer and in the safeguarding of the gut epithelial permeability from the invasion of pathogens are discussed.

Mapping the Key Technological and Functional Characteristics of Indigenous Lactic Acid Bacteria Isolated from Greek Traditional Dairy Products

The aim of the current study was to isolate indigenous lactic acid bacteria (LAB) from traditional Greek cheeses and assess their biochemical, technological, and functional characteristics, so as to develop novel cultures with multi-functional properties. Hence, 109 LAB isolates were recovered from traditional fresh cheeses and were evaluated in vitro for their gas production; proteolytic, lipolytic, and haemolytic activity; exopolysaccharide production (EPS); enzymatic potential; and ability to grow at 6.5% NaCl and at different pH, temperature, and anaerobic conditions. Consequently, 48 selected isolates were further evaluated for their survival under simulated gastrointestinal tract conditions, partial bile salt hydrolase activity, antibiotic resistance, and antimicrobial activity against pathogens. These isolates were also incorporated as co-cultures in yogurt production to examine their sensory characteristics and their survival in the product. Some prominent isolates that showed favorable technological and functional characteristics (good survival rates at low pH and bile salts, ability to produce β-galactosidase, and EPS) and attributed desirable sensory characteristics to yogurt were Lactococcuslactis (SRX2, SRX3, SRX5, and SMX16), Lactobacillus paracasei SRX10, and Lactiplantibacillusplantarum (FRX7, FB1), while Leuconostoc mesenteroides FMX3 and L. lactis SMX2 showed an anti-listerial activity in vitro. The results of the present study are promising for the production of novel dairy functional products with an enhanced quality and safety.

Role of Probiotics in the Management of COVID-19: A Computational Perspective

Coronavirus disease 2019 (COVID-19) was declared a pandemic at the beginning of 2020, causing millions of deaths worldwide. Millions of vaccine doses have been administered worldwide; however, outbreaks continue. Probiotics are known to restore a stable gut microbiota by regulating innate and adaptive immunity within the gut, demonstrating the possibility that they may be used to combat COVID-19 because of several pieces of evidence suggesting that COVID-19 has an adverse impact on gut microbiota dysbiosis. Thus, probiotics and their metabolites with known antiviral properties may be used as an adjunctive treatment to combat COVID-19. Several clinical trials have revealed the efficacy of probiotics and their metabolites in treating patients with SARS-CoV-2. However, its molecular mechanism has not been unraveled. The availability of abundant data resources and computational methods has significantly changed research finding molecular insights between probiotics and COVID-19. This review highlights computational approaches involving microbiome-based approaches and ensemble-driven docking approaches, as well as a case study proving the effects of probiotic metabolites on SARS-CoV-2.

The forgotten role of food cultures

Fermentation is one of if not the oldest food processing technique, yet it is still an emerging field when it comes to its numerous mechanisms of action and potential applications. The effect of microbial activity on the taste, bioavailability and preservation of the nutrients and the different food matrices has been deciphered by the insights of molecular microbiology. Among those roles of fermentation in the food chain, biopreservation remains the one most debated. Presumably because it has been underestimated for quite a while, and only considered - based on a food safety and technological approach - from the toxicological and chemical perspective. Biopreservation is not considered as a traditional use, where it has been by design - but forgotten - as the initial goal of fermentation. The 'modern' use of biopreservation is also slightly different from the traditional use, due mainly to changes in cooling of food and other ways of preservation, Extending shelf life is considered to be one of the properties of food additives, classifying - from our perspective - biopreservation wrongly and forgetting the role of fermentation and food cultures. The present review will summarize the current approaches of fermentation as a way to preserve and protect the food, considering the different way in which food cultures and this application could help tackle food waste as an additional control measure to ensure the safety of the food.

A critical review of antibiotic resistance in probiotic bacteria

Probiotics are defined as live microorganisms that, when administered in adequate amounts, confer a health benefit upon the host. At present, probiotics are gaining popularity worldwide and are widely used in food and medicine. Consumption of probiotics is increasing with further in-depth research on the relationship between intestinal flora and host health. Most people pay more attention to the function of probiotics but ignore their potential risks, such as infection and antibiotic resistance transfer to pathogenic microbes. Physiological functions, effects and mechanisms of action of probiotics were covered in this review, as well as the antibiotic resistance phenotypes, mechanisms and genes found in probiotics. Typical cases of antibiotic resistance of probiotics were also highlighted, as well as the potential risks (including pathogenicity, infectivity and excessive immune response) and corresponding strategies (dosage, formulation, and administration route). This timely study provides an avenue for further research, development and application of probiotics.

Are Probiotic Really Safe for Humans?

Probiotic bacteria have been used as a health-promoting factor for a very long time. Nowadays, products containing probiotic bacteria are becoming more and more popular on the market. The term probiotics refers to the products belonging to the following groups: probiotic drugs (medicinal products – live biotherapeutic products for human use), medical devices, probiotic foods (e.g. foods, food ingredients, dietary supplements or food for special medical purposes), directly fed microorganisms (for animal use) and designer probiotics (genetically modified probiotics). Safety assessment of bacterial strains used as probiotics should be carefully studied. Even though probiotic bacteria have the generally recognized as safe (GRAS status), there are several reports about side effects triggered by the presence of these organisms. Microorganisms used as probiotics may cause systemic infections, stimulate the immune system, disturb metabolism and participate in horizontal gene transfer.

Amalgamation of polyphenols and probiotics induce health promotion

The residing microbiome with its vast repertoire of genes provide distinctive properties to the host by which they can degrade and utilise nutrients that otherwise pass the gastro-intestinal tract unchanged. The polyphenols in our diet have selective growth promoting effects which is of utmost importance as the state of good health has been linked to dominance of particular microbial genera. The polyphenols in native form might more skilfully exert anti-oxidative and anti-inflammatory properties but in a living system it is the microbial derivatives of polyphenol that play a key role in determining health outcome. This two way interaction has invoked great interest among researchers who have commenced several clinical surveys and numerous studies in in-vitro, simulated environment and living systems to find out in detail about the biomolecules involved in such interaction along with their subsequent physiological benefits. In this review, we have thoroughly discussed these studies to develop a fair idea on how the amalgamation of probiotics and polyphenol has an immense potential as an adjuvant therapeutic for disease prevention as well as treatment.

Microbial characterization of probiotics--advisory report of the Working Group "8651 Probiotics" of the Belgian Superior Health Council (SHC)

When ingested in sufficient numbers, probiotics are expected to confer one or more proven health benefits on the consumer. Theoretically, the effectiveness of a probiotic food product is the sum of its microbial quality and its functional potential. Whereas the latter may vary much with the body (target) site, delivery mode, human target population, and health benefit envisaged microbial assessment of the probiotic product quality is more straightforward. The range of stakeholders that need to be informed on probiotic quality assessments is extremely broad, including academics, food and biotherapeutic industries, healthcare professionals, competent authorities, consumers, and professional press. In view of the rapidly expanding knowledge on this subject, the Belgian Superior Health Council installed Working Group "8651 Probiotics" to review the state of knowledge regarding the methodologies that make it possible to characterize strains and products with purported probiotic activity. This advisory report covers three main steps in the microbial quality assessment process, i.e. (i) correct species identification and strain-specific typing of bacterial and yeast strains used in probiotic applications, (ii) safety assessment of probiotic strains used for human consumption, and (iii) quality of the final probiotic product in terms of its microbial composition, concentration, stability, authenticity, and labeling.

Food fermentations: microorganisms with technological beneficial use

Microbial food cultures have directly or indirectly come under various regulatory frameworks in the course of the last decades. Several of those regulatory frameworks put emphasis on "the history of use", "traditional food", or "general recognition of safety". Authoritative lists of microorganisms with a documented use in food have therefore come into high demand. One such list was published in 2002 as a result of a joint project between the International Dairy Federation (IDF) and the European Food and Feed Cultures Association (EFFCA). The "2002 IDF inventory" has become a de facto reference for food cultures in practical use. However, as the focus mainly was on commercially available dairy cultures, there was an unmet need for a list with a wider scope. We present an updated inventory of microorganisms used in food fermentations covering a wide range of food matrices (dairy, meat, fish, vegetables, legumes, cereals, beverages, and vinegar). We have also reviewed and updated the taxonomy of the microorganisms used in food fermentations in order to bring the taxonomy in agreement with the current standing in nomenclature.

The evidence to support health claims for probiotics

As the health benefits of ingesting live bacteria become more evident, foods are now being produced that contain probiotic bacteria. The data to support label health claims for probiotic products are often difficult to provide. The experimental evidence to identify probiotic microorganisms and to demonstrate their efficacy in clinical trials is more challenging than for other potential functional foods because effects are mediated by living microorganisms and may therefore be influenced by the status of these microorganisms. Clinical trials to show efficacy are expensive. Obtaining appropriate samples is difficult. A scientific consensus is building to support the claim that the ingestion of certain probiotic bacteria reduces lactose intolerance and can reduce the duration of rotavirus diarrheas. Some probiotic bacteria have "generally accepted as safe" status; proof of the safety of any probiotic is essential. Japanese health regulatory officials, using their Foods for Specific Health Use system, have approved human health claims for over 20 probiotic products. On the other hand, at this time, no probiotic product is sold in Canada that carries a label health claim. This illustrates the considerable discrepancies across countries in perception of health effects of probiotics.

Freezing resistance improvement of Lactobacillus reuteri by using cell immobilization

Lactobacillus reuteri shows certain beneficial effects to human health and is recognized as a probiotic. However, its application in frozen foods is still not popular because of its low survival during freezing and frozen storage. Cell immobilization technique could effectively exert protection effects to microbial cells in order to enhance their endurance to unfavorable environmental conditions as well as to improve their viability and cell concentration. Ca-alginate and kappa-carrageenan were used to immobilize L. reuteri in this research, and the immobilized cells were exposed to different freezing temperatures, i.e. -20 degrees C, -40 degrees C, -60 degrees C, -80 degrees C, and stored at -40 degrees C and -80 degrees C for 12 weeks. The objectives were to study the protection effects of cell immobilization against the adverse conditions of freezing and frozen storage, and the effects of freezing temperatures to the immobilized cells. Cell immobilization was used to raise the survival of L. reuteri during freezing and frozen storage in order to develop frozen foods with the probiotic effects of L. reuteri. Results indicated that immobilized L. reuteri possessed better survival in both freezing and frozen storage. The survival of immobilized L. reuteri was higher than that of free cells, and the effects of lower freezing temperature were better than higher freezing temperature. The immobilization effects of Ca-alginate were found to be superior to kappa-carrageenan. Cell immobilized L. reuteri exhibits potential to be used in frozen foods.

New methods for selecting and evaluating probiotics

Recent studies have increased our understanding on the mechanistic basis of the proposed probiotic health effects. Well designed human studies have demonstrated that specific probiotic strains have health benefits in the human population. These have led to a wide acceptation of the probiotic concept. However, current probiotics have not been selected for specific purposes. Novel methods to select and characterise target-specific probiotic strains are thus needed. In addition to the traditional selection procedures, in recent years, knowledge on intestinal microbiota, nutrition, immunity and mechanisms of action has increased dramatically and can now be combined with genomic data to allow the isolation and characterization of new target- or site-specific probiotics. We should expect to see new, third generation probiotics emerging in the near future and also new selection criteria further defining the targets of future probiotics.

Removal of the cyanobacterial toxin microcystin-LR by human probiotics

Three human probiotics, Lactobacillus rhamnosus strains GG and LC-705, and Bifidobacterium lactis strain Bb12, were found to bind the cyanobacterial peptide toxin microcystin-LR from water solutions. The highest removal percentage was 46%, observed with heat-treated L. rhamnosus strain GG (10(10) cells/ml) and a microcystin-LR concentration of 0.5 microg/ml during an incubation of 7 h at 35 degrees C.