Probiotic characterization of Lactobacillus strains isolated from breast milk and employment for the elaboration of a fermented milk product

Isolation and evaluation of Pediococcus acidilactici YH-15 from cat milk: Potential probiotic effects and antimicrobial properties

The study aimed to screen for the possible presence of lactic acid bacteria (LAB) in cat milk in order to evaluate their probiotic properties. The isolates were characterized by biochemical identification, morphological tests and 16S rDNA sequencing. Afterward, gastrointestinal passage, in vitro safety and probiotic properties were evaluated. The results showed that the isolates had 10 strains of Pediococcus acidilactici permitted in the feed additive catalog. The high survival rate in the acid and bile salt resistance test reflected the good strain tolerance of the isolates to the simulated gastrointestinal conditions of the host in vitro. The mean inhibitory diameters of the 10 strains against chloramphenicol and tetracycline were 23.6 mm and 17.4 mm, respectively; none of the hemolytic tests showed α/β hemolytic ring. The bacteriostatic test showed that P. acidilactici YH-9, YH-14 and YH-15 had inhibitory effects on four common pathogenic bacteria, including Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and Streptococcus. The adhesion test showed that P. acidilactici YH-15 had good adhesion to HT-29 cells. Based on these results, we concluded that P. acidilactici YH-15 extracted from cat milk has potential application as a clinical probiotic therapy and health care product.

Human Breast Milk: The Role of Its Microbiota and Metabolites in Infant Health

This review explores the role of microorganisms and metabolites in human breast milk and their impact on neonatal health. Breast milk serves as both a primary source of nutrition for newborns and contributes to the development and maturation of the digestive, immunological, and neurological systems. It has the potential to reduce the risks of infections, allergies, and asthma. As our understanding of the properties of human milk advances, there is growing interest in incorporating its benefits into personalized infant nutrition strategies, particularly in situations in which breastfeeding is not an option. Future infant formula products are expected to emulate the composition and advantages of human milk, aligning with an evolving understanding of infant nutrition. The long-term health implications of human milk are still under investigation.

Chitosan-based films grafted with citrus waste-derived antifungal agents: An innovative and sustainable approach to enhance post-harvest preservation of citrus fruit

This paper reports the synthesis, characterization, and properties of chitosan films (CHI) grafted with a natural antifungal agent with the aim of developing active films of natural origin to prevent post-harvest losses of citrus fruit. The antifungal agent was prepared by fermentation using lemon peel (AntiFun-LM), a citrus waste, and grafted on chitosan using different coupling agents (CHI/AntiFun-LM). Bioactive films were prepared by solvent casting. FTIR-ATR and ToF-SIMS analyses provided compelling evidence of the successful grafting process. TGA-DSC demonstrated that the films are stable after grafting. SEM studies showed the continuous and compact surface of the films. WCA measurements proved that CHI/AntiFun-LM films are more hydrophilic than CHI films. Moreover, the CHI/AntiFun-LM films showed stronger UV shielding effect when compared to CHI. The biological evaluation demonstrated that CHI/AntiFun-LM films gained considerable antifungal properties against most fungi responsible for post-harvest decay. Cytotoxicity tests showed that CHI/AntiFun-LM films did not cause any toxic effect against L929 fibroblasts. This study highlights the great potential of chemical grafting of antifungal agents produced from citrus waste to chitosan and preparation of natural-based films to act as a powerful alternative in post-harvest protection of citrus fruit in a perspective of circular economy.

An overview of fermentation in the food industry - looking back from a new perspective

Fermentation is thought to be born in the Fertile Crescent, and since then, almost every culture has integrated fermented foods into their dietary habits. Originally used to preserve foods, fermentation is now applied to improve their physicochemical, sensory, nutritional, and safety attributes. Fermented dairy, alcoholic beverages like wine and beer, fermented vegetables, fruits, and meats are all highly valuable due to their increased storage stability, reduced risk of food poisoning, and enhanced flavor. Over the years, scientific research has associated the consumption of fermented products with improved health status. The fermentation process helps to break down compounds into more easily digestible forms. It also helps to reduce the amount of toxins and pathogens in food. Additionally, fermented foods contain probiotics, which are beneficial bacteria that help the body to digest food and absorb nutrients. In today's world, non-communicable diseases such as cardiovascular disease, type 2 diabetes, cancer, and allergies have increased. In this regard, scientific investigations have demonstrated that shifting to a diet that contains fermented foods can reduce the risk of non-communicable diseases. Moreover, in the last decade, there has been a growing interest in fermentation technology to valorize food waste into valuable by-products. Fermentation of various food wastes has resulted in the successful production of valuable by-products, including enzymes, pigments, and biofuels.

Lactic acid bacteria viability in different refrigerated food matrices: a systematic review and Meta‑analysis

The aim of this systematic review and meta-analysis was to determine which variables affect the viability of lactic acid bacteria (LAB) added to different types of refrigerated foods during the first 28 days. Scopus, ScienceDirect, PubMed and Cochrane Central Register of Reviews databases were searched from 1997 to April 2022. A total of 278 studies, which showed randomized and controlled experiments published in peer reviewed journals, were included. The viability of LAB in different moments during the storage process was synthesized as mean point estimate (MPE) via random-effects meta-analyses and the effect of multiple factors on the LAB´s viability was evaluated by multiple meta-regression. The meta-analysis showed that the decrease in LAB viability will be more abrupt the greater the initial dose. The physical structure of food may influence bacterial viability. Fruit was the type of product that most quickly lost viability. Co-culture of two or more species did not affect viability. Preservation methods had an unfavorable effect and prebiotics had a beneficial effect on bacterial viability. Viability was genus dependent. The data obtained in this study provide an overview of the factors to be taken into account for the design of new foods.

Potential probiotic lactobacilli strains isolated from artisanal Mexican Cocido cheese: evidence-based biosafety and probiotic action-related traits on in vitro tests

The biosafety of four potentially probiotic lactobacilli strains, isolated from artisanal Mexican Cocido cheese, was assessed through in vitro tests aimed to determine (1) the antibiotic susceptibility profile by broth microdilution, (2) the transferability of antibiotic resistance determinants by filter-mating, and (3) the phenotypic and genotypic stability during serial batch sub-culture (100-day period) by evaluating physiological and probiotic features and RAPD-PCR fingerprinting. Lactobacilli strains exhibited multidrug-resistance; however, resistance determinants were not transferred in the filter-mating assay. Significant (p < 0.05) differences were observed in bacterial morphology and some functional and technological properties when strains were serially sub-cultured over 50 generations (G50), compared to the initial cultures (G0). Conversely, the strains did not show mucinolytic and hemolytic activities either at G0 or after 100 generations (G100). Genetic polymorphism and genomic template instability on selected strains were detected, which suggest possible evolutionary arrangements that may occur when these bacteria are largely cultured. Our findings suggest that the assessed strains did not raise in vitro biosafety concerns; however, complementary studies are still needed to establish the safe potential applications in humans and animals.

Evaluating the Probiotic Potential of Lactic Acid Bacteria Implicated in Natural Fermentation of Table Olives, cv. Cobrançosa

The probiotic features of Lactiplantibacillus (L.) pentosus and L. paraplantarum strains, endogenous in Cobrançosa table olives from northeast Portugal, were assessed in terms of functional properties and health benefits. Fourteen lactic acid bacteria strains were compared with Lacticaseibacillus casei from a commercial brand of probiotic yoghurt and L. pentosus B281 from Greek probiotic table olives, in attempts to select strains with higher probiotic performances than those references. For functional properties, the i53 and i106 strains, respectively, exhibited: 22.2 ± 2.2% and 23.0 ± 2.2% for Caco-2 cell adhesion capacity; 21.6 ± 7.8% and 21.5 ± 1.4% for hydrophobicity; 93.0 ± 3.0% and 88.5 ± 4.5% for autoaggregation ability by 24 h of incubation; and ability to co-aggregate with selected pathogens-from 29 to 40% to Gram+ (e.g., Staphylococcus aureus ATCC 25923 and Enterococcus faecalis ATCC 29212); and from 16 to 44% for Gram- (e.g., Escherichia coli ATCC 25922 and Salmonella enteritidis ATCC 25928). The strains proved to be resistant (i.e., halo zone ≤14 mm) to some antibiotics (e.g., vancomycin, ofloxacin, and streptomycin), but susceptible (i.e., halo zone ≥ 20 mm) to others (e.g., ampicillin and cephalothin). The strains exhibited health-beneficial enzymatic activity (such as acid phosphatase and naphthol-AS-BI-phosphohydrolase), but not health-harmful enzymatic activity (such as β-glucuronidase and N-acetyl-β-glucosaminidase). Additionally, the antioxidant activity and cholesterol assimilation features, respectively, of the strains were 19.6 ± 2.8% and 77.5 ± 0.5% for i53, and 19.6 ± 1.8% and 72.2 ± 0.9% for i106. This study indicated that the addition of L. pentosus strains i53 and/or i106 to Cobrançosa table olives is likely to enhance the added value of the final product, in view of the associated potential benefits upon human health.

Characterization, High-Density Fermentation, and the Production of a Directed Vat Set Starter of Lactobacilli Used in the Food Industry: A Review

Lactobacilli have been widely concerned for decades. Bacteria of the genus Lactobacillus have been commonly employed in fermented food to improve the appearance, smell, and taste of food or prolong its shelf-life. They comprise 261 species (by March 2020) that are highly diverse at the phenotypic, ecological, and genotypic levels. Some Lactobacilli strains have been documented to be essential probiotics, which are defined as a group of living microorganisms that are beneficial to the health of the host when ingested in sufficiency. However, the characterization, high-density fermentation, and the production of a directed vat set (DVS) starter of Lactobacilli strains used in the food industry have not been systematically reported. This paper mainly focuses on reviewing Lactobacilli as functional starter cultures in the food industry, including different molecular techniques for identification at the species and strain levels, methods for evaluating Lactobacilli properties, enhancing their performance and improving the cell density of Lactobacilli, and the production techniques of DVS starter of Lactobacilli strains. Moreover, this review further discussed the existing problems and future development prospects of Lactobacilli in the food industry. The viability and stability of Lactobacilli in the food industry and gastrointestinal environment are critical challenges at the industrial scale. The new production equipment and technology of DVS starter of Lactobacilli strains will have the potential for large-scale application, for example, developing low-temperature spray drying, freezing granulation drying, and spray freeze-drying.

Evaluation of probiotic potential of autochthonous lactobacilli strains isolated from Zabuli yellow kashk, an Iranian dairy product

AIMS

The aim of this study was evaluating the probiotic potential and anti-biofilm activity of five lactobacilli strains which isolated and identified from an Iranian product.

METHODS AND RESULTS

Five lactobacilli strains which were isolated from Zabuli yellow kashk, were evaluated for the presence of probiotic properties, such as resistance to low pH, resistance to simulated gastrointestinal conditions, bile salt tolerance, hydrophobicity, auto- and co-aggregation. In addition, antimicrobial susceptibility, adherence to Caco-2 cells (human colon cancer cell line), anti-adhesion activity, ability against biofilm formation, and biofilm degradation of mentioned strains against Pseudomonas aeruginosa PTCC 1707 were assessed. All the strains tested showed acceptable characteristics, but Lactiplantibacillus plantarum TW57-4 appeared of particular interest. Some probiotic properties of this strain were similar and in some cases higher than the commercial probiotic strain Lacticaseibacillus rhamnosus GG (standard sample). Cholesterol assimilation and radical-scavenging activity of Lpb. plantarum TW57-4 were70.2 % and 62.3 %, respectively. The adhesion degree of Lpb. plantarum TW57-4 was 10.6 %. Applying competition and inhibition assay, this strain showed 55.3 % and 62.3 % of competition and inhibition activity in adhesion of P. aeruginosa PTCC 1707 to the intestinal cells, respectively.

CONCLUSIONS

According to the obtained results, it can be concluded that Lpb. plantarum TW57-4 strain can be used as a promising candidate for in-vivo studies with the aim of developing new probiotic starter cultures.

SIGNIFICANCE AND IMPACT OF STUDY

The present study furthers our understanding of lactobacilli strains behavior after consumption to establish their beneficial effects.

Correlation between metabolites of lactic acid bacteria isolated from dairy traditional fermented Tunisian products and antifungal and antioxidant activities

AIMS

The objective of this study is to identify and investigate the antifungal and antioxidant potential of lactic acid bacteria (LAB) isolated from traditional fermented products.

METHODS AND RESULTS

In this work, a collection of LAB was isolated from traditional fermented products collected in four Tunisian regions. After first screening using the overlay method, seven bacterial strains were retained due to their high antifungal effect. Four strains of Limosilactobacillus fermentum were identified, one strain of Lacticaseibacillus paracasei, one strain of Lacticaseibacillus rhamnosus and one strain of Enterococcus faecium. The antifungal as well as the antioxidant potential of these bacteria were then evaluated. Bacterial strains were effective against six fungal strains with a minimum inhibitory concentrations ranging from 25 to 100 mg/mL and a minimum fungicidal concentrations ranging from 50 to 200 mg/mL. Cell free supernatants of LAB were analyzed by HPLC-DAD and LC-MS-qTOF-MS analysis. Results showed significant production of organic acids as well as several phenolic compounds. Correlation analysis confirmed that PLA and 1,2-Dihydroxybenzene were positively correlated with antifungal potential. The results of the antioxidant activity highlighted an ABTS radical cation scavenging activity ranging from 49% to 57% and a DPPH trapping percentage ranging from 80% to 97%.

CONCLUSIONS

Therefore, due to these characteristics, identified lactic acid bacteria strains have shown their effectiveness to perform as antifungal and antioxidant agents.

SIGNIFICANCE AND IMPACT OF THE STUDY

Since microbial contamination is at the root of extensive losses in the food sector, the identified strains or their metabolites can potentially be used as additives to limit microorganism spoilage in food products and increase their shelf life.