Lactic acid bacteria as starter cultures: An update in their metabolism and genetics

Correlation between microbial communities and flavor compounds in Suantangzi dough from Liaoning Province, China

Suantangzi is a fermented corn food product with Manchu characteristics from Liaoning Province, China. To analyze the microbial diversity and flavor compounds in Suantangzi dough, this study utilized high-throughput sequencing of the 16S rRNA and internal transcribed spacer regions, high-performance liquid chromatography, and gas chromatography time-of-flight mass spectrometry. Spearman correlation analysis and random forest model were conducted to investigate the correlation between the dominant genera and flavor compounds. A total of 267 and 123 bacterial and fungal genera, respectively, were identified. Flavor compound analysis identified 7 and 156 organic acids and other flavor compounds, respectively, and partial least squares discriminant analysis was used to screen 22 differential flavor compounds. Additionally, Paucilactobacillus, Pediococcus, and Tausonia genera were speculated to produce different flavors in Suantangzi dough made in different regions. These findings provide a theoretical foundation for microbial community dynamics and the formation of key flavor compounds in Suantangzi dough.

Unraveling the color evolution and metabolic pathways of pelargonidin-3-O-glucoside during lactic acid fermentation of the strawberry juice color simulation system: A novel perspective through untargeted metabolomics

This study aimed to unraveling the color evolution and metabolic pathways of pelargonidin-3-O-glucoside (P3G) during lactic acid fermentation of the strawberry juice color simulation system. The results revealed that fermentation with both Lactobacillus plantarum and Lactobacillus acidophilus caused a decline in pH of the strawberry juice color simulation system and significantly accelerated the decrease in P3G content. The CIELAB space model pointed out that parameters a⁎ and b⁎ of the group treated with both lactic acid bacteria and P3G initially increased to a peak level and then gradually decreased, shifting the overall color towards orange and then gradually fading. Furthermore, untargeted metabolomics results revealed that P3G was progressively degraded and converted to pyruvate, methylparaben, 3,4-dihydroxybenzoic acid, p-anisic acid, and terephthalic acid, affecting the metabolic pathways of glycolysis, d-amino acids, benzoate degradation, aromatic compounds degradation, and aminobenzoate degradation in lactic acid bacteria.

Effects of single fermentation of Lactobacillus sakei and compound fermentation with Staphylococcus carnosus on the metabolomics of beef sausages

To illustrate the mechnism of the better flavor and color in combined fermented sausages than single fermentation with L. sakei, the growth behavior, pH, and metabolomics of L. sakei in single fermentation and in combination with S. carnosus at 0, 3, 6, 12, 24, and 48 h were studied, and the sensory evaluation of fermented beef sausage was conducted. Through KEGG topology analysis found that L. sakei is related to caffeine metabolism and citrate cycle, L. sakei and S. carnosus are related to metabolism of purine metabolism, caffeine metabolism, and alanine, aspartate and glutamate metabolism. Compared with L. sakei fermentation alone, the compound fermentation with S. carnosus increased the content of asparagine. The content of the bitter substance tyrosine decreased during the compound fermentation. As starter cultures for the L. sakei applied to provide a basis for the fermented beef sausage.

Predicting Lactobacillus delbrueckii subsp. bulgaricus-Streptococcus thermophilus interactions based on a highly accurate semi-supervised learning method

Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus) and Streptococcus thermophilus (S. thermophilus) are commonly used starters in milk fermentation. Fermentation experiments revealed that L. bulgaricus-S. thermophilus interactions (LbStI) substantially impact dairy product quality and production. Traditional biological humidity experiments are time-consuming and labor-intensive in screening interaction combinations, an artificial intelligence-based method for screening interactive starter combinations is necessary. However, in the current research on artificial intelligence based interaction prediction in the field of bioinformatics, most successful models adopt supervised learning methods, and there is a lack of research on interaction prediction with only a small number of labeled samples. Hence, this study aimed to develop a semi-supervised learning framework for predicting LbStI using genomic data from 362 isolates (181 per species). The framework consisted of a two-part model: a co-clustering prediction model (based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) dataset) and a Laplacian regularized least squares prediction model (based on K-mer analysis and gene composition of all isolates datasets). To enhance accuracy, we integrated the separate outcomes produced by each component of the two-part model to generate the ultimate LbStI prediction results, which were verified through milk fermentation experiments. Validation through milk fermentation experiments confirmed a high precision rate of 85% (17/20; validated with 20 randomly selected combinations of expected interacting isolates). Our data suggest that the biosynthetic pathways of cysteine, riboflavin, teichoic acid, and exopolysaccharides, as well as the ATP-binding cassette transport systems, contribute to the mutualistic relationship between these starter bacteria during milk fermentation. However, this finding requires further experimental verification. The presented model and data are valuable resources for academics and industry professionals interested in screening dairy starter cultures and understanding their interactions.

Bacteriocin-Producing Enterococci Modulate Cheese Microbial Diversity

Cheese production involves various lactic acid bacteria (LAB) that break down lactose, milk proteins, and fats, producing key nutrients and influencing the cheese's flavor. They form communities that play a crucial role in determining the cheese's organoleptic properties. The composition of cheeses' microbial communities is shaped by physicochemical factors (e.g., temperature, pH, and salinity) and biological factors (i.e. microbial interactions). While starter cultures are introduced to control these communities, non-starter LAB represent a significant portion of the final microbial assemblage, but their interactions remain unclear. LAB often produce bacteriocins, antimicrobial peptides that antagonize other bacteria, but their role within LAB communities is not fully understood. This study aimed to assess the impact of bacteriocin production on LAB diversity in cheese, using Enterococcus as a model organism, a common bacteriocin producer. We analyzed enterocin production of enterococcal isolates by antimicrobial assays and microbial diversity differences in raw milk cheeses by two approaches: 16S RNA gene amplicon metagenomic sequencing for the whole microbial community and multi-locus sequence analysis (MLSA) for the enterococcal diversity. Our results revealed that LAB communities were dominated by lactococci, lactobacilli, and streptococci, with enterococci present in lower numbers. However, cheeses containing bacteriocin-producing enterococci exhibited higher microbial diversity. Interestingly, the highest diversity occurred at low levels of bacteriocin producers, but this effect was not observed within enterococcal populations. These findings suggest that bacteriocin production plays a key role in shaping LAB communities during cheese ripening, although further research is needed to understand its broader implications in other microbial ecosystems.

Microbial Fermentation in Food and Beverage Industries: Innovations, Challenges, and Opportunities

Microbial fermentation is a primary method by which a variety of foods and beverages are produced. The term refers to the use of microbes such as bacteria, yeasts, and molds to transform carbohydrates into different substances. Fermentation is important for preserving, enhancing flavor, and improving the nutritional quality of various perishable foods. Historical records clearly show that fermented foods and drinks, such as wine, beer, and bread, have been consumed for more than 7000 years. The main microorganisms employed were Saccharomyces cerevisiae, which are predominantly used in alcohol fermentation, and Lactobacillus in dairy and vegetable fermentation. Typical fermented foods and drinks made from yogurt, cheese, beer, wine, cider, and pickles from vegetables are examples. Although there are risks of contamination and spoilage by pathogenic and undesirable microorganisms, advanced technologies and proper control procedures can mitigate these risks. This review addresses microbial fermentation and clarifies its past importance and contribution to food preservation, flavoring, and nutrition. It systematically separates yeasts, molds, and bacteria and explains how they are used in food products such as bread, yogurt, beer, and pickles. Larger producers employ primary production methods such as the artisanal approach, which are explored along with future trends such as solid-state fermentation, the potential of biotechnology in developing new products, and sustainability in new product development. Future research and development strategies can lead to innovations in methods that improve efficiency, product range, and sustainability.

Investigation of in situ and ex situ mode of lactic acid bacteria incorporation and the effect on dough extensibility, bread texture and flavor quality during shelf-life

Lactococcus lactis subsp. diacetylactis, Lactobacillus delbrueckii subsp. bulgaricus, and Lb. rhamnosus were evaluated for their efficiencies in preserving bread texture and flavor during shelf-life. The investigated LABs exhibited efficiency during preliminary screening in expressing selected enzymes (protease, xylanase, α-amylase, laccase, and glucose oxidase) and producing exopolysaccharide (EPS). Dough samples were supplemented with either sourdough starters containing live LAB cells or LAB cell lysates. Prolonged fermentation further enhanced the protective advantage of sourdough starter incorporation. During the 5-day shelf-life period, in situ enrichment with Lb. rhamnosus led to a mere 12.5-35.4 % hardness change and 13.8-20.7 % overall texture change. Furthermore, sourdough bread with live LAB cell supplementation displayed a more diverse and intense flavor profile, with high concentration of bread key odorants maintained during shelf-life, including 2,3-butanedione, 2-acetyl-1-pyrroline, and 3-methylbutanal. Meanwhile, no significant improvement was found in bread enriched with LAB cell lysates during shelf-life.

Enhancing safety and quality in the global cheese industry: A review of innovative preservation techniques

The global cheese industry faces challenges in adopting new preservation methods due to microbiological decay and health risks associated with chemical preservatives. Ensuring the safety and quality control of hard and semi-hard cheeses is crucial given their prolonged maturation and storage. Researchers are urged to create cheese products emphasizing safety, minimal processing, eco-labels, and clean labels to address consumer health and environmental worries. This review aims to explore effective strategies for ensuring the safety and quality of ripened cheeses, covering traditional techniques like aging, maturation, and salting, along with innovative methods such as modified and vacuum packaging, high-pressure processing, and active and intelligent packaging. Additionally, sustainable cheese preservation approaches, their impact on shelf life extension, and the physiochemical and quality attributes post-preservation are all analyzed. Overall, the cheese industry stands to benefit from this evaluation through enhanced market value, increased consumer satisfaction, and better environmental sustainability.The integration of novel preservation techniques in the cheese industry not only addresses current challenges but also paves the way for a more sustainable and consumer-oriented approach. By continually refining and implementing safety measures, quality control processes, and environmentally friendly practices, cheese producers can meet evolving consumer demands while ensuring the longevity and integrity of their products. Through a concerted effort to embrace innovation and adapt to changing market dynamics, the global cheese industry is poised to thrive in a competitive landscape where safety, quality, and sustainability are paramount.

Opuntia ficus indica cladode as fermentation feedstock for lactic acid production by Lactobacillus acidophilus LA 5

Opuntia ficus-indica cladodes are by-products which contain high amounts of fibres, bioactive and functional compounds. Given their high annual productivity per hectare, cladodes represent a cheap and suitable substrate, usable for fermentation processes. We investigated their potential as a substrate for the growth and production of lactic acid from Lactobacillus acidophilus LA-5. A separate hydrolysis and fermentation was performed. The concentration of reducing sugars obtained after the dilute acid and enzymatic hydrolysis was 28.45 g/L. The lactobacillus count ranged from 6.03 to 8.1 log CFU/mL, whereas lactic acid yield and productivity were 0.63 g/g and 0.73 g/L h, respectively. The maximum lactic acid concentration was found to be 17.5 g/L. This study reports the possibility of using the O. ficus indica cladode for lactic acid production by LA-5 aiming to reduce costs for sustainable industrial production.

Multifunctional Applications of Lactic Acid Bacteria: Enhancing Safety, Quality, and Nutritional Value in Foods and Fermented Beverages

Lactic Acid Bacteria (LAB) have garnered significant attention in the food and beverage industry for their significant roles in enhancing safety, quality, and nutritional value. As starter cultures, probiotics, and bacteriocin producers, LAB contributes to the production of high-quality foods and beverages that meet the growing consumer demand for minimally processed functional and health-promoting food products. Industrial food processing, especially in the fresh produce and beverage sector, is shifting to the use of more natural bioproducts in food production, prioritizing not only preservation but also the enhancement of functional characteristics in the final product. Starter cultures, essential to this approach, are carefully selected for their robust adaptation to the food environment. These cultures, often combined with probiotics, contribute beyond their basic fermentation roles by improving the safety, nutritional value, and health-promoting properties of foods. Thus, their selection is critical in preserving the integrity, quality, and nutrition of foods, especially in fresh produce and fruits and vegetable beverages, which have a dynamic microbiome. In addition to reducing the risk of foodborne illnesses and spoilage through the metabolites, including bacteriocins they produce, the use of LAB in these products can contribute essential amino acids, lactic acids, and other bioproducts that directly impact food quality. As a result, LAB can significantly alter the organoleptic and nutritional quality of foods while extending their shelf life. This review is aimed at highlighting the diverse applications of LAB in enhancing safety, quality, and nutritional value across a range of food products and fermented beverages, with a specific focus on essential metabolites in fruit and vegetable beverages and their critical contributions as starter cultures, probiotics, and bacteriocin producers.

Adding rumen microorganisms to improve fermentation quality, enzymatic efficiency, and microbial communities of hybrid Pennisetum silage

Hybrid Pennisetum, a top biomass energy source, faces usage limitations because of its scarce lactic acid bacteria and high fiber content. This study assessed the influence of rumen fluid pretreatment on hybrid Pennisetum's silage, with focus on silage duration and rumen fluid effects on quality and fiber decomposition. Advanced third-generation sequencing was used to track microbial diversity changes and revealed that rumen fluid considerably enhanced dry matter, crude protein, and water-soluble carbohydrates, thus improving fermentation quality to satisfactory pH levels (3.40-3.67). Ideal results, including the highest fiber breakdown and enzymatic efficiency (47.23 %), were obtained with 5 % rumen fluid in 60 days. The addition of rumen fluid changed the dominant species, including Paucilactobacillus vaccinostercus (0.00 % vs. 18.21 %) and Lactiplantibacillus plantarum (21.03 % vs. 47.02 %), and no Enterobacter was detected in the high-concentration treatments. Moreover, strong correlations were found between specific lactic acid bacteria and fermentation indicators, revealing the potential of achieving efficient and economically beneficial hybrid Pennisetum production.

Organic acid type in kimchi is a key factor for determining kimchi starters for kimchi fermentation control

This study was conducted to confirm the effectiveness of kimchi starters (KSs) by investigating their growth characteristics. First, we assessed the growth characteristics of five lactic acid bacteria (LAB) strains (Lactococcus lactis WiKim0124; Companilactobacillus allii WiKim39; and Leuconostoc mesenteroides WiKim0121, WiKim33, and WiKim32) and assessed the effects of different parameters, including organic acids, salinity, acidity, and temperature, on the growth of these LAB. The findings showed that organic acids, particularly acetic and lactic acids that accumulated with the progress in fermentation, were the major players determining the microbial composition of kimchi and the growth of the KSs. Leuconostoc mesenteroides grew well in the presence of acetic and lactic acids than other starts, so it is confirmed that Leuconostoc mesenteroides can dominant in kimchi. In addition, malic acid, which is derived from kimchi ingredients, is used to induce malolactic fermentation by Lactobacillus species, and the progression of malolactic fermentation can be controlled through KSs. Our results suggest that KSs promote the production of organic acids, and the profiling of organic acids, as well as the progress of malolactic fermentation, can be controlled by selecting the suitable KS. Overall, this study demonstrates that kimchi fermentation can be controlled more effectively if the characteristics of KS are understood and used appropriately.

Health benefits of fermented olives, olive pomace and their polyphenols: a focus on the role of lactic acid bacteria

Fermented foods have regained popularity in Western diets for their health-promoting potential, mainly related to the role of lactic acid bacteria (LAB) during the fermentation process. Nowadays, there is an increasing demand for vegetable-based fermented foods, representing an environmentally sustainable options to overcome the limitations of lactose intolerance, vegetarian, or cholesterol-restricted diets. Among them, table olives and their co-products (i.e., olive pomace) represent important plant-origin matrices, whose exploitation is still limited. Olives are an important source of fiber and bioactive molecules such as phenolic compounds with recognized health-promoting effects. Based on that, this minireview offer a brief overview about the potential beneficial role of fermented table olives/olive pomace, with a particular focus on the role of LAB to obtain healthy and/or probiotic-enriched fermented foods.

Physicochemical, Sensory, and Microbiological Analysis of Fermented Drinks Made from White Kidney Bean Extract and Cow's Milk Blends during Refrigerated Storage

Due to its low dietary impact and bioactive compounds, such as polyphenols and flavonoids, white kidney bean extract is an attractive raw material for fermented drinks. It can be utilized either on its own or blended with cow's milk, offering a promising solution to help meet dairy product demand during mid-season shortages. Therefore, this study aimed to explore the physicochemical characteristics, sensory properties, and microbiological profile of fermented milk-like drinks made from white kidney bean extract, cow's milk and their blends during 28 days of storage at 4 °C. Three blends of fermented milk-like drinks (FMLDs) were prepared from different ratios of cow's milk (CM) and kidney bean extract (BE): FMLD1 (CM 30%:BE 70%); FMLD2 (CM 50%:BE 50%), FMLD3 (CM 70%:BE 30%), along with plain fermented kidney been extract (FBE; CM 0%:BE 100%), and plain fermented cow's milk (FCM; CM 100%:BE 0%). The mixtures were pasteurized at 92 °C for 25 min and fermented with a probiotic-type starter culture (S. thermophilus, B. bifidum, L. acidophilus) at 43 °C. FBE exhibited the lowest levels of carbohydrates (2.14%), fat (0.11%), and protein (1.45%) compared to fermented cow's milk and blends. The FBE and the fermented blends with a higher ratio of bean extract had lower viscosity and lactic acid contents, greener hue, more pronounced aftertaste and off-flavors, and received lower overall acceptability scores. Although the FCM had higher counts of S. thermophilus and L. acidophilus, the FBE displayed significantly higher counts of B. bifidum. This study demonstrated the potential of using white kidney bean extract and its blends with cow's milk to create unique fermented products with a lower dietary impact, highlighting the importance of further optimizing the formulations to enhance sensory qualities and reduce the beany off-flavors in the products with added kidney bean extract.

Novel formulations for developing fresh hybrid cheese analogues utilizing fungal-fermented brewery side-stream flours

This study investigated the development of hybrid cheese analogues (HCA) made with fermented brewery side-stream ingredients (spent yeast and malt rootlets) and dairy milk. Different percentages of side-stream flours (3.5%, 5%, and 7.5%) were mixed with pasteurized milk, and the developed HCA were evaluated for their biochemical and textural properties. The addition of a fermentation step improved nutrient availability and led to pH (range 4.79-5.60) and moisture content (range 45.86%-61.29%) similar to traditional animal-based fresh cheeses (control). The inclusion of side-stream flours led to coagulation, even without rennet addition. The higher the concentration of the flour used, the faster the coagulation time, suggesting synergistic effect between the enzymes of the rennet and the enzymes present in the fermented side-stream flours. Nevertheless, textural properties were inferior compared to the control. Selected HCA formulations with added 3.5% flour exhibited increased counts of enterococci and enterobacteria cell densities, ranging from 7.28 ± 0.03 to 7.72 ± 0.09 log CFU/g and 4.90 ± 0.16 to 5.41 ± 0.01 log CFU/g, respectively. Compared to the control sample, HCA formulations exhibited higher concentrations of organic acids, peptides, and free amino acids (FAAs). Lactic acid reached up to 23.78 ± 0.94 g/kg of dry matter (DM), while the peptide area reached up to 22918.50 ± 2370.93 mL⋅AU. Additionally, the total concentration of individual FAAs reached up to 2809.74 ± 104.85 mg/kg of DM, contrasted with the control, which resulted in lower concentrations (847.65 ± 0.02 mg/kg of DM). The overall findings suggested that despite challenges in microbiological quality and textural properties, HCA produced with the inclusion of up to 3.5% brewery side-stream flours could be a sustainable solution to produce nutritious dairy alternatives.

Lactobacilli and Their Fermented Foods as a Promising Strategy for Enhancing Bone Mineral Density: A Review

Lactobacilli fermentation possesses special nutritional and health values to food, especially in improving diseases related to the gut microbiota such as osteoporosis risk. Previous research indicates that lactobacilli-fermented foods have the potential to enhance the bone mineral density (BMD), as suggested by some clinical studies. Nonetheless, there is currently a lack of comprehensive summaries of the effects and potential mechanisms of lactobacilli-fermented foods on BMD. This review summarizes findings from preclinical and clinical studies, revealing that lactobacilli possess the potential to mitigate age-related and secondary factor-induced bone loss. Furthermore, these findings imply that lactobacilli are likely mediated through the modulation of bone remodeling via gut inflammation-related pathways. Additionally, lactobacilli fermentation may augment calcium accessibility through directly promoting calcium absorption or modifying food constituents. Considering the escalating global health challenge of bone-related issues among the elderly population, this review may offer a valuable reference for the development of food strategies aimed at preventing osteoporosis.

Carbon metabolism of a novel isolate from Lacticaseibacillus rhamnosus Probio-M9 derived through space mutant

AIMS

Carbon source is a necessary nutrient for bacterial strain growth. In industrial production, the cost of using different carbon sources varies greatly. Moreover, the complex environment in space may cause metabolic a series of changes in the strain, and this method has been successfully applied in some basic research. To date, space mutagenesis is still limited number of studies, particularly in carbon metabolism of probiotics.

METHODS AND RESULTS

HG-R7970-41 was isolated from bacterium suspension (Probio-M9) after space flight, which can produce capsular polysaccharide after space mutagenesis. Phenotype Microarray (PM) was used to evaluated the metabolism of HG-R7970-41 in 190 single carbon sources. RNA sequencing and total protein identification of two strains revealed their different carbon metabolism mechanisms. PM results demonstrated the metabolism of 10 carbon sources were different between Probio-M9 and HG-R7970-41. Transcriptomic and proteomic analyses revealed that this change in carbon metabolism of HG-R7970-41 mainly related to changes in phosphorylation and the glycolysis pathway. Based on the metabolic mechanism of different carbon sources and related gene cluster analysis, we found that the final metabolic activities of HG-R7970-41 and Probio-M9 were mainly regulated by PTS-specific membrane embedded permease, carbohydrate kinase and two rate-limiting enzymes (phosphofructokinase and pyruvate kinase) in the glycolysis pathway. The expanded culture test also confirmed that HG-R7970-41 had different metabolic characteristics from original strain.

CONCLUSIONS

These results suggested that space environment could change carbon metabolism of Probio-M9. The new isolate (HG-R7970-41) showed a different carbon metabolism pattern from the original strain mainly by the regulation of two rate-limiting enzymes.

Overview of cloning in lactic acid bacteria: Expression and its application of probiotic potential in inflammatory bowel diseases

Inflammatory bowel disease (IBD) imposes a significant impact on the quality of life for affected individuals. However, there was a current lack of a systematic summary regarding the latest epidemic trends and the underlying pathogenesis of IBD. This highlights the need for a thorough examination of both the epidemiological aspects of IBD and the specific mechanisms by which lactic acid bacteria (LAB) contribute to mitigating this condition. In developed countries, higher incidences and death rates of IBD have been observed, influenced by a combination of environmental and genetic factors. LAB offer significant advantages and substantial potential for enhancing IBD treatment. LAB's capabilities include the production of bioactive metabolites, regulation of gut immunity, protection of intestinal mechanical barriers, inhibition of oxidative damage, and restoration of imbalanced gut microbiota. The review suggests that screening effective LAB using cell models and metabolites, optimizing LAB intake through dose-effect studies, enhancing utilization through nanoencapsulation and microencapsulation, investigating mechanisms to deepen the understanding of LAB, and refining clinical study designs. These efforts aim to contribute to comprehending the epidemic trend, pathogenesis, and treatment of IBD, ultimately fostering the development of targeted therapeutic products, such as LAB-based interventions.

Fermentation of Rice, Oat, and Wheat Flour by Pure Cultures of Common Starter Lactic Acid Bacteria: Growth Dynamics, Sensory Evaluation, and Functional Properties

Recent consumer demand for non-dairy alternatives has forced many manufacturers to turn their attention to cereal-based non-alcoholic fermented products. In contrast to fermented dairy products, there is no defined and standardized starter culture for manufacturing cereal-based products. Since spontaneous fermentation is rarely suitable for large-scale commercial production, it is not surprising that manufacturers have started to adopt centuries-known dairy starters based on lactic acid bacteria (LABs) for the fermentation of cereals. However, little is known about the fermentation processes of cereals with these starters. In this study, we combined various analytical tools in order to understand how the most common starter cultures of LABs affect the most common types of cereals during fermentation. Specifically, 3% suspensions of rice, oat, and wheat flour were fermented by the pure cultures of 16 LAB strains belonging to five LAB species-Lacticaseibacillus paracasei, Lactobacillus delbrueckii, Lactobacillus helveticus, Streptococcus thermophilus, and Lactococcus lactis. The fermentation process was described in terms of culture growth and changes in the pH, reducing sugars, starch, free proteins, and free phenolic compounds. The organoleptic and rheological features of the obtained fermented products were characterized, and their functional properties, such as their antioxidant capacity and angiotensin-converting enzyme inhibitory activity, were determined.

Advances in aptamer-based biosensors for monitoring foodborne pathogens

Biosensors are analytical devices for detecting a wide range of targets, including cells, proteins, DNA, enzymes, and chemical and biological compounds. They mostly rely on using bioprobes with a high binding affinity to the target for specific detection. However, low specificity and effectiveness of the conventional biosensors has led to the search for novel materials, that can specifically detect biomolecules. Aptamers are a group of single-stranded DNA or RNA oligonucleotides, that can bind to their targets with high specificity and serve as effective bioprobes for developing aptamer-based biosensors. Aptamers have a shorter production time, high stability, compared to traditional bioprobes, and possess ability to develop them for specific target molecules for tailored applications. Thus, various aptasensing approaches, including electrochemical, optical, surface plasmon resonance and chip-dependent approaches, have been investigated in recent times for various biological targets, including foodborne pathogens. Hence, this article is an overview of various conventional foodborne pathogen detection methods, their limitations and the ability of aptamer-based biosensors to overcome those limitations and replace them. In addition, the current status and advances in aptamer-based biosensors for the detection of foodborne pathogens to ensure food safety were also discussed.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05889-8.

Metabolomic analysis reveals Ligilactobacillus salivarius CCFM 1266 fermentation improves dairy product quality

Previous studies have demonstrated that Ligilactobacillus salivarius CCFM 1266 exhibits anti-inflammatory properties and the capability to synthesize niacin. This study aimed to investigate the fermentative abilities of L. salivarius CCFM 1266 in fermented milk. Metabonomic analysis revealed that fermentation by L. salivarius CCFM 1266 altered volatile flavor compounds and metabolite profiles, including heptanal, nonanal, and increased niacin production. Genomic investigations confirmed that L. salivarius CCFM 1266 possess essential genes for the metabolism of fructose and mannose, affirming its proficiency in utilizing fructooligosaccharides and mannan oligosaccharides. The addition of fructooligosaccharides and mannan oligosaccharides during the fermentation process significantly facilitated the proliferation of L. salivarius CCFM 1266 in fermented milk, with growth exceeding 107 colony-forming units (CFU)/mL. This intervention not only augmented the microbial density but also modified the metabolite composition of fermented milk, resulting in an elevated presence of advantageous flavor compounds such as nonanal, 2,3-pentanedione, and 3-methyl-2-butanone. However, its influence on improving the texture of fermented milk was observed to be minimal. Co-fermentation of L. salivarius CCFM 1266 with commercial fermentation starters indicated that L. salivarius CCFM 1266 was compatible, similarly altering metabolite composition and increasing niacin content in fermented milk. In summary, the findings suggest that L. salivarius CCFM 1266 holds substantial promise as an adjunctive fermentation starter, capable of enhancing the nutritional diversity of fermented milk products.

Probiotics in Action: Enhancing Immunity and Combatting Diseases for Optimal Health

This review offers an in-depth examination of the mechanisms underlying the microbiome's defense against viral infections, with a specific focus on probiotic interventions. Mycotoxins, secondary compounds produced by microfungi, pose significant health risks. Yet, certain strains of Lactic Acid Bacteria (LAB) have exhibited remarkable efficacy in eliminating aflatoxin B1 (AFB1), the most toxic member of the aflatoxin family. Experimental setups demonstrated AFB1 binding to specific LAB strains, persisting even after gastric digestion. Laboratory studies revealed a potential protective mechanism wherein pre-incubation of probiotics with mycotoxins reduced their adhesion to mucus. Animal trials further underscored the benefits of oral probiotic administration, showcasing increased fecal excretion of mycotoxins and mitigation of associated health risks. Cyanobacteria-generated microcystins in drinking water pose a significant threat to human health. Probiotic bacteria, particularly strains like Bifidobacterium longum and Lactobacillus rhamnosus, have demonstrated exceptional efficacy in removing the cyanobacterial peptide toxin microcystin-LR. Optimized conditions resulted in rapid toxin elimination, highlighting the potential of probiotics in water purification. Engineered probiotics represent a cutting-edge approach to tailor microorganisms for specific therapeutic applications, exhibiting promise in treating metabolic disorders, Alzheimer's disease, and type 1 diabetes. Additionally, they serve as innovative diagnostic tools, capable of detecting pathogens and inflammation markers within the body. In the realm of antimicrobial peptide production, probiotics offer a promising platform, with genetically modified strains engineered to produce human β-defensin 2 (HBD2) for treating Crohn's disease, showcasing their potential in targeted theurapetic delivery. Biocontainment strategies have been implemented to prevent unintended environmental impacts.

Comprehensive Review of Aflatoxin and Ochratoxin A Dynamics: Emergence, Toxicological Impact, and Advanced Control Strategies

Filamentous fungi exhibit remarkable adaptability to diverse substrates and can synthesize a plethora of secondary metabolites. These metabolites, produced in response to environmental stimuli, not only confer selective advantages but also encompass potentially deleterious mycotoxins. Mycotoxins, exemplified by those originating from Alternaria, Aspergillus, Penicillium, and Fusarium species, represent challenging hazards to both human and animal health, thus warranting stringent regulatory control. Despite regulatory frameworks, mycotoxin contamination remains a pressing global challenge, particularly within cereal-based matrices and their derived by-products, integral components of animal diets. Strategies aimed at mitigating mycotoxin contamination encompass multifaceted approaches, including biological control modalities, detoxification procedures, and innovative interventions like essential oils. However, hurdles persist, underscoring the imperative for innovative interventions. This review elucidated the prevalence, health ramifications, regulatory paradigms, and evolving preventive strategies about two prominent mycotoxins, aflatoxins and ochratoxin A. Furthermore, it explored the emergence of new fungal species, and biocontrol methods using lactic acid bacteria and essential mustard oil, emphasizing their efficacy in mitigating fungal spoilage and mycotoxin production. Through an integrative examination of these facets, this review endeavored to furnish a comprehensive understanding of the multifaceted challenges posed by mycotoxin contamination and the emergent strategies poised to ameliorate its impact on food and feed safety.

Biosynthesis, classification, properties, and applications of Weissella bacteriocins

This review aims to comprehensively chronicle the biosynthesis, classification, properties, and applications of bacteriocins produced by Weissella genus strains, particularly emphasizing their potential benefits in food preservation, human health, and animal productivity. Lactic Acid Bacteria (LAB) are a class of microorganisms well-known for their beneficial role in food fermentation, probiotics, and human health. A notable property of LAB is that they can synthesize antimicrobial peptides known as bacteriocins that exhibit antimicrobial action against both closely related and other bacteria as well. Bacteriocins produced by Weissella spp. are known to exhibit antimicrobial activity against several pathogenic bacteria including food spoilage species, making them highly invaluable for potential application in food preservation and food safety. Importantly, they provide significant health benefits to humans, including combating infections, reducing inflammation, and modulating the gut microbiota. In addition to their applications in food fermentation and probiotics, Weissella bacteriocins show promising prospects in poultry production, processing, and improving animal productivity. Future research should explore the utilization of Weissella bacteriocins in innovative food safety measures and medical applications, emphasizing their potential to combat antibiotic-resistant pathogens, enhance gut microbiota composition and function, and synergize with existing antimicrobial therapies.

Synergistic effects of combined probiotics Bacillus pumilis D5 and Leuconostoc mesenteroide B4 on immune enhancement and disease resistance in Litopenaeus vannamei

This study investigated the effects of two distinct probiotics, Leuconostoc mesenteroides B4 (B4) and Bacillus pumilus D5 (D5), along with their combination, on the diet of white shrimp (Litopenaeus vannamei) during an eight-week feeding trial. The diets tested included B4 + dextran at 107 CFU/g feed (the B4 group), D5 alone at 107 CFU/g feed (the D5 group), and a combination of B4 + dextran and D5 at 5 × 106 CFU/g feed each (the B4+dextran + D5 group). Relative to the control group, those administered probiotics exhibited moderate enhancements in growth. By the eighth week, the weight gain for the B4, D5, and B4+D5 groups was 696.50 ± 78.15%, 718.53 ± 130.73%, and 693.05 ± 93.79%, respectively, outperforming the control group's 691.66 ± 31.10% gain. The feed conversion ratio was most efficient in the B4 group (2.16 ± 0.06), closely followed by B4+D5 (2.21 ± 0.03) and D5 (2.22 ± 0.06), with the control group having the highest ratio (2.27 ± 0.03). While phenoloxidase activity was somewhat elevated in the B4 and D5 groups, no significant differences were noted in respiratory burst activity or total hemocyte count across all groups. Challenge tests at weeks 4 and 8 showed that the B4 + D5 combination offered superior protection against AHPND-causing Vibrio parahaemolyticus. The 4-week cumulative survival rate was highest in shrimp treated with B4 + dextran + D5 (56.25%), followed by B4 + dextran (31.25%), control (18.75%), and lowest in D5 (12.5%). By week 8, the B4 + dextran + D5 (43.75%) and B4 + dextran (37.5%) groups significantly outperformed the control group (6.25%, p < 0.05), with no significant difference observed between the D5 group (37.5%) and the control group at day 56. Analysis of the shrimp's foregut microbiota revealed an increase in unique OTUs in the B4 and B4 + D5 groups. Compared to the control, Proteobacteria abundance was reduced in all probiotic groups. Potential pathogens like Vibrio, Bacteroides, Neisseria, Botrytis, Clostridioides, and Deltaentomopoxvirus were detected in the control but were reduced or absent in probiotic groups. Beneficial microbes such as Methanobrevibacter and Dictyostelium in the B4+D5 group, and Sugiyamaella in the B4 group, showed significant increases. Probiotics also led to higher transcript levels of nitric oxide synthase in the hemocytes, and lysozyme and transglutaminase in the midgut, along with lysozyme and α2-macroglobulin in the foregut. Notably, the combined B4 + D5 probiotics synergistically enhanced the expression of superoxide dismutase and prophenoloxidase in the foregut, indicating an improved immune response. In summary, this study demonstrates that the probiotics evaluated, especially when used in combination, significantly boost the expression of specific immune-related genes, enhance the bacterial diversity and richness of the intestine, and thus prevent the colonization and proliferation of Vibrio spp. in L. vannamei.

Isolation, identification, and characterization of thermophilic lactic acid bacteria isolated from whey of Kars Kashar cheeses

Kars Kashar cheese is an artisanal pasta-filata type cheese and geographically marked in Eastern Anatolia of Turkey. The aims of this research were to determine for the first time thermophilic lactic acid bacteria (LAB) of Kars Kashar cheese and characterize the technological properties of obtained isolates. In our research, a number of 15 samples of whey were collected from the different villages in Kars. These samples were incubated at 45 °C and used as the source material for isolating thermophilic LAB. A total of 250 colonies were isolated from thermophilic whey, and 217 of them were determined to be presumptive LAB based on their Gram staining and catalase test. A total of 170 isolates were characterized by their phenotypic properties and identified using the MALDI-TOF mass spectrometry method. Phenotypic identification of isolates displayed that Enterococcus and Lactobacillus were the predominant microbiota. According to MALDI-TOF MS identification, 89 isolates were identified as Enterococcus (52.35%), 57 isolates as Lactobacillus (33.53%), 23 isolates as Streptococcus (13.53%), and one isolate as Lactococcus (0.59%). All thermophilic LAB isolates were successfully identified to the species level and it has been observed that MALDI-TOF MS can be successfully used for the identification of selected LAB. The acidification and proteolytic activities of the isolated thermophilic LAB were examined, and the isolates designated for use as starter cultures were also genotypically defined.

A promising area of research in medicine: recent advances in properties and applications of Lactobacillus-derived exosomes

Lactobacillus-derived exosomes, small extracellular vesicles released by bacteria, have emerged as a promising area of research in recent years. These exosomes possess a unique structural and functional diversity that allows them to regulate the immune response and promote gut health. The isolation and purification of these exosomes are crucial for their effective use as a therapeutic agent. Several isolation and purification methods have been developed, including differential ultracentrifugation, density gradient centrifugation, and size-exclusion chromatography. Lactobacillus-derived exosomes have been demonstrated to have therapeutic potential in various diseases, such as inflammatory bowel disease, liver disease, and neurological disorders. Moreover, they have been shown to serve as effective carriers for drug delivery. Genetic engineering of these exosomes has also shown promise in enhancing their therapeutic potential. Overall, Lactobacillus-derived exosomes represent a promising area of research for the development of novel therapeutics for immunomodulation, gut health, and drug delivery.

Comparative genomics of four lactic acid bacteria identified with Vitek MS (MALDI-TOF) and whole-genome sequencing

Lactic acid bacteria (LAB) can be used as a probiotic or starter culture in dairy, meat, and vegetable fermentation. Therefore, their isolation and identification are essential. Recent advances in omics technologies and high-throughput sequencing have made the identification and characterization of bacteria. This study firstly aimed to demonstrate the sensitivity of the Vitek MS (MALDI-TOF) system in the identification of lactic acid bacteria and, secondly, to characterize bacteria using various bioinformatics approaches. Probiotic potency-related genes and secondary metabolite biosynthesis gene clusters were examined. The Vitek MS (MALDI-TOF) system was able to identify all of the bacteria at the genus level. According to whole genome sequencing, the bacteria were confirmed to be Lentilactobacillus buchneri, Levilactobacillus brevis, Lactiplantibacillus plantarum, Levilactobacillus namurensis. Bacteria had most of the probiotic potency-related genes, and different toxin-antitoxin systems such as PemIK/MazEF, Hig A/B, YdcE/YdcD, YefM/YoeB. Also, some of the secondary metabolite biosynthesis gene clusters, some toxic metabolite-related genes, and antibiotic resistance-related genes were detected. In addition, Lentilactobacillus buchneri Egmn17 had a type II-A CRISPR/Cas system. Lactiplantibacillus plantarum Gmze16 had a bacteriocin, plantaricin E/F.

Investigating the Probiotic Potential of Vegan Puree Mixture: Viability during Simulated Digestion and Bioactive Compound Bioaccessibility

This study aimed to develop a fermented puree mixture containing plant-based ingredients and potential probiotic strains Lacticaseibacillus rhamnosusK3 and Lactobacillus johnsonii K4. The survival of potential probiotic strains, changes in sugar and organic acid concentrations, bioaccessibility of polyphenols, and antioxidant capacity after simulated digestion were examined with sensory quality. The mixture of apple puree, chia seeds, and oat bran or oat flakes was fermented. The sensory quality of the puree mixture was assessed by the quantitative descriptive profile (QDP) method. In vitro digestion was simulated using a static gastrointestinal model. Antioxidant capacity and total polyphenol content were analyzed before and after the digestion phases. All samples changed sensory profiles after fermentation. The overall quality was above six out of ten for every product. Fermentation also changed the organic acid composition, with significant increases in lactic, succinic, and acetic acids. After the digestion process, the survival rate remained above 5.8 log10 CFU/g. As a result of fermentation with potential probiotics, the bioaccessibility of the total phenolics and antioxidant activity increased. These results showed that the addition of potential probiotic strains increases nutritional value and could help with healthy nourishment habits. This knowledge can guide the development of consumer-satisfying products in the food industry, expanding the probiotic food market with innovative alternatives.

Study of the physicochemical characteristics, antimicrobial activity, and in vitro multiplication of wild blackberry species from the Peruvian highlands

The Peruvian Andes are the natural habitat of several wild blackberry species that are little known and exploited due to the lack of technological and scientific development to support their agricultural potential. In this context, a study was conducted to understand the physicochemical composition, bioactive compounds, antimicrobial activity, and in vitro multiplication of four wild blackberry (Rubus sp.) species from the northern Peruvian highlands. The results indicate that fruits of R. floribundus presented the highest content of total soluble solids (9.58 ± 1.83°Brix) and titratable acidity (1.88 ± 0.07% citric acid). The fruits of R. weberbaueri recorded the highest total phenolic content (415.06 ± 8.69 mg GAE/100 g Ff). The antioxidant capacity determined by the DPPH assay varied significantly among species, with the highest value found in fruits of R. andicola (50.27 ± 0.11 mg TE/100 g Ff). The fruit extracts of R. weberbaueri and R. andicola showed better antimicrobial activity, with Staphylococcus aureus being the most sensitive bacterium. In the in vitro multiplication phase, the results show that BAP (6-Benzylaminopurine) has a significant effect at a dose of 1.5 mg l-1 on shoot number, leaf number, and shoot length. The results may help in the management of genetic resources.

Phenotypic, Technological, Safety, and Genomic Profiles of Gamma-Aminobutyric Acid-Producing Lactococcus lactis and Streptococcus thermophilus Strains Isolated from Cow's Milk

Gamma-aminobutyric acid (GABA)-producing lactic acid bacteria (LAB) can be used as starters in the development of GABA-enriched functional fermented foods. In this work, four GABA-producing strains each of Lactococcus lactis and Streptococcus thermophilus species were isolated from cow's milk, and their phenotypic, technological, and safety profiles determined. Genome analysis provided genetic support for the majority of the analyzed traits, namely, GABA production, growth in milk, and the absence of genes of concern. The operon harboring the glutamate decarboxylase gene (gadB) was chromosomally encoded in all strains and showed the same gene content and gene order as those reported, respectively, for L. lactis and S. thermophilus. In the latter species, the operon was flanked (as in most strains of this species) by complete or truncated copies of insertion sequences (IS), suggesting recent acquisition through horizontal gene transfer. The genomes of three L. lactis and two S. thermophilus strains showed a gene encoding a caseinolytic proteinase (PrtP in L. lactis and PrtS in S. thermophilus). Of these, all but one grew in milk, forming a coagulum of good appearance and an appealing acidic flavor and taste. They also produced GABA in milk supplemented with monosodium glutamate. Two L. lactis strains were identified as belonging to the biovar. diacetylactis, utilized citrate from milk, and produced significant amounts of acetoin. None of the strains showed any noticeable antibiotic resistance, nor did their genomes harbor transferable antibiotic resistance genes or genes involved in toxicity, virulence, or pathogenicity. Altogether these results suggest that all eight strains may be considered candidates for use as starters or components of mixed LAB cultures for the manufacture of GABA-enriched fermented dairy products.

Genomic characterization and probiotic potential of lactic acid bacteria isolated from feces of guinea pig (Cavia porcellus)

Background

Presently, there exists a growing interest in mitigating the utilization of antibiotics in response to the challenges emanating from their usage in livestock. A viable alternative strategy encompasses the introduction of live microorganisms recognized as probiotics, exerting advantageous impacts on the immune system and nutritional aspects of the host animals. Native lactic acid bacteria, inherently possessing specific properties and adaptive capabilities tailored to each animal, are deemed optimal contenders for probiotic advancement.

Aim

In the current investigation, microorganisms exhibiting probiotic potential were isolated, characterized, and identified from the fecal samples of guinea pigs (Cavia porcellus) belonging to the Peruvian breed.

Methods

The lactic acid bacteria isolated on Man, Rogosa, and Sharpe agar underwent Gram staining, catalase testing, proteolytic, amylolytic, and cellulolytic activity assays, low pH tolerance assessment, hemolytic evaluation, antagonism against Salmonella sp., determination of autoaggregation and coaggregation capacity, and genotypic characterization through sequencing of the 16S rRNA gene.

Results

A total of 33 lactic acid bacteria were isolated from the feces of 30 guinea pigs, also 10 isolates were selected based on Gram staining and catalase testing. All strains exhibited proteolytic activity, while only one demonstrated amylolytic capability, and none displayed cellulase activity. These bacteria showed higher tolerance to pH 5.0 and, to a lesser extent, to pH 4.0. Furthermore, they exhibited antagonistic activity against Salmonella sp. Only two bacteria demonstrated hemolytic activity, and were subsequently excluded from further evaluations. Subsequent assessments revealed autoaggregation capacities ranging from 4.55% to 23.19%, with a lesser degree of coaggregation with Salmonella sp. ranging from 3.53% to 8.94% for the remaining eight bacterial isolates. Based on these comprehensive tests, five bacteria with notable probiotic potential were identified by molecular assays as Leuconostoc citreum, Enterococcus gallinarum, Exiguobacterium sp., and Lactococcus lactis.

Conclusion

The identified bacteria stand out as promising probiotic candidates, deserving further assessment in Peruvian breed guinea pigs. This exploration aims to enhance production outcomes while mitigating the adverse effects induced by pathogenic microorganisms.

Impact of ultrasonicated Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus and Lactiplantibacillus plantarum AF1 on the safety and bioactive properties of stirred yoghurt during storage

In this study, the effects of ultrasonicated Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus and Lactiplantibacillus plantarum AF1 (100 W, 30 kHz, 3 min) on the safety and bioactive properties of stirred yoghurt during storage (4 °C for 21 days) were investigated. The results showed that sonicated cultures were more effective in reducing pathogens than untreated ones. The highest antioxidant activity (DPPH and ABTS), α-glucosidase and α-amylase inhibition capacity were found in yoghurt containing sonicated probiotic + sonicated yoghurt starter cultures (P + Y + ). The highest amount of peptides (12.4 mg/g) was found in P + Y + yoghurts at the end of the storage time. There were not significant differences between the exopolysaccharide content of P + Y+ (17.30 mg/L) and P + Y- (17.20 mg/L) yoghurts, although it was significantly (P ≤ 0.05) higher than the other samples. The use of ultrasonicated cultures could enhance the safety of stirred yoghurt and improve its functional and bioactive properties.

Milk Fat Globules: 2024 Updates

Milk fat globules (MFGs) are a remarkable example of nature's ingenuity. Human milk (HM) carries contains 3-5% fat, 0.8-0.9% protein, 6.9-7.2% carbohydrate calculated as lactose, and 0.2% mineral constituents. Most of these nutrients are carried in these MFGs, which are composed of an energy-rich triacylglycerol (TAG) core surrounded by a triple membrane structure. The membrane contains polar lipids, specialized proteins, glycoproteins, and cholesterol. Each of these bioactive components serves important nutritional, immunological, neurological, and digestive functions. These MFGs are designed to release energy rapidly in the upper gastrointestinal tract and then persist for some time in the gut lumen so that the protective bioactive molecules are conveyed to the colon. These properties may shape the microbial colonization and innate immune properties of the developing gastrointestinal tract. Milk fat globules in milk from humans and ruminants may resemble in structure but there are considerable differences in size, profile, composition, and specific constituents. There are possibilities to not only enhance the nutritional composition in a goal-oriented fashion to correct specific deficiencies in the infant but also to use these fat globules as a nutraceutical in infants who require specific treatments. To mention a few, there might be possibilities in enhancing neurodevelopment, in defense against gastrointestinal and respiratory tract infections, improving insulin sensitivity, treating chronic inflammation, and altering plasma lipids. This review provides an overview of the composition, structure, and biological activities of the various components of the MFGs. We have assimilated research findings from our own laboratory with an extensive review of the literature utilizing key terms in multiple databases including PubMed, EMBASE, and Science Direct. To avoid bias in the identification of studies, keywords were short-listed a priori from anecdotal experience and PubMed's Medical Subject Heading (MeSH) thesaurus.

CRISPR-Cas systems feature and targeting phages diversity in Lacticaseibacillus rhamnosus strains

One of the most important adaptive immune systems in bacteria against phages is clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (CAS) genes. In this investigation, an approach based on genome mining was employed to characterize the CRISPR-Cas systems of Lacticaseibacillus rhamnosus strains. The analysis involved retrieving complete genome sequences of L. rhamnosus strains, and assessing the diversity, prevalence, and evolution of their CRISPR-Cas systems. Following this, an analysis of homology in spacer sequences from identified CRISPR arrays was carried out to investigate and characterize the range of target phages. The findings revealed that 106 strains possessed valid CRISPR-Cas structures (comprising CRISPR loci and Cas genes), constituting 45% of the examined L. rhamnosus strains. The diversity observed in the CRISPR-Cas systems indicated that all identified systems belonged to subtype II-A. Analyzing the homology of spacer sequences with phage and prophage genomes discovered that strains possessing only CRISPR-Cas subtype II targeted a broader spectrum of foreign phages. In summary, this study suggests that while there is not significant diversity among the CRISPR-Cas systems identified in L. rhamnosus strains, there exists notable variation in subtype II-A systems between L. rhamnosus and other lactobacilli. The diverse nature of these CRISPR-Cas systems underscores their natural activity and importance in adaptive immunity.

A review of fermented milks: potential beneficial effects on human nutrition and health

Fermented dairy products are formed during the acidification of milk through fermentation by suitable microorganisms; it contains different microorganisms in sufficient numbers and in an active state. A wide range of fermented milk products are produced and consumed around the world, including yogurt, kefir, koumiss, and yogurt beverages. There are various health benefits associated with the consumption of fermented dairy. Many studies reported that some fermented milk products have antimicrobial, antimutagenic, anticarcinogenic, and antihypertensive properties as well as provide benefits on mineral metabolism, reduce lactose intolerance symptoms and cholesterol levels. In addition to these effects, it has many other beneficial effects such as positive effects on type 2 diabetes and hypertension, antimutagen and antioxidant effects, and reduction of allergic symptoms. Dairy products including fermented milk are known to be the main carrier of probiotic microorganisms, and many clinical studies show the effects of probiotic strains on health. In this study, the effects of fermented milks on human nutrition and health are mentioned.

The intricate symbiotic relationship between lactic acid bacterial starters in the milk fermentation ecosystem

Fermentation is one of the most effective methods of food preservation. Since ancient times, food has been fermented using lactic acid bacteria (LAB). Fermented milk is a very intricate fermentation ecosystem, and the microbial metabolism of fermented milk largely determines its metabolic properties. The two most frequently used dairy starter strains are Streptococcus thermophilus (S. thermophilus) and Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus). To enhance both the culture growth rate and the flavor and quality of the fermented milk, it has long been customary to combine S. thermophilus and L. bulgaricus in milk fermentation due to their mutually beneficial and symbiotic relationship. On the one hand, the symbiotic relationship is reflected by the nutrient co-dependence of the two microbes at the metabolic level. On the other hand, more complex interaction mechanisms, such as quorum sensing between cells, are involved. This review summarizes the application of LAB in fermented dairy products and discusses the symbiotic mechanisms and interactions of milk LAB starter strains from the perspective of nutrient supply and intra- and interspecific quorum sensing. This review provides updated information and knowledge on microbial interactions in a fermented milk ecosystem.

Potential of Cheese-Associated Lactic Acid Bacteria to Metabolize Citrate and Produce Organic Acids and Acetoin

Lactic acid bacteria (LAB) are pivotal in shaping the technological, sensory, and safety aspects of dairy products. The evaluation of proteolytic activity, citrate utilization, milk pH reduction, and the production of organic compounds, acetoin, and diacetyl by cheese associated LAB strains was carried out, followed by Principal Component Analysis (PCA). Citrate utilization was observed in all Leuconostoc (Le.) mesenteroides, Le. citreum, Lactococcus (Lc.) lactis, Lc. garvieae, and Limosilactobacillus (Lm.) fermentum strains, and in some Lacticaseibacillus (Lact.) casei strains. Most strains exhibited proteolytic activity, reduced pH, and generated organic compounds. Multivariate PCA revealed Le. mesenteroides as a prolific producer of acetic, lactic, formic, and pyruvic acids and acetoin at 30 °C. Enterococcus sp. was distinguished from Lact. casei based on acetic, formic, and pyruvic acid production, while Lact. casei primarily produced lactic acid at 37 °C. At 42 °C, Lactobacillus (L.) helveticus and some L. delbrueckii subsp. bulgaricus strains excelled in acetoin production, whereas L. delbrueckii subsp. bulgaricus and Streptococcus (S.) thermophilus strains primarily produced lactic acid. Lm. fermentum stood out with its production of acetic, formic, and pyruvic acids. Overall, cheese-associated LAB strains exhibited diverse metabolic capabilities which contribute to desirable aroma, flavor, and safety of dairy products.

Probiotic management and inflammatory factors as a novel treatment in cirrhosis: A systematic review and meta-analysis

The interaction between intestinal microecological dysregulation, altered inflammatory factors, and cirrhosis is unclear. The aim of this systematic review and meta-analysis was to synthesize the results of previous studies to assess the efficacy of probiotics in the treatment of cirrhosis and their effect on inflammatory factors, as well as to explore the relationship between gut microecological dysregulation and liver disease to gain a deeper understanding of this interaction. Up to December 2022, eligible studies were identified by searching the following databases: National Knowledge Infrastructure (CNKI), Wanfang Data, Web of Science, PubMed, Embase, Medline, and the Cochrane Library. Statistical analysis was performed using software RevMan Version 5.4. A total of 33 eligible randomized controlled trials were included in the study, and data on probiotic strains, duration of intervention, measures in the control group, and outcomes were extracted and evaluated. Compared to the control group, the experimental group had significant improvements in overall efficacy. The results of the meta-analysis revealed that probiotic use significantly decreased biochemical parameters for liver function, including aspartate transaminase, alanine aminotransferase, and total bilirubin. Similar result was obtained in interleukin-6, tumor necrosis factor-α, and endotoxin. However, probiotic intervention did not significantly affect interleukin-2 and interleukin-10. The current meta-analysis illustrates that probiotic supplementation reduces inflammatory markers and biochemical parameters for liver function in patients with cirrhosis, suggesting that probiotic management may be a novel treatment for cirrhosis. Furthermore, the interaction of the gut microbiota, associated metabolites, and inflammation factors with cirrhosis may provide a promising therapeutic target for the pharmacological and clinical treatment of cirrhosis.

Development of a Technology for Protein-Based, Glueless Belevskaya Pastille with Study of the Impact of Probiotic Sourdough Dosage and Technological Parameters on Its Rheological Properties

The proper functioning of the gastrointestinal tract plays an important role in strengthening the immune system. It is an undeniable fact that lactic acid microorganisms are necessary for the proper functioning of the gastrointestinal tract, the source of which are mainly dairy products. However, there is a problem with the digestibility of lactose; therefore, alternative sources and carriers of probiotics are of particular interest. Due to its dietary and natural properties, protein marshmallow can serve as such a carrier. Therefore, the direction of this study is to identify the dependence of technological factors on the rheological properties of the product and the growth of lactic acid microorganisms in confectionery products enriched with lyophilised strains. According to the results of the study, the following was determined: the optimal technology to produce enriched Belevskaya pastille with a mixture of Lactobacillus acidophilus makes it possible to obtain a product with the necessary rheological properties, utilising a mass drying mode in a dehydrator at 50 °C for 16 h. The strains L. acidophilus M3 and L. acidophilus M4 were the most resistant to a high concentration of bile (40%) in the substrate. Based on the analysis of variance and the obtained regression equations, it was revealed that the growth of lactic acid microorganisms in the product was strongly influenced by the amount of ferment introduced (R² = 0.96). The level of penetration is influenced by factors such as the amount of probiotic starter introduced, the drying time and the interaction of drying time factors on the amount of starter added. The higher the level of penetration, the crumblier the product. The resulting functional product can be characterized as symbiotic since the main raw material of plant origin contains a large amount of fibre, which acts as a prebiotic, and the strain of microorganism, which acts as a probiotic. The data described in the article can be applied in the technological processes of similar products to regulate the structure of the product and vary the dosage of enrichment with probiotic starter cultures.

The potentials and challenges of using fermentation to improve the sensory quality of plant-based meat analogs

Despite the advancements made in improving the quality of plant-based meat substitutes, more work needs to be done to match the texture, appearance, and flavor of real meat. This review aims to cover the sensory quality constraints of plant-based meat analogs and provides fermentation as a sustainable approach to push these boundaries. Plant-based meat analogs have been observed to have weak and soft textural quality, poor mouth feel, an unstable color, and unpleasant and beany flavors in some cases, necessitating the search for efficient novel technologies. A wide range of microorganisms, including bacteria such as Lactobacillus acidophilus and Lactiplantibacillus plantarum, as well as fungi like Fusarium venenatum and Neurospora intermedia, have improved the product texture to mimic fibrous meat structures. Additionally, the chewiness and hardness of the resulting meat analogs have been further improved through the use of Bacillus subtilis. However, excessive fermentation may result in a decrease in the final product's firmness and produce a slimy texture. Similarly, several microbial metabolites can mimic the color and flavor of meat, with some concerns. It appears that fermentation is a promising approach to modulating the sensory profiles of plant-derived meat ingredients without adverse consequences. In addition, the technology of starter cultures can be optimized and introduced as a new strategy to enhance the organoleptic properties of plant-based meat while still meeting the needs of an expanding and sustainable economy.

Metabolic inputs in the probiotic bacterium Lacticaseibacillus rhamnosus contribute to cell-wall remodeling and increased fitness

Lacticaseibacillus rhamnosus GG (LGG) is a Gram-positive beneficial bacterium that resides in the human intestinal tract and belongs to the family of lactic acid bacteria (LAB). This bacterium is a widely used probiotic and was suggested to provide numerous benefits for human health. However, as in most LAB strains, the molecular mechanisms that mediate the competitiveness of probiotics under different diets remain unknown. Fermentation is a fundamental process in LAB, allowing the oxidation of simple carbohydrates (e.g., glucose, mannose) for energy production under oxygen limitation, as in the human gut. Our results indicate that fermentation reshapes the metabolome, volatilome, and proteome architecture of LGG. Furthermore, fermentation alters cell envelope remodeling and peptidoglycan biosynthesis, which leads to altered cell wall thickness, aggregation properties, and cell wall composition. In addition, fermentable sugars induced the secretion of known and novel metabolites and proteins targeting the enteric pathogens Enterococcus faecalis and Salmonella enterica Serovar Typhimurium. Overall, our results link simple carbohydrates with cell wall remodeling, aggregation to host tissues, and biofilm formation in probiotic strains and connect them with the production of broad-spectrum antimicrobial effectors.

Flavor Characterization of Traditional Fermented Soybean Pastes from Northeast China and Korea

This study compares the physicochemical properties, taste, and volatile compounds of Northeastern Chinese dajiang (C) and Korean doenjang (K) and distinguishes the discriminant volatile metabolites between them. The result revealed that compared to group C, group K exhibited more similar physicochemical properties and had lower pH, moisture, and amino acid nitrogen content, while demonstrating higher titratable acidity, salt content, and reduced sugar content. The electronic tongue analysis showed that the saltiness and umami of soybean pastes had high response values, enabling clear differentiation of the overall taste between the two types of soybean pastes. A total of 71 volatile substances from the soybean pastes were identified through solid-phase microextraction gas chromatography-mass spectrometry. Furthermore, orthogonal partial least squares discriminant analysis revealed 19 volatile compounds as differentially flavored metabolites. Our study provides a basis for explaining the differences in flavor difference of Northeastern Chinese dajiang and Korean doenjang from the perspective of volatile metabolites.

U.S. Consumer Practices of Homemade Nut-based Dairy Analogs and Soaked Nuts

Tree nuts, a low-moisture food, are typically perceived as being a low risk for foodborne illness. In the past five decades, the consumption of tree nuts (dry, soaked, or as nut-based dairy analogs [NBDA]) has increased along with corresponding foodborne illness outbreaks and recalls associated with these products. We developed an online survey to assess tree nut handling practices of U.S. consumers, and to select study participants who have soaked tree nuts and/or made NBDA at home. We distributed our initial survey questions in October 2021 to a convenience sample (n = 12) to test for clarity and comprehension. In January 2022, participants (n = 981) who met the criteria completed the survey. The most popular soaked tree nuts were almonds (54%), followed by cashews (36%), walnuts (32%), and pistachios (22%). Participants soaked tree nuts for direct consumption (67%) and during the preparation of NBDA (80%). Participants soaked tree nuts under refrigerated conditions for 1-24 h (22%), on the countertop at room temperature (est. 65-75°F [18-24°C]) for 1-5 h (21%), or at room temperature for 12 h or more (6%); 16% used a hot or boiling water, short time treatment. Some participants added acid (28%) or salt (25%) to the soaking water. Among those participants who dried their tree nuts after soaking (63%), 89% reported drying at a temperature lower than 46°C (115°F). Some participants (34%) used their tree nuts to make fermented dairy analogs (e.g., "cheese" or "yogurt") by adding "probiotics" (56-86%) or a yogurt starter culture (37-99%), respectively, and then, most frequently, holding at or below 20°C (68°F) for 12 h or less (29%). The safety of many of these practices has not been adequately investigated, but the findings of this study will inform future risk assessment and risk modeling studies on tree nut food safety in home kitchen settings.

Transforming the fermented fish landscape: Microbiota enable novel, safe, flavorful, and healthy products for modern consumers

Regular consumption of fish promotes sustainable health while reducing negative environmental impacts. Fermentation has long been used for preserving perishable foods, including fish. Fermented fish products are popular consumer foods of historical and cultural significance owing to their abundant essential nutrients and distinct flavor. This review discusses the recent scientific progress on fermented fish, especially the involved flavor formation processes, microbial metabolic activities, and interconnected biochemical pathways (e.g., enzymatic/non-enzymatic reactions associated with lipids, proteins, and their interactions). The multiple roles of fermentation in preservation of fish, development of desirable flavors, and production of health-promoting nutrients and bioactive substances are also discussed. Finally, prospects for further studies on fermented fish are proposed, including the need of monitoring microorganisms, along with the precise control of a fermentation process to transform the traditional fermented fish to novel, flavorful, healthy, and affordable products for modern consumers. Microbial-enabled innovative fermented fish products that consider both flavor and health benefits are expected to become a significant segment in global food markets. The integration of multi-omics technologies, biotechnology-based approaches (including synthetic biology and metabolic engineering) and sensory and consumer sciences, is crucial for technological innovations related to fermented fish. The findings of this review will provide guidance on future development of new or improved fermented fish products through regulating microbial metabolic processes and enzymatic activities.

The Impacts of Acidophilic Lactic Acid Bacteria on Food and Human Health: A Review of the Current Knowledge

The need to improve the safety/quality of food and the health of the hosts has resulted in increasing worldwide interest in acidophilic lactic acid bacteria (LAB) for the food, livestock as well as health industries. In addition to the use of acidophilic LAB with probiotic potential for food fermentation and preservation, their application in the natural disposal of acidic wastes polluting the environment is also being investigated. Considering this new benefit that has been assigned to probiotic microorganisms in recent years, the acceleration in efforts to identify new, efficient, promising probiotic acidophilic LAB is not surprising. One of these effots is to determine both the beneficial and harmful compounds synthesized by acidophilic LAB. Moreover, microorganisms are of concern due to their possible hemolytic, DNase, gelatinase and mucinolytic activities, and the presence of virulence/antibiotic genes. Hence, it is argued that acidophilic LAB should be evaluated for these parameters before their use in the health/food/livestock industry. However, this issue has not yet been fully discussed in the literature. Thus, this review pays attention to the less-known aspects of acidophilic LAB and the compounds they release, clarifying critical unanswered questions, and discussing their health benefits and safety.

The Comparative Effect of Lactic Acid Fermentation and Germination on the Levels of Neurotoxin, Anti-Nutrients, and Nutritional Attributes of Sweet Blue Pea (Lathyrus sativus L.)

Grass pea (Lathyrus sativus L.), an indigenous legume of the subcontinental region, is a promising source of protein and other nutrients of health significance. Contrarily, a high amount of β-N-oxalyl-l-α,β-diaminopropionic acid (β-ODAP) and other anti-nutrients limits its wider acceptability as healthier substitute to protein of animal and plant origin. This study was aimed at investigating the effect of different processing techniques, viz. soaking, boiling, germination, and fermentation, to improve the nutrient-delivering potential of grass pea lentil and to mitigate its anti-nutrient and toxicant burden. The results presented the significant (p < 0.05) effect of germination on increasing the protein and fiber content of L. sativus from 22.6 to 30.7% and 15.1 to 19.4%, respectively. Likewise, germination reduced the total carbohydrate content of the grass pea from 59.1 to 46%. The highest rate of reduction in phytic acid (91%) and β-ODAP (37%) were observed in germinated grass pea powder, whereas fermentation anticipated an 89% reduction in tannin content. The lactic acid fermentation of grass pea increased the concentration of calcium, iron, and zinc from 4020 to 5100 mg/100 g, 3.97 to 4.35 mg/100 g, and 3.52 to 4.97 mg/100 g, respectively. The results suggest that fermentation and germination significantly (p < 0.05) improve the concentration of essential amino acids including threonine, leucine, histidine, tryptophan, and lysine in L. sativus powder. This study proposes lactic acid fermentation and germination as safer techniques to improve the nutrient-delivering potential of L. sativus and suggests processed powders of the legume as a cost-effective alternative to existing plant proteins.