Search Results (2,437)

The logistic modeling of diauxic growth and biphasic antibacterial activity (AA) production was enhanced for four lactic acid bacteria (Lactococcus lactis CECT 539, Pediococcus acidilactici NRRL B-5627, Lactobacillus casei CECT 4043, and Enterococcus faecium CECT 410) during realkalized fed-batch fermentations. The improved growth model, also validated for describing the diauxic growth of Mos breed roosters and foals, overcomes a key limitation of the bi-logistic model, which assumes the existence of two distinct populations growing from the start of the culture, each following a different growth profile. In contrast, the improved logistic growth model developed in this study accounts for a single population growing at two rates, offering a fit to the experimental data comparable to that of the commonly used bi-logistic model. The enhanced model for product synthesis accurately describes biphasic AA production, assuming that antibacterial products are synthesized as growth-associated metabolites, depending on the final pH reached in the cultures at each sampling time. Additionally, it is easier to apply than the unmodified or modified differential forms of the Luedeking–Piret model. This study demonstrated, for the first time, the applicability of these two models in describing the diauxic growth and biphasic AA synthesis of LAB. Full article

The aim of this study was to develop fermented milks using strains of lactic acid bacteria with probiotic potential isolated from Minas artisanal cheese. For this purpose, the strains Lacticaseibacillus casei B5 and Lactiplantibacillus plantarum B7 were used in a 6 × 4 experimental design, with six fermented milk treatments and four analyses on days 1, 15, 30 and 45 to characterize the product and evaluate the viability of the bacteria. Additionally, a sensory analysis was conducted using a preference ranking test. All treatments showed viable counts of microorganisms above 10⁶ CFU/mL until the end of the storage period, as well as variations in pH and titratable acidity values on day 45, being the lowest value of both verified in the TRAT1B7 sample. Based on the application of a sensory analysis, it was observed that the type of treatment and the strain directly impacted the sample chosen by the tasters. According to results gathered from the present study, milk fermented by L. casei B5 stands out in the order of preference, however milk fermented by L. plantarum B7 has also obtained favorable results, indicating that this strain of bacteria can be used in dairy technology. Full article

Okara, a protein-rich byproduct of soymilk production, is highly perishable because of its high moisture content. This study evaluated the preservation and nutritional value of okara fermented by lactic acid bacteria for use in dairy cattle diets. Fermentation effectively reduced pH within 2 weeks and maintained quality for up to 6 weeks. However, aerobic exposure increased the concentration of ammonia, indicating a decline in stability. In vitro assessments revealed no significant differences in in vitro true dry matter digestibility, in vitro neutral detergent fiber digestibility, or gas production between fermented and fresh okara, although fermented okara had a higher concentration of ammonia nitrogen. In situ analysis revealed slightly lower dry matter effective degradability (ED) in fermented okara, but similar rumen-degradable and undegradable protein fractions. When fermented okara was used to replace soybean meal in total mixed rations, 25–50% inclusion-maintained digestibility and fermentation characteristics, with 25% replacement yielding the highest ED at a low ruminal passage rate (0.02 h⁻¹). Taken together, these results suggest that fermented okara can be strategically incorporated into dairy rations as a sustainable protein alternative, supporting both rumen function and bypass protein supply. Full article

This study investigated the microbiological, physicochemical, textural, and sensory characteristics of ayran and kefir samples produced from milk treated with different doses of UV-C radiation. For this purpose, raw milk was passed through a UV-C column at three different flow rates (15, 30, and 45 mL/min), and irradiated with doses of 72, 36, and 24 J/mL, respectively, corresponding to the flow rate. Samples produced from milk pasteurised by thermal treatment were used as the control group. This research indicated that UV-C treatment effectively reduced the microbial load in milk to a level comparable to that achieved through conventional pasteurisation. A reduction of 2.15 log cfu/mL in total aerobic mesophilic bacteria count was achieved, while total coliform group bacteria counts were decreased to an undetectable level. Samples produced from milk treated with UV-C showed lower pH and higher titration acidity (% lactic acid). Furthermore, the organic acid content was higher in these samples. Lactic acid, the main organic acid, levels in the ayran and kefir samples were measured at their highest as 11,951.51 mg/kg and 12,989.34 mg/kg, respectively, in the UV45 sample with a radiation dose of 24 J/mL. The treatment of UV-C resulted in a minor change in the colour and textural properties of the samples. Nonetheless, this change was not significant enough to influence consumer acceptance. The application of UV-C to raw milk, depending on the radiation level used, can enhance the fermentation process in the production of ayran and kefir. This study showed that the application of UV-C has improved the quality of drinkable fermented milk products. This research has shown that, while reducing nutritional losses caused by thermal processing, microbial safety is obtained at an approximate value similar to pasteurisation. As a result, UV-C application decreases the loss of dietary compounds and provides an alternative method for microbial inactivation. Full article

The quality of the Serbian dry fermented sausage, Sremska, was evaluated without added nitrite and pasteurized post-ripening. As an extra safety measure to eliminate Salmonella, mild heat treatments (47 °C/6.5 h or 53 °C/22.1 min) were used. The effect of starter culture on product quality was also examined. Sausages were tested at the start of production and after 30 days of storage, measuring physicochemical properties, microbiota populations, biogenic amines, lipid oxidation, and sensory qualities. The absence of nitrite did not cause significant changes in microbiota. Pasteurization lowered total viable counts and lactic acid bacteria by up to 3.5 log CFU/g, especially in sausages with starter culture. Enterobacteriaceae were fully eliminated only in pasteurized products. Pathogens like Listeria monocytogenes and Staphylococcus aureus were not detected. Moderate biogenic amine levels were found in all samples (189.4–312.2 mg/kg), with higher amounts in sausages without nitrite. Neither starter culture nor pasteurization significantly affected biogenic amine levels, although pasteurization helped limit their buildup during storage. Lipid oxidation remained low (0.14–0.25 mg/kg), with slightly higher levels in sausages with starter culture; no changes due to pasteurization or nitrite absence were observed. Sensory evaluation showed all sausages received high scores. Texture, juiciness, aroma, and flavor of sausages made with starter culture were unaffected by nitrite absence or pasteurization. Sausages without starter culture scored slightly lower without nitrite compared to those with it. Pasteurization improved texture, juiciness, aroma plus flavor, and overall acceptability of all sausages without starter culture. Overall, the study concluded that nitrite-free Sremska sausages, when pasteurized with a mild heat process, maintained good quality and enhanced safety. Full article

Ensiling forage under low-temperature conditions often leads to poor fermentation and nutrient losses. This study evaluated the effects of a cold-tolerant Pediococcus pentosaceus OL77 strain on oat silage. Silages were prepared with or without Pediococcus pentosaceus inoculation (1 × 10⁵ cfu/g FM). After 90 days, OL77-treated silage showed markedly higher lactic acid (45.83 vs. 30.51 g/kg DM), lower pH (3.88 vs. 4.443), and better preservation of WSC (64.68 vs. 47.60 g/kg DM) and crude protein (89.26 vs. 65.52 g/kg DM) than the control. Microbial analysis revealed accelerated colonization by Pediococcus, reduced bacterial diversity, and faster stabilization of the fermentation process. Functional predictions indicated enhanced carbohydrate and energy metabolism. These findings demonstrate that OL77 can effectively improve fermentation quality and nutrient preservation of oat silage under low-temperature conditions, offering a practical inoculant option for cold regions. Full article

Pediococcus pentosaceus is a lactic acid bacterium used inter alia for the fermentation of milk, meat, vegetables, fruits, and even for brewing beer. Several health-promoting effects, such as antibacterial and antifungal activities or microphage and immune system stimulation, have been attributed. Apart from refining foods during the fermentation process, P. pentosaceus strains are added to meat and meat products as protective cultures to improve food safety, while leaving the organoleptic properties untouched. Since knowledge on the latter issue is still limited, we investigated 32 isolates from milk samples and teat canal biofilms regarding their antibacterial efficacy as a prerequisite for possible application as protective cultures. P. pentosaceus strains were unequivocally identified by DNA sequencing of the rrnA gene encoding 16S rRNA. Binary matrices obtained from random amplification of polymorphic DNA experiments showed that all isolates differed by more than 5% and thus represented subspecies. The antibacterial profiles against eight food-borne pathogens and food spoilage bacteria were determined. They efficiently combatted, although to various extents, Gram-negative bacteria such as Pseudomonas aeruginosa or Salmonella enterica, and Gram-positive bacteria such as Staphylococcus aureus and Listeria monocytogenes. Interestingly, acid production was dependent on the presence of the challenged pathogen and did not correlate with the extent of inhibition. Bioinformatic analyses of the genomes of the three top-ranked isolates revealed a pronounced genomic plasticity with a core genome of 1460 genes and additional 91, 130, and 161 unique genes, respectively. Each strain included a set of three, five, or six plasmids and was equipped with different genes encoding bacteriocins. The data suggest that multiple strains of P. pentosaceus should be included in order to optimize the selection of a culture for food preservation. The approach could also be applicable to other bacterial species. Full article

Ulva sp. is a fast-growing, widely distributed marine alga with significant potential across various sectors, yet it remains underutilised. This study optimised pressurised liquid extraction (PLE) to obtain high-value fractions from Ulva biomass. Using a Box–Behnken design and response surface methodology, the effects of sulfuric acid concentration, temperature, and extraction time on yield, reducing sugars, total carbohydrates, and phenolic content were evaluated. Optimal conditions were identified as 110 °C, three 15 min cycles, and 3.6% sulfuric acid. Under these parameters, the extract yielded 46.9 g/100 g dry weight (DW), with 244.0 mg of reducing sugars/g DW, and 15.4 mg GAE/g DW, aligning with model predictions. The hydrolysate supported fermentation by Lactiplantibacillus plantarum, resulting in a growth of ~9 log CFU and the production of 3.3 g/L of lactic acid within 48 h. The antioxidant capacity remained stable post-fermentation, with CUPRAC, DPPH, and ABTS values of ~52, 38, and 18 mg TE/g DW, respectively. This work demonstrates the effectiveness of PLE in extracting valuable compounds and the feasibility of microbial fermentation of the extracts. This integrated approach highlights the potential of Ulva biomass and offers a platform for further applications in food, cosmetics, and nutraceuticals. Full article

Dairy products harbor complex and dynamic microbial communities that contribute to their sensory properties, safety, and cultural distinctiveness. Raw milk contains a diverse microbiota shaped by seasonality, storage conditions, lactation stage, animal health, farm management, and genetics, serving as a variable starting point for further processing. Fermentation, whether spontaneous or starter driven, selects for subsets of lactic acid bacteria (LAB), yeasts, and molds, resulting in microbial succession that underpins both artisanal and industrial products such as kefir and cheese. Kefir represents a balanced LAB–yeast symbiosis, with species composition influenced by grain origin, milk type, and processing parameters, whereas the cheese microbiota reflects the interplay of starter and non-starter LAB, coagulants, ripening conditions, and “house microbiota”. Methodological factors—including DNA extraction, sequencing platform, and bioinformatic pipelines—further impact the reported microbial profiles, highlighting the need for standardization across studies. This review synthesizes current knowledge on raw milk, kefir, and cheese microbiomes, emphasizing the biological, technological, environmental, and methodological factors shaping microbial diversity. A holistic understanding of these drivers is essential to preserve product authenticity, ensure safety, and harness microbial resources for innovation in dairy biotechnology. Full article

Ensiling is the microbial processing of forage, based on the fermentation of plant sap that acidifies the silage to pH < 5. This acidity threshold prevents microbial activity that could otherwise produce inhibitory, toxic, malodorous or otherwise undesired metabolites. Anaerobic conditions are key to silage production and storage in silos because aerobic exposure would change the microbiota to counterproductive metabolism. This review outlines the principal microbial groups involved in the open ensiling process and discusses some additive effects with externally added compounds that have been used in this industry to enhance anaerobiosis, lactic acid fermentation, preservation, and safe storage. The ensiling process and the type of forage in the silage may impact methanogenesis in ruminants, and additional effects on ruminal digestion have also been reported. Full article

Ensiling high-moisture alfalfa with peanut vine not only avoids alfalfa nutrient loss during the wilting stage but also maximizes the use of agricultural waste peanut vine. The appropriate mixed ratio of high-moisture alfalfa and peanut vine has been studied in our previous study. However, the effect of additives on improving the nutrition and fermentation quality of the mixed silage of alfalfa and peanut vine has not been investigated. This study aimed to assess the adaptation and association of Lactiplantibacillus plantarum, cellulase and tannin in the mixed silage of alfalfa and peanut vine alone or in combination on fermentation quality, chemical composition, and microbial communities. The harvested fresh alfalfa and dry peanut vine were cut into 2 cm lengths by a crop chopper and they were thoroughly mixed at a ratio of 7:3. The mixtures were treated with no addition (CK), L. plantarum (Lp, 1 × 10⁶ CFU/g fresh weight), cellulase (Ce, 5 g/kg fresh weight), tannin (Ta, 40 g/kg dry matter), and their combinations (LpCe, LpTa, CeTa, LpCeTa). After 45 days of fermentation, silage treated with Lp, Ce, and Ta had lower pH and ammonia-N (NH₃-N) content and higher concentrations of lactic acid compared with the CK group. LpCeTa-treated silage inhibited protein degradation by reducing pH value and ammonia-N concentrations during ensiling processes. The LpCeTa group increased (p < 0.05) water-soluble carbohydrate (WSC) content and reduced (p < 0.05) acid detergent fiber and neutral detergent fiber contents in mixed silage. Furthermore, the LpCeTa group increased the relative abundance of Lactobacillus and decreased the relative abundance of Enterococcus and Weissella as compared with the CK group. Results of the current study indicated that the combined use of L. plantarum, cellulase, and tannin could serve as a promising strategy for the preservation of ensiling fresh alfalfa mixed with peanut vine and provide a reference for the re-utilization of by-product. Full article

Streptococcus thermophilus is a Gram-positive, homofermentative lactic acid bacterium classified within the Firmicutes phylum, recognized for its probiotic properties and significant role in promoting human health. This review consolidates existing understanding of its metabolic pathways, functional metabolites, and diverse applications, highlighting evidence-based insights to enhance scientific integrity. S. thermophilus predominantly ferments lactose through the Embden-Meyerhof-Parnas pathway, resulting in L(+)-lactic acid as the primary end-product, along with secondary metabolites including acetic acid, formic acid, and pyruvate derivatives. Exopolysaccharides (EPS) are composed of repeating units of glucose, galactose, rhamnose, and N-acetylgalactosamine. They display strain-specific molecular weights ranging from 10 to 2000 kDa and contribute to the viscosity of fermented products, while also providing antioxidant and immunomodulatory benefits. Aromatic compounds such as acetaldehyde and phenylacetic acid are products of amino acid catabolism and carbohydrate metabolism, playing a significant role in the sensory characteristics observed in dairy fermentations. Bacteriocins, such as thermophilins (e.g., Thermophilin 13, 110), exhibit extensive antimicrobial efficacy against pathogens including Listeria monocytogenes and Bacillus cereus. Their activity is modulated by quorum-sensing mechanisms that involve the blp gene cluster, and they possess significant stability under heat and pH variations, making them suitable for biopreservation applications. In food applications, S. thermophilus functions as a Generally Recognized as Safe (GRAS) starter culture in the production of yogurt and cheese, working in conjunction with Lactobacillus delbrueckii subsp. bulgaricus to enhance acidification and improve texture. Specific strains have been identified to mitigate lactose intolerance, antibiotic-related diarrhea, and inflammatory bowel diseases through the modulation of gut microbiota, the production of short-chain fatty acids, and the inhibition of Helicobacter pylori. The genome, characterized by a G + C content of approximately 37 mol%, facilitates advancements in Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas technology and heterologous protein expression, with applications extending to non-dairy fermentations and the development of postbiotics. This review emphasizes the adaptability of S. thermophilus, showcasing the variability among strains and the necessity for thorough preclinical and clinical validation to fully utilize its potential in health, sustainable agriculture, and innovation. It also addresses challenges such as susceptibility to bacteriophages and limitations in proteolytic activity. Full article

Fermented vegetables, which are valued for their distinctive organoleptic properties and nutritional profile, are susceptible to quality deterioration during processing and storage because microorganisms inhabit vegetable raw materials. The metabolic processes of these microorganisms may induce texture degradation, chromatic alterations, flavor diminution, and spoilage. Conventional inactivation methods employing thermal sterilization or chemical preservatives achieve microbial control through nonselective inactivation, inevitably compromising the regional sensory characteristics conferred by indigenous fermentative microbiota. Recent advances in existing antimicrobial technologies offer promising alternatives for selective microbial management in fermented vegetable matrices. Existing modalities, including cold plasma, electromagnetic wave-based inactivation (e.g., photodynamic inactivation, pulsed light, catalytic infrared radiation, microwave, and radio frequency), natural essential oils, and lactic acid bacterial metabolites, demonstrate targeted pathogen inactivation while maintaining beneficial microbial consortia essential for quality preservation when properly optimized. This paper explores the applications, mechanisms, and targeted microbes of these technologies in fermented vegetable ingredients, aiming to provide a robust theoretical and practical framework for the use of selective inactivation strategies to manage the fermentation process. By assessing their impact on the initial microbial community, this review aims to guide the development of methods that ensure product safety while safeguarding the characteristic flavor and quality of fermented vegetables. Full article

Increasing food consumption and waste generation are today’s most difficult economic and environmental challenges. In line with the sustainable production and consumption concept, wasted food, as a source of valuable resources, can be reused to produce new products of higher value than the raw materials from which they were made. This concept was used in this work to design products that are a plant-based alternative to fermented milk drinks, which arouse great interest among consumers due to their health-promoting properties. This study aimed to design potential probiotic beverages from food industry waste, including wheat-rye bread and chokeberry pomace, using lactic acid fermentation with different strains of lactic acid bacteria (LAB) and to evaluate selected quality features of the obtained beverages. In the first stage of the research, the group of LAB strains was tested for their efficiency in bakery waste fermentation, and then the potential probiotic properties of chosen LAB strains (Lactiplantibacillus plantarum A7, Lacticaseibacillus paracasei INV001, Lacticaseibacillus rhamnosus INV002, Lentilactobacillus buchneri P7, Loigolactobacillus coryniformis INV014) were characterized according to FAO/WHO requirements. For the prepared beverages, microbiological quality, antioxidant properties, and the content of polyphenolic compounds were determined. It was found that bakery and chokeberry waste may constitute a good base for obtaining fermented beverages with some beneficial properties, including a high number of potentially probiotic bacteria, reaching 10⁸ CFU/mL, and antioxidant properties, which positively verified their functional properties. The research confirms the high potential of lactic acid fermentation in managing food waste to create innovative, sustainable food products with probiotic properties. Full article

This study aimed to (i) investigate the effect of using grape water in the production of traditional sourdough; (ii) select seeds for use in laboratory-scale sourdough bread production; and (iii) assess the effect of incorporating fresh germinated seeds into recipe of organic sourdough bread on nutritional, technological, and sensory properties. The pH of both control (CSD, flour only) and boosted (BSD, supplemented with “grape water”) sourdough fell below 4.5 by day 3. After 10 days of back-slopping and fermentation, both sourdoughs harbored 9 log CFU/g of lactic acid bacteria, whereas yeast cell density in the CSD was 1 log cycle higher. Based on their high germination rates (~90%), lentil and wheat seeds were selected as additional ingredients (5%). Bread with germinated lentils (GL) and bread with germinated wheat (GW) were compared with control bread (without seeds). GL and GW breads showed gas cell areas of 28.6% and 18.1%, respectively, which were higher than the control. In addition, GL and GW received higher scores for taste (8.6) and softness (5.6), respectively. Additionally, GL contained more proteins (9.9%) and fewer lipids (0.3%) than the two other bread types, in addition to being potentially labeled as a “source of fiber”. Full article