Search

Abstract: Aims: Selection projects aiming at the identification of new Saccharomyces strains are always on going as the use of the suitable yeast can strongly improve fermented food production, particularly winemaking. They are mainly targeted on Saccharomyces cerevisiae, but other species in the Saccharomyces genus are of interest. For this reason, more and more efficient molecular techniques for yeast identification able to accelerate yeast selection process are always needed. Among the Saccharomyces genus, four yeasts are widespread in natural environments: S. cerevisiae; S. uvarum; S. kudriavzevii and S. paradoxus. Therefore, among the Saccharomyces species, their discrimination is of great interest. Methods and Results: A two‐step protocol is proposed. Firstly the Saccharomyces genus identification is achieved by multiplex PCR analysis. Then, the Saccharomyces species is determined by a new method based on high‐resolution melting analysis (HRMA). Conclusions: For HRMA two primer pairs have been proposed. The first was able to achieve the simultaneous identification of the four widespread Saccharomyces species, the second was used for the unambiguous discrimination of S. cerevisiae within its taxonomical genus. Significance and Impact of the Study: This assay allowed an easy, rapid and simultaneous discrimination of S. cerevisiae, S. uvarum and S. paradoxus during yeast selection programs. [ABSTRACT FROM AUTHOR]

In this work the fermentation performances of seven vineyard strains, together with the industrial strain EC1118, have been investigated at three differing yeast assimilable nitrogen (YAN) concentrations (300 mg N l−1, 150 mg N l−1 and 70 mg N l−1) in synthetic musts. The results indicated that the response to different nitrogen levels is strain dependent. Most of the strains showed a dramatic decrease of the fermentation at 70 mg N l−1 but no significant differences in CO2 production were found when fermentations at 300 mg N l−1 and 150 mg N l−1 were compared. Only one among the vineyard strains showed a decrease of the fermentation when 150 mg N l−1 were present in the must. These results contribute to shed light on strain nitrogen requirements and offer new perspectives to manage the fermentation process during winemaking. Significance and Impact of the Study Selected vineyard Saccharomyces cerevisiae strains can improve the quality and the complexity of local wines. Wine quality is also influenced by nitrogen availability that modulates yeast fermentation activity. In this work, yeast nitrogen assimilation was evaluated to clarify the nitrogen requirements of vineyard strains. Most of the strains needed high nitrogen levels to express the best fermentation performances. The results obtained indicate the critical nitrogen levels. When the nitrogen concentration was above the critical level, the fermentation process increased, but if the level of nitrogen was further increased no effect on the fermentation was found. [ABSTRACT FROM AUTHOR]

Ten commercial plain stirred yogurts, seven produced in Italy, two in Croatia and one in Germany, were analysed. Some relevant chemical characteristics were widely variable among the samples. As regards microbiological composition, Streptococcus thermophilus cells were always numerous, while great fluctuations were found in the Lactobacillus delbrueckii subsp. bulgaricus. A RAPD analysis was performed to evaluate the presence of genetic variability among isolates from different products and a panel test with ten non-trained persons was set up to evaluate some organoleptic characteristics. A statistical analysis conducted to highlight relationships among the parameters tested, revealed that product characteristics seem to be influenced more by the amount of bacteria, particularly Lactobacillus, than by strain diversity. [ABSTRACT FROM AUTHOR]

For over 7 centuries, production of rice (Oryza sativa L.) in Egypt has benefitted from rotation with Egyptian berseem clover (Trifolium alexandrinum). The nitrogen supplied by this rotation replaces 25--33% of the recommended rate of fertilizer-N application for rice production. This benefit to the rice cannot be explained solely by an increased availability of fixed N through mineralization of N-rich clover crop residues. Since rice normally supports a diverse microbial community of internal root colonists, we have examined the possibility that the clover symbiont, Rhizobium leguminosarum bv. trifolii colonizesrice roots endophytically in fields where these crops are rotated, and if so, whether this novel plant-microbe association benefits rice growth. MPN plant infection studies were performed on macerates of surface-sterilized rice roots inoculated on T. alexandrinum as the legume trap host. The results indicated that the root interior of rice grown in fields rotated with clover in the Nile Delta contained ~ 106 clover-nodulating rhizobial endophytes g-1 freshweight of root. Plant tests plus microscopical, cultural, biochemical, and molecular structure studies indicated that the numerically dominant isolates of clover-nodulating rice endophytes represent 3--4 authentic strains of R. leguminosarum bv. trifolii that were Nod+ Fix+ on berseem clover. Pure cultures of selected strains were able to colonize the interior of rice roots grown under gnotobiotic conditions. These rice endophytes were reisolated from surface-sterilized roots and shown by molecular methods to be the same asthe original inoculant strains, thus verifying Koch's postulates. Two endophytic strains of R. leguminosarum bv. trifolii significantly increased shoot and root growth of rice in growth chamber experiments,and grain yield plus agronomic fertilizer N-use efficiency of Giza-175 hybrid rice in a field inoculation experiment conducted in the Nile De [ABSTRACT FROM AUTHOR]

This study explores the biological mechanisms behind colour changes in white wine fermentation using different strains of Starmerella bacillaris. We combined food engineering, genomics, machine learning, and physicochemical analyses to examine interactions between S. bacillaris and Saccharomyces cerevisiae. Significant differences in total polyphenol content were observed, with S. bacillaris fermentation yielding 6 % higher polyphenol content compared to S. cerevisiae EC1118. Genomic analysis identified 12 genes in S. bacillaris with high variant counts that could impact phenotypic properties related to wine color. Notably, SNP analysis revealed numerous missense and synonymous variants, as well as stop-gained and start-lost variants between PAS13 and FRI751, suggesting changes in metabolic pathways affecting pigment production. Besides that, high upstream gene variants in SSK1 and HIP1R indicated potential regulatory changes influencing gene expression. Fermentation trials revealed FRI751 consistently showed high antioxidant activity and polyphenol content (Total Polyphenol: 299.33 ± 3.51 mg GAE/L, DPPH: 1.09 ± 0.01 mmol TE/L, FRAP: 0.95 ± 0.02 mmol TE/L). PAS13 exhibited a balanced profile, while EC1118 had lower values, indicating moderate antioxidant activity. The Weibull model effectively captured nitrogen consumption dynamics, with EC1118 serving as a reliable benchmark. The scale parameter delta for EC1118 was 23.04 ± 2.63, indicating moderate variability in event times. These findings highlight S. bacillaris as a valuable component in sustainable winemaking, offering an alternative to chemical additives for maintaining wine quality and enhancing colours profiles. This study provides insights into the biotechnological and fermented food systems applications of yeast strains in improving food sustainability and supply chain, opening new avenues in food engineering and microbiology., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Green tea kombucha (GTK) is a fermented beverage with promising health benefits, but few studies proved its impact on human health. Thus, we aimed to investigate the impact of GTK on weight loss, inflammation, and salivary microbiota in individuals with excess body weight., Methods: This is a randomized controlled clinical trial that lasted 10 weeks with two groups of individuals with excess body weight: control (CG; n = 29; caloric restriction) and kombucha (KG; n = 30; caloric restriction + 200 mL GTK). Body composition, anthropometry, saliva, and blood collection were performed in the beginning and end of the intervention. Plasma interleukins were determined by flow cytometry. Salivary microbiota was analyzed by 16S rRNA sequencing., Results: Both groups decreased weight, BMI, and body fat ( p < 0.001) after the intervention, but there were no differences between groups. The KG reduced lipid accumulation product (LAP) ( p = 0.029). Both groups decreased IL-1β and IL-8, but IL-6 increased in the CG ( p = 0.023) compared to the kombucha group. Alpha and beta diversity of salivary microbiota increased in the KG. Moreover, the KG presented lower Bacillota/Bacteroidota ratio ( p = 0.028), and BMI was positively associated with the Bacillota phylum., Conclusions: GTK did not enhance weight loss, but it decreased the LAP. GTK helped in the inflammatory profile and induced positive changes in oral microbiota composition., Competing Interests: The authors declare no conflicts of interest.

Over the last few decades, advancements in process safety and quality methods have been significantly improved, yet new challenges continue to emerge in the sustainable food supply chain. This study aimed to investigate some physicochemical and microbiological parameters impacting meat products, particularly cooked sausages, within a sustainable supply chain, focusing on quality, spoilage populations, and syneresis formation under vacuum conditions. A comprehensive analysis was conducted on 355 samples collected over four seasons using high-throughput sequencing (16S/ITS) and microbiological and physicochemical [pH and water activity (a w )] assessments. The microbial growth predictor MicroLab&#95;ShelfLife was employed, and multiple factor analysis (MFA) and agglomerative hierarchical clustering (AHC) were utilized to understand how these variables influence the microbiome resilience of these products. Lactic and acetic acids were correlated with the microbiome of the sausages and the liquid coating covering them using metagenomic analyses. The study highlighted that 52% of the evaluated meat industries in southeastern Brazil are implementing effective protocols for sustainable chain production. The results indicated that the durability of vacuum-packaged cooked sausages was primarily influenced by storage temperature (RV coefficient of 0.906), initial microbial load (0.755), and a w (0.624). Average microbial counts were 4.30 log cfu/g (initial), 4.61 (7°C/4 days), 4.90 (7°C/8 days), 6.06 (36°C/4 days), and 6.79 (36°C/8 days). Seasonal durability analysis revealed that winter had the highest average durability of 45.58 days, while summer had the lowest at 26.33 days. Yeast populations, including Trichosporon sp. and Candida sp., were identified as key genera influencing spoilage dynamics. In addition, Bacillus species emerged as dominant spoilage microorganisms, highlighting the need for new critical controls. This study demonstrates the impact of metagenomic approaches, including ITS and 16S amplicon sequencing, in revealing microbial community dynamics, storage temperature, and a w , which are essential for developing targeted interventions to enhance food safety and quality sustainably., Competing Interests: LM and CA were employed by BRC Ingredientes Ltda. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Lemos Junior, Marques Costa, Alberto Guerra, Sales de Oliveira, Gava Barreto, Alves de Oliveira, Paula, Esmerino, Corich, Giacomini and Guerra.)

The widespread use of copper-based pesticides in winemaking can affect wine fermentation. Therefore, it is crucial to assess the resistance levels of Saccharomyces cerevisiae wine strains in enological growth conditions. In the context of winemaking, grape juice is a complex environment capable of chelating copper and is characterized by a distinctly acidic pH. In this work, the effects of copper concentration on the growth of 10  S. cerevisiae strains, isolated from an enological environment, and one commercial starter were tested in YNB minimal medium and synthetic must, mimicking enological conditions. In minimal medium, resistance to copper varied among yeasts (50-600 μM), revealing the presence of three resistance levels (high, intermediate, and low). Representative strains of the three groups were tested at a pH range from 5.2 to 3.0 at the copper concentration that showed a 20-25 % growth reduction. At pH range 5.2-4.5, a growth reduction was observed, while, conversely, a strain-specific recovery was observed at pH range 3.2-3.0. In synthetic must, the strains showed higher copper resistance levels than in minimal medium (50-4000 μM). In both synthetic must and minimal medium, a significant logarithmic correlation was found between copper resistance and CUP1 gene copy number. The copy number tended to better explain resistance in minimal medium compared to synthetic must. The results shed light on the role of CUP1 copy number within an enological environment., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier Ltd.)

Background: This study explores the biosynthesis, characteristics, and functional properties of exopolysaccharide produced by the strain Liquorilactobacillus mali T6-52. The strain demonstrated significant EPS production with a non-ropy phenotype., Results: The genomic analysis unveiled genes associated with EPS biosynthesis, shedding light on the mechanism behind EPS production. These genes suggest a robust EPS production mechanism, providing insights into the strain's adaptability and ecological niche. Chemical composition analysis identified the EPS as a homopolysaccharide primarily composed of glucose, confirming its dextran nature. Furthermore, it demonstrated notable functional properties, including antioxidant activity, fat absorption capacity, and emulsifying activity. Moreover, the EPS displayed promising cryoprotective activities, showing notable performance comparable to standard cryoprotective agents. The EPS concentration also demonstrated significant freeze-drying protective effects, presenting it as a potential alternative cryoprotectant for bacterial storage., Conclusions: The functional properties of L. mali T6-52 EPS reveal promising opportunities across various industrial domains. The strain's safety profile, antioxidant prowess, and exceptional cryoprotective and freeze-drying characteristics position it as an asset in food processing and pharmaceuticals., (© 2024. The Author(s).)

Wine protein haze formation is a problem due to grape proteins aggregation during wine storage. The cell wall components of wine yeasts, particularly high molecular weight mannoproteins, have a protective effect against haze formation, although their involvement remains poorly understood. This study aimed at characterizing glycosylated proteins released by Starmerella bacillaris and Saccharomyces cerevisiae during single and sequential fermentations in a synthetic must, and testing their impact on wine protein stability. Mannoproteins-rich extracts from sequential fermentations showed an increase in the low MW polysaccharide fraction and, when added to an unstable wine, had a greater effect on protein stability than S. cerevisiae extracts. Shotgun proteomics approaches revealed that the identified cell wall proteins exclusively found in sequential fermentations were produced by both S. bacillaris (MKC7, ENG1) and S. cerevisiae (Bgl2p). Moreover, sequential fermentations significantly increased the expression of Scw4p and 1,3-beta-glucanosyltransferase (GAS5), produced by S. cerevisiae. Finally, some of the key proteins identified might play a positive role in increasing wine protein stability., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Commercial Saccharomyces cerevisiae starters are single-strain cultures widely used in winemaking to optimise the fermentation process and improve the organoleptic quality of wine. Unfortunately, the worldwide extensive use of a limited number of industrial strains led to the standardisation of the sensory properties, reducing the identity of wines. Therefore, the use of multi-strain S. cerevisiae starters can be an alternative tool to alter the sensory profile of wines, increasing the diversity of wine styles. However, this strategy may be interesting only if the overall fermentation kinetics is not affected. To date, there is a lack of information regarding the influence of multi-strain starters on the overall fermentation process in wine. In this context, killer toxins, affecting the viability of sensitive strains, can play a significant role. This study aimed to evaluate the effects of pairing eight wine strains of S. cerevisiae (two sensitive, three neutral and three killer) in co-fermentations compared to single-strain fermentations. Results evidenced that, among co-fermentations where the strain prevalence was significant, the killer strains constituted 79% to 100% of the total yeast population when co-inoculated with a sensitive one. However, in most of the cases, co-fermentations kinetics were similar to those of sensitive strains or worse than both strains. Thus, the presence of a killer strain alone is not sufficient to predict the overall fermentation progress, which is an essential information in winemaking. Interestingly, the neutral strain P304.4 was always prevalent, regardless of the second strain and, in most of the co-fermentations, the overall fermentation trend was similar to the P304.4 single-strain fermentation. Regardless of killer activity, our results suggest that the effect of strains on fermentative kinetics is still unpredictable, and further studies are needed to thoroughly explore strain to strain interactions in winemaking., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Sica et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The biotechnological reuse of winery by-products has great potential to increase the value and sustainability of the wine industry. Recent studies revealed that yeast biomass can be an exciting source of bioactive peptides with possible benefits for human health, and its incorporation in plant-based foods is considered innovative and sustainable. In this study, we aimed to identify, through in silico analyses, potential bioactive peptides from yeast extracts after in vitro digestion. Wine lees from a non-Saccharomyces oenological yeast, Starmerella bacillaris FRI751, Saccharomyces cerevisiae EC1118, and sequential fermentation performed with both strains (SEQ) were recovered in a synthetic must. Cellular pellets were enzymatically treated with zymolyase, and the yeast extracts were submitted to in vitro gastrointestinal digestions. LC-MS/MS sequenced the hydrolyzed peptides, and their potential bioactivity was inferred. S. bacillaris FRI751 fermentation showed 132 peptide sequences, S. cerevisiae EC1118 60, SEQ 89. A total of 243 unique peptide sequences were identified across the groups. Furthermore, based on the peptide sequence, the FRI751 extract showed the highest potential antihypertensive with 275 bioactive fragments. Other bioactivities, such as antimicrobial and immunomodulatory, were also identified in all yeast extracts. A potential antiobesity bioactive peptide VVP was identified only in the yeast extract from S. bacillaris single strain. The wine lees from S. bacillaris single strain and SEQ fermentation are a richer source of potential bioactive peptides than those from S. cerevisiae fermentation. This study opens new possibilities in the valorization of winemaking by-products., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

The present study outlines a comprehensive correlation between the natural microbial load, which is predominantly composed of heat-resistant sporous-forming Bacillus, and the changes in the original properties related to the superficial color of vacuum-packaged cooked sausages. For this purpose, microbial growth curves were plotted by stimulating the growth of the natural microbiota in sausage packages at different temperatures. The correlations were investigated during sample incubation by the instrumental evaluation of color and the ropy slime detection on the sausage surface. The entrance of the natural microbiota into the stationary phase (ca. 9.3 log cfu/g) resulted in changes in the superficial color, which was demonstrated by the discoloration of vacuum-packaged cooked sausages. Therefore, it seems to be a suitable borderline for predictive models applied in durability studies that aim to estimate the period in which vacuum-packaged cooked sausages keep their typical superficial color, anticipating product refusal in markets., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023. Published by Elsevier Ltd.)

Aim: Comprehensive evaluation of antibiotic susceptibility patterns in Lactiplantibacillus plantarum strains isolated from grape marc, based on genomic and phenotypic assessment., Methods and Results: We assessed the antibiotic resistance-susceptibility patterns of 20 L. plantarum strains for 16 antibiotics. Genomes of relevant strains were sequenced for in silico assessment and comparative genomic analysis. Results showed high MIC values for spectinomycin, vancomycin, and carbenicillin, indicating natural resistance to these antibiotics. Besides, these strains revealed MIC values for ampicillin higher than previously established by the EFSA, indicating the possible presence of acquired resistance genes in the genomes. However, genomic analysis by complete genome sequencing did not reveal presence of ampicillin resistance genes., Conclusion: Comparative genomic analysis between our strains and other L. plantarum genomes present in the literature showed several substantial genomic differences, and suggested the need to adjust the cut-off value for ampicillin in L. plantarum. However, further sequence analysis will reveal how these strains have acquired antibiotic resistance., (© The Author(s) 2023. Published by Oxford University Press on behalf of Applied Microbiology International.)

Starmerella bacillaris is a non- Saccharomyces yeast proposed for must fermentation together with Saccharomyces cerevisiae because of its high glycerol and moderate volatile acidity production. Furthermore, it was demonstrated that the same S. bacillaris strains that possess interesting technological properties exhibited antifungal activity against Botrytis cinerea , suggesting the release of this yeast in the vineyard. To obtain a positive effect during the following winemaking process, the maintenance of suitable concentrations of S. bacillaris is essential. Therefore, to obtain information on the survival of S. bacillaris , a small-scale field trial was performed. One week before the harvest, two different concentrations of S. bacillaris (10 6 and 10 7 cells/mL) were sprayed on Pinot grigio bunches, and the strain concentration was monitored by means of qPCR during the subsequent fermentation process. In addition, the combined effect of different winemaking techniques was evaluated, i.e., the vinification of juice, juice with marc and cryomaceration treatment. Results demonstrated that, under the tested conditions, S. bacillaris released in the vineyard remained viable for one week on grape bunches and increased glycerol content during the subsequent fermentation process. Different vinification protocols influenced cell concentrations. In particular, the cryomaceration treatment, due to the use of low temperature, supported S. bacillaris growth due to its cryotolerant aptitude. The collected data open new perspectives on the control of alcoholic fermentation, involving both vineyard and cellar management., Competing Interests: The authors declare no conflicts of interest.

The Western diet can negatively affect the gut microbiota and is associated with metabolic disorders. Kombucha, a tea fermented by a symbiotic culture of bacteria and yeast (SCOBY), is known for its bioactive properties and has become popular in the last years. In this study, we evaluated the effects of regular kombucha consumption on the gut microbiota and on outcomes related to the intestinal health of Wistar rats fed a high-fat high-fructose diet. After eight weeks receiving a standard diet (AIN-93M) (n = 10) or a high-fat and high-fructose diet (HFHF) (n = 30) to induce metabolic disorders, the animals were subdivided into four groups: AIN-93M (n = 10); HFHF (n = 10); GTK (HFHF + green tea kombucha (n = 10); and BTK (HFHF + black tea kombucha; n = 10) for 10 weeks. Although body composition did not differ among the groups, the HFHF diet was associated with metabolic alterations, and stimulated the growth of gram-negative bacteria such as Proteobacteria and Bacteroides . Kombucha ingestion could somewhat modulate the gut microbiota, attenuating the effects of a Western diet by increasing propionate production and favoring the growth of beneficial bacteria, such as Adlercreutzia in the GTK group. Our results suggest that regular kombucha consumption may be beneficial to intestinal health, which can be mostly attributed to its high content and diversity of phenolic compounds.

The use of probiotic microorganisms in food with the aim to confer health benefits to the host is one of the most critical roles of functional foods. Many pediococci bacteria frequently related to the meat environment, have technological properties, and are therefore commercially used as starter in the production of fermented meat products, such as different types of sausages. In this study, different lactic acid bacteria were isolated, identified to the species level, and then evaluated for their safety and functionality as possible probiotics. Different properties, such as resistance to simulated human gastrointestinal conditions, antimicrobial activity, and cholesterol-lowering effects, have been studied. Finally, the complete genome of one strain, namely P. acidilactici IRZ12B, which showed interesting features as a promising probiotic candidate, was sequenced and further studied. The results revealed that IRZ12B possesses interesting probiotic properties, particularly cholesterol-lowering capability and antimicrobial activity. In silico analysis evidenced the absence of plasmids, transmissible antibiotic resistance genes, and virulence factors. We also detected a bacteriocin encoding gene and a cholesterol assimilation-related protein. The phenotypical and genomic outcomes described in this study make P. acidilactici IRZ12B a very interesting cholesterol-lowering potential probiotic strain to be considered for the development of novel non-dairy-based functional foods., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The main objective of this study was to assess the microbiota diversity in milk samples collected from Holstein cows with different estimated breeding values for predicted feed efficiency, milk coagulation, resilience to mastitis, and consequently, to study its effects on milk quality. One hundred and twenty milk samples were collected in two seasons (summer and winter) from different commercial dairy farms in the Nord-east of Italy. For each trait, 20 animals divided into two groups of the high (10 cows) and the low (10 cows) were selected to study the microbiota profile using 16S rRNA metabarcoding sequencing. The alpha and beta diversity analysis revealed significant differences between the high and the low groups for feed efficiency and resilience to mastitis, while no significant difference was detected for milk coagulation. Moreover, remarkable differences among the taxa were detected between the two seasons, where the winter was more diverse than summer when applied the Chao1 index. Lastly, the linear discriminant analysis (LDA) effect size (LEfSe) indicated Aerococcus, Corynebacterium, Facklamia, and Psychrobacter taxa with more abundance in the high group of feed efficiency, whereas, in resilience to mastitis, only two genera of Mycoplana and Rhodococcus were more abundant in the low group. In addition, LEfSe analysis between the seasons showed significant differences in the abundance of Bacteroides, Lactobacillus, Corynebacterium, Escherichia, Citrobacter, Pantoea, Pseudomonas, and Stenotrophomonas. These findings indicate that the different genetic predisposition for feed efficiency and resilience to mastitis could affect the raw milk microbiota and, consequently, its quality. Moreover, we found more abundance of mastitis-associated bacteria in the milk of dairy cows with a higher feed efficiency index., (© 2022. The Author(s).)

Recognized worldwide for its history, flavor, and high nutritional quality, Grana Padano (GP) is one of the most traditional Italian raw-milk, hard-cooked, long-ripened cheese. Throughout GP manufacturing, some well-known and undesired bacterial species, such as clostridia, can proliferate and lead to spoilage defects that mischaracterize the final product; however, little is known about the development of late-blowing defects in hard cheese samples without clostridia. Therefore, in this study we aimed to use metataxonomic analysis to identify bacterial taxa associated with the development of late-blowing defect in GP samples. Furthermore, the presence of several heterofermentative lactobacilli species in defective zones were verified by primer-specific PCR assay. Considering α- and β-diversity analyses, no statistically significant differences were detected between cheese samples with and without blowing defect. Following taxonomic assignment, Lactobacillus and Streptococcus were the dominant genera, whereas clostridia-related taxa were not detected in any of the 20 analyzed samples. Using EdgeR, the genera Propionibacterium and Acinetobacter were found to be prevalently more abundant in samples categorized as having "big regular holes." In samples with "small regular holes," multiplex PCR amplification revealed differences in terms of Lactobacillus population composition, mainly obligate homofermentative lactobacilli, between defective and non-defective zones of the same cheese wheel. This study demonstrated that GP samples with blowing defects not caused by clostridial development share similar biodiversity indices with GP collected from control zones, but an imbalance of obligate homofermentative lactobacilli was noticed between samples, which requires further analysis to better comprehend the exact mechanism involved in this process., (The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Lactic acid bacteria (LAB) have gained particular attention among different exopolysaccharide-producing microorganisms due to their safety status and effects on human health and food production. Exopolysaccharide-producing LAB play a crucial role in different ways, such as improving texture, mouthfeel, controlling viscosity, and for low-calorie food production. In this study, we isolated a multifunctional strain with good exopolysaccharide production properties. Limosilactobacillus fermentum ING8 was isolated from an Indian traditional fermented milk (Dahi) and evaluated for its safety, enzymatic activity, NaCl resistance and temperature tolerance, milk coagulation, and storage stability. Finally, the complete genome of this strain was sequenced and subjected to safety in silico evaluation and genomic analysis. The results revealed that L. fermentum ING8 possesses relevant technological properties, such as exopolysaccharide production, antimicrobial activity, and galactose utilization. Besides, this strain showed very high stability to storage conditions at refrigeration temperature. In addition, the genomic analysis did not evidence any possible deleterious elements, such as acquired antibiotic resistance genes, virulence genes, or hemolysis-related genes. However, all structural genes related to the galactose operon and EPS production were detected. Therefore, L. fermentum ING8 can be considered a promising multifunctional bacterium to be proposed as non-starter in different types of dairy productions.

This paper reports on a common experiment performed by 17 Research Units of the Italian Group of Microbiology of Vine and Wine (GMVV), which belongs to the Scientific Society SIMTREA, with the aim to validate a protocol for the characterization of wine strains of Saccharomyces cerevisiae . For this purpose, two commercial S. cerevisiae strains (EC 1118 and AWRI796) were used to carry out inter-laboratory-scale comparative fermentations using both synthetic medium and grape musts and applying the same protocol to obtain reproducible, replicable, and statistically valid results. Ethanol yield, production of acetic acid, glycerol, higher alcohols, and other volatile compounds were assessed. Moreover, the Fourier transform infrared spectroscopy was also applied to define the metabolomic fingerprint of yeast cells from each experimental trial. Data were standardized as unit of compounds or yield per gram of sugar (glucose and fructose) consumed throughout fermentation, and analyzed through parametric and non-parametric tests, and multivariate approaches (cluster analysis, two-way joining, and principal component analysis). The results of experiments carried out by using synthetic must showed that it was possible to gain comparable results from three different laboratories by using the same strains. Then, the use of the standardized protocol on different grape musts allowed pointing out the goodness and the reproducibility of the method; it showed the main traits of the two yeast strains and allowed reducing variability amongst independent batches (biological replicates) to acceptable levels. In conclusion, the findings of this collaborative study contributed to the validation of a protocol in a specific synthetic medium and in grape must and showed how data should be treated to gain reproducible and robust results, which could allow direct comparison of the experimental data obtained during the characterization of wine yeasts carried out by different research laboratories., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Romano, Siesto, Capece, Pietrafesa, Lanciotti, Patrignani, Granchi, Galli, Bevilacqua, Campaniello, Spano, Caridi, Poiana, Foschino, Vigentini, Blaiotta, Corich, Giacomini, Cardinali, Corte, Toffanin, Agnolucci, Comitini, Ciani, Mannazzu, Budroni, Englezos, Rantsiou, Iacumin, Comi, Capozzi, Grieco and Tufariello.)

Generally, endospore contamination can occur from different sources during product manufacturing in many industries and therefore lower its quality by affecting physicochemical properties and shelf-life. Bacterial endospores can germinate inside the product and produce several enzymes, which can cause several undesirable changes. This study assessed the spores thermal resistance and applied a microwave decontamination technique toward herbal extracts (Tilia tomentosa and Centella asiatica) containing ethanol or glycerol. Based on 16S rRNA analysis, the detected contaminant endospores belonged to different Bacillus species, namely B. subtilis, B. zhangzhouensis, and B. pumilus. The thermal resistance assessment using inoculated endospores in the actual products revealed B. pumilus T2 as the most resistant endospore to the heat treatments tested in both T. tomentosa and C. asiatica extracts. Finally, a high-performance microwave technique was used to decontaminate T. tomentosa extract against the mixture of Bacillus spores. Results from the microwave technique indicate that the increase of temperature from 100°C to 105°C not only decontaminated the product but also could dramatically decrease the effective thermal treatment time (10 times), which can benefit the product quality. The results provided in this study considerably contribute to improving an original decontamination method for products containing glycerol and ethanol with the most negligible effect on product quality., Competing Interests: The authors have declared that no competing interests exist.

The present study evaluated the use of the probiotic Lacticaseibacillus paracasei DTA-83 as a nitrite-reducing agent to produce potentially probiotic or postbiotic pre-converted nitrite from celery. The results obtained were compared to those achieved by direct addition of sodium nitrite for the typical reddish color formation in cooked pork sausages and the inhibitory potential against the growth of target microorganisms, including the clostridia group. Regarding the sausages color, similar findings were observed when comparing the use of pre-converted nitrite from celery produced by L. paracasei DTA-83 and the direct addition of sodium nitrite. Additionally, it presented an inhibitory effect against Salmonella spp., which was not observed with the direct addition of nitrite, revealing a potential strategy to control salmonellosis in the matrix. However, a non-equivalent preservative effect against Clostridium perfringens (INCQS 215) was determined. The results highlight a promising alternative to produce probiotic or postbiotic meat ingredients; however, further studies should be conducted to investigate doses that achieve microbial control., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

A large diversity of yeasts can be involved in alcoholic fermentation; however, Starmerella bacillaris strains have gained great attention due to their relevant and particular characteristics. S. bacillaris is commonly known as an osmotolerant, acidogenic, psychrotolerant, and fructophilic yeast. Most strains of this species are high producers of glycerol and show low ethanol production rates, being highlighted as promising alternatives to the manufacture of low-alcohol beverages. The increased production of high alcohols, such as benzyl alcohol that has antifungal and antibacterial properties, highlights S. bacillaris potential as a biocontrol agent. After harvest, antifungal yeasts become part of the must microbiota and may also improve the fermentation process. Moreover, during the fermentation, S. bacillaris releases important molecules with biotechnological properties, such as mannoproteins and glutathione. Considering the potential biotechnological properties of S. bacillaris strains, this review presents an overview of recent trends concerning the application of S. bacillaris in fermented beverages. KEY POINTS: •S. bacillaris as an alternative to the production of low-alcohol beverages. •S. bacillaris strains present biocontrol potential. •Molecules released by S. bacillaris may be of great biotechnological interest.

We evaluated the effects of the probiotic candidate Lactobacillus paracasei DTA81 (DTA81) on liver oxidative stress, colonic cytokine profile, and gut microbiota in mice with induced early colon carcinogenesis (CRC) by 1,2-dimethylhydrazine (DMH). Animals were divided into four different groups ( n = 6) and received the following treatments via orogastric gavage for 8 weeks: Group skim milk (GSM): 300 mg/freeze-dried skim milk/day; Group L. paracasei DTA81 (DTA81): 3 × 10 9 colony-forming units (CFU)/day; Group Lactobacillus rhamnosus GG (LGG): 3 × 10 9 CFU/day; Group non-intervention (GNI): 0.1 mL/water/day. A single DMH dose (20 mg/kg body weight) was injected intraperitoneally (i.p), weekly, in all animals (seven applications in total). At the end of the experimental period, DTA81 intake reduced hepatic levels of carbonyl protein and malondialdehyde (MDA). Moreover, low levels of the pro-inflammatory cytokines Interleukin-6 (IL-6) and IL-17, as well as a reduced expression level of the proliferating cell nuclear antigen (PCNA) were observed in colonic homogenates. Lastly, animals who received DTA81 showed an intestinal enrichment of the genus Ruminiclostridium and increased concentrations of caecal acetic acid and total short-chain fatty acids. In conclusion, this study indicates that the administration of the probiotic candidate DTA81 can have beneficial effects on the initial stages of CRC development.

"Yellow curd" (YC) is one of the most popular homemade Persian fermented foods and is consumed by many people. Notwithstanding, no studies are available to date on its nutritional and microbiological composition. In this study, we examined YC samples obtained from different local markets of Sistan and Baluchestan province, Iran. The results of the chemical analyses revealed a homogenous content of protein (13.71% ± 1.07), lipids (4.09% ± 0.73), and carbohydrates (61% ± 2.13) among the samples. By comparing the average mineral content of YC with yogurt, many relevant differences were detected. Apart from the calcium content, which was similar on average to that of YC, all other minerals tested are present in higher amounts in YC than in yogurt. The analysis of the main sugars present (i.e., lactose, galactose and glucose) highlighted relevant differences among samples, indicating that different YC samples contain natural strains with different capabilities to metabolize sugars. The concentration of galactose in YC samples should be taken into consideration by galactose intolerant people. From the microbiological perspective, the metagenomics analysis revealed that lactic acid bacteria, and particularly the genera Lactobacillus , Pediococcus , and Streptococcus, were dominant in YC. The information provided shows that YC is an interesting base for the preparation of novel functional foods with a good content of beneficial bacteria.