Exploitation of Black Olive (Olea europaea L. cv. Piantone di Mogliano) Pomace for the Production of High-Value Bread.

In this study, the morpho-textural features, total phenolic content (TPC), and antioxidant capacity (AOC) of bread fortified with olive (Olea europaea L.) pomace were evaluated. Fresh olive pomace was subjected to microbiological and chemical (TPC, AOC, and fiber) analyses; then, the same olive pomace was analyzed during 1 to 6 months of storage at 4 °C or -20 °C. All olive pomace samples were used in 10%, 15%, or 20% amounts to produce type 0 soft wheat (Triticum aestivum) and whole wheat bread samples. The volatile organic compounds (VOCs) in the bread samples were also analyzed to assess the effect of the addition of the olive pomace on the flavor profile of the baked products. The TPC and AOC evaluation of olive pomace showed no differences among the analyzed samples (fresh, refrigerated, or frozen). Regarding the bread containing olive pomace, the specific volume was not affected by the amount or the storage methods of the added pomace. Bread samples produced with soft wheat flour showed the lowest hardness values relative to those produced with whole wheat flour, irrespective of the amount or storage method of the olive pomace. Regarding color, the crust and crumb of the bread samples containing 20% olive pomace were significantly darker. The bread samples containing 20% olive pomace had the highest TPC. The bread samples with fresh olive pomace were characterized by terpenoids, ketones, and aldehydes, whereas the bread samples containing refrigerated olive pomace were characterized by alcohols (mainly ethanol), acids, esters, and acetate. Finally, the bread samples with frozen olive pomace showed a volatile profile similar to that of bread produced with fresh olive pomace. Olive pomace was shown to be a suitable ingredient for producing bread with high nutritional value.

Search for carbapenem-resistant bacteria and carbapenem resistance genes along swine food chains in Central Italy.

The presence of carbapenem-resistant bacteria and carbapenem resistance genes (CRGs) in livestock is increasing. To evaluate the presence of carbapenemase-producing Enterobacteriaceae (CPE) and the main CRGs along swine food chains of the Marche Region (Central Italy), samples of faeces, feed, and animal-food derived products were collected from seven small/medium, medium, and large-scale pig farms. A total of 191 samples were analysed using a culture-dependent method, with the aim of isolating CPE. Isolates were analysed for their resistance to carbapenems using a modified Hodge test and the microdilution method for the minimum inhibitory concentration (MIC) determination. Moreover, the extraction of microbial DNA from each sample was performed to directly detect selected CRGs via qPCR. Among the 164 presumptive resistant isolates, only one strain from a liver sample, identified as Aeromonas veronii, had an ertapenem MIC of 256 µg/mL and carried a carbapenemase- (cphA) and a ß-lactamase- (blaOXA-12) encoding genes. A low incidence of CRGs was found; only nine and four faecal samples tested positive for blaNDM-1 and blaOXA-48, respectively. Overall, the importance of monitoring CPE and CRGs in livestock and their food chains should be stressed to control all potential non-human CPE and CRGs reservoirs and to determine safety levels for human health.

Spotlight on autochthonous microbiota, morpho-textural characteristics, and volatilome of a traditional Polish cold-smoked raw sausage.

The aim of the present study was to obtain information on the bacterial diversity of traditional Polish cold-smoked raw sausages (Kielbasa polska wedzona) manufactured by two artisanal producers using different selective growth media and a metataxonomic analysis. Physico-chemical and morpho-textural characteristics were also carried out, together with Microextraction-Gas Chromatography/Mass Spectrometry (HS-SPMEGC/MS) to study the volatile organic compounds (VOCs). The results overall obtained allowed a picture of the microbiota, the morpho-textural characteristics, and the volatilome of traditional Polish cold-smoked raw sausages (Kielbasa polska wedzona) to be drawn for the first time. In more detail, viable counting revealed active populations of presumptive lactobacilli, enterococci, coagulase-negative cocci, and a few spoilage microorganisms typically occurring in raw meat products. The metataxonomic analysis revealed the dominance of Latilactobacillus sakei occurring with a relative frequency between 77% and 89%. Pediococcus pentosaceus, Weissella hellenica, and Leuconostoc carnosum were detected among the minority taxa. In the sausages herein studied, no histamine levels of concern were detected. The Principal Component Analysis (PCA) performed on the Amplicon Sequence Variants (ASVs) did not show significant differences in the microbiota composition among producers. The HS-SPMEGC/MS analysis allowed the detection and identification of more than 90 volatile components belonging to ten main classes, namely: aldehydes, ketones, esters and acetates, acids, alcohols, phenols, furans, sulphur compounds, terpenoids, and benzene derivatives. The detected VOCs originated from spices, smoke, and microbial metabolism. The PCA of volatile compounds allowed differences between the sausage samples of the two producers to be identified.

Fermented fish and fermented fish-based products, an ever-growing source of microbial diversity: A literature review.

Fermented fish and fermented fish-based products are part of the diet of many countries all over the world. Their popularity is not only due to the unique flavor, the distinct texture, and the good nutritional quality, but also to the easiness of the production process, that is commonly based on empirical traditional methods. Fish fermentation techniques ususally rely on the combination of some key steps, including salting, addition of spices or additives, and maintenance of anaerobic conditions, thus selecting for the multiplication of some pro-technological microorganisms. The objective of the present review was to provide an overview of the current knowledge of the microbial communities occurring in fermented fish and fish-based products. Specific information was collected from scientific publications published from 2000 to 2022 with the aim of generating a comprehensive database. The production of fermented fish and fish-based foods was mostly localized in West African countries, Northern European countries, and Southeast Asian countries. Based on the available literature, the microbial composition of fermented fish and fish-based products was delineated by using viable counting combined with identification of isolates, and culture-independent techniques. The data obtained from viable counting highlighted the occurrence of microbial groups usually associated with food fermentation, namely lactic acid bacteria, staphylococci, Bacillus spp., and yeasts. The identification of isolates combined with culture-independent methods showed that the fermentative process of fish-based products was generally guided by lactobacilli (Lactiplantibacillus plantarum, Latilactobacillus sakei, and Latilactobacillus curvatus) or Tetragenococcus spp. depending on the salt concentration. Among lactic acid bacteria populations, Lactococcus spp., Pediococcus spp., Leuconostoc spp., Weissella spp., Enterococcus spp., Streptococcus spp., and Vagococcus spp. were frequently identified. Staphylococcus spp. and Bacillus spp. confirmed a great adaptation to fermented fish-based products. Other noteworthy bacterial taxa included Micrococcus spp., Pseudomonas spp., Psychrobacter spp., Halanaerobium spp., and Halomonas spp. Among human pathogenic bacteria, the occurrence of Clostridium spp. and Vibrio spp. was documented. As for yeast populations, the predominance of Candida spp., Debaryomyces spp., and Saccharomyces spp. was evidenced. The present literature review could serve as comprehensive database for the scientific community, and as a reference for the food industry in order to formulate tailored starter or adjunctive cultures for product improvement.

Microbial Dynamics of a Specialty Italian Raw Ewe's Milk Cheese Curdled with Extracts from Spontaneous and Cultivated Onopordum tauricum Willd.

Milk coagulants prepared by maceration of flowers harvested from both spontaneous and cultivated Onopordum tauricum Willd. and a commercially available coagulant obtained from Cynara cardunculus L. (control) were assayed for small-scale manufacturing of Caciofiore, an Italian specialty raw ewe's milk cheese produced in a family run dairy farm located in the Marche region (Central Italy). The microbiota of the three thistle-based milk coagulants and their effect on the microbial dynamics of raw milk cheeses during fermentation and maturation (from day 0 up until day 60) were investigated through a combined approach based on viable counting and Illumina DNA sequencing. In both the control and experimental cheeses, despite the slight differences emerged depending on the coagulant used, Lactococcus lactis and Debaryomyces hansenii were the prevalent species among bacteria and fungi, respectively. Moreover, raw ewe's milk was the main factor affecting the evolution of both the bacterial and fungal microbiota in all cheeses. The overall similarities between control and experimental cheeses herein analyzed supports the exploitation of Onopordum tauricum Willd. as an alternative milk coagulating agent for production of Caciofiore and, more in general, raw ewe's milk cheeses.

Staphylococcus aureus artificially inoculated in mealworm larvae rearing chain for human consumption: Long-term investigation into survival and toxin production.

The present research reports the results of a long-term study (70 days) of the dynamics of Staphylococcus aureus artificially inoculated in a Tenebrio molitor rearing chain for human consumption. To this end, a rearing substrate consisting of organic wheat middlings was spiked with S. aureus to obtain three initial contamination levels, namely 1 (low level), 5 (medium level) and 7 (high level) Log colony forming unit per gram. Microbial viable counting coupled with metataxonomic analysis were performed to evaluate: i) the persistence and growth of S. aureus in the rearing substrate; ii) the colonization and growth of S. aureus in the insect larvae; iii) the occurrence and load of S. aureus in the frass (excrement from larvae mixed with substrate residues); iv) the presence of S. aureus enterotoxins in the rearing substrate, frass, and larvae. The results of the present study highlighted that wheat middlings contaminated with S. aureus do not represent a suitable environment for the multiplication of the pathogen, irrespective of the initial contamination level. Of note, frass originated from the larvae reared on contaminated wheat middlings might potentially represent a source of S. aureus, with cell loads depending on the initial contamination level. A complex resident microbiota was revealed by metataxonomic analysis. Interestingly, co-occurrence/co-exclusions analysis did not reveal associations between the target microorganism and the microbiota of wheat middlings, larvae, or frass. Considering safety aspects of larvae, the results overall collected suggested that, under the applied conditions, T. molitor represents an inhospitable or even hostile environment for S. aureus, with this latter showing counts below the detection limit in the larvae at the end of the 70-day rearing trial, irrespective of the initial contamination level. The results also suggested that a combination of bactericidal factors, including unfavorable environmental conditions (such as low aw of wheat middlings and frass), might have established in the rearing chain. Finally, the absence of staphylococcal toxins suggests that, even when S. aureus is present at high contamination levels, it is not able to produce toxins in wheat middlings, larvae, or frass.

Fate of Escherichia coli artificially inoculated in Tenebrio molitor L. larvae rearing chain for human consumption.

The edible insect food chain represents a relatively novel food-producing system; hence, associated biological risks still need to be exhaustively evaluated. In the present study, the dynamics of Escherichia coli during the whole living period of Tenebrio molitor larvae (from eggs to pupae) were studied. To this end, a rearing substrate consisting of organic wheat middlings was spiked with E. coli cells at two initial contamination levels: 1 log cfu g-1 (low) and 6 log cfu g-1 (high). Microbial viability counting coupled with metataxonomic analyses was used to assess i) the persistence and growth of E. coli in the rearing substrate (wheat middlings); ii) the colonization and growth of E. coli in the insect larvae; and iii) the occurrence and load of E. coli in the frass (excrement from larvae mixed with substrate residues). The results highlighted a very limited persistence of the pathogen in all analyzed samples. In more detail, the results suggested that when E. coli was present at very low levels in the eggs of the insect, the pathogen was not able to reach concerning levels in the larvae. Moreover, when E. coli was present in the wheat middlings used for rearing, the environmental conditions of the substrate (low aw values) were not favorable for its survival and multiplication, irrespective of the presence of the larvae and their frass. Surprisingly, under the conditions applied in the present study, the larvae fed wheat middlings contaminated with E. coli seemed to be inhospitable or even hostile environments for microbial survival or multiplication. To explain the low levels of E. coli cells in the larvae reared in the present study, many factors can be considered, including the immune response of the host, microbial composition and interactions established in the gut of larvae, and insect species. Of note, part of the major fraction of the microbiota of larvae at the end of rearing was represented by Lactococcus, thus suggesting a possible effect of this lactic acid bacterium on E. coli decay. Further research is needed to better clarify the interactions between E. coli and the insect gut, as well as the interactions established among the target microorganism and those naturally harbored by the insect gut.

Unfolding microbiota and volatile organic compounds of Portuguese Painho de Porco Preto fermented sausages.

In the present study, bacterial and fungal diversity, as well as volatile profiles, of ready-to-eat Portuguese Painho de Porco Preto fermented sausages manufactured by two artisanal producers in the districts of Beja (producer A) and Evora (producer B) were studied. To this end, different selective growth media and a metataxonomic analysis were combined with Headspace Solid-Phase Microextraction-Gas Chromatography/Mass Spectrometry (HS-SPME-GC/MS) analysis. The results of the microbiological viable counts revealed active microbial populations of lactic acid bacteria (up to 8 Log cfu g-1), coagulase negative cocci (up to 6 Log cfu g-1), and eumycetes (up to 6 Log cfu g-1). Bacterial populations were characterized by high relative frequencies of Latilactobacillus sakei (up to 72%), together with Weissella and Staphylococcus equorum. The mycobiota was mainly dominated by Debaryomyces hansenii (up to 55% of the relative frequency) and Kurtzmaniella zeylanoides (up to 24% of the relative frequency). Unexpected species as Wickerhamomyces subpelliculosus and Zygosaccharomyces rouxii were also detected. HS-SPME-GC/MS analysis allowed to identify a complex volatile profile, showing 159 volatile organic compounds (VOCs). VOCs belonged to twelve classes, such as aldehydes, ketones and lactones, esters and acetates, alcohols, terpenoids, sulfur compounds, aliphatic hydrocarbons, aromatic hydrocarbons, nitrogen compounds, acids, furans and pyrans, and phenols. The analysis of VOCs composition provided evidence that samples from the two producers (A and B) were different, as confirmed by the Principal Component Analysis. Hence, it is likely that the raw materials used, as well as variations related with the empirical practice of the butchers, strongly influenced the final product. The results obtained in the present study represent a further advancement in the knowledge on the biodiversity and VOCs composition of Portuguese fermented sausages. To better understand the interactions occurring between the autochthonous microorganisms and the meat batter in the Painho de Porco Preto fermented sausage, microbial and VOCs dynamics must be further deepened throughout the production process.

Profiling of autochthonous microbiota and characterization of the dominant lactic acid bacteria occurring in fermented fish sausages.

The use of fish flesh to produce fermented sausages is uncommon, especially in European countries where fermented sausages are mainly obtained using mammalian meat. In the present study, the microbiota naturally occurring in novel fermented fish sausages, handcrafted using marine fish species caught in the Mediterranean Sea, was studied. To this end, fish sausages were subjected to physico-chemical analyses (including histamine quantification). Microbiological traits of sausages were studied via viable counting and metataxonomic analysis. Sausages were also subjected to the detection of genes encoding histidine decarboxylase of both Gram-positive (hdcA) and -negative (hdc) bacteria. The results of histamine quantification showed different contents among fish sausage samples. Moreover, the presence of the hdcA gene was below the detection limit in all the samples, whereas the hdc gene was detected only in samples from batch 2, characterized by high levels of Enterobacteriaceae. In the analysed samples, viable lactic acid bacteria, coagulase-negative staphylococci, and eumycetes were detected. Bacterial composition displayed the highest frequency of Latilactobacillus sakei, whereas eumycetic composition displayed the highest frequency of Kurtzmaniella zeylanoides. In order to select potential adjunct cultures for product improvement, 60 lactic acid bacteria (22 isolates of L. sakei and 38 of Latilactobacillus curvatus) were isolated from sausage samples and characterized for: i) the presence of the hdcA gene; ii) the production of exopolysaccharides (EPS); iii) the presence of genes involved in the production of EPS; iv) the production of bacteriocins against Listeria innocua. None of the isolates tested positive for the presence of the hdcA gene. Moreover, 39 out of 60 isolates showed the formation of mucoid colonies, thus attesting the production of EPS. Interestingly, 56 out of 60 isolates were positive for the gene epsD/E, whereas 37 out of 60 isolates were positive for the gene epsA, all these genes encoding the production of heteropolysaccharides. Of note, the EPS production capability and the absence of hdcA gene could represent a starting point for future selection of the isolates as autochthonous adjunct cultures to improve texture, sensory traits and safety of the fermented fish sausages under study. None of the L. sakei or L. curvatus isolates exerted a bactericidal effect against L. innocua.

Unravelling microbial populations and volatile organic compounds of artisan fermented liver sausages manufactured in Central Italy.

The aim of the present study was to obtain information on the occurrence of bacteria and eumycetes in ready-to-eat fermented liver sausages manufactured by 20 artisan producers located in the Marche Region (Italy). To this end, culture-dependent analyses and metataxonomic sequencing were carried out. Physico-chemical parameters and volatilome of the fermented liver sausages were also studied. Finally, the presence of hepatitis E virus (HEV) was also assessed via real-time-RT-(q)PCR assays. Active microbial populations mainly represented by lactic acid bacteria, enterococci, coagulase-negative cocci, and eumycetes were detected. Enterobacteriaceae, Pseudomonadaceae, and sulfite-reducing anaerobes were not detected in most of the samples. Latilactobacillus sakei dominated in all the analyzed samples, reaching abundances up to 80%. Staphylococcus xylosus and Staphylococcus equorum were also detected. Among minority bacterial taxa, Weissella spp., Leuconostoc spp., Macrococcus caseolyticus, Brochothrix thermosphacta, Staphylococcus succinus, Lactobacillus coryniformis, Lactiplantibacillus plantarum, Lactococcus garviae, Psychrobacter spp., and Carnobacterium viridans were detected. The mycobiota was mainly composed by Debaryomyces hansenii that was present in all samples at the highest frequency. Among minority fungal taxa, Aspergillus spp., Penicillium spp., Kurtzmaniella zeylanoides, Candida spp., Yamadazyma spp., Scopulariopsis spp., Yarrowia spp., and Starmerella spp. were detected. Interestingly, associations between some taxa and some physico-chemical parameters were also discovered. The absence of HEV in all the samples attested a high level of safety. Finally, most of the VOCs detected in the analyzed fermented liver sausages belonged to six classes as: terpenoids, aldehydes, ketones, alcohols, esters, and acids. Nitrogen compounds, sulfur compounds, phenols, hydrocarbons, lactones, furans, and aromatic hydrocarbons were also identified. Several significant relationships were observed between mycobiota and VOCs.

Tetracycline Resistance Genes in the Traditional Swedish Sour Herring surströmming as Revealed Using qPCR.

Antibiotic resistance (AR) represents a global concern for human health. To the best of the authors' knowledge, no study addressing AR in surströmming, a traditional Swedish fermented herring, has been performed to date. The aim of the present research was to study the prevalence of tet(O), tet(S), tet(W), tet(K), and tet(M) genes encoding for resistance to tetracycline using quantitative PCR (qPCR) applied to ready-to-eat surströmming samples collected from three producers located in Sweden. The tet(M) gene was found in all the analyzed samples, and it was also the most abundant among the tested tet genes; moreover, tet(O) was the least frequently detected gene. As a general trend, all the analyzed samples showed a high occurrence of the target genes, with slight variations among the producers. A principal component analysis did not reveal any separation among the samples or producers. All the collected data allowed for a drawing of a first picture of the occurrence of tetracycline resistance genes in ready-to-eat surströmming samples. Since no differences among the samples manufactured by the different producers were observed, it is likely that the detected genes were homogeneously spread among the microbial species shared by the herrings used as raw materials. Moreover, it can be hypothesized that the presence of the detected genes was also the result of a selective pressure of the natural marine environment on the herrings' gut microbiota and, hence, on the pro-technological microorganisms responsible for the fermentation of surströmming. However, the contribution of the manufacturers to the contamination of the processed herrings cannot be excluded.

Microbial communities and volatile profile of Queijo de Azeitão PDO cheese, a traditional Mediterranean thistle-curdled cheese from Portugal.

The production of ovine or caprine milk cheeses with thistle rennet is a common practice in the Mediterranean basin. The aim of the present study was to obtain information on bacteria and yeast communities harboured by Queijo de Azeitão PDO cheese through viable counting and, for the first time, via metataxonomic analysis. Moreover, solid phase microextraction (SPME) technique was applied to characterize Queijo de Azeitão PDO cheese volatile compounds. Nine cheese samples were collected from three different artisan producers located in Portugal. The results of physico-chemical analyses showed significant differences between producers, with mean values ranging from 5.40 ±â€¯0.25 (Producer 1) to 6.00 ±â€¯0.22 (Producer 2). As for TTA, Producer 1 showed the highest mean value attesting at 18.04 ±â€¯6.57 mL of 0.1 M NaOH used to reach pH 8.3. Regarding lactic acid concentration, Producer 1 showed the highest mean value attesting at 0.488 ±â€¯0.106 g 100 g-1, whereas, for acetic acid, no significant differences were evidenced among producers with values comprised between 0.141 ±â€¯0.021 g 100 g-1 and 0.245 ±â€¯0.016 g 100 g-1. No significant differences were observed between overall mean values of the three producers for viable counts of presumptive lactococci, thermophilic cocci, presumptive lactobacilli, thermophilic lactobacilli and total mesophilic aerobes with values in the order of 7-8 log cfu g-1. Moreover, no significant differences were evidenced for viable counts of coagulase-negative cocci, enterococci, Enterobacteriaceae and Pseudomonadaceae. As for eumycetes, cheeses from Producer 1 showed the lowest mean value (2.78 ±â€¯2.42 log cfu g-1) in respect with values detected in cheeses from Producer 2 and 3. Concerning microbiota and mycobiota of the analyzed cheeses, the alpha diversity index did not show any significant difference between the three producers in terms of composition and complexity of the microbial population. A simple composition was apparently shared by the three producers, whose cheese manufactures were dominated by the presence of Leuconostoc mesenteroides (37% of the relative frequency in average), Lactococcus lactis (29%), Lacticaseibacillus zeae (4.7%), Lentilactobacillus kefiri (4.4%), Serratia spp. (3.5%), Lactiplantibacillus plantarum (2.7%), and Latilactobacillus sakei (2.5%). The mycobiota composition showed the neat dominance of Yarrowia lipolytica (46.7% of the relative frequency in average), followed by Candida ethanolica (13.6%), Kurtzmaniella zeylanoides (9.4%), Geotrichum candidum (8.8%), Galactomyces geotrichum (8.7%), Kluyveromyces lactis (3.5%), and Geotrichum silvicola (2.7%). The volatile profile analysis allowed 24 different compounds to be identified: 7 acids, 7 esters, 4 alcohols, 3 ketones, 2 aromatic hydrocarbons, and 1 aldehyde. The most represented volatile organic compounds (VOCs) were 2-butanone, butanoic acid and hexanoic acid. A positive correlation between Len. kefiri and hexanoic acid and isopentyl isobutyrate was observed (P < 0.05), whereas Y. lipolytica displayed the highest number of positive correlations with 3-methyl-butanal, 2-pentanone and 2-pentanol (P < 0.05). To the authors' knowledge, this is the very first detection of Len. kefiri in a raw ewe's milk cheese coagulated with vegetable rennet.

Prevalence of Histidine Decarboxylase Genes of Gram-Positive Bacteria in Surströmming as Revealed by qPCR.

Histamine is a degradation product of the bacterial decarboxylation of the amino acid histidine; such activity is determined by histidine decarboxylase encoded by a gene cluster, carried by some Gram-positive bacteria, that includes the hdcA gene. In this study, the presence of the hdcA gene in ready-to-eat surströmming samples collected from three producers based in Sweden was directly assessed via qPCR analysis for the very first time. Samples from producer A showed hdcA average gene abundance of 6.67 ± 0.13 Log cells/gene copies g-1; in samples from producer B the average value attested at 5.56 ± 0.06 Log cells/gene copies g-1, whereas for samples of producer C hdcA average gene abundance attested at 5.30 ± 0.08 Log cells/gene copies g-1. ANOVA showed a significantly higher average hdcA gene copy number in samples from producer A, whereas no significant differences were seen between average values of hdcA gene copy numbers detected in samples from producer B and C. The hdcA gene copies detected in the present study could give an estimation of the load of potential histamine-producing bacteria in surströmming.

The Microbial Diversity of Non-Korean Kimchi as Revealed by Viable Counting and Metataxonomic Sequencing.

Kimchi is recognized worldwide as the flagship food of Korea. To date, most of the currently available microbiological studies on kimchi deal with Korean manufactures. Moreover, there is a lack of knowledge on the occurrence of eumycetes in kimchi. Given these premises, the present study was aimed at investigating the bacterial and fungal dynamics occurring during the natural fermentation of an artisan non-Korean kimchi manufacture. Lactic acid bacteria were dominant, while Enterobacteriaceae, Pseudomonadaceae, and yeasts progressively decreased during fermentation. Erwinia spp., Pseudomonasveronii, Pseudomonasviridiflava, Rahnellaaquatilis, and Sphingomonas spp. were detected during the first 15 days of fermentation, whereas the last fermentation phase was dominated by Leuconostoc kimchi, together with Weissellasoli. For the mycobiota at the beginning of the fermentation process, Rhizoplaca and Pichia orientalis were the dominant Operational Taxonomic Units (OTUs) in batch 1, whereas in batch 2 Protomyces inundatus prevailed. In the last stage of fermentation, Saccharomyces cerevisiae, Candida sake,Penicillium, and Malassezia were the most abundant taxa in both analyzed batches. The knowledge gained in the present study represents a step forward in the description of the microbial dynamics of kimchi produced outside the region of origin using local ingredients. It will also serve as a starting point for further isolation of kimchi-adapted microorganisms to be assayed as potential starters for the manufacturing of novel vegetable preserves with high quality and functional traits.

Portuguese cacholeira blood sausage: A first taste of its microbiota and volatile organic compounds.

Among typical Portuguese sausages, the cacholeira blood sausage undoubtedly represents one of the most popular preparations. To the authors' knowledge, a lack of information on both the microbiota and the volatile organic compounds (VOCs) of this blood-containing sausage emerges from the available scientific literature. This study represents the first characterization of physico-chemical, microbiological and volatile traits of Portuguese cacholeira blood sausage. To this end, ready-to-eat cacholeira blood sausages were collected from two production batches manufactured in summer (batch 1) and autumn (batch 2). Viable counts showed active microbial communities mainly composed by lactic acid bacteria, coagulase negative cocci, enterococci and eumycetes. The metataxonomic approach showed a simple bacterial composition, which was dominated by Lactobacillus sakei in both the analyzed batches (1 and 2) considered. Carnobacterium, Enterococcus, Kluyvera, Lactococcus and Serratia were found as minor genera. The mycobiota varied according to the production season. Batch 1 was dominated by Starmerella apicola, Debaryomyces hansenii and Candida tropicalis, whereas batch 2 was dominated by D. hansenii. Moreover, Aspergillus spp., Kurtzmaniella zeylanoides, Saccharomyces cerevisiae, Kurtzmaniella santamariae, Brettanomyces bruxellensis and Pichia kluyveri were detected in both the batches as minority species. Seventy-two volatile compounds were identified, including esters, phenols, terpenoids, acids, alcohols, ketones, aldehydes, lactones, furans, sulphur and nitrogen compounds. Significant differences were seen in the amount of some compounds, as a feasible consequence of differences in the raw materials, artisan production and seasonality.

Selection of cereal-sourced lactic acid bacteria as candidate starters for the baking industry.

The quality of sourdough bread mainly depends on metabolic activities of lactic acid bacteria (LAB). The exopolysaccharides (EPS) produced by LAB affect positively the technological and nutritional properties of the bread, while phytases improve the bioavailability of the minerals by reducing its phytate content. In the present study, a pool of 152 cereal-sourced LAB were screened for production of phytases and EPS for potential use as sourdough starter cultures for the baking industry. There was large heterogeneity in the phytase activity observed among the screened isolates, with 95% showing the ability to degrade sodium phytate on plates containing Sourdough Simulation Medium (SSM). The isolates Lactobacillus brevis LD65 and Lactobacillus plantarum PB241 showed the highest enzymatic activity, while the isolates ascribed to Weissella confusa were characterized by low or no phytase activity. Only 18% of the screened LAB produced EPS, which were distinguished as ropy or mucoid phenotypes on SSM supplemented with sucrose. Almost all the EPS producers carried one or more genes (epsD/E and/or epsA) involved in the production of heteropolysaccharides (HePS), whereas the isolates ascribed to Leuconostoc citreum and W. confusa carried genes involved in the production of both HePS and homopolysaccharides (HoPS). Monosaccharide composition analysis of the EPS produced by a selected subset of isolates revealed that all the HePS included glucose, mannose, and galactose, though at different ratios. Furthermore, a few isolates ascribed to L. citreum and W. confusa and carrying the gtf gene produced ß-glucans after fermentation in an ad hoc formulated barley flour medium. Based on the overall results collected, a subset of candidate sourdough starter cultures for the baking industry was selected, including Lb. brevis LD66 and L. citreum PB220, which showed high phytase activity and positive EPS production.

Discovering microbiota and volatile compounds of surströmming, the traditional Swedish sour herring.

In this study, the microbiota of ready-to-eat surströmming from three Swedish producers were studied using a combined approach. The pH values of the samples ranged between 6.67 ± 0.01 and 6.98 ± 0.01, whereas their aw values were between 0.911 ± 0.001 and 0.940 ± 0.001. The acetic acid concentration was between 0.289 ± 0.009 g/100 g and 0.556 ± 0.036 g/100 g. Very low concentrations of lactic acid were measured. Viable counting revealed the presence of mesophilic aerobes, mesophilic lactobacilli and lactococci as well as halophilic lactobacilli and lactococci, coagulase-negative staphylococci, halophilic aerobes and anaerobes. Negligible counts for Enterobacteriaceae, Pseudomonadaceae and total eumycetes were observed, whereas no sulfite-reducing anaerobes were detected. Listeria monocytogenes and Salmonella spp. were absent in all samples. Multiplex real-time PCR revealed the absence of the bont/A, bont/B, bont/E, bont/F, and 4gyrB (CP) genes, which encode botulinic toxins, in all the samples analyzed. Metagenomic sequencing revealed the presence of a core microbiota dominated by Halanaerobium praevalens, Alkalibacterium gilvum, Carnobacterium spp., Tetragenococcus halophilus, Clostridiisalibacter spp. and Porphyromonadaceae. Psychrobacter celer, Ruminococcaceae, Marinilactibacillus psychrotolerans, Streptococcus infantis and Salinivibrio costicola were detected as minor OTUs. GC-MS analysis of volatile components revealed the massive presence of trimethylamine and sulphur compounds. Moreover, 1,2,4-trithiolane, phenols, ketones, aldehydes, alcohols, esters and long chain aliphatic hydrocarbons were also detected. The data obtained allowed pro-technological bacteria, which are well-adapted to saline environments, to be discovered for the first time. Further analyses are needed to better clarify the extent of the contribution of either the microbiota or autolytic enzymes of the fish flesh in the aroma definition.

Lesser mealworm (Alphitobius diaperinus) powder as a novel baking ingredient for manufacturing high-protein, mineral-dense snacks.

Increasing interest in consuming foods that are high in protein, vitamin, amino acid, and mineral contents is steering growth in the market for fortified snacks. The aim of the present study was to evaluate the use of lesser mealworm (Alphitobius diaperinus) powder (LP) (at 10 or 30% substitution for wheat flour) for the protein and mineral fortification of crunchy snacks (rusks). Hence, the technological, microbiological, nutritional, and sensory characteristics of the fortified rusks were evaluated. The protein content was enriched up to 99.3% in rusks with 30% substitution; moreover, a notable increase in the essential amino acids content was observed, with histidine fortification reaching up to 129.1% in rusks with 30% substitution. The incorporation of LP has led to an enrichment of almost all the minerals considered here, and especially Fe, P and Zn, with Zn showing fortification percentages of up to 300% in rusks with 30% substitution for LP. The experimental rusks showed pleasant sensory traits and low aw values. In view of the potential industrial manufacturing of insect-based rusks, the proposed product can be assigned to level 4 (validation in a laboratory environment) of the Technology Readiness Level (TRL) scale, and it is thus ready to be tested in a simulated production environment.

Is there any still undisclosed biodiversity in Ciauscolo salami? A new glance into the microbiota of an artisan production as revealed by high-throughput sequencing.

Ciauscolo is a fermented sausage with the Protected Geographical Indication (PGI) status. To disclose the microbial ecology of a model Ciauscolo salami manufacture during its natural fermentation, viable counting, amplicon-based sequencing and real-time PCR were applied. The volatilome during fermentation was also characterized. The results allowed previously undetected species to be discovered. The core microbiota was composed by Lactobacillus algidus, Leuconostoc carnosum, Lactobacillus sakei, Debaryomyces hansenii, Glomus hyderabadensis, Tilletiopsis washingtonensis, and Kurtzmaniella zeylanoides. Salmonella spp. and Listeria monocytogenes were absent in all the samples; moreover, multiplex real-time PCR revealed the absence of the target genes bont/A, bont/B, bont/E, bont/F, and 4gyrB (CP), encoding botulinic toxins. Volatilome, deeply depending on microbiological metabolism, was characterized by spices-derived components. Limonene, sabinene, α- and ß-pinene, 3-carene, and α-thujene were the most represented monoterpene hydrocarbons, whereas ß- and α-copaene were the most represented sesquiterpene hydrocarbons. Allyl methyl sulphide and diallyl disulphide were the major aliphatic sulphur compounds, together with diallyl sulphide and allyl methyl disulphide.