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Principal Coordinate Analysis (PCA) constructed using FactoMineR, factoextra and corrplot R packages. Figure is showing clustering of the feta cheese samples based on fungi diversity (duplicates are included) in genus level. FTI, feta-type cheese with immobilized L. plantarum T571 cells on whey protein; FTF, feta-type cheese with L. plantarum T571 free cells; FTC, feta-type cheese control.
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Background
Cheese microbiome plays a key role in determining the organoleptic and physico-chemical properties and may be also used as an authenticity tool for distinguishing probiotic cultures. Due to significant reduction of cell viability often witnessed during food production processes and storage, immobilization is proposed to ascertain high pr...
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The maturation of a traditional Swedish long-ripened cheese has shown increasing variation in recent years and the ripening time is now generally longer than in the past. While the cheese is reliant on non-starter lactic acid bacteria for the development of its characteristic flavour, we hypothesised that the observed changes could be due to variat...
Citations
... Members of this genus are distributed mainly in aquatic environments; however, because of their adaptive potential, they can also be found in other environments such as soils, plants, fruits, vegetables, birds, reptiles, amphibians, and among others in immuno-compromised humans and children where they can cause diarrhea (Gonçalves Pessoa et al., 2019). Furthermore, due to their psychrotrophic nature, they can thrive in cold-stored foods (Isonhood & Drake, 2002), so it is not surprising that aeromonids have been detected in several kinds of cheese, mainly prepared from raw milk (Abdulaal, 2019;Castellanos-Rozo et al., 2020;Mitropoulou et al., 2022;SAAD et al., 2019). However, the hypothesis of environmental contamination combined with DNA preservation seems to be the most plausible as, to our knowledge, no cases of food poisoning have been reported. ...
... The Shannon index, which measures the diversity of species present in a sample, as well as the Simpson index, which assesses the dominance of species within the sample, were also calculated. Concerning the results, a greater bacterial diversity was observed as a result of the incorporation of immobilized cells in the cheese sample, which has also been noted by Mitropoulou et al. [48]. Of note, increased bacterial diversity can upgrade the nutritional value of fermented foods, given that different microorganisms, utilizing different metabolic pathways, are responsible for the formation of various metabolites, flavors and unique characteristics in the final product [49]. ...
... Of note, increased bacterial diversity can upgrade the nutritional value of fermented foods, given that different microorganisms, utilizing different metabolic pathways, are responsible for the formation of various metabolites, flavors and unique characteristics in the final product [49]. Regarding phyla, Firmicutes was the predominant phylum in all cheese samples, while Bacteroidetes and Proteobacteria were in higher levels in the control cheese compared to the samples with P. acidilactici ORE5 culture, in accordance with previous studies [47,48]. At the genera level, Pediococcus were detected, as expected, in higher percentages in samples with free or immobilized P. acidilactici ORE5 cells compared to the control. ...
... Likewise, Flavobacterium was found only in the control cheese (KC), and it is considered part of natural cheese microflora, while some strains are associated with food spoilage [55]. Overall, NGS technology provides useful information about the microbiome composition of complex ecosystems like cheese, overcoming the limitations of the culture-dependent studies [48,56]. ...
Nowadays, functional foods supplemented with health-promoting microorganisms have attracted consumer attention due to their health benefits. However, maintaining high cell loads, which consist of an essential requirement for conferring the health effect, is a real bottleneck for the food industry due to viability declines during food processing and storage. Hence, freeze-drying and cell immobilization have been suggested to enhance cell viability. The aim of our study was to assess the effect of freeze-dried immobilized P. acidilactici ORE5 on pistachio nuts on the functional regulation of the Katiki Domokou-type cheese microbiome. Supplementation of Katiki Domokou-type cheese with free or immobilized P. acidilactici ORE5 culture resulted in cell loads > 8.5 logcfu/g up to 7 days of storage. Both free and immobilized P. acidilactici ORE5 cells suppressed the growth of L. monocytogenes after deliberate inoculation, acting as a protecting shield. HS-SPME GC/MS analysis showed that the incorporation of P. acidilactici ORE5 culture in cheese resulted in an improved volatile compounds profile, as verified by the preliminary sensory evaluation. According to Next-Generation Sequencing analysis, a wide range of bacterial diversity was revealed among samples. The most abundant genus was Lactococcus in all samples, while the results showed an increased presence of Pediococcus spp. in cheese fortified with P. acidilactici ORE5 culture, highlighting the ability of the strain to survive in the final product. Furthermore, the incorporation of P. acidilactici ORE5 culture in cheese had a significant impact on cheese microbiome composition, as the presence of spoilage bacteria, such as Chryseobacterium, Acinetobacter and Pseudomonas, was significantly less compared to the control cheese, indicating quality improvement and prolongation of the product’s shelf-life.
... In this study, the effect of P. acidilactici ORE5 cells incorporated in Katiki Domokou cheese on the cheese microbiome was investigated after 16S rRNA sequencing. Concerning the results of Shannon and Simpson indices, the greater bacterial diversity as a result of the incorporation of immobilized cells in cheese sample have also been noted by Mitropoulou et al. [46]. Regarding phyla, Firmicutes was the predominant phylum in all cheese samples, while Bacteroidetes and Proteobacteria were in higher levels in control cheese compared to the samples with P. acidilactici ORE5 culture, in accordance with previous studies [45,46]. ...
... Concerning the results of Shannon and Simpson indices, the greater bacterial diversity as a result of the incorporation of immobilized cells in cheese sample have also been noted by Mitropoulou et al. [46]. Regarding phyla, Firmicutes was the predominant phylum in all cheese samples, while Bacteroidetes and Proteobacteria were in higher levels in control cheese compared to the samples with P. acidilactici ORE5 culture, in accordance with previous studies [45,46]. At genera level, Pediococcus were detected, as expected, in higher percentages in samples with free or immobilized P. acidilactici ORE5 cells compared to control. ...
... Likewise, Flavobacterium was found only in the control cheese (KC), and it is considered part of natural cheese microflora, while some strains are associated with food spoilage [53]. Overall, NGS technology provides useful information about the microbiome composition of complex ecosystems like cheese, overcoming the limitations of the culture-dependent studies [46]. ...
Nowadays, functional foods supplemented with health-promoting microorganisms have attracted the consumers attention due to their health benefits. However, maintaining high cell loads, which consists of an essential requirement for conferring the health effect is a real bottleneck for the food industry, due to viability decline during food processing and storage. Hence, freeze-drying and cell immobilization have been suggested to enhance cell viability. The aim of our study was to assess the effect of freeze-dried immobilized P. acidilactici ORE5 on pistachio nuts on functional regulation of Katiki Domokou-type cheese microbiome. Supplementation of Katiki Domokou-type cheese with free or immobilized P. acidilactici ORE5 culture resulted in cell loads > 8.5 logcfu/g up to 7 days of storage. Both free and immobilized P. acidilactici ORE5 cells suppressed the growth of L. monocytogenes after deliberate inoculation, acting as a protecting shield. SPME GC/MS analysis showed that incorporation of P. acidilactici ORE5 culture in cheese resulted in an improved volatile compounds profile, as verified by the preliminary sensory evaluation. According to Next-Generation Sequencing analysis, a wide range of bacterial diversity was revealed among samples. The most abundant genus was Lactococcus in all samples, while the results showed increased presence of Pediococcus spp. in cheese fortified with P. acidilactici ORE5 culture, highlighting the ability of the strain to survive in the final product. Furthermore, the incorporation of P. acidilactici ORE5 culture in cheese had a significant impact on cheese microbiome composition, as the presence of spoilage bacteria, such as Chryseobacterium, Acinetobacter and Pseudomonas, were significantly lower compared to the control cheese, indicating quality improvement and prolongation of the product’s shelf- life.
The term Conjugated Linoleic Acid (CLA) refers generically to a class of positional and geometric conjugated dienoic isomers of linoleic acid. Among the isomers of linoleic acid cis9, trans11-CLA (c9, t11-CLA) and trans10, cis12-CLA (t10, c12-CLA) are found to be biologically active isomers, and they occur naturally in milk, dairy products and meat from ruminants. In addition, some vegetables and some seafoods have also been reported to contain CLA. Although the CLA levels in these natural sources are insufficient to confer the essential health benefits, anti-carcinogenic or anti-cancer effects are of current interest. In the rumen, CLA is an intermediate of isomerization and the biohydrogenation process of linoleic acid to stearic acid conducted by ruminal microorganisms. In addition to rumen bacteria, some other bacteria, such as Propionibacterium, Bifidobacterium and some lactic acid bacteria (LAB) are also capable of producing CLA. In this regard, Lactiplantibacillus plantarum (formerly Lactobacillus plantarum) has demonstrated the ability to produce CLA isomers from linoleic acid by multiple enzymatic activities, including hydration, dehydration, and isomerization. L. plantarum is one of the most versatile species of LAB and the bacterium is widely used in the food industry as a microbial food culture. Thus, in this review we critically analyzed the literature produced in the last ten years with the aim to highlight the potentiality as well as the optimal conditions for CLA production by L. plantarum. Evidence was provided suggesting that the use of appropriate strains of L. plantarum, as a starter or additional culture in the production of some fermented foods, can be considered a critical factor in the design of new CLA-enriched functional foods.
