Publications by authors named "Cinzia Caggia"

42 Publications

Coating Lacticaseibacillus rhamnosus GG in Alginate Systems: an Emerging Strategy Towards Improved Viability in Orange Juice.

AAPS PharmSciTech 2021 Apr 5;22(3):123. Epub 2021 Apr 5.

Department of Agriculture, Food and Environment (Di3A), University of Catania, Via Santa Sofia 100, 95123, Catania, Italy.

Fruit juices are successfully proposed as suitable probiotic vehicles, but researchers' efforts should be developed to avoid effects of bacteria overgrowing on sensory and nutritional cues of final products and to preserve viability of probiotic bacteria during storage. In the present study, encapsulation of Lacticaseibacillus rhamnosus GG strain in alginate systems was performed through ionotropic gelation technology. The alginate systems were optimized by using Box-Behnken Design to investigate the influence of three independent variables at three different levels: particle mean size and polydispersity index. The optimized probiotic-loaded alginate particles were added to orange juice samples. The viability of the probiotic strain, both as free and microencapsulated, was evaluated in orange juice stored at 5°C for 35 days. Morphology and size of probiotic-loaded alginate particles were found suitable for incorporation into juice. TEM analysis revealed that unloaded systems were clustered as nanoparticles (CL_NP), while the loaded sample appeared as a coated system (Coated_LGG). Microbiological evaluation revealed that the encapsulation assured the survival of Coated_LGG, with a reduction of less than 1-unit log in cellular density after 35 days of refrigerated storage in orange juice. Results indicated that the encapsulated bacteria did not affect the macroscopic properties neither the microbiological characteristic of orange juice; thus, it can be proposed as functional food.
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http://dx.doi.org/10.1208/s12249-021-01996-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8021512PMC
April 2021

Microbial Application to Improve Olive Mill Wastewater Phenolic Extracts.

Molecules 2021 Mar 30;26(7). Epub 2021 Mar 30.

Council for Agricultural Research and Economics (CREA), Research Centre for Olive, Fruit and Citrus Crops, 95024 Acireale, Italy.

Olive mill wastewater (OMW) contains valuable and interesting bioactive compounds, among which is hydroxytyrosol, which is characterized by a remarkable antioxidant activity. Due to the health claims related to olive polyphenols, the aim of this study was to obtain an extract from OMW with an increased level of hydroxytyrosol by means of microbial enzymatic activity. For this purpose, four commercial adsorbent resins were selected and tested. The beta-glucosidase and esterase activity of strains of , and were also investigated and compared to those of a commercial enzyme and an strain. The strain showed the best enzymatic performances. The SP207 resin showed the best efficiency in selective recovery of hydroxytyrosol, tyrosol, oleuropein, and total phenols. The bioconversion test of the OMW extract was assessed by using both culture broths and pellets of the tested strains. The results demonstrated that the pellets of and were the most effective in hydroxytyrosol increasing in phenolic extract. The interesting results suggest the possibility to study new formulations of OMW phenolic extracts with multifunctional microorganisms.
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http://dx.doi.org/10.3390/molecules26071944DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8036537PMC
March 2021

Hybridization of Sourdough Strains with Cryotolerant NBRC1948 as a Strategy to Increase Diversity of Strains Available for Lager Beer Fermentation.

Microorganisms 2021 Mar 2;9(3). Epub 2021 Mar 2.

Department of Life Sciences, University of Modena and Reggio Emilia, via Amendola 2, 42122 Reggio Emilia, Italy.

The search for novel brewing strains from non-brewing environments represents an emerging trend to increase genetic and phenotypic diversities in brewing yeast culture collections. Another valuable tool is hybridization, where beneficial traits of individual strains are combined in a single organism. This has been used successfully to create hybrids from parental brewing strains by mimicking natural ale × lager yeast hybrids. Here, we integrated both these approaches to create synthetic hybrids for lager fermentation using parental strains from niches other than beer. Using a phenotype-centered strategy, sourdough strains and the × strain NBRC1948 (also referred to as ) were chosen for their brewing aptitudes. We demonstrated that, in contrast to × crosses, hybridization yield was positively affected by time of exposure to starvation, but not by staggered mating. In laboratory-scale fermentation trials at 20 °C, one triple × × hybrid showed a heterotic phenotype compared with the parents. In 2 L wort fermentation trials at 12 °C, this hybrid inherited the ability to consume efficiently maltotriose from NBRC1948 and, like the sourdough parent, produced appreciable levels of the positive aroma compounds 3-methylbutyl acetate (banana/pear), ethyl acetate (general fruit aroma) and ethyl hexanoate (green apple, aniseed, and cherry aroma). Based on these evidences, the phenotype-centered approach appears promising for designing lager beer hybrids and may help to diversify aroma profiles in lager beer.
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http://dx.doi.org/10.3390/microorganisms9030514DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8000887PMC
March 2021

A clinical pilot study on the effect of the probiotic Lacticaseibacillus rhamnosus TOM 22.8 strain in women with vaginal dysbiosis.

Sci Rep 2021 Jan 28;11(1):2592. Epub 2021 Jan 28.

Department of General Surgery and Medical Surgical Specialties, University of Catania, 95123, Catania, Italy.

Lactobacilli with probiotic features play an essential role in maintaining a balanced vaginal microbiota and their administration has been suggested for the treatment and prevention of vaginal dysbiosis. The present study was aimed to in vitro and in vivo investigate the probiotic potential of the Lacticaseibacillus rhamnosus TOM 22.8 strain, isolated from the vaginal ecosystem of a healthy woman. For this purpose, safety and functional properties were in depth evaluated. The strain exhibited a broad spectrum of antagonistic activity against vaginal pathogens; adhesion capacity to both the vaginal VK2/E6E7 and the intestinal Caco-2 cells; anti-inflammatory and antioxidant activities, suggesting its promising probiotic features. In addition, an in vivo pilot-study was planned. Based on both clinical and microbiological parameters, the oral or vaginal strain administration, determined a significant pathogens reduction after 10 days of administration and a maintenance of eubiosis up to 30 days after the end of the treatment. Therefore, the L. rhamnosus TOM 22.8 strain can be proposed as valuable oral and/or vaginal treatment for vaginal dysbiosis.
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http://dx.doi.org/10.1038/s41598-021-81931-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7843994PMC
January 2021

Adjunct Culture of Non-Starter Lactic Acid Bacteria for the Production of Provola Dei Nebrodi PDO Cheese: In Vitro Screening and Pilot-Scale Cheese-Making.

Microorganisms 2021 Jan 15;9(1). Epub 2021 Jan 15.

Department of Agricultural, Food and Environment, University of Catania, 95123 Catania, Italy.

The present study aimed at selecting non-starter lactic acid bacteria strains, with desirable technological and enzymatic activities, suitable as adjunct culture for the Provola dei Nebrodi cheese production. One hundred and twenty-one lactic acid bacteria, isolated from traditional Provola dei Nebrodi cheese samples, were genetically identified by Rep-PCR genomic fingerprinting, using the (GTG)-primer, and by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS). Twenty-seven strains, included in the qualified presumption of safety (QPS) list, were tested for technological and proteinase/peptidase activities. Results showed that technological features and flavour formation abilities were strain-dependent. Among the selected strains, PN 76 and PN 101 were used as adjunct culture in pilot-scale cheese-making trials. Data revealed that adjunct cultures positively affected the flavour development of cheese, starting from 30 days of ripening, contributing to the formation of key flavour compounds. The volatile organic compound profiles of experimental cheeses was significantly different from those generated in the controls, suggesting that the selected adjunct strains were able to accelerate the flavour development, contributing to a unique profile of Provola dei Nebrodi cheese.
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http://dx.doi.org/10.3390/microorganisms9010179DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7829852PMC
January 2021

The Wide Range of Antibiotic Resistance and Variability of Genotypic Profiles in from Domestic Animals in Eastern Sicily.

Antibiotics (Basel) 2020 Dec 31;10(1). Epub 2020 Dec 31.

Istituto Zooprofilattico Sperimentale of Sicily, 90129 Palermo, Italy.

The emergence of multidrug resistance among Enterobacteriaceae in livestock poses a serious public health threat. , a usual host of intestinal microbiota, is recognized also as etiological agent of numerous infections widespread in both humans and animals. The colibacillosis is one of the most reported zoonoses worldwide, typically treated with antibiotics in the primary stages. This strategy has promoted the onset of antibiotic-resistant serotypes of , reducing the effectiveness of therapeutic treatments and contributing to antibiotic resistance spread. The current study focused on biodiversity, pathogenicity, and antibiotic resistance profile of 104 strains isolated from domestic animals in Eastern Sicily. The strains were isolated from sick animals and carcasses of six different animal species and screened for resistance against 16 antibiotic molecules, as recommended by WHO and OIE. The antibiotic resistance patterns highlighted that all strains were multi-resistant, showing resistance to at least three antibiotic classes. The highest incidence of resistance was observed against amoxicillin (100%), tylosin (97%), sulfamethoxazole (98%), and erythromycin (92%), while the lowest for colistin (8%). The pathotype characterization identified two EPEC strains and the study of genetic linkage (PFGE) showed a wide variety of profiles. The current study emphasized the wide range of multidrug resistance and genotyping profiles in isolated in Easter Sicily.
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http://dx.doi.org/10.3390/antibiotics10010028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7823817PMC
December 2020

Effects of Different Stress Parameters on Growth and on Oleuropein-Degrading Abilities of Strains Selected as Tailored Starter Cultures for Naturally Table Olives.

Microorganisms 2020 Oct 19;8(10). Epub 2020 Oct 19.

Department of Agricultural, Food and Environment, University of Catania, 95123 Catania, Italy.

The use of β-glucosidase positive strains, as tailored-starter cultures for table olives fermentation, is a useful biotechnological tool applied to accelerate the debittering process. Nowadays, strains belonging to species are selected for their high versatility and tolerance to stress conditions. The present study investigated the effect of different stress factors (pH, temperature and NaCl) on growth and on oleuropein-degrading abilities of selected strains. In addition, the presence of the beta-glucosidase gene was investigated by applying a PCR based approach. Results revealed that, overall, the performances of the tested strains appeared to be robust toward the different stressors. However, the temperature of 16 °C significantly affected the growth performance of the strains both singularly and in combination with other stressing factors since it prolongs the latency phase and reduces the maximum growth rate of strains. Similarly, the oleuropein degradation was mainly affected by the low temperature, especially in presence of low salt content. Despite all strains displayed the ability to reduce the oleuropein content, the beta-glucosidase gene was detected in five out of the nine selected strains, demonstrating that the ability to hydrolyze the oleuropein is not closely related to the presence of beta-glucosidase. Data of the present study suggest that is extremely important to test the technological performances of strains at process conditions in order to achieve a good selection of tailored starter cultures for table olives.
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http://dx.doi.org/10.3390/microorganisms8101607DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7590217PMC
October 2020

FoodOmics as a new frontier to reveal microbial community and metabolic processes occurring on table olives fermentation.

Food Microbiol 2020 Dec 1;92:103606. Epub 2020 Aug 1.

Department of Agricultural, Food and Environment, University of Catania, Italy. Electronic address:

Table olives are considered the most widespread fermented food in the Mediterranean area and their consumption is expanding all over the world. This fermented vegetable can be considered as a natural functional food thanks to their high nutritional value and high content of bioactive compounds that contribute to the health and well-being of consumers. The presence of bioactive compounds is strongly influenced by a complex microbial consortium, traditionally exploited through culture-dependent approaches. Recently, the rapid spread of omics technologies has represented an important challenge to better understand the function, the adaptation and the exploitation of microbial diversity in different complex ecosystems, such as table olives. This review provides an overview of the potentiality of omics technologies to in depth investigate the microbial composition and the metabolic processes that drive the table olives fermentation, affecting both sensorial profile and safety properties of the final product. Finally, the review points out the role of omics approaches to raise at higher sophisticated level the investigations on microbial, gene, protein, and metabolite, with huge potential for the integration of table olives composition with functional assessments.
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http://dx.doi.org/10.1016/j.fm.2020.103606DOI Listing
December 2020

Employ of Citrus By-product as Fat Replacer Ingredient for Bakery Confectionery Products.

Front Nutr 2020 16;7:46. Epub 2020 Apr 16.

Di3A - Dipartimento di Agricoltura, Alimentazione e Ambiente, University of Catania, Catania, Italy.

Citrus fruits processing is one of the foremost industrial activities in Sicily and the main residual by-product consists in peels and seeds (known as "pastazzo"). Traditionally this by-product has been used for different purposes, and only most recently, it has been described as source of a wide range of healthy bioactive compounds and dietary fibers. In the present work, a debittered food grade orange fiber (DOF), extracted from orange juice by-product, was experimentally obtained and tested as fat-replacer at different percentages (30, 50, and 70%) in bakery confectionery products (brioches). The DOF showed high total fiber content, low water activity and a high water binding capacity. The obtained bakery products were characterized for nutritional, technological and microbiological parameters through storage at room temperature. Results highlighted that the addition of DOF results in final products with increased moisture content, mainly after 1 day of storage, and good textural proprieties. Furthermore, the fat-replacing strategy, at different levels of DOF, resulted in final products with, besides a constant content of carbohydrates, showed lowered fat content, increased content of dietary fiber and protein. In particular, the 50% fat replacement allowed to obtain brioches with improved technological properties and with desirable microbiological traits, mostly within the first 24 h from production and up to 5 days of storage.
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http://dx.doi.org/10.3389/fnut.2020.00046DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7179755PMC
April 2020

Effects of Microencapsulated Blend of Organic Acids and Essential Oils as a Feed Additive on Quality of Chicken Breast Meat.

Animals (Basel) 2020 Apr 7;10(4). Epub 2020 Apr 7.

Department of Agriculture, Food and Environment (Di3A), University of Catania, Via Valdisavoia, 5, 95123 Catania, Italy.

The present study aims to investigate the effect of dietary supplementation based on a blend of microencapsulated organic acids (sorbic and citric) and essential oils (thymol and vanillin) on chicken meat quality. A total of 420 male Ross 308 chicks were randomly assigned to two dietary treatments: the control group was fed with conventional diet (CON), while the other group received the control diet supplemented with 0.5% of a microencapsulated blend of organic acids and essential oils (AVI). In breast meat samples, intramuscular fat content and saturated/polyunsaturated fatty acids ratio were reduced by AVI supplementation (p < 0.05). Moreover, atherogenic (p < 0.01) and thrombogenic (p < 0.05) indices were lower in AVI than CON treatment. AVI raw meat showed a lower density of psychrotrophic bacteria (p < 0.05) at an initial time, and higher loads of enterococci after 4 days of refrigerated storage (p < 0.05). No contamination of Listeria spp., Campylobacter spp., and Clostridium spp. was found. TBARS values of the cooked meat were lower in the AVI treatment compared to CON (p < 0.01). Among colour parameters, a*, b* and C* values increased between 4 and 7 days of storage in AVI cooked meat (p < 0.05). Overall, organic acids and essential oils could improve the quality and shelf-life of poultry meat.
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http://dx.doi.org/10.3390/ani10040640DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7222737PMC
April 2020

Dietary Supplementation of Tannin-Extracts to Lambs: Effects on Meat Fatty Acids Composition and Stability and on Microbial Characteristics.

Foods 2019 Oct 10;8(10). Epub 2019 Oct 10.

Department of Agriculture, Food and Environment, University of Catania, 95123 Catania, Italy.

Two extracts derived from plant material rich in hydrolysable (Tara, T; ) or condensed (Mimosa, M; ) tannins were added to lamb's diet and their effects on meat quality and on microbial population were evaluated; a diet without tannins represented the Control (C). Meat pH, vitamin E, intramuscular fat content and muscle fatty acid composition were determined. Oxidative stability and microbiological analyses were performed on meat samples after 0, 4 and 7 days of refrigerated storage. Psychrotrophic bacteria were identified through MALDI-TOF MS analysis. Regarding meat fatty acids, Tara treatment decreased the percentage of monounsaturated fatty acids. The counts of all microbial groups were similar among dietary treatments at day 0, while a significant reduction of microbial loads was observed in T-group at day 7. group count was significantly affected by T extract supplementation. The MALDI-TOF MS identification revealed the dominance of species in all samples while , and were revealed only in control ones. In conclusions, the tannin extract supplementation is a promising dietary strategy to preserve lamb meat quality.
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http://dx.doi.org/10.3390/foods8100469DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6836261PMC
October 2019

Piacentinu Ennese PDO Cheese as Reservoir of Promising Probiotic Bacteria.

Microorganisms 2019 Aug 12;7(8). Epub 2019 Aug 12.

Department of Agricultural, Food and Environment, University of Catania, 95123 Catania, Italy.

Piacentinu Ennese is a protected designation of origin (PDO) cheese produced in the surrounding area of Enna (Sicily, Italy), using raw ewe's milk without the addition of any starter cultures. In the present study, the population of Piacentinu Ennese PDO cheese was in vitro screened in order to select promising probiotic strains to be further used in humans. One hundred and sixty-nine lactic acid bacteria (LAB) were isolated from 90 days ripened cheeses and identified by Rep-PCR genomic fingerprinting, using the (GTG)-primer, and by MALDI-TOF MS. One hundred and thirteen (113) isolates belonging to QPS-list species were characterized for both safety and functional properties. All tested isolates were considered safe because none showed either gelatinase, DNase, mucinase, or hemolytic activity. Tolerance to lysozyme, bile salts, and acidic conditions, along with ability to survive under simulated gastrointestinal digestion, were observed. In addition, based on antimicrobial activity against pathogens, cell surface characteristics, Caco-2 adhesion abilities, and anti-inflammatory potential, it was possible to confirm the strain-dependent functional aptitude, suggesting that Piacentinu Ennese PDO cheese may be considered a precious source of probiotic candidates.
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http://dx.doi.org/10.3390/microorganisms7080254DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6723934PMC
August 2019

Beneficial Effects of Pomegranate Peel Extract and Probiotics on Pre-adipocyte Differentiation.

Front Microbiol 2019 3;10:660. Epub 2019 Apr 3.

Dipartimento di Scienze del Farmaco, Sezione di Biochimica, Università di Catania, Catania, Italy.

The beneficial effects of pomegranate are due to the ellagitannins and anthocyanins content, which are protective toward a wide variety of diseases including inflammatory diseases. Many investigators have reported that pomegranate waste (peel and seeds) extracts, made from waste product of industrial processing, show free radical scavenger and a potent antioxidant capacity. Pomegranate extracts (PEs) were also reported to possess noteworty antibacterial, antiviral, hypolipidemic, and anti-inflammatory bioactivities thanks to the polyphenolic compounds content, which includes punicalagins, gallic acid, and ellagic acid derivatives. The focus of the present manuscript was to study the prebiotic potentiality of a PE, soluble in water, and characterized through HPLC-PDA-ESI/MS for its phenolic content. Moreover, since it has been reported that pomegranate extracts decreased the level of lipids in the blood and that a number of probiotic strains have been shown to affect adipogenesis in cell culture, this study was also performed to test the effects of PE and probiotic GG ATCC 53103 strain (LGG) on 3T3-L1 cell line. PE and probiotics substantially reduced the triglyceride content and intracellular lipid increase, compared to the control group. However, the combination treatment of PE and LGG filtered spent broth (SB) was the most effective in reducing triglyceride content and intracellular lipid accumulation. The mRNA expression levels of the main transcriptional factors implicated in adipocyte differentiation were substantially lower in 3T3-L1 cells treated with PE and LGG filtered SB. These results evidenced that a synergistic effect of probiotics and polyphenols contained in PE may affect adipogenesis and may contribute in development of new nutraceutical/probiotic-based remedies to prevent and to treat obesity.
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http://dx.doi.org/10.3389/fmicb.2019.00660DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6456667PMC
April 2019

Detection of vaginal lactobacilli as probiotic candidates.

Sci Rep 2019 03 4;9(1):3355. Epub 2019 Mar 4.

Department of Agricultural, Food and Environment, University of Catania, Catania, Italy.

The vaginal microbiota of healthy women is dominated by lactobacilli, which exerts important health-promoting effects to the host. In the present study, 261 lactobacilli isolated from vagina of healthy women were screened for their potential probiotic characteristics. Safety features (haemolytic activity, antibiotic susceptibility, bile salt hydrolase activity) and functional properties (resistance to low pH and bile salts, lysozyme tolerance, gastrointestinal survival, antagonistic activity against pathogens, hydrophobicity, auto-aggregation, and co-aggregation abilities, hydrogen peroxide production, biofilm formation, exopolysaccharide production, adhesion capacity to both normal human vagina epithelial cells and Caco-2 epithelial cells, and lactic acid production) were in depth evaluated. Seven strains, identified as Lactobacillus rhamnosus, Lactobacillus helveticus and Lactobacillus salivarius fulfilled the criteria described above. Therefore, the vaginal ecosystem represents a suitable source of probiotic candidates that could be used in new functional formulates for both gastrointestinal and vaginal eubiosis.
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http://dx.doi.org/10.1038/s41598-019-40304-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6399336PMC
March 2019

Effect of Molasses and Dried Orange Pulp as Sheep Dietary Supplementation on Physico-Chemical, Microbiological and Fatty Acid Profile of Comisana Ewe's Milk and Cheese.

Front Nutr 2019 5;6. Epub 2019 Feb 5.

Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, Messina, Italy.

The use of agro-industrial by-products for ruminant feed represents both an economical and environmental convenient way for reducing waste discharge and waste management costs for food industries. Large amounts of waste from citrus processing industries are available in Sicily, Italy. In the present study, the effect of dried citrus pulp as sheep dietary supplementation was evaluated on physico-chemical, microbiological and fatty acid composition of resulting milk and cheese. Pelleted feed integrated with molasses and blond orange pulp, replacing cane molasses, beet pulp and part of the maize and sunflower in ration, were administrated to ewes as an experimental treatment The experiment involved sixty Comisana breed sheep divided into two groups and two feeding trials (experimental and control). Ewe's milk and cheese samples were collected from January to April and analyzed for physico-chemical, microbiological and fatty acid profile composition. Results suggested that both the experimental milk and cheese were different from the controls. In particular, an increase of experimental milk yield and fat content were registered whilst the cheese samples exhibited a significant decrease of pH values and an increase in fat and protein contents. In addition, an increase of conjugated linoleic acids as well as of the oxidative stability were observed indicating the beneficial effect of dietary supplementation. Furthermore, among the main microbial groups, the experimental and control samples, no differences were detected. However, with the exception of streptococci, which was found higher in experimental cheeses, and staphylococci, which was significantly reduced by experimental feed. Moreover, the application of culture-independent methods highlighted the dominance of group in the experimental cheese, suggesting a driving role of the dietary supplementation in the cheese microbiota composition. The present study demonstrated that the inclusion of citrus by-products in the diet of small dairy ruminants is a promising feeding, which could positively affect milk composition and cheese manufacture.
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http://dx.doi.org/10.3389/fnut.2019.00001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6370666PMC
February 2019

Effect of Sequential Inoculum of Beta-Glucosidase Positive and Probiotic Strains on Brine Fermentation to Obtain Low Salt Sicilian Table Olives.

Front Microbiol 2019 8;10:174. Epub 2019 Feb 8.

Department of Agricultural, Food and Environment, University of Catania, Catania, Italy.

In the present study, the β-glucosidase positive strain F3. 3 was used as starter during the fermentation of Sicilian table olives (Nocellara Etnea cultivar) at two different salt concentrations (5 and 8%), in order to accelerate the debittering process. The latter was monitored through the increase of hydroxytyrosol compound. In addition, the potential probiotic N24 strain was added after 60 days of fermentation. Un-inoculated brine samples at 5 and 8% of salt were used as control. The fermentation was monitored till 120 days through physico-chemical and microbiological analyses. In addition, volatile organic compounds and sensorial analyses were performed during the process and at the end of the fermentation, respectively. Lactic acid bacteria and yeasts were, in depth, studied by molecular methods and the occurrence of the potential probiotic N24 strain in the final products was determined. Results highlighted that inoculated brines exhibited a higher acidification and debittering rate than control ones. In addition, inoculated brines at 5% of salt exhibited higher polyphenols (hydoxytyrosol, tyrosol, and verbascoside) content compared to samples at 8% of NaCl, suggesting a stronger oleuropeinolytic activity of the starter at low salt concentration. Lactobacilli and yeasts dominated during the fermentation process, with the highest occurrence of and , respectively. Moreover, the potential probiotic N24 strain was able to survive in the final product. Hence, the sequential inoculum of beta-glucosidase positive and potential probiotic strains could be proposed as a suitable technology to produce low salt Sicilian table olives.
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http://dx.doi.org/10.3389/fmicb.2019.00174DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6376858PMC
February 2019

Occurrence, diversity, and persistence of antibiotic resistant enterococci in full-scale constructed wetlands treating urban wastewater in Sicily.

Bioresour Technol 2019 Feb 8;274:468-478. Epub 2018 Dec 8.

Department of Agriculture, Food and Environment (Di3A), University of Catania, Via Santa Sofia 100, Catania 95123, Italy.

Enterococci isolated from different sites of an urban wastewater treatment plant (consisting of three horizontal subsurface flow constructed wetlands) were investigated. One-hundred-thirty isolates were identified at species level and tested for resistance to eleven antibiotics, by microdilution method, and their clonal relatedness was established by SmaI-PFGE analysis. Results highlighted the persistence of enterococcal population in all effluents and the dominance of E. faecium species. A high incidence of antibiotic resistance against erythromycin, chloramphenicol, rifampicin and ampicillin was observed, with 120 strains (93%) showing a multi-drug-resistance. Numerous pulso-types with a unique pattern were detected indicating a high diversity within enterococcal population. The recurrence of some pulso-types in different effluents was disclosed and, within the same pulso-types, different resistance patterns were observed. Comparing the MIC values of strains from inlet and outlet, different trends were observed, highlighting a certain variability among constructed wetlands in affecting the antibiotic resistance among enterococcal population.
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http://dx.doi.org/10.1016/j.biortech.2018.12.017DOI Listing
February 2019

Constructed wetlands combined with disinfection systems for removal of urban wastewater contaminants.

Sci Total Environ 2019 Mar 28;656:558-566. Epub 2018 Nov 28.

Department of Agricultural, Food and Environment (Di3A), University of Catania, Via Santa Sofia 100, Catania 95123, Italy.

The removal efficiency of an urban wastewater treatment plant (WWTP) to obtain an effluent suitable for agriculture reuse was evaluated in a one-year period, taking into account the Italian wastewater limits and the recent European proposal for the minimum requirements water quality for agricultural irrigation. The secondary effluent of WWTP was treated by three full-scale horizontal sub-surface flow (H-SSF) constructed wetlands (CWs), working in parallel, planted with different macrophytes species, and combined with a UV device and a lagooning system running in series. The H-SSF CW system effectively reduced physico-chemical pollutants and its efficiency was steady over the investigation period, while, Escherichia coli densities always exceed the Italian limits required for wastewater reuse in agriculture. The UV system significantly reduced the microbiological indicators, eliminating E. coli, in compliance with the Italian regulation, and somatic coliphages, although a variable efficacy against total coliforms and enterococci, especially in winter season, was achieved. Although the lagooning unit provides a high removal of the main microbial groups, it did not reduce physico-chemical parameters. Even if the overall performance target, for the whole treatment chain, met the recent log reduction (≥5.0), required by the European Commission, the persistence of enterococci, especially in winter season, poses a matter of concern for public health, for the potential risk to serve as a genetic reservoir of transferable antibiotic-resistance.
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http://dx.doi.org/10.1016/j.scitotenv.2018.11.417DOI Listing
March 2019

Enterococcus spp. in Ragusano PDO and Pecorino Siciliano cheese types: A snapshot of their antibiotic resistance distribution.

Food Chem Toxicol 2018 Oct 20;120:277-286. Epub 2018 Jul 20.

Dipartimento di Agricoltura Alimentazione e Ambiente (Di3A), University of Catania, Italy.

In the present study, 110 enterococci were isolated from two Sicilian cheese types, Ragusano PDO and Pecorino Siciliano. Isolates, firstly identified by MALDI-TOF/MS and a multiplex PCR assay, were tested for susceptibility to the most relevant clinical antibiotics. Clonal relationships among isolates were evaluated by pulsed-field-gel electrophoresis (PFGE) analysis and the presence of vanA and vanB genes, in vancomycin resistant enterococci (VRE), was investigated. Overall, E. faecalis, E. durans (35% for each species) and E. faecium (28%) were the major identified species. Different occurrence between cheese types was revealed. Most isolates from Ragusano PDO cheese were identified as E. durans (46%) and/or E. faecalis (43%), while E. faecium (605) was mainly detected in Pecorino Siciliano cheese. High incidence of resistance (97% of total strains) was detected for rifampicin, erythromycin and ampicillin. Moreover, 83 isolates (75%) exhibited multidrug-resistant phenotypes and the one VRE (vanB) isolate was identified as E. durans. PFGE analysis clustered isolates into 22 genotypes and the presence of the same PFGE types, for both E. durans and E. faecalis, in the two cheese types, suggest the link between enterococci and geographical area of production. Results of present study raise concerns about possible role of dairy enterococci as reservoirs of antibiotic resistance.
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http://dx.doi.org/10.1016/j.fct.2018.07.023DOI Listing
October 2018

Fermentation of Nocellara Etnea Table Olives by Functional Starter Cultures at Different Low Salt Concentrations.

Front Microbiol 2018 5;9:1125. Epub 2018 Jun 5.

Department of Agricultural, Food and Environment, University of Catania, Catania, Italy.

Nocellara Etnea is one of the main Sicilian cultivars traditionally used to produce both olive oil and naturally fermented table olives. In the present study, the effect of different salt concentrations on physico-chemical, microbiological, sensorial, and volatile organic compounds (VOCs) formation was evaluated in order to obtain functional Nocellara Etnea table olives. The experimental design consisted of 8 treatments as follow: fermentations at 4, 5, 6, and 8% of salt with (E1-E4 samples) and without (C1-C4 samples) the addition of starters. All the trials were carried out at room temperature (18 ± 2°C) and monitored for an overall period of 120 d. In addition, the persistence of the potential probiotic N24 at the end of the process was investigated. Microbiological data revealed the dominance of lactic acid bacteria (LAB), starting from the 7th d of fermentation, and the reduction of yeasts and enterobacteria in the final product inoculated with starters. VOCs profile highlighted a high amount of aldehydes at the beginning of fermentation, which significantly decreased through the process and a concomitant increase of alcohols, acids, esters, and phenols. In particular, esters showed an occurrence percentage higher in experimental samples rather than in control ones, contributing to more pleasant flavors. Moreover, acetic acid, ethanol, and phenols, which often generate off-flavors, were negatively correlated with mesophilic bacteria and LAB. It is interesting to note that salt content did not affect the performances of starter cultures and slightly influenced the metabolome of table olives. Sensory data demonstrated significant differences among samples registering the highest overall acceptability in the experimental sample at 5% of NaCl. The persistence of the N24 strain in experimental samples, at the end of the process, revealed its promising perspectives as starter culture for the production of functional table olives with reduced salt content.
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http://dx.doi.org/10.3389/fmicb.2018.01125DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5996112PMC
June 2018

Effects of selected bacterial cultures on safety and sensory traits of Nocellara Etnea olives produced at large factory scale.

Food Chem Toxicol 2018 May 3;115:491-498. Epub 2018 Apr 3.

Di3A, Department of Agriculture Food and Environment, University of Catania, Via Santa Sofia 98, 95123 Catania, Italy. Electronic address:

This work investigates the effects of different combinations of selected lactic acid bacteria strains on Lactobacillus species occurrence, on safety and on sensory traits of natural green table olives, produced at large factory scale. Olives belonging to Nocellara Etnea cv were processed in a 6% NaCl brine and inoculated with six different bacterial cultures, using selected strains belonging to Lactobacillus plantarum, Lactobacillus paracasei and Lactobacillus pentosus species. The fermentation process was strongly influenced by the added starters and the identification of lactic acid bacteria isolated throughout the process confirms that L. pentosus dominated all fermentations, followed by L. plantarum, whereas L. casei was never detected. Pathogens were never found, while histamine and tyrosine were detected in control and in two experimental samples. The samples with the lowest final pH values showed a safer profile and the most appreciated sensory traits. The present study highlights that selected starters promote prevalence of L. pentosus over the autochthonous microbiota throughout the whole process of Nocellara Etnea olives.
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http://dx.doi.org/10.1016/j.fct.2018.03.045DOI Listing
May 2018

Polyphasic approach to study physico-chemical, microbiological and sensorial characteristics of artisanal Nicastrese goat's cheese.

Food Microbiol 2018 Apr 13;70:143-154. Epub 2017 Sep 13.

Department of Agricultural, Food and Environment, University of Catania, Italy.

Nicastrese goat's cheese is produced in the South of Italy under traditional procedures, from raw goat milk without any starter cultures addition. Samples from milk to ripened cheese provided by 4 different farms were subjected to a polyphasic approach to study their physico-chemical, microbiological and sensorial characteristics. In addition, volatile organic compounds formation in the final products was studied. Overall, gross composition and microbiological data revealed a significant variability among samples, which was confirmed by both the volatile organic compounds generated in the final products and by the sensorial data. Conventional technique allowed us to identify 720 isolates, mainly belonging to Lactococcus lactis, Lactobacillus plantarum, Lactobacillus casei, Lactobacillus brevis, Leuconostoc mesenteroides, and Enterococcus faecalis. Culture-independent methods revealed shifts in the microbial community structure, with an increase in biodiversity of metabolically active bacterial species, from milk to cheese samples. Analysis of volatile organic compounds (VOCs) allowed the identification of 36 compounds; free fatty acids and ketones represented the main detected, followed by alcohols and esters. Moreover, statistical analysis was performed in order to correlate VOCs to bacterial species. Data showed that ester compounds as well as alcohol and aldehydes were positively correlated to NSLAB, indicating that the occurrence of L. casei, L. plantarum and L. brevis species is relevant for the VOCs formation in the final product.
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http://dx.doi.org/10.1016/j.fm.2017.09.005DOI Listing
April 2018

Bacterial biota of women with bacterial vaginosis treated with lactoferrin: an open prospective randomized trial.

Microb Ecol Health Dis 2017 1;28(1):1357417. Epub 2017 Jan 1.

Department of General Surgery and Medical Surgical Specialties, Gynecological Clinic, University of Catania, Policlinico Universitario, Catania, Italy.

Bacterial vaginosis is the most frequent condition associated to the vaginal microbiota imbalance, affecting about the 40-50% of women in the world. Even if antibiotics are effcetive for bacterial vaginosis treatment a long-term recurrence rates, higher than 70%, is recorded. Lactoferrin is an iron-binding glycoprotein with bacteriostatic and bactericidal properties. It owns the ability to protect the host against infection, by binding and regulating the iron needed for the bacterial proliferation. : The present study was an open prospective randomized trial (registration no. SHI-EVE-2014.01) aimed at characterizing the bacterial biota of women affected by bacterial vaginosis (BV) and assessing the effects of two different lactoferrin concentrations (100 mg and 200 mg vaginal pessaries) on the composition and dynamics of the vaginal bacterial biota. : Sixty women with BV were recruited and randomized into two groups to receive lactoferrin pessaries for 10 days. Clinical evaluation was based on Amsel criteria and Nugent scores. Culture-dependent methods and Ion Torrent PGM sequencing of the 16S rRNA gene were applied to study in depth the overall structure of the vaginal bacterial biota and its dynamics during the treatment. : Vaginal lactoferrin administration modified the vaginal microbiota composition in patients with BV. During treatment, both 100 mg and 200 mg lactoferrin vaginal pessaries significantly decreased the occurrence of bacteria associated with BV, such as , , and , and increased the occurrence species. The bacterial biota balance was maintained up to 2 weeks after treatment only in women treated with 200 mg lactoferrin pessaries. : This study indicates that lactoferrin could be proposed as an alternative therapeutic approach for BV. Our data showed, for the first time, the dominance of species during and after vaginal lactoferrin treatment.
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http://dx.doi.org/10.1080/16512235.2017.1357417DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5614382PMC
January 2017

Survival of potential probiotic lactobacilli used as adjunct cultures on Pecorino Siciliano cheese ripening and passage through the gastrointestinal tract of healthy volunteers.

Int J Food Microbiol 2017 Jul 21;252:42-52. Epub 2017 Apr 21.

Department of Agriculture, Food and Environment (Di3A), University of Catania, Santa Sofia 98, 95123 Catania, Italy.

In the present study, two lactobacilli strains, Lactobacillus rhamnosus H25 and Lactobacillus paracasei N24, used as adjunct cultures, were evaluated for their heat resistance both with and without prior heat adaptation and for their survival, at industrial scale, during the production and ripening of the Pecorino Siciliano cheese. In addition, the viability and persistence of the lactobacilli strains after passage through the gastrointestinal tract of healthy volunteers were evaluated by using rep-PCR analysis of viable cells. Both strains exhibited good heat resistance and survival throughout cheese production and ripening, and positively influenced the physico-chemical, the microbiological and the sensorial characteristics of the final product. In addition, the molecular typing of the lactobacilli isolates, retrieved from fecal samples of healthy volunteers during and after 15 days of the experimental cheese administration, revealed a high survival of the strains, highlighting their persistence during passage into the GI tract. In conclusion, this study proposes the two adjunct cultures as potential probiotic candidate deliverable by cheese.
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http://dx.doi.org/10.1016/j.ijfoodmicro.2017.04.012DOI Listing
July 2017

Microbiota and metabolome during controlled and spontaneous fermentation of Nocellara Etnea table olives.

Food Microbiol 2017 Aug 2;65:136-148. Epub 2017 Feb 2.

Department of Agricultural, Food and Environment, University of Catania, Italy.

This study is aimed to investigate bacterial community and its dynamics during the fermentation of Nocellara Etnea table olives and to study its effect on metabolome formation. Six different combination of bacterial cultures (BC1-BC6) were used as starters for table olive fermentation and one additional process, conducted without addition of any starters, was used as control (C). The processes were conducted in triplicate and, overall, 21 vessels were performed at industrial scale. The fermentation was monitored for 120 days through culture-dependent and -independent approaches. Microbial counts of the main microbial groups revealed slight differences among brine samples, with the exception of LAB counts and Enterobacteriaceae, which were higher and lower, respectively, in most of the inoculated samples than the control ones. In addition, results demonstrated that the use of bacterial cultures (except the BC1), singly or in different combinations, clearly influenced the fermentation process reducing the final pH value below 4.50. When microbiota was investigated through sequencing analysis, data revealed the presence of halophilic bacteria and, among lactobacilli, the dominance of Lactobacillus plantarum group at the initial stage of fermentation, in all brine samples, except in the BC5 in which dominated Lactobacillus casei group. At 60 and 120 days of fermentation, an overturned bacterial ecology and an increase of biodiversity was observed in all samples, with the occurrence of Lactobacillus paracollinoides, Lactobacillus acidipiscis and Pediococcus parvulus. Correlation between bacterial OTU and volatile organic compounds (VOCs) revealed that, aldehydes and alcohol compounds exhibited a positive correlation with Proteobacteria, while several esters with LAB and Hafnia. In particular, esters, associated with fruity and floral notes, were positively correlated to L. paracollinoides, L. acidipiscis, and P. parvulus species. Although the VOCs amounts were sample-specific, overall aldehydes were mostly produced at the beginning of the fermentation, while acids, alcohols and esters at the end of the process.
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http://dx.doi.org/10.1016/j.fm.2017.01.022DOI Listing
August 2017

Influence of PDO Ragusano cheese biofilm microbiota on flavour compounds formation.

Food Microbiol 2017 Feb 13;61:126-135. Epub 2016 Sep 13.

Department of Agricultural, Food and Environment, University of Catania, via Santa Sofia 98, 95124 Catania, Italy.

The objectives of the present study were to characterize the biofilm microbiota of 11 different farms (from A to K), producing PDO Ragusano cheese, and to investigate on its ability to generate volatile organic compounds (VOCs) in milk samples inoculated with biofilm and incubated under Ragusano cheese making conditions. The biofilms were subjected to plate counting and PCR/T/DGGE analysis and the VOCs generated in incubated milk samples were evaluated through SmartNose, GC/O, and GC/MS. Streptococcus thermophilus was the dominant species both in biofilms and in incubated milks. Lactobacillus, Lactococcus, Enterococcus and Leuconostoc were also identified. Low levels of Pseudomonas spp. and yeasts counts were detected, whereas coliforms, Listeria monocytogenes and Salmonella spp., were never found. SmartNose and GC/O analyses were able to differentiate incubated milk samples on the basis of the odour compounds, highlighting that samples E and F overlapped and sample C was clearly separated from the others. These results complied with those acquired by GC/MS analysis, that detected in total 20 VOCs. Principal component analysis showed positive correlations (r > 0.6; P < 0.05) between some lactic acid bacteria (LAB) and VOCs: such as Enterococcus hirae with alcohols, Lactococcus lactis, Lactobacillus plantarum, Lactobacillus casei and Lactobacillus delbrueckii with aldehydes, and Lactobacillus fermentum, Lactobacillus helveticus and Lactobacillus hilgardii with ketones. This work demonstrates that biofilm represents an excellent source of LAB biodiversity, which contribute to generate VOCs during the production of PDO Ragusano cheese.
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http://dx.doi.org/10.1016/j.fm.2016.09.006DOI Listing
February 2017

A large factory-scale application of selected autochthonous lactic acid bacteria for PDO Pecorino Siciliano cheese production.

Food Microbiol 2016 Oct 18;59:66-75. Epub 2016 May 18.

Dipartimento Scienze Agrarie e Forestali, Università degli Studi di Palermo, Viale delle Scienze Ed. 5, 90128 Palermo, Italy.

The main hypothesis of this study was that the autochthonous lactic acid bacteria (LAB) selected for their dairy traits are able to stabilize the production of PDO (Protected Denomination of Origin) Pecorino Siciliano cheese, preserving its typicality. The experimental plan included the application of a multi-strain lactic acid bacteria (LAB) culture, composed of starter (Lactococcus lactis subsp. lactis CAG4 and CAG37) and non starter (Enterococcus faecalis PSL71, Lactococcus garviae PSL67 and Streptococcus macedonicus PSL72) strains, during the traditional production of cheese at large scale level in six factories located in different areas of Sicily. The cheese making processes were followed from milk to ripened cheeses and the effects of the added LAB were evaluated on the microbiological, chemico-physical and sensorial characteristics of the final products. Results highlighted a high variability for all investigated parameters and the dominance of LAB cocci in bulk milk samples. The experimental curds showed a faster pH drop than control curds and the levels of LAB estimated in 5-month ripened experimental cheeses (7.59 and 7.27 Log CFU/g for rods and cocci, respectively) were higher than those of control cheeses (7.02 and 6.61 Log CFU/g for rods and cocci, respectively). The comparison of the bacterial isolates by randomly amplified polymorphic DNA (RAPD)-PCR evidenced the dominance of the added starter lactococci over native milk and vat LAB, while the added non starter LAB were found at almost the same levels of the indigenous strains. The sensory evaluation showed that the mixed LAB culture did not influence the majority of the sensory attributes of the cheeses and that each factory produced cheeses with unique characteristics. Finally, the multivariate statistical analysis based on all parameters evaluated on the ripened cheeses showed the dissimilarities and the relationships among cheeses. Thus, the main hypothesis of the work was accepted since the quality parameters of the final cheeses were stabilized, but all cheeses maintained their local typicality.
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http://dx.doi.org/10.1016/j.fm.2016.05.011DOI Listing
October 2016

Comparative genomic and functional analysis of 100 Lactobacillus rhamnosus strains and their comparison with strain GG.

PLoS Genet 2013 15;9(8):e1003683. Epub 2013 Aug 15.

Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland.

Lactobacillus rhamnosus is a lactic acid bacterium that is found in a large variety of ecological habitats, including artisanal and industrial dairy products, the oral cavity, intestinal tract or vagina. To gain insights into the genetic complexity and ecological versatility of the species L. rhamnosus, we examined the genomes and phenotypes of 100 L. rhamnosus strains isolated from diverse sources. The genomes of 100 L. rhamnosus strains were mapped onto the L. rhamnosus GG reference genome. These strains were phenotypically characterized for a wide range of metabolic, antagonistic, signalling and functional properties. Phylogenomic analysis showed multiple groupings of the species that could partly be associated with their ecological niches. We identified 17 highly variable regions that encode functions related to lifestyle, i.e. carbohydrate transport and metabolism, production of mucus-binding pili, bile salt resistance, prophages and CRISPR adaptive immunity. Integration of the phenotypic and genomic data revealed that some L. rhamnosus strains possibly resided in multiple niches, illustrating the dynamics of bacterial habitats. The present study showed two distinctive geno-phenotypes in the L. rhamnosus species. The geno-phenotype A suggests an adaptation to stable nutrient-rich niches, i.e. milk-derivative products, reflected by the alteration or loss of biological functions associated with antimicrobial activity spectrum, stress resistance, adaptability and fitness to a distinctive range of habitats. In contrast, the geno-phenotype B displays adequate traits to a variable environment, such as the intestinal tract, in terms of nutrient resources, bacterial population density and host effects.
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http://dx.doi.org/10.1371/journal.pgen.1003683DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3744422PMC
March 2014

Comparative genomic and functional analysis of Lactobacillus casei and Lactobacillus rhamnosus strains marketed as probiotics.

Appl Environ Microbiol 2013 Mar 11;79(6):1923-33. Epub 2013 Jan 11.

Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland.

Four Lactobacillus strains were isolated from marketed probiotic products, including L. rhamnosus strains from Vifit (Friesland Campina) and Idoform (Ferrosan) and L. casei strains from Actimel (Danone) and Yakult (Yakult Honsa Co.). Their genomes and phenotypes were characterized and compared in detail with L. casei strain BL23 and L. rhamnosus strain GG. Phenotypic analysis of the new isolates indicated differences in carbohydrate utilization between L. casei and L. rhamnosus strains, which could be linked to their genotypes. The two isolated L. rhamnosus strains had genomes that were virtually identical to that of L. rhamnosus GG, testifying to their genomic stability and integrity in food products. The L. casei strains showed much greater genomic heterogeneity. Remarkably, all strains contained an intact spaCBA pilus gene cluster. However, only the L. rhamnosus strains produced mucus-binding SpaCBA pili under the conditions tested. Transcription initiation mapping demonstrated that the insertion of an iso-IS30 element upstream of the pilus gene cluster in L. rhamnosus strains but absent in L. casei strains had constituted a functional promoter driving pilus gene expression. All L. rhamnosus strains triggered an NF-κB response via Toll-like receptor 2 (TLR2) in a reporter cell line, whereas the L. casei strains did not or did so to a much lesser extent. This study demonstrates that the two L. rhamnosus strains isolated from probiotic products are virtually identical to L. rhamnosus GG and further highlights the differences between these and L. casei strains widely marketed as probiotics, in terms of genome content, mucus-binding and metabolic capacities, and host signaling capabilities.
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http://dx.doi.org/10.1128/AEM.03467-12DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3592221PMC
March 2013

Diversity of bacterial population of table olives assessed by PCR-DGGE analysis.

Food Microbiol 2012 Oct 8;32(1):87-96. Epub 2012 May 8.

Dipartimento di Scienze delle Produzioni Agrarie e Alimentari, University of Catania, Catania, Italy.

Nocellara Etnea and Geracese table olives are produced according to traditional process, in which lactic acid bacteria (LAB) and yeasts are the dominant microorganisms. With the aim to evaluate the effect of selected starter cultures on dynamics of bacterial population during fermentation and on growth/survival of Listeria spp. artificially inoculated into the olive brine, a polyphasic approach based on the combination of culturing and PCR-DGGE analysis was applied. Plating results showed a different concentration of the major bacterial groups considered among cultivars and the beneficial effect of LAB starters, which clearly inhibited Enterobacteriaceae. Moreover, results indicated that the brine conditions applied did not support the growth/survival of Listeria monocytogenes strain, artificially inoculated, highlighting the importance of selecting right fermentation parameters for assuring microbiological safety of the final products. Comparison of DGGE profile of Nocellara Etnea and Geracese table olives, displayed a great difference among cultivars, revealing a wide biodiversity within Lactobacillus population during Geracese olives fermentation. Based on cloning and sequencing of the most dominant amplicons, the presence, among others, of Lactobacillus paracollinoides and Lactobacillus coryniformis in Geracese table olives was revealed in table olives for the first time.
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http://dx.doi.org/10.1016/j.fm.2012.04.013DOI Listing
October 2012