CoRFiLaC

Ragusa, Italy
Ragusa, Italy
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Carpino S.,CoRFiLaC | Randazzo C.L.,University of Catania | Pino A.,University of Catania | Russo N.,CoRFiLaC | And 3 more authors.
Food Microbiology | Year: 2017

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. © 2016 Elsevier Ltd


Aissaoui Zitoun O.,University of Mentouri Constantine | Carpino S.,CoRFiLaC | Fuca N.,CoRFiLaC | Mansour M.L.,Ferhat Abbas University Setif | And 2 more authors.
Springer Proceedings in Physics | Year: 2017

Scanning electron microscopy and confocal laser scanning microscopy (CLSM) were used to visualize changes in the microstructure of a goatskin bag cheese “Bouhezza” during manufacturing and ripening. The exceptional cheesemaking process is based on the successive addition of salted fermented milk “Lben” in the goatskin bag for few weeks and then adding raw milk at the end of ripening. The SEM observation shows a proteinic aggregates organised in an open space matrix in which lipids and whey are entrapped in the proteinic mass. We observe the limits of micelles where caseins are not completely fused between them. During the manufacturing the semi-liquid structure of the Lben change to a gel structure and the formed cheese grows rich out of proteins and its structure becomes denser, specially marked enter the first and the third week of manufacturing. Then and to 6 weeks, the structure of cheese does not changed and the proteinic network became just more dense. This structure allows the continuous draining of the whey through the perforations of the goatskin. The CLSM shows the same observation. © Springer International Publishing AG 2017.


Pino A.,University of Catania | Van Hoorde K.,Ghent University | Pitino I.,University of Catania | Russo N.,University of Catania | And 3 more authors.
International Journal of Food Microbiology | Year: 2017

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. © 2017


Licitra G.,University of Catania | Carpino S.,CoRFiLaC
Microbiology Spectrum | Year: 2014

Approximately 39 Italian cheeses carry protected designation of origin (PDO) status. These cheeses differ in their manufacturing technology and the microbial flora which comprise the finished products. The evolution of lactic microflora in cheeses with PDO status is of particular interest because the biochemical activities of these organisms participate in cheesemaking and may play an acknowledged role in the development of organoleptic characteristics during ripening. Nonstarter lactic acid bacteria (NSLAB) constitute complex microbial associations that are characterized by the occurrence of various species and many biotypes as a result of a number of selective conditions persisting during the manufacturing process and different ecological niches. The evolution of different species during ripening of Fiore Sardo showed that, when present, Lactobacillus paracasei persists and dominates the microflora of the cheese in the last period of ripening, suggesting that this species, more resistant to the constraints of the mature cheese, could be involved in proteolysis and in other enzymatic processes occurring during cheese ripening. In contrast, the stretching step typical of pasta filata cheese, such as Ragusano, induced a simplification of the raw milk profiles, allowing the persistence only of some predominant species, such as Streptococcus thermophilus, Lactobacillus delbrueckii subsp. lactis, Lactococcus lactis, and Streptococcus macedonicus, after the stretching step. Lactobacillus plantarum and L. paracasei were isolated from ripened Castelmagno PDO cheese samples with the highest frequencies. These species, generally absent in the milk, occur in dairy ecosystems and dominate the bacterial flora of many ripened semihard cheeses. In PDO long-ripened Italian cheese such as Parmigiano Reggiano, the NSLAB population is mainly formed by L. paracasei, Lactobacillus rhamnosus, and Pediococcus acidilactici. Lactobacillus helveticus, L. delbrueckii subsp. lactis, and L. delbrueckii subsp. © 2014 American Society for Microbiology.


Licitra G.,CoRFiLaC | Licitra G.,University of Catania
Dairy Science and Technology | Year: 2010

Traditional cheeses are characterized by strong links to their territory of origin and are testimonial of the history and the culture of the community that produces them. Every traditional cheese originates from a complex system which results in unique organoleptic characteristics. The development of these unique characteristics is linked to several biodiverse factors: the environment, the climate, the natural pasture, the breed of the animals, the use of raw milk and its natural microflora, the cheesemaking technology with the unique role of human beings rather than automated technology, historical tools as well as the natural aging conditions. In many countries traditional products are almost banned, even in Europe, despite Article 8 of the Directive 92/46 of the EEC, which grants derogations for the manufacture of cheese with a period of aging or ripening of at least 60 days. Issues relating to "food safety" are frequently given as a "false" argument to explain the banning of traditional products. Reviews of food safety outbreaks have demonstrated that raw-milk cheeses do not pose any greater risk than industrial cheeses made from pasteurized milk. Improper pasteurization, post-processing contamination, storage and cross-contamination are the main contributing factors that are responsible for these outbreaks. Traditional cheeses cannot be identified simply by the use of "raw milk"; there are a "multiplicity of practices" that have the potential to make safe products. The challenge for the research community is to demonstrate the role and the importance of those practices to deliver the maximum safety benefits to the consumer. Eliminating the production of traditional cheeses would make it much easier to market industrial products. However, consumers would lose the opportunity to compare the natural aroma, the health benefits, the cultural background as well as the biodiversity of traditional products. © INRA, EDP Sciences, 2010.


La Terra S.,CoRFiLaC | Marino V.M.,CoRFiLaC | Manenti M.,CoRFiLaC | Licitra G.,CoRFiLaC | And 2 more authors.
Dairy Science and Technology | Year: 2010

Polyunsaturated fatty acids and lipo-soluble vitamins in the milk are considered as neutraceutical compounds due to their beneficial effects on human health. The aim of the present study was to evaluate the changes in fatty acid composition and fat-soluble antioxidant content in plasma and milk from cows fed with different dietary proportions from pasture. Cows from a farm in the Hyblean mountain region in Italy were randomly divided into three groups (12 animals per group): CTRL fed only a total mix ration (TMR); 30P fed a TMR supplemented with 30% dry matter (DM) from pasture and 70P fed a TMR supplemented with 70% DM of pasture. Blood and milk samples were collected, stored and analysed for their content of fatty acids and fat-soluble antioxidants. Fatty acid profiles were significantly modified by different diets. CLA, vaccenic acid (VA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) significantly (P < 0.05) increased in plasma as a function of the proportion of pasture added to the diet. In agreement with these data, a progressively significant (P < 0.05) increase in concentrations of VA, CLA and EPA was observed in the milk. Such changes in fatty acid composition were accompanied by a concomitant increase in the concentrations of α-tocopherol and β-carotene in both plasma and milk. The increase in EPA, DHA and CLA, β-carotene and α-tocopherol in plasma may not only have a beneficial impact for milk and meat quality, but may also result in an increased protection against inflammatory events. © INRA, EDP Sciences, 2010.


Fuca N.,CoRFiLaC | McMahon D.J.,Utah State University | Caccamo M.,CoRFiLaC | Tuminello L.,CoRFiLaC | And 4 more authors.
Journal of Dairy Science | Year: 2012

Composition and physical properties of cheeses are influenced by temperature, salt, and calcium concentration of brine. This work aimed to examine conditions of brine under which the cheese matrix contracts or expands in absence of restrictions imposed by surface rind development during overnight block formation. Three experimental 4-kg blocks of Ragusano cheese were produced at 3 different stretching temperatures (70, 80, and 90°C) and cut into pieces weighing approximately 40 to 50. g. One piece from each was chemically analyzed at time 0. All other pieces were measured for weight and volume and placed in plastic bags containing 300. mL of different brine solutions (2% NaCl with 0.1% Ca; 10% NaCl with 0, 0.1, 0.2, or 0.4% Ca; 18% NaCl with 0.1% Ca; and 26% NaCl with 0.1% Ca) at 3 different temperatures (4, 12, and 20°C). After 24. h of brining, the cheeses were analyzed for weight, volume, chemical, and microstructural changes. Salt concentration in brine significantly influenced composition, weight, and volume of the cheeses after brining. Salt concentration was inversely related to cheese volume and weight. Changes in weight caused by altering the brining temperature were sufficient to reach statistical significance, and statistically significant volume changes were induced by brining temperature and its interaction with salt content. The highest volume increase (30%) occurred in the cheese stored in the 2% NaCl brine at the coldest temperature, whereas the greatest volume decrease was recorded in cheeses brined in the 26% NaCl brine. Composition was not affected by brining temperature. Calcium concentration did influence weight, volume, and composition, except on a fat-on-dry-basis. When cheeses were brined without added calcium, cheese volume and weight increased at all temperatures. At high calcium levels (0.4%), syneresis occurred and volume decreased, especially at 20°C (-16.5%). Microstructural investigation with porosity measurement confirmed weight and volume changes. © 2012 American Dairy Science Association.


Settanni L.,University of Palermo | Gaglio R.,University of Palermo | Guarcello R.,University of Palermo | Francesca N.,University of Palermo | And 3 more authors.
International Dairy Journal | Year: 2013

To evaluate the efficacy of lactic acid bacteria (LAB) to improve the hygienic safety of a traditional raw milk cheese, the raw ewes' milk protected denomination of origin (PDO) Pecorino Siciliano cheese was used as a model system. Different Pecorino Siciliano curds and cheeses were used as sources of autochthonous LAB subsequently used as starter and non-starter LAB. These were screened for their acidification capacity and autolysis. Starter LAB showing the best performance were genotypically differentiated and identified: two strains of Lactococcus lactis subsp. lactis were selected. From the non-starter LAB, Enterococcus faecalis, Lactococcus garvi e ae and Streptococcus macedonicus strains were selected. The five cultures were used in individual or dual inocula to produce experimental cheeses in a dairy factory for which production was characterised by high numbers of undesirable bacteria. At 5-month of ripening, the experimental cheeses produced with LAB were characterised by undetectable levels of enterobacteria and pseudomonads and the typical sensory attributes. © 2013 Elsevier Ltd.


PubMed | CoRFiLaC and University of Catania
Type: | Journal: Food microbiology | Year: 2016

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.


PubMed | CoRFiLaC, Cornell University and University of Catania
Type: Comparative Study | Journal: Journal of dairy science | Year: 2014

The influence of stage of lactation and corresponding diets on rates of protein degradation (kd) is largely unstudied. Study objectives were to measure and compare in situ ruminal kd of crude protein (CP) and estimate rumen CP escape (rumen-undegradable protein; RUP) of selected feeds by cows at 3 stages of lactation fed corresponding diets, and to determine the incubation times needed in an enzymatic in vitro procedure, using 0.2 units of Streptomyces griseus protease per percent of true CP, that predicted in situ RUP. Residue CP was measured after in situ fermentation for 4, 8, 12, 24, 36, 48, and 72 h of 5 protein sources and 3 total mixed rations, which were fed to the in situ cows. Two nonlactating (dry) cows and 2 cows each at 190 (mid) and 90 (peak) days of lactation were used. Each pair of cows was offered free-choice diets that differed in composition to meet their corresponding nutrient requirements. Diets had decreasing proportions of forages and contained (dry matter basis) 11.9, 15.1 and 16.4% CP and 54.3, 40.3 and 35.3% neutral detergent fiber, for dry, mid, and peak TMR (TMR1, TMR2, and TMR3), respectively. Intakes were 10.3, 21.4, and 23.8kg of dry matter/d, respectively. Kinetic CP fractions (extractable, potentially degradable, undegradable, or slowly degradable) were unaffected by treatment. Lag time and kd varied among feeds. The kd was faster for all feeds (0.136/h) when incubated in dry-TMR1 cows compared with mid-TMR2 (0.097/h) or peak-TMR3 (0.098/h) cows, and no differences in lag time were detected. Calculated RUP, using estimated passage rates for each cow based on intake, differed between dry-TMR1 (0.382) and mid-TMR2 (0.559) or peak-TMR3 (0.626) cows, with a tendency for mid-TMR2 to be different from peak-TMR3. Using the average kd and lag time obtained from dry-TMR1 to calculate RUP for mid-TMR2 and peak-TMR3 cows using their passage rates reduced RUP values by 6.3 and 9.5 percentage units, respectively. Except for that of herring meal, in vitro residue CP at 6, 12, and 48h of enzymatic hydrolysis was correlated (r=0.90) with in situ RUP of peak-TMR3, mid-TMR2, and dry-TMR1, respectively. Although confounded within treatments, stage of lactation, diet, and intake appeared to affect CP degradation parameters and RUP. Using kd from nonlactating cows, or the RUP calculated from them, may bias diet evaluation or ration formulation for lactating cows. In addition, enzymatic in vitro predictions of RUP should be measured using incubation times that are appropriate for lactating cows.

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