Carlo Spanu

Università degli Studi di Sassari, Sassari, Sardinia, Italy

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Publications (13)10.74 Total impact

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    ABSTRACT: Fluid goat milk submitted to thermal treatment has interesting nutritional properties and a potential expanding market. The present study was aimed to conduct fatty acids profile characterisation of goat milk placed on market. Forty-nine fluid milk samples were collected: 12 pasteurised, 12 pasteurised at high temperature, 11 ultrahigh temperature (UHT) whole milk and 14 UHT semi-skimmed milk. Milk samples were collected at retail level from 7 different companies and from different production batches. After extraction and methilation, fatty acids (FAs) profile was determined on each sample using a gas chromatograph with flame ionisation detector (GC-FID) with high-polarity capillary column. The concentration (g/100mL) of saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), trans fatty acids (t-FAs), and isomers of conjugated linoleic acid (CLA) was determined. N-6/n-3 ratio, atherogenic index (AI) and thrombogenic index (TI) were also assessed. Fluid goat milk lipid profile was characterised by SFAs (68.4% of total FAs), PUFAs (5.3%), MUFAs (21.3%), t-FAs (3.6%) and CLA (0.8%). The most represented fatty acids were: 16:0 (24.5%), 9cis-18:1 (18.2%), 18:0 (9.6%), 14:0 (9.5%), 10:0 (9.3%) and 12:0 (4.5%). Nutritional indices were 2.8-6.8 for n-6/n-3 ratio; 2.3-2.9 for AI; and 2.7-3.2 for TI. Milk produced by small scale plants, with no milk fat standardisation, showed greater differences in fatty acid profile as compared to industrial plants milk. Large scale production is characterised by commingled bulk tank milk of different origins and then is more homogeneous. The whole goat milk supply chain should be controlled to obtain milk with fatty acids of high nutritional value.
    Italian Journal of Food Safety. 10/2013; 2(3):117.
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    ABSTRACT: Abstract The presence of Staphylococcus aureus in raw milk can represent a potential threat to human health, due to the introduction of pathogenic strains into dairy food supply chain. The present study was performed to investigate the genetic variation among S. aureus strains isolated from bulk tank goat's milk. The virulence profiles were also assessed to link the isolates with the potential source of milk contamination. A population study was performed on 60 strains using distance-based methods such as pulsed-field gel electrophoresis (PFGE), and the output was analyzed using Structure statistical software (University of Chicago; http://pritch.bsd.uchicago.edu/structure.html ). This Bayesian clustering model tool allows one to assign individuals into a population with no predefined structure. In order to assess partition of genetic variability among isolates, groups obtained by Structure were also investigated using analysis of molecular variance. S. aureus was recovered in 60 out of 78 samples (76.9%) collected from 26 farms. According to PFGE analysis, the strains were divided into 25 different pulsotypes and grouped into two main clusters. Restriction profiles, analyzed by Structure, allowed us to identify two distinct S. aureus genetic groups. Within each group, the strains showed a high coefficient of membership. A great part of genetic variability was attributable to within-groups variation. On the basis of the virulence profile, 45% of the isolates were linked to "animal" biovar, while 6.7% could be assigned to "human" biovar. Out of 60 strains, 27 were characterized by in vitro production of either enterotoxins A (5.0%), C (38.3%), or D (1.7%). The present study showed a high prevalence of bulk tank goat's milk contamination with S. aureus of animal origin. The presence in goat's milk of S. aureus strains able to produce enterotoxins and their potential introduction into dairy chain may represent a serious threat to human health.
    Foodborne Pathogens and Disease 03/2013; · 2.28 Impact Factor
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    ABSTRACT: Listeria monocytogenes harbouring niches established in the processing plant support post-process contamination of dairy products made from pasteurised or thermised milk. The present study investigated L. monocytogenes environmental contamination in two sheep’s milk cheese-making plants. Persistence of contamination in the area at higher risk was also investigated. During a one-year survey 7 samplings were carried out in each dairy plant, along the production lines of Pecorino Romano and ricotta salata cheese. A total of 613 environmental samples collected from food contact and non-food contact surfaces were analysed according to ISO 11290-1:2005 standard method. Identification of the isolated strains was carried out by polymerase chain reaction. L. monocytogenes prevalence was 23.2% in dairy A and 13.1% in dairy B, respectively. The higher prevalence rate was found in the following areas: salting, products washing, packaging, ricotta salata storage and Pecorino Romano ripening rooms. L. monocytogenes was never found in the cheese-making area. The probability of observing samples positive for the presence of L. monocytogenes was associated with dairy plant, sampling area and the period of cheese-making (P<0.001). The greater persistence of contamination over time was observed in the washing, salting, and Pecorino Romano ripening areas. The control of persistent environmental contamination relies on the identification of L. monocytogenes niches within the processing environment and the prevention of harborage sites formation. The importance of strict cleaning and sanitising procedure in controlling L. monocytogenes environmental contamination is confirmed by the lower level of contamination observed after these procedures were correctly implemented.
    Italian Journal of Food Safety. 01/2013; 2(2):109-112.
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    ABSTRACT: The aim of the present study was to investigate the prevalence of S. aureus in raw sheep milk cheese and to assess the enterotoxigenic profile of the isolated strains. N.16 raw milk sheep cheese, collected from 8 artisan dairies, were analyzed to detect the presence of Coagulase Positive Staphylococci (CPS). In the frame of Regulation (EC) No 2073/2005 cheese samples were tested for the presence of staphylococcal enterotoxins (SEs) when a CPS count >105 cfu/g was detected. CPS isolates identified as S. aureus were analyzed using multiplex PCR for the detection of classical (sea-see) and enterotoxins-like (seh, sek, sel, sem, seo, sep) genes. S. aureus was recovered in all cheese samples and in 50% with levels >105 cfu/g. 14 strains carried at least one of the genes coding for enterotoxins. In none of the cheese samples SEs were detected. Although a correct acidification (pH 5.1-5.4 at 6 hours) was observed in dairies using natural starter culture, in cheese samples obtained from these dairies, CPS counts were greater (P<0.05) as compared with those where starter culture were not used. This result might be related to the main role of microbial competition on the control of S. aureus in early stage of cheesemaking. Further research is needed to better understand the effect of lactic acid bacteria competition on the growth of S. aureus.
    Italian Journal of Food Safety. 06/2012; 1(4):91-96.
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    ABSTRACT: Concentrations of 7 polychlorinated dibenzo-p-dioxins (PCDDs), 10 polychlorinated dibenzofurans (PCDFs) and 22 polychlorinated biphenyls (PCBs), including 12 dioxin like-PCBs (non- and mono-ortho PCBs) were measured in 80 sheep milk samples from farms located in an industrialized area of Sardinia, Italy. PCDDs and PCDFs mean concentrations were 2.45 and 3.69 pgg(-1) fat basis, respectively. The mean dl-PCB concentration was 2.01 ngg(-1) fat basis, while cumulative ndl-PCB levels ranged from 1.02 to 20.42, with a mean of 4.92 ngg(-1) fat. The results expressed in pg WHO-TEQ/g fat showed that contamination level of milk was below the limit values for human consumption established by EC legislation. In the same way, all the investigated milk exhibited PCDD/Fs concentrations below EU action levels, while dl-PCBs concentrations exceeded the action level of 2.0 pg WHO-TEQ/g fat. These findings point to the need to continue to conduct general monitoring programmes, including also milk samples from areas not close to the contaminant-emitting industries, in order to better evaluate the impact of industrial activities on surrounding environment.
    Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 01/2012; 50(5):1413-7. · 2.99 Impact Factor
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    International Dairy Journal 01/2012; · 2.33 Impact Factor
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    ABSTRACT: Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (DL-PCBs) are widespread contaminants with important implications for the environment protection and for the human health. Milk and dairy products consumption has been classified as one of the primary pathways of human exposure to these toxic chemicals. In this study we evaluated the levels of 17 laterally substituted PCDD/Fs and 12 DL-PCBs in 45 sheep milk samples collected from small dairy sheep farms in Sardinia (Italy). Mean concentrations of PCDDs and PCDFs were 2.31 and 3.11 pg g-1 fat basis, respectively. With regard to the DL-PCBs only PCB 118 was detected in 51.1% of samples (0.73 ng g-1 fat basis), while the rest of the studied congeners was never detected. The contamination of milk by PCDD/Fs and DL-PCBs (0.92 pg WHO-TEQ/g fat) being within the permissible limit set by the European Commission (6 pg WHO-TEQ/g fat) gives no indication of particular health risk. However, continuous surveillance on PCDD/Fs and DL-PCBs levels in milk is needed in order to correctly evaluate either the environmental impact and human health risk.
    Italian Journal of Food Safaty. 12/2011; 1(2):75-80.
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    ABSTRACT: Contamination of dairy products with Staphylococcus aureus can be of animal or human origin. The host pathogen relationship is an important factor determining genetic polymorphism of the strains and their potential virulence. The aim of the present study was to carry out an extensive characterization of virulence factors and to study the genetic variability of S. aureus strains isolated from raw ewe's milk cheese. A total of 100 S. aureus strains isolated from cheese samples produced in 10 artisan cheese factories were analyzed for the presence of enterotoxins (sea-see) and enterotoxins-like genes (seh, sek, sel, sem, seo, sep), leukocidins, exfoliatins, haemolysins, toxic shock syndrome toxin 1 (TSST-1) and the accessory gene regulator alleles (agr). Strains were also typed using pulsed-field gel electrophoresis (PFGE). AMOVA analysis carried out on PFGE and PCR data showed that the major component explaining genetic distance between strains was the dairy of origin. Of the total isolates 81% had a pathogenicity profile ascribable to "animal" biovar while 16% could be related to "human" biovar. The biovar allowed to estimate the most likely origin of the contamination. Minimum inhibitory concentrations (MICs) of nine antimicrobial agents and the presence of the corresponding genes coding for antibiotic resistance was also investigated. 18 strains carrying blaZ gene showed resistance to ampicillin and penicillin and 6 strains carrying tetM gene were resistant to tetracycline. The presence of mecA gene and methicillin resistance, typical of strains of human origin, was never detected. The results obtained in the present study confirm that S. aureus contamination in artisan cheese production is mainly of animal origin.
    International journal of food microbiology 10/2011; 153(1-2):53-7. · 3.01 Impact Factor
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    ABSTRACT: The aim of the study was to investigate the prevalence of Vibrio spp isolated from gilthead sea bream (Sparus aurata) farmed on sea cages and to identify and characterize the pathogen by molecular techniques. Eighty fish were collected from two hatcheries located on the North-Est Sardinian Mediterranean coast, and microbiological analysis were performed on different body parts such as skin, gills, muscle and intestinal tract. Subsequently 100 pure colonies with typical morphology and phenotypic characteristics were selected and submitted to the molecular identification. The analysis on the prevalence of Vibrio spp showed the effect of the hatchery rearing system (P<0.001), of the date of sampling (P<0.001), and of the body part (P<0.001). All the strains selected were confirmed to be members of the genus Vibrio spp by the molecular method/techinique/identification, whereas the rpoA gene sequence analyses allowed to identify 89 strains belonging to the species Vibrio harveyi, 6 to V. diabolicus, 2 to V. parahaemolyticus and 1 to V. mediterranei.
    Italian Journal of Food Safety. 06/2011; 1:115-119.
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    ABSTRACT: The Aflatoxin M1 (AFM1) content in 118 bulk-tank sheep milk samples was evaluated using an ELISA commercial kit. During a lactation, three bulk-tank milk samples were collected from each of 40 semi-extensive farms, selected on the basis of high level of concentrate supplementation as risk factor for exposure to Aflatoxin B1 (AFB1). The AFM1 content was also determined in 38 sheep cheese samples collected from a dairy plant where the farms enrolled in the survey shipped the milk. In the three sampling the concentrate supplementation recorded in the farms ranged between (mean±sd) 492.2±257.7 and 397.7±214.3. AFM1 was detected in 1 bulk-tank sheep milk sample (0.8%) at concentrations as little as 5.2 ng/L while in 117 it was not detectable (<5 ng/L). AFM1 was also detected in 5 (13.2%) out of 38 samples of ripened sheep cheese at levels (mean±sd) of 58.1±7.8 ng/Kg. A very low AFM1 content in bulk mik and cheese was observed, as the result of the implementation of good agricultural and good farming practices.
    Italian Journal of food safety. 06/2011; 1:93-97.
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    ABSTRACT: Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (DL-PCBs) are widespread contaminants with important implications for environmental and human health. Milk and dairy products consumption has been classified as one of the primary pathways of human exposure to these toxic chemicals. In this study we evaluated the levels of 17 laterally substituted PCDD/Fs and 12 DL-PCBs in 45 sheep milk samples collected from 15 farms in Sardinia (Italy). Mean concentrations of PCDDs and PCDFs were 2.31 and 3.11 pg.g-1 fat basis, respectively. Among DL-PCBs, only PCB 118 was detected in 51.1% of samples. Contamination of milk by PCDD/Fs and DL-PCBs (0.92 pg WHO-TEQ g-1 fat) being within the permissible limit set by the European Commission (6 pg WHO-TEQ g-1 fat) gives no indication of particular health risk. However, continuous surveillance in milk is needed to correctly evaluate both the environmental impact and the human health risk.
    IDF International Symposium on Sheep, Goat and other non-Cow Milk; 05/2011
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    Large Animal Review 10/2010; 16(5):106. · 0.12 Impact Factor
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    ABSTRACT: Antimicrobial resistance patterns and gene coding for methicillin resistance (mecA) were determined in 25 S. aureus and 75 Coagulase Negative Staphylococci (CNS) strains isolates from half-udder milk samples collected from goats with subclinical mastitis. Fourteen (56.0%) S. aureus and thirty-one (41.3%) CNS isolates were resistant to one or more antimicrobial agents. S. aureus showed the highest resistance rate against kanamycin (28.0%), oxytetracycline (16.0%), and ampicillin (12.0%). The CNS tested were more frequently resistant to ampicillin (36.0%) and kanamycin (6.7%). Multiple antimicrobial resistance was observed in eight isolates, and one Staphylococcus epidermidis was found to be resistant to six antibiotics. The mecA gene was not found in any of the tested isolates. Single resistance against beta-lactamics or aminoglicosides is the most common trait observed while multiresistance is less frequent.
    Veterinary medicine international. 01/2010; 2010:517060.